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Sample records for cold atoms coupled

  1. Generalized Rashba-Dresselhaus spin-orbit coupling for cold atoms

    International Nuclear Information System (INIS)

    Juzeliunas, Gediminas; Ruseckas, Julius; Dalibard, Jean

    2010-01-01

    We study the possibility for generating a new type of spin-orbit coupling for the center-of-mass motion of cold atoms, using laser beams that resonantly couple N atomic internal ground states to an extra state. After a general analysis of the scheme, we concentrate on the tetrapod setup (N=4) where the atomic state can be described by a three-component spinor, evolving under the action of a Rashba-Dresselhaus-type spin-orbit coupling for a spin 1 particle. We illustrate a consequence of this coupling by studying the negative refraction of atoms at a potential step and show that the amplitude of the refracted beam is significantly increased in comparison to the known case of spin 1/2 Rashba-Dresselhaus coupling. Finally, we explore a possible implementation of this tetrapod setup, using stimulated Raman couplings between Zeeman sublevels of the ground state of alkali-metal atoms.

  2. Optical coupling of cold atoms to a levitated nanosphere

    Science.gov (United States)

    Montoya, Cris; Witherspoon, Apryl; Fausett, Jacob; Lim, Jason; Kitching, John; Geraci, Andrew

    2017-04-01

    Cooling mechanical oscillators to their quantum ground state enables the study of quantum phenomena at macroscopic levels. In many cases, the temperature required to cool a mechanical mode to the ground state is below what current cryogenic systems can achieve. As an alternative to cooling via cryogenic systems, it has been shown theoretically that optically trapped nanospheres could reach the ground state by sympathetically cooling the spheres via cold atoms. Such cooled spheres can be used in quantum limited sensing and matter-wave interferometry, and could also enable new hybrid quantum systems where mechanical oscillators act as transducers. In our setup, optical fields are used to couple a sample of cold Rubidium atoms to a nanosphere. The sphere is optically levitated in a separate vacuum chamber, while the atoms are trapped in a 1-D optical lattice and cooled using optical molasses. This work is partially supported by NSF, Grant No. PHY-1506431.

  3. Optimized coupling of cold atoms into a fiber using a blue-detuned hollow-beam funnel

    Energy Technology Data Exchange (ETDEWEB)

    Poulin, Jerome; Light, Philip S.; Kashyap, Raman; Luiten, Andre N. [Frequency Standards and Metrology Group, School of Physics, University of Western Australia, Western Australia 6009, Perth (Australia); Department of Engineering Physics, Ecole Polytechnique de Montreal, Montreal, Quebec, Canada H3C 3A7 (Canada); Frequency Standards and Metrology, School of Physics, University of Western Australia, Western Australia 6009, Perth (Australia)

    2011-11-15

    We theoretically investigate the process of coupling cold atoms into the core of a hollow-core photonic-crystal optical fiber using a blue-detuned Laguerre-Gaussian beam. In contrast to the use of a red-detuned Gaussian beam to couple the atoms, the blue-detuned hollow beam can confine cold atoms to the darkest regions of the beam, thereby minimizing shifts in the internal states and making the guide highly robust to heating effects. This single optical beam is used as both a funnel and a guide to maximize the number of atoms into the fiber. In the proposed experiment, Rb atoms are loaded into a magneto-optical trap (MOT) above a vertically oriented optical fiber. We observe a gravito-optical trapping effect for atoms with high orbital momentum around the trap axis, which prevents atoms from coupling to the fiber: these atoms lack the kinetic energy to escape the potential and are thus trapped in the laser funnel indefinitely. We find that by reducing the dipolar force to the point at which the trapping effect just vanishes, it is possible to optimize the coupling of atoms into the fiber. Our simulations predict that by using a low-power (2.5 mW) and far-detuned (300 GHz) Laguerre-Gaussian beam with a 20-{mu}m-radius core hollow fiber, it is possible to couple 11% of the atoms from a MOT 9 mm away from the fiber. When the MOT is positioned farther away, coupling efficiencies over 50% can be achieved with larger core fibers.

  4. High-flux cold rubidium atomic beam for strongly-coupled cavity QED

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Basudev [Indian Institute of Science Education and Research, Kolkata (India); University of Maryland, MD (United States); Scholten, Michael [University of Maryland, MD (United States)

    2012-08-15

    This paper presents a setup capable of producing a high-flux continuous beam of cold rubidium atoms for cavity quantum electrodynamics experiments in the region of strong coupling. A 2D{sup +} magneto-optical trap (MOT), loaded with rubidium getters in a dry-film-coated vapor cell, fed a secondary moving-molasses MOT (MM-MOT) at a rate greater than 2 x 10{sup 10} atoms/s. The MM-MOT provided a continuous beam with a tunable velocity. This beam was then directed through the waist of a cavity with a length of 280 μm, resulting in a vacuum Rabi splitting of more than ±10 MHz. The presence of a sufficient number of atoms in the cavity mode also enabled splitting in the polarization perpendicular to the input. The cavity was in the strong coupling region, with an atom-photon dipole coupling coefficient g of 7 MHz, a cavity mode decay rate κ of 3 MHz, and a spontaneous emission decay rate γ of 6 MHz.

  5. Sympathetic cooling of nanospheres with cold atoms

    Science.gov (United States)

    Montoya, Cris; Witherspoon, Apryl; Ranjit, Gambhir; Casey, Kirsten; Kitching, John; Geraci, Andrew

    2016-05-01

    Ground state cooling of mesoscopic mechanical structures could enable new hybrid quantum systems where mechanical oscillators act as transducers. Such systems could provide coupling between photons, spins and charges via phonons. It has recently been shown theoretically that optically trapped dielectric nanospheres could reach the ground state via sympathetic cooling with trapped cold atoms. This technique can be beneficial in cases where cryogenic operation of the oscillator is not practical. We describe experimental advances towards coupling an optically levitated dielectric nanosphere to a gas of cold Rubidium atoms. The sphere and the cold atoms are in separate vacuum chambers and are coupled using a one-dimensional optical lattice. This work is partially supported by NSF, Grant Nos. PHY-1205994,PHY-1506431.

  6. Hybrid Systems: Cold Atoms Coupled to Micro Mechanical Oscillators =

    Science.gov (United States)

    Montoya Monge, Cris A.

    Micro mechanical oscillators can serve as probes in precision measurements, as transducers to mediate photon-phonon interactions, and when functionalized with magnetic material, as tools to manipulate spins in quantum systems. This dissertation includes two projects where the interactions between cold atoms and mechanical oscillators are studied. In one of the experiments, we have manipulated the Zeeman state of magnetically trapped Rubidium atoms with a magnetic micro cantilever. The results show a spatially localized effect produced by the cantilever that agrees with Landau-Zener theory. In the future, such a scalable system with highly localized interactions and the potential for single-spin sensitivity could be useful for applications in quantum information science or quantum simulation. In a second experiment, work is in progress to couple a sample of optically trapped Rubidium atoms to a levitated nanosphere via an optical lattice. This coupling enables the cooling of the center-of-mass motion of the nanosphere by laser cooling the atoms. In this system, the atoms are trapped in the optical lattice while the sphere is levitated in a separate vacuum chamber by a single-beam optical tweezer. Theoretical analysis of such a system has determined that cooling the center-of-mass motion of the sphere to its quantum ground state is possible, even when starting at room temperature, due to the excellent environmental decoupling achievable in this setup. Nanospheres cooled to the quantum regime can provide new tests of quantum behavior at mesoscopic scales and have novel applications in precision sensing.

  7. Thermoelectric transport and Peltier cooling of cold atomic gases

    Science.gov (United States)

    Grenier, Charles; Kollath, Corinna; Georges, Antoine

    2016-12-01

    This brief review presents the emerging field of mesoscopic physics with cold atoms, with an emphasis on thermal and 'thermoelectric' transport, i.e. coupled transport of particles and entropy. We review in particular the comparison between theoretically predicted and experimentally observed thermoelectric effects in such systems. We also show how combining well-designed transport properties and evaporative cooling leads to an equivalent of the Peltier effect with cold atoms, which can be used as a new cooling procedure with improved cooling power and efficiency compared to the evaporative cooling currently used in atomic gases. This could lead to a new generation of experiments probing strong correlation effects of ultracold fermionic atoms at low temperatures.

  8. Cold atoms near superconductors: atomic spin coherence beyond the Johnson noise limit

    International Nuclear Information System (INIS)

    Kasch, B; Hattermann, H; Cano, D; Judd, T E; Zimmermann, C; Kleiner, R; Koelle, D; Fortagh, J; Scheel, S

    2010-01-01

    We report on the measurement of atomic spin coherence near the surface of a superconducting niobium wire. As compared to normal conducting metal surfaces, the atomic spin coherence is maintained for time periods beyond the Johnson noise limit. The result provides experimental evidence that magnetic near-field noise near the superconductor is strongly suppressed. Such long atomic spin coherence times near superconductors open the way towards the development of coherently coupled cold atom/solid state hybrid quantum systems with potential applications in quantum information processing and precision force sensing.

  9. A miniature magnetic waveguide for cold atoms

    International Nuclear Information System (INIS)

    Key, M.G.

    2000-09-01

    This thesis presents the first demonstration of a guide for cold atoms based on a miniature structure of four current-carrying wires. The four wires are embedded within a hollow silica fibre. Atoms are guided along the centre of a fifth hole on the axis of the fibre by the Stern-Gerlach force. A vapour cell Magneto Optical Trap (MOT), formed 1 cm above the mouth of the waveguide is the source of cold 85 Rb atoms. After cooling the atoms to 25 μK in optical molasses they fall under the influence of gravity through a magnetic funnel into the waveguide. After propagating for 2 cm, the atoms are reflected by the field of a small pinch coil wound around the base of the guide. The atoms then travel back up the fibre and out into the funnel, where they can be imaged either in fluorescence or by recapturing in the MOT. A video sequence of atoms falling into the guide and re-emerging after reflection from the pinch coil graphically illustrates the operation of the guide. The coupling efficiency and transverse temperature of the atoms is measured experimentally and in a Monte-Carlo simulation. We find an optimum coupling efficiency of 12% and we measure the spatial extent of the cloud within the fibre to be of order 100 μm. We find good agreement between experimental data and results from the numerical simulation. We have also been able to observe different thresholds for the reflection of different positive m F levels. In another experiment we are able to trap the atoms in an elongated Ioffe trap for up to two seconds, increasing the distance over which the atoms are guided. We are able to guide the atoms over distances of 40 cm with a loss rate indistinguishable from the free space loss rate. (author)

  10. Applicability of multisyringe chromatography coupled to cold-vapor atomic fluorescence spectrometry for mercury speciation analysis

    International Nuclear Information System (INIS)

    Guzmán-Mar, J.L.; Hinojosa-Reyes, L.; Serra, A.M.; Hernández-Ramírez, A.; Cerdà, V.

    2011-01-01

    Graphical abstract: An automatic system, based on the applicability of multisyringe chromatography (MSC) coupled to cold-vapor atomic fluorescence spectrometry (CV/AFS) detection is developed for mercury speciation. Highlights: ► The on-line coupling of MSC to CV/AFS was developed for mercury speciation analysis. ► The speciation of MeHg + , Hg 2+ and EtHg + was achieved on a RP C18 monolithic column. ► The hyphenated system provided higher sample throughput compared to HPLC–CV/AFS. ► The limits of detection for mercury species were comparable or better than those reported by HPLC–CV/AFS. ► The developed method also provided low instrumental and operational costs. - Abstract: In this paper, a novel automatic approach for the speciation of inorganic mercury (Hg 2+ ), methylmercury (MeHg + ) and ethylmercury (EtHg + ) using multisyringe chromatography (MSC) coupled to cold-vapor atomic fluorescence spectrometry (CV/AFS) was developed. For the first time, the separation of mercury species was accomplished on a RP C18 monolithic column using a multi-isocratic elution program. The elution protocol involved the use of 0.005% 2-mercapthoethanol in 240 mM ammonium acetate (pH 6)–acetonitrile (99:1, v/v), followed by 0.005% 2-mercapthoethanol in 240 mM ammonium acetate (pH 6)–acetonitrile (90:10, v/v). The eluted mercury species were then oxidized under post-column UV radiation and reduced using tin(II) chloride in an acidic medium. Subsequently, the generated mercury metal were separated from the reaction mixture and further atomized in the flame atomizer and detected by AFS. Under the optimized experimental conditions, the limits of detection (3σ) were found to be 0.03, 0.11 and 0.09 μg L −1 for MeHg + , Hg 2+ and EtHg + , respectively. The relative standard deviation (RSD, n = 6) of the peak height for 3, 6 and 3 μg L −1 of MeHg + , Hg 2+ and EtHg + (as Hg) ranged from 2.4 to 4.0%. Compared with the conventional HPLC–CV/AFS hyphenated systems

  11. Bichromatic electromagnetically induced transparency in cold rubidium atoms

    International Nuclear Information System (INIS)

    Wang, J.; Jiang, K.J.; Zhan, M.S.; Zhu Yifu

    2003-01-01

    In a three-level atomic system coupled by two equal-amplitude laser fields with a frequency separation 2δ, a weak probe field exhibits a multiple-peaked absorption spectrum with a constant peak separation δ. The corresponding probe dispersion exhibits steep normal dispersion near the minimum absorption between the multiple absorption peaks, which leads to simultaneous slow group velocities for probe photons at multiple frequencies separated by δ. We report an experimental study in such a bichromatically coupled three-level Λ system in cold 87 Rb atoms. The multiple-peaked probe absorption spectra under various experimental conditions have been observed and compared with the theoretical calculations

  12. Laser-Free Cold-Atom Gymnastics

    Science.gov (United States)

    Gould, Harvey; Feinberg, Benedict; Munger, Charles T., Jr.; Nishimura, Hiroshi

    2017-01-01

    We have performed beam transport simulations on ultra cold (2 μK) and cold (130 μK) neutral Cs atoms in the F = M = + 4 (magnetic weak-field seeking) ground state. We use inhomogeneous magnetic fields to focus and accelerate the atoms. Acceleration of neutral atoms by an inhomogeneous magnetic field was demonstrated by Stern and Gerlach in 1922. In the simulations, a two mm diameter cloud of atoms is released to fall under gravity. A magnetic coil focuses the falling atoms. After falling 41 cm, the atoms are reflected in the magnetic fringe field of a solenoid. They return to their starting height, about 0.7 s later, having passed a second time through the focusing coil. The simulations show that > 98 % of ultra cold Cs atoms and > 70 % of cold Cs atoms will survive at least 15 round trips (assuming perfect vacuum). More than 100 simulations were run to optimize coil currents and focusing coil diameter and height. Simulations also show that atoms can be launched into a fountain. An experimental apparatus to test the simulations, is being constructed. This technique may find application in atomic fountain clocks, interferometers, and gravitometers, and may be adaptable for use in microgravity. It may also work with Bose-Einstein condensates of paramagnetic atoms.

  13. Nanophotonic Optical Isolator Controlled by the Internal State of Cold Atoms

    Directory of Open Access Journals (Sweden)

    Clément Sayrin

    2015-12-01

    Full Text Available The realization of nanophotonic optical isolators with high optical isolation even at ultralow light levels and low optical losses is an open problem. Here, we employ the link between the local polarization of strongly confined light and its direction of propagation to realize low-loss nonreciprocal transmission through a silica nanofiber at the single-photon level. The direction of the resulting optical isolator is controlled by the spin state of cold atoms. We perform our experiment in two qualitatively different regimes, i.e., with an ensemble of cold atoms where each atom is weakly coupled to the waveguide and with a single atom strongly coupled to the waveguide mode. In both cases, we observe simultaneously high isolation and high forward transmission. The isolator concept constitutes a nanoscale quantum optical analog of microwave ferrite resonance isolators, can be implemented with all kinds of optical waveguides and emitters, and might enable novel integrated optical devices for fiber-based classical and quantum networks.

  14. Cold atoms in singular potentials

    International Nuclear Information System (INIS)

    Denschlag, J. P.

    1998-09-01

    We studied both theoretically and experimentally the interaction between cold Li atoms from a magnetic-optical trap (MOT) and a charged or current-carrying wire. With this system, we were able to realize 1/r 2 and 1/r potentials in two dimensions and to observe the motion of cold atoms in both potentials. For an atom in an attractive 1/r 2 potential, there exist no stable trajectories, instead there is a characteristic class of trajectories for which atoms fall into the singularity. We were able to observe this falling of atoms into the center of the potential. Moreover, by probing the singular 1/r 2 potential with atomic clouds of varying size and temperature we extracted scaling properties of the atom-wire interaction. For very cold atoms, and very thin wires the motion of the atoms must be treated quantum mechanically. Here we predict that the absorption cross section for the 1/r 2 potential should exhibit quantum steps. These quantum steps are a manifestation of the quantum mechanical decomposition of plane waves into partial waves. For the second part of this work, we realized a two dimensional 1/r potential for cold atoms. If the potential is attractive, the atoms can be bound and follow Kepler-like orbits around the wire. The motion in the third dimension along the wire is free. We were able to exploit this property and constructed a novel cold atom guide, the 'Kepler guide'. We also demonstrated another type of atom guide (the 'side guide'), by combining the magnetic field of the wire with a homogeneous offset magnetic field. In this case, the atoms are held in a potential 'tube' on the side of the wire. The versatility, simplicity, and scaling properties of this guide make it an interesting technique. (author)

  15. New sources of cold atoms for atomic clocks

    International Nuclear Information System (INIS)

    Aucouturier, E.

    1997-01-01

    The purpose of this doctoral work is the realisation of new sources of cold cesium atoms that could be useful for the conception of a compact and high-performance atomic clock. It is based on experiences of atomic physics using light induced atomic manipulation. We present here the experiences of radiative cooling of atoms that have been realised at the Laboratoire de l'Horloge Atomique from 1993 to 1996. Firstly, we applied the techniques of radiative cooling and trapping of atoms in order to create a three-dimensional magneto-optical trap. For this first experience, we developed high quality laser sources, that were used for other experiments. We imagined a new configuration of trapping (two-dimensional magneto-optical trap) that was the basis for a cold atom source. This design gives the atoms a possibility to escape towards one particular direction. Then, we have extracted the atoms from this anisotropic trap in order to create a continuous beam of cold atoms. We have applied three methods of extraction. Firstly, the launching of atoms was performed by reducing the intensity of one of the cooling laser beams in the desired launching direction. Secondly, a frequency detuning between the two laser laser beams produced the launching of atoms by a so-called 'moving molasses'. The third method consisted in applying a static magnetic field that induced the launching of atoms in the direction of this magnetic field. At the same time, another research on cold atoms was initiated at the I.H.A. It consisted in cooling a large volume of atoms from a cell, using an isotropic light. This offers an interesting alternative to the traditional optical molasses. (author)

  16. Applicability of multisyringe chromatography coupled to cold-vapor atomic fluorescence spectrometry for mercury speciation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Guzman-Mar, J.L.; Hinojosa-Reyes, L. [Department of Chemistry Sciences, Universidad Autonoma de Nuevo Leon, Cd. Universitaria, Pedro de Alba s/n, C.P. 66451 San Nicolas de los Garza, Nuevo Leon (Mexico); Serra, A.M. [Department of Chemistry, University of the Balearic Islands, E-07122 Palma de Mallorca (Spain); Hernandez-Ramirez, A. [Department of Chemistry Sciences, Universidad Autonoma de Nuevo Leon, Cd. Universitaria, Pedro de Alba s/n, C.P. 66451 San Nicolas de los Garza, Nuevo Leon (Mexico); Cerda, V., E-mail: victor.cerda@uib.es [Department of Chemistry, University of the Balearic Islands, E-07122 Palma de Mallorca (Spain)

    2011-12-05

    Graphical abstract: An automatic system, based on the applicability of multisyringe chromatography (MSC) coupled to cold-vapor atomic fluorescence spectrometry (CV/AFS) detection is developed for mercury speciation. Highlights: Black-Right-Pointing-Pointer The on-line coupling of MSC to CV/AFS was developed for mercury speciation analysis. Black-Right-Pointing-Pointer The speciation of MeHg{sup +}, Hg{sup 2+} and EtHg{sup +} was achieved on a RP C18 monolithic column. Black-Right-Pointing-Pointer The hyphenated system provided higher sample throughput compared to HPLC-CV/AFS. Black-Right-Pointing-Pointer The limits of detection for mercury species were comparable or better than those reported by HPLC-CV/AFS. Black-Right-Pointing-Pointer The developed method also provided low instrumental and operational costs. - Abstract: In this paper, a novel automatic approach for the speciation of inorganic mercury (Hg{sup 2+}), methylmercury (MeHg{sup +}) and ethylmercury (EtHg{sup +}) using multisyringe chromatography (MSC) coupled to cold-vapor atomic fluorescence spectrometry (CV/AFS) was developed. For the first time, the separation of mercury species was accomplished on a RP C18 monolithic column using a multi-isocratic elution program. The elution protocol involved the use of 0.005% 2-mercapthoethanol in 240 mM ammonium acetate (pH 6)-acetonitrile (99:1, v/v), followed by 0.005% 2-mercapthoethanol in 240 mM ammonium acetate (pH 6)-acetonitrile (90:10, v/v). The eluted mercury species were then oxidized under post-column UV radiation and reduced using tin(II) chloride in an acidic medium. Subsequently, the generated mercury metal were separated from the reaction mixture and further atomized in the flame atomizer and detected by AFS. Under the optimized experimental conditions, the limits of detection (3{sigma}) were found to be 0.03, 0.11 and 0.09 {mu}g L{sup -1} for MeHg{sup +}, Hg{sup 2+} and EtHg{sup +}, respectively. The relative standard deviation (RSD, n = 6) of the

  17. Cold atoms as a coolant for levitated optomechanical systems

    Science.gov (United States)

    Ranjit, Gambhir; Montoya, Cris; Geraci, Andrew A.

    2015-01-01

    Optically trapped dielectric objects are well suited for reaching the quantum regime of their center-of-mass motion in an ultrahigh-vacuum environment. We show that ground-state cooling of an optically trapped nanosphere is achievable when starting at room temperature, by sympathetic cooling of a cold-atomic gas optically coupled to the nanoparticle. Unlike cavity cooling in the resolved-sideband limit, this system requires only a modest cavity finesse and it allows the cooling to be turned off, permitting subsequent observation of strongly coupled dynamics between the atoms and sphere. Nanospheres cooled to their quantum ground state could have applications in quantum information science or in precision sensing.

  18. Cold atoms in a cryogenic environment

    International Nuclear Information System (INIS)

    Haslinger, S.

    2011-01-01

    The idea of quantum information processing attracts increasingly interest, where a complex collection of quantum objects and quantum bits are employed to find the ideal building blocks for quantum information systems. Hybrid quantum systems are therefore promising objects as they countervail the particular drawbacks of single quantum objects. Based on superconducting resonator technology, microwave coplanar waveguides provide a well suited interconnection for photons and solid-state quantum bits (qubits), extensively investigated in recent years. Since a quantum memory is presently missing in those electrical accessible circuit cavity quantum devices, connecting the fast processing in a solid sate device to the exceptional long coherence times in atomic ensembles, the presented work is focused to establish the technological foundations for the hybridization of such quantum systems. The microwave photons stored in a superconducting high finesse microwave resonator are therefore an ideal connection between the atom and the solid state quantum world. In the last decade, the miniaturization and integration of quantum optics and atomic physics manipulation techniques on to a single chip was successfully established. Such atom chips are capable of detailed quantum manipulation of ultra-cold atoms and provide a versatile platform to combine the manipulation techniques from atomic physics with the capability of nano-fabrication. In recent years several experiments succeeded in realization of superconducting atom chips in cryogenic environments which opens the road for integrating super-conductive microwave resonators to magnetically couple an atomic ensemble to photons stored in the coplanar high finesse cavity. This thesis presents the concept, design and experimental setup of two approaches to establish an atomic ensemble of rubidium atoms inside a cryogenic environment, based on an Electron beam driven alkali metal atom source for loading a magneto optical trap in a

  19. Strongly correlated states of a small cold-atom cloud from geometric gauge fields

    International Nuclear Information System (INIS)

    Julia-Diaz, B.; Dagnino, D.; Barberan, N.; Guenter, K. J.; Dalibard, J.; Grass, T.; Lewenstein, M.

    2011-01-01

    Using exact diagonalization for a small system of cold bosonic atoms, we analyze the emergence of strongly correlated states in the presence of an artificial magnetic field. This gauge field is generated by a laser beam that couples two internal atomic states, and it is related to Berry's geometrical phase that emerges when an atom follows adiabatically one of the two eigenstates of the atom-laser coupling. Our approach allows us to go beyond the adiabatic approximation, and to characterize the generalized Laughlin wave functions that appear in the strong magnetic-field limit.

  20. Strongly correlated states of a small cold-atom cloud from geometric gauge fields

    Energy Technology Data Exchange (ETDEWEB)

    Julia-Diaz, B. [Dept. ECM, Facultat de Fisica, U. Barcelona, E-08028 Barcelona (Spain); ICFO-Institut de Ciencies Fotoniques, Parc Mediterrani de la Tecnologia, E-08860 Barcelona (Spain); Dagnino, D.; Barberan, N. [Dept. ECM, Facultat de Fisica, U. Barcelona, E-08028 Barcelona (Spain); Guenter, K. J.; Dalibard, J. [Laboratoire Kastler Brossel, CNRS, UPMC, Ecole Normale Superieure, 24 rue Lhomond, F-75005 Paris (France); Grass, T. [ICFO-Institut de Ciencies Fotoniques, Parc Mediterrani de la Tecnologia, E-08860 Barcelona (Spain); Lewenstein, M. [ICFO-Institut de Ciencies Fotoniques, Parc Mediterrani de la Tecnologia, E-08860 Barcelona (Spain); ICREA-Institucio Catalana de Recerca i Estudis Avancats, E-08010 Barcelona (Spain)

    2011-11-15

    Using exact diagonalization for a small system of cold bosonic atoms, we analyze the emergence of strongly correlated states in the presence of an artificial magnetic field. This gauge field is generated by a laser beam that couples two internal atomic states, and it is related to Berry's geometrical phase that emerges when an atom follows adiabatically one of the two eigenstates of the atom-laser coupling. Our approach allows us to go beyond the adiabatic approximation, and to characterize the generalized Laughlin wave functions that appear in the strong magnetic-field limit.

  1. Suppression of Zeeman relaxation in cold collisions of 2P1/2 atoms

    International Nuclear Information System (INIS)

    Tscherbul, T. V.; Dalgarno, A.; Buchachenko, A. A.; Lu, M.-J.; Weinstein, J. D.

    2009-01-01

    We present a combined experimental and theoretical study of angular momentum depolarization in cold collisions of 2 P atoms in the presence of an external magnetic field. We show that collision-induced Zeeman relaxation of Ga( 2 P 1/2 ) and In( 2 P 1/2 ) atoms in cold 4 He gas is dramatically suppressed compared to atoms in 2 P 3/2 states. Using rigorous quantum-scattering calculations based on ab initio interaction potentials, we demonstrate that Zeeman transitions in collisions of atoms in 2 P 1/2 electronic states occur via couplings to the 2 P 3/2 state induced by the anisotropy of the interaction potential. Our results suggest the feasibility of sympathetic cooling and magnetic trapping of 2 P 1/2 -state atoms, such as halogens, thereby opening up exciting areas of research in precision spectroscopy and cold-controlled chemistry.

  2. Gauss Sum Factorization with Cold Atoms

    International Nuclear Information System (INIS)

    Gilowski, M.; Wendrich, T.; Mueller, T.; Ertmer, W.; Rasel, E. M.; Jentsch, Ch.; Schleich, W. P.

    2008-01-01

    We report the first implementation of a Gauss sum factorization algorithm by an internal state Ramsey interferometer using cold atoms. A sequence of appropriately designed light pulses interacts with an ensemble of cold rubidium atoms. The final population in the involved atomic levels determines a Gauss sum. With this technique we factor the number N=263193

  3. Mott-insulating phases in unidimensional multi-components fermionic cold atoms

    International Nuclear Information System (INIS)

    Nonne, Heloise

    2011-01-01

    This thesis is devoted to the investigation of the Mott insulating phases arising in one-dimensional multicomponent fermionic cold atoms systems. The first part of this work is the study of a model with alkaline-earth cold atoms with nuclear spin I = 1/2. Those atoms enjoy an additional orbital degree of freedom, due to the presence of a metastable excited state; they thus have a total of four components. Our investigation is carried at half-filling, at strong and at weak couplings by means of analytic methods (conformal theory, bosonization, refermionization, renormalisation group). We found that the zero temperature phase diagram of the system is very rich: it contains seven Mott insulating phases, among which three are particularly interesting, since they display a hidden order, related to the Haldane physics of the antiferromagnetic spin-1 Heisenberg chain. Our conclusions are checked against numerical simulations, that were carried out with the density matrix renormalization group (DMRG) algorithm for intermediate couplings. The comparison shows an adiabatic continuity between the different regimes. A similar study for a model of cold atoms with hyperfine spin-3/2 highlights the Haldane physics in the charge sector of the degrees of freedom, with an effective model given by an antiferromagnetic pseudo-spin-1 chain. This analysis provides us an opportunity to investigate the zero temperature properties of the SO(5) bilinear-bi-quadratic Heisenberg chain. We show the presence of two gapped phases: one is dimerized, the other has a hidden symmetry (Z 2 x Z 2 ) 2 and spin-3/2 edge states, and they are separated by a critical point that belongs to the SO(5) 1 universality class. Finally, we investigate half-integer hyperfine spin cold atoms systems with 2N components which generalized the results obtained for the hyperfine spin-3/2 model. This leads us to find an even/odd effect according to the parity of N, very similar to the even/odd effect of spin chains

  4. Experiments with cold hydrogen atoms

    International Nuclear Information System (INIS)

    Leonas, V.B.

    1981-01-01

    Numerous investigations of atomic processes in Waseous phase on the surface with participation of ''cold'' hydrogen atoms, made during the last years, are considered. The term ''cold atom'' means the range of relative collision energies E<10 MeV (respectively 'ultracold ' atoms at E< or approximately 1 MeV) which corresponds to the range of temperatures in tens (units) of K degrees. Three main ranges of investigations where extensive experimental programs are realized are considered: study of collisional processes with hydrogen atom participation, hydrogen atoms being of astrophysical interest; study of elastic atom-molecular scattering at superlow energies and studies on the problem of condensed hydrogen. Hydrogen atoms production is realized at dissociation in non-electrode high-frequency or superhigh-frequency discharge. A method of hydrogen quantum generator and of its modifications appeared to be rather an effective means to study collisional changes of spin state of hydrogen atoms. First important results on storage and stabilization of the gas of polarized hydrogen atoms are received

  5. Quantum Phase Transition in a Cold Atomic Spin-Boson Mixture

    Science.gov (United States)

    Orth, Peter P.; Stanic, Ivan; Le Hur, Karyn

    2008-03-01

    We theoretically implement a spin array in a tunable bosonic environment using cold bosonic atoms with two (hyperfine) ground states, trapped by different potentials [1]. The first specie lies in a deep optical lattice with tightly confining wells and forms a spin array; spin-up/down corresponds to occupation by one/no atom at each site. The second specie forms a superfluid reservoir. Different species are coupled coherently via laser transitions and collisions. Whereas the laser coupling mimics a transverse field for the spins, the coupling to the reservoir phonons (sound modes) induces a ferromagnetic (Ising) coupling as well as dissipation. This results in a peculiar ferro-paramagnetic quantum phase transition where the effect of dissipation can be studied in a controllable manner. [1] Peter P. Orth, Ivan Stanic, and Karyn Le Hur, arXiv:0711.2309 [cond-mat.other].

  6. Quantum incommensurate skyrmion crystals and commensurate to in-commensurate transitions in cold atoms and materials with spin-orbit couplings in a Zeeman field

    Science.gov (United States)

    Sun, Fadi; Ye, Jinwu; Liu, Wu-Ming

    2017-08-01

    In this work, we study strongly interacting spinor atoms in a lattice subject to a two dimensional (2d) anisotropic Rashba type of spin orbital coupling (SOC) and an Zeeman field. We find the interplay between the Zeeman field and the SOC provides a new platform to host rich and novel classes of quantum commensurate and in-commensurate phases, excitations and phase transitions. These commensurate phases include two collinear states at low and high Zeeman field, two co-planar canted states at mirror reflected SOC parameters respectively. Most importantly, there are non-coplanar incommensurate Skyrmion (IC-SkX) crystal phases surrounded by the four commensurate phases. New excitation spectra above all the five phases, especially on the IC-SKX phase are computed. Three different classes of quantum commensurate to in-commensurate transitions from the IC-SKX to its four neighboring commensurate phases are identified. Finite temperature behaviors and transitions are discussed. The critical temperatures of all the phases can be raised above that reachable by current cold atom cooling techniques simply by tuning the number of atoms N per site. In view of recent impressive experimental advances in generating 2d SOC for cold atoms in optical lattices, these new many-body phenomena can be explored in the current and near future cold atom experiments. Applications to various materials such as MnSi, {Fe}}0.5 {Co}}0.5Si, especially the complex incommensurate magnetic ordering in Li2IrO3 are given.

  7. Superfluorescence with cold trapped neon atoms

    International Nuclear Information System (INIS)

    Zachorowski, Jerzy

    2003-01-01

    A method for observation of superfluorescence in a cloud of cold metastable Ne atoms is proposed. Means of achieving a cold sample of trapped metastable atoms are discussed. The feasibility of obtaining conditions for a superfluorescence pulse is studied. The paper also discusses the prospects for obtaining intense pulses of extreme ultraviolet radiation

  8. Limit Cycles and Chaos via Quasi-periodicity in Two Coupled Ensembles of Ultra-cold Atoms.

    Science.gov (United States)

    Patra, Aniket; Yuzbashyan, Emil; Altshuler, Boris

    We study the dynamics of two mesoscopic ensembles of ultra-cold two level atoms, which are collectively coupled to an optical cavity and are being pumped incoherently to the excited state. Whereas the time independent steady states are well understood, little is known about the time dependent ones. We explore and categorize various time dependent steady states, e.g. limit cycles and chaotic behavior. We draw a non-equilibrium phase diagram indicating different steady-state behaviors in different parts of the parameter space. We discuss the synchronization of the two ensembles in the time dependent steady states. We also show the onset of chaos via quasi-periodicity. The rich time dependent steady-state behavior, especially the existence of chaos, opens up possibilities for several engineering applications. Supported in part by the University and Louis Bevier Graduate Fellowship.

  9. Formation of cold molecules through the photo-association of cold atoms of Cesium. Existence of long range forces between between cold excited atoms of Cesium

    International Nuclear Information System (INIS)

    Comparat, D.

    1999-09-01

    This thesis deals with the experimental study and the theoretical interpretation of the processes involved in photo-association and the formation of cold caesium molecules. It also presents a study of the dipolar forces between a pair of cold excited caesium atoms. We present here the first photo-association experiment on cold caesium atoms: two cold atoms absorb a photon to form an excited electronically excited molecules in a rotation-vibration level. The first production of cold molecules which was realised experimentally, after the spontaneous deexcitation of the photo-associated molecules, is described, stressing the role of the potential well of the molecular states O g - (6s+6p 3/2 ) or 1 u (6s+6p 3/2 ) of caesium. The detection of the formed caesium molecules is based on a two-photons resonant ionisation that creates Cs 2 + ions, afterwards selectively detected. Temperatures around 20-200 μK have been measured. The photo-associative spectroscopy is described on the theoretical point of view: a detailed theoretical study allows to calculate precisely the asymptotic parts of the potential curves. On the experimental point of view, we present the spectroscopy of the extern potential well of the caesium state O g - (6s+6p 3/2 ) and the construction of an effective potential curve of the RKR type. A unified theory of photo-association in weak field, considered as a collision assisted by laser, is developed. The cold atoms experiments allow to study and control the collision between two atoms whose mutual interaction is of the dipole-dipole type. Two different physical systems are studied: a sample of Rydberg atoms, and the photo-association process which is a laser-assisted collision. A modification of the motion of one pair of atoms makes it possible to control the bipolar forces and to choose the atoms relative speeds. (author)

  10. State-selective imaging of cold atoms

    NARCIS (Netherlands)

    Sheludko, D.V.; Bell, S.C.; Anderson, R.; Hofmann, C.S.; Vredenbregt, E.J.D.; Scholten, R.E.

    2008-01-01

    Atomic coherence phenomena are usually investigated using single beam techniques without spatial resolution. Here we demonstrate state-selective imaging of cold 85Rb atoms in a three-level ladder system, where the atomic refractive index is sensitive to the quantum coherence state of the atoms. We

  11. Dynamic of cold-atom tips in anharmonic potentials

    Science.gov (United States)

    Menold, Tobias; Federsel, Peter; Rogulj, Carola; Hölscher, Hendrik; Fortágh, József

    2016-01-01

    Background: Understanding the dynamics of ultracold quantum gases in an anharmonic potential is essential for applications in the new field of cold-atom scanning probe microscopy. Therein, cold atomic ensembles are used as sensitive probe tips to investigate nanostructured surfaces and surface-near potentials, which typically cause anharmonic tip motion. Results: Besides a theoretical description of this anharmonic tip motion, we introduce a novel method for detecting the cold-atom tip dynamics in situ and real time. In agreement with theory, the first measurements show that particle interactions and anharmonic motion have a significant impact on the tip dynamics. Conclusion: Our findings will be crucial for the realization of high-sensitivity force spectroscopy with cold-atom tips and could possibly allow for the development of advanced spectroscopic techniques such as Q-control. PMID:28144505

  12. Theory of a Quantum Scanning Microscope for Cold Atoms.

    Science.gov (United States)

    Yang, D; Laflamme, C; Vasilyev, D V; Baranov, M A; Zoller, P

    2018-03-30

    We propose and analyze a scanning microscope to monitor "live" the quantum dynamics of cold atoms in a cavity QED setup. The microscope measures the atomic density with subwavelength resolution via dispersive couplings to a cavity and homodyne detection within the framework of continuous measurement theory. We analyze two modes of operation. First, for a fixed focal point the microscope records the wave packet dynamics of atoms with time resolution set by the cavity lifetime. Second, a spatial scan of the microscope acts to map out the spatial density of stationary quantum states. Remarkably, in the latter case, for a good cavity limit, the microscope becomes an effective quantum nondemolition device, such that the spatial distribution of motional eigenstates can be measured backaction free in single scans, as an emergent quantum nondemolition measurement.

  13. Cold atoms close to surfaces

    DEFF Research Database (Denmark)

    Krüger, Peter; Wildermuth, Stephan; Hofferberth, Sebastian

    2005-01-01

    Microscopic atom optical devices integrated on atom chips allow to precisely control and manipulate ultra-cold (T atoms and Bose-Einstein condensates (BECs) close to surfaces. The relevant energy scale of a BEC is extremely small (down to ... be utilized as a sensor for variations of the potential energy of the atoms close to the surface. Here we describe how to use trapped atoms as a measurement device and analyze the performance and flexibility of the field sensor. We demonstrate microscopic magnetic imaging with simultaneous high spatial...

  14. Many-body physics using cold atoms

    Science.gov (United States)

    Sundar, Bhuvanesh

    Advances in experiments on dilute ultracold atomic gases have given us access to highly tunable quantum systems. In particular, there have been substantial improvements in achieving different kinds of interaction between atoms. As a result, utracold atomic gases oer an ideal platform to simulate many-body phenomena in condensed matter physics, and engineer other novel phenomena that are a result of the exotic interactions produced between atoms. In this dissertation, I present a series of studies that explore the physics of dilute ultracold atomic gases in different settings. In each setting, I explore a different form of the inter-particle interaction. Motivated by experiments which induce artificial spin-orbit coupling for cold fermions, I explore this system in my first project. In this project, I propose a method to perform universal quantum computation using the excitations of interacting spin-orbit coupled fermions, in which effective p-wave interactions lead to the formation of a topological superfluid. Motivated by experiments which explore the physics of exotic interactions between atoms trapped inside optical cavities, I explore this system in a second project. I calculate the phase diagram of lattice bosons trapped in an optical cavity, where the cavity modes mediates effective global range checkerboard interactions between the atoms. I compare this phase diagram with one that was recently measured experimentally. In two other projects, I explore quantum simulation of condensed matter phenomena due to spin-dependent interactions between particles. I propose a method to produce tunable spin-dependent interactions between atoms, using an optical Feshbach resonance. In one project, I use these spin-dependent interactions in an ultracold Bose-Fermi system, and propose a method to produce the Kondo model. I propose an experiment to directly observe the Kondo effect in this system. In another project, I propose using lattice bosons with a large hyperfine spin

  15. A Compact, High-Flux Cold Atom Beam Source

    Science.gov (United States)

    Kellogg, James R.; Kohel, James M.; Thompson, Robert J.; Aveline, David C.; Yu, Nan; Schlippert, Dennis

    2012-01-01

    The performance of cold atom experiments relying on three-dimensional magneto-optical trap techniques can be greatly enhanced by employing a highflux cold atom beam to obtain high atom loading rates while maintaining low background pressures in the UHV MOT (ultra-high vacuum magneto-optical trap) regions. Several techniques exist for generating slow beams of cold atoms. However, one of the technically simplest approaches is a two-dimensional (2D) MOT. Such an atom source typically employs at least two orthogonal trapping beams, plus an additional longitudinal "push" beam to yield maximum atomic flux. A 2D atom source was created with angled trapping collimators that not only traps atoms in two orthogonal directions, but also provides a longitudinal pushing component that eliminates the need for an additional push beam. This development reduces the overall package size, which in turn, makes the 2D trap simpler, and requires less total optical power. The atom source is more compact than a previously published effort, and has greater than an order of magnitude improved loading performance.

  16. Improvement on Temperature Measurement of Cold Atoms in a Rubidium Fountain

    International Nuclear Information System (INIS)

    Lü De-Sheng; Qu Qiu-Zhi; Wang Bin; Zhao Jian-Bo; Liu Liang; Wang Yu-Zhu

    2011-01-01

    The time-of-flight (TOF) method is one of the most common ways to measure the temperature of cold atoms. In the cold atomic fountain setup, the geometry of the probe beam will introduce the measurement errors to the spatial distribution of cold atomic cloud, which will lead to the measurement errors on atomic temperature. Using deconvolution, we recover the atomic cloud profile from the TOF signal. Then, we use the recovered signals other than the TOF signals to obtain a more accurate atomic temperature. This will be important in estimating the effects of cold atom collision shift and the shift due to transverse cavity phase distribution on an atomic fountain clock. (atomic and molecular physics)

  17. Mercury determination in non- and biodegradable materials by cold vapor capacitively coupled plasma microtorch atomic emission spectrometry

    International Nuclear Information System (INIS)

    Frentiu, Tiberiu; Mihaltan, Alin I.; Ponta, Michaela; Darvasi, Eugen; Frentiu, Maria; Cordos, Emil

    2011-01-01

    Highlights: → Use of a miniaturized analytical system with microtorch plasma for Hg determination. → Determination of Hg in non- and biodegradable materials using cold vapor generation. → Figures of merit and advantages of the miniaturized system for Hg determination. - Abstract: A new analytical system consisting of a low power capacitively coupled plasma microtorch (20 W, 13.56 MHz, 150 ml min -1 Ar) and a microspectrometer was investigated for the Hg determination in non- and biodegradable materials by cold-vapor generation, using SnCl 2 reductant, and atomic emission spectrometry. The investigated miniaturized system was used for Hg determination in recyclable plastics from electronic equipments and biodegradable materials (shopping bags of 98% biodegradable polyethylene and corn starch) with the advantages of easy operation and low analysis costs. Samples were mineralized in HNO 3 -H 2 SO 4 mixture in a high-pressure microwave system. The detection limits of 0.05 ng ml -1 or 0.08 μg g -1 in solid sample were compared with those reported for other analytical systems. The method precision was 1.5-9.4% for Hg levels of 1.37-13.9 mg kg -1 , while recovery in two polyethylene certified reference materials in the range 98.7 ± 4.5% (95% confidence level).

  18. Excited-state imaging of cold atoms

    NARCIS (Netherlands)

    Sheludko, D.V.; Bell, S.C.; Vredenbregt, E.J.D.; Scholten, R.E.; Deshmukh, P.C.; Chakraborty, P.; Williams, J.F.

    2007-01-01

    We have investigated state-selective diffraction contrast imaging (DCI) of cold 85Rb atoms in the first excited (52P3/2) state. Excited-state DCI requires knowledge of the complex refractive index of the atom cloud, which was calculated numerically using a semi-classical model. The Autler-Townes

  19. Temporal interference with frequency-controllable long photons from independent cold atomic sources

    Science.gov (United States)

    Qian, Peng; Gu, Zhenjie; Wen, Rong; Zhang, Weiping; Chen, J. F.

    2018-01-01

    The interference of single photons from independent sources is an essential tool in quantum information processing. However, the interfering of photons with long temporal states in a time-resolved manner has rarely been studied. This is because without transmitting spectral filters or coupling to a cavity mode single photons generated in traditional nonlinear crystals suffer from a short temporal profile below 1 ns. With spectral correlation maintained in the biphotons generated from spontaneous four-wave mixing process in cold atom clouds, here we demonstrate the temporal interference of two frequency-tunable long photons from two independent cold atomic sources. We observe and analyze the interference of frequency-mismatched photons, where the phenomenon of the quantum beat at megahertz separation is displayed. Our paper provides more details for the quantum beat of two independent narrow-band single photons, which may find potential application in frequency-encoded photonic qubits in quantum information processing.

  20. Generation and storage of quantum states using cold atoms

    DEFF Research Database (Denmark)

    Dantan, Aurelien Romain; Josse, Vincent; Cviklinski, Jean

    2006-01-01

    Cold cesium or rubidium atomic samples have a good potential both for generation and storage of nonclassical states of light. Generation of nonclassical states of light is possible through the high non-linearity of cold atomic samples excited close to a resonance line. Quadrature squeezing, polar...

  1. Laser guiding of cold atoms in photonic crystals

    International Nuclear Information System (INIS)

    Tarasishin, A V; Magnitskiy, Sergey A; Shuvaev, V A; Zheltikov, Aleksei M

    2000-01-01

    The possibility of using photonic crystals with a lattice defect for the laser guiding of cold atoms is analysed. We have found a configuration of a photonic-crystal lattice and a defect ensuring the distribution of a potential in the defect mode of the photonic crystal allowing the guiding of cold atoms along the defect due to the dipole force acting on atoms. Based on quantitative estimates, we have demonstrated that photonic crystals with a lattice defect permit the guiding of atoms with much higher transverse temperatures and a much higher transverse localisation degree than in the case of hollow-core fibres. (laser applications and other topics in quantum electronics)

  2. Taming light with cold atoms

    International Nuclear Information System (INIS)

    Vestergaard Hau, Lene

    2002-01-01

    Much of the extraordinary progress of developments in communication (e-mail, and/or internet) has been achieved due to improvements in optical communication. This paper describes a new approach which could improve the speed of communication. The ability to stop light in its tracks by passing it through a cloud of ultracold atoms could lead to new techniques for optical storage. The described slow-light experiments have triggered new physics both on the experimental and theoretical fronts. The cold atom system allows the steepest possible refractive index profiles, and therefore the most dramatic effects, as Doppler effects are eliminated. Furthermore, cold atoms provide maximum flexibility in the choice of beam geometry. This is important for the storage and retrieval of multiple pulses of optical information in an atomic medium, as it would allow individual pulses to be selectively addressed. Slow and stopped light have many potential applications in optical communication and processing, including optical information storage, ultra-sensitive optical switches, and optical delay lines. It could also be used in quantum-information processing, in which quantum-mechanical information is used for computing and communication purposes. On a very different front, slow light provides us with a totally new way of probing the unusual properties of Bose-Einstein condensates

  3. Photoassociation of cold metastable helium atoms

    NARCIS (Netherlands)

    Woestenenk, G.R.

    2001-01-01

    During the last decades the study of cold atoms has grown in a great measure. Research in this field has been made possible due to the development of laser cooling and trapping techniques. We use laser cooling to cool helium atoms down to a temperature of 1 mK and we are able to

  4. Mercury determination in non- and biodegradable materials by cold vapor capacitively coupled plasma microtorch atomic emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Frentiu, Tiberiu, E-mail: ftibi@chem.ubbcluj.ro [Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, Arany Janos 11, 400028 Cluj-Napoca (Romania); Mihaltan, Alin I., E-mail: alinblaj2005@yahoo.com [National Institute for Research and Development of Optoelectronics Bucharest - Research Institute for Analytical Instrumentation, Donath 67, 400293 Cluj-Napoca (Romania); Ponta, Michaela, E-mail: mponta@chem.ubbcluj.ro [Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, Arany Janos 11, 400028 Cluj-Napoca (Romania); Darvasi, Eugen, E-mail: edarvasi@chem.ubbcluj.ro [Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, Arany Janos 11, 400028 Cluj-Napoca (Romania); Frentiu, Maria, E-mail: frentiu.maria@yahoo.com [National Institute for Research and Development of Optoelectronics Bucharest - Research Institute for Analytical Instrumentation, Donath 67, 400293 Cluj-Napoca (Romania); Cordos, Emil, E-mail: emilcordos@gmail.com [National Institute for Research and Development of Optoelectronics Bucharest - Research Institute for Analytical Instrumentation, Donath 67, 400293 Cluj-Napoca (Romania)

    2011-10-15

    Highlights: {yields} Use of a miniaturized analytical system with microtorch plasma for Hg determination. {yields} Determination of Hg in non- and biodegradable materials using cold vapor generation. {yields} Figures of merit and advantages of the miniaturized system for Hg determination. - Abstract: A new analytical system consisting of a low power capacitively coupled plasma microtorch (20 W, 13.56 MHz, 150 ml min{sup -1} Ar) and a microspectrometer was investigated for the Hg determination in non- and biodegradable materials by cold-vapor generation, using SnCl{sub 2} reductant, and atomic emission spectrometry. The investigated miniaturized system was used for Hg determination in recyclable plastics from electronic equipments and biodegradable materials (shopping bags of 98% biodegradable polyethylene and corn starch) with the advantages of easy operation and low analysis costs. Samples were mineralized in HNO{sub 3}-H{sub 2}SO{sub 4} mixture in a high-pressure microwave system. The detection limits of 0.05 ng ml{sup -1} or 0.08 {mu}g g{sup -1} in solid sample were compared with those reported for other analytical systems. The method precision was 1.5-9.4% for Hg levels of 1.37-13.9 mg kg{sup -1}, while recovery in two polyethylene certified reference materials in the range 98.7 {+-} 4.5% (95% confidence level).

  5. Angular momentum coupling in atom-atom collisions

    International Nuclear Information System (INIS)

    Grosser, J.

    1986-01-01

    The coupling between the electronic angular momentum and the rotating atom-atom axis in the initial or the final phase of an atom-atom collision is discussed, making use of the concepts of radial and rotational (Coriolis) coupling between different molecular states. The description is based on a limited number of well-understood approximations, and it allows an illustrative geometric representation of the transition from the body fixed to the space fixed motion of the electrons. (orig.)

  6. Atom chips: mesoscopic physics with cold atoms

    International Nuclear Information System (INIS)

    Krueger, P.; Wildermuth, S.; Hofferberth, S.; Haller, E.; GAllego Garcia, D.; Schmiedmayer, J.

    2005-01-01

    Full text: Cold neutral atoms can be controlled and manipulated in microscopic potentials near surfaces of atom chips. These integrated micro-devices combine the known techniques of atom optics with the capabilities of well established micro- and nanofabrication technology. In analogy to electronic microchips and integrated fiber optics, the concept of atom chips is suitable to explore the domain of mesoscopic physics with matter waves. We use current and charge carrying structures to form complex potentials with high spatial resolution only microns from the surface. In particular, atoms can be confined to an essentially one-dimensional motion. In this talk, we will give an overview of our experiments studying the manipulation of both thermal atoms and BECs on atom chips. First experiments in the quasi one-dimensional regime will be presented. These experiments profit from strongly reduced residual disorder potentials caused by imperfections of the chip fabrication with respect to previously published experiments. This is due to our purely lithographic fabrication technique that proves to be advantageous over electroplating. We have used one dimensionally confined BECs as an ultra-sensitive probe to characterize these potentials. These smooth potentials allow us to explore various aspects of the physics of degenerate quantum gases in low dimensions. (author)

  7. Majorana edge States in atomic wires coupled by pair hopping.

    Science.gov (United States)

    Kraus, Christina V; Dalmonte, Marcello; Baranov, Mikhail A; Läuchli, Andreas M; Zoller, P

    2013-10-25

    We present evidence for Majorana edge states in a number conserving theory describing a system of spinless fermions on two wires that are coupled by pair hopping. Our analysis is based on a combination of a qualitative low energy approach and numerical techniques using the density matrix renormalization group. In addition, we discuss an experimental realization of pair-hopping interactions in cold atom gases confined in optical lattices.

  8. A high resolution ion microscope for cold atoms

    International Nuclear Information System (INIS)

    Stecker, Markus; Schefzyk, Hannah; Fortágh, József; Günther, Andreas

    2017-01-01

    We report on an ion-optical system that serves as a microscope for ultracold ground state and Rydberg atoms. The system is designed to achieve a magnification of up to 1000 and a spatial resolution in the 100 nm range, thereby surpassing many standard imaging techniques for cold atoms. The microscope consists of four electrostatic lenses and a microchannel plate in conjunction with a delay line detector in order to achieve single particle sensitivity with high temporal and spatial resolution. We describe the design process of the microscope including ion-optical simulations of the imaging system and characterize aberrations and the resolution limit. Furthermore, we present the experimental realization of the microscope in a cold atom setup and investigate its performance by patterned ionization with a structure size down to 2.7 μ m. The microscope meets the requirements for studying various many-body effects, ranging from correlations in cold quantum gases up to Rydberg molecule formation. (paper)

  9. Comparing and contrasting nuclei and cold atomic gases

    DEFF Research Database (Denmark)

    Zinner, Nikolaj Thomas; Jensen, Aksel Stenholm

    2013-01-01

    The experimental revolution in ultracold atomic gas physics over the past decades has brought tremendous amounts of new insight to the world of degenerate quantum systems. Here we compare and contrast the developments of cold atomic gases with the physics of nuclei since many concepts, techniques......, and nomenclatures are common to both fields. However, nuclei are finite systems with interactions that are typically much more complicated than those of ultracold atomic gases. The similarities and differences must therefore be carefully addressed for a meaningful comparison and to facilitate fruitful......, interactions, and relevant length and energy scales of cold atoms and nuclei. Next we address some attempts in nuclear physics to transfer the concepts of condensates in nuclei that can in principle be built from bosonic alpha-particle constituents. We also consider Efimov physics, a prime example of nuclear...

  10. Mercury determination in non- and biodegradable materials by cold vapor capacitively coupled plasma microtorch atomic emission spectrometry.

    Science.gov (United States)

    Frentiu, Tiberiu; Mihaltan, Alin I; Ponta, Michaela; Darvasi, Eugen; Frentiu, Maria; Cordos, Emil

    2011-10-15

    A new analytical system consisting of a low power capacitively coupled plasma microtorch (20 W, 13.56 MHz, 150 ml min(-1) Ar) and a microspectrometer was investigated for the Hg determination in non- and biodegradable materials by cold-vapor generation, using SnCl(2) reductant, and atomic emission spectrometry. The investigated miniaturized system was used for Hg determination in recyclable plastics from electronic equipments and biodegradable materials (shopping bags of 98% biodegradable polyethylene and corn starch) with the advantages of easy operation and low analysis costs. Samples were mineralized in HNO(3)-H(2)SO(4) mixture in a high-pressure microwave system. The detection limits of 0.05 ng ml(-1) or 0.08 μg g(-1) in solid sample were compared with those reported for other analytical systems. The method precision was 1.5-9.4% for Hg levels of 1.37-13.9 mg kg(-1), while recovery in two polyethylene certified reference materials in the range 98.7 ± 4.5% (95% confidence level). Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Cold atomic beams of high brightness

    International Nuclear Information System (INIS)

    Rozhdestvensky, Yu V

    2004-01-01

    The possibility is studied for obtaining intense cold atomic beams by using the Renyi entropy to optimise the laser cooling process. It is shown in the case of a Gaussian velocity distribution of atoms, the Renyi entropy coincides with the density of particles in the phase space. The optimisation procedure for cooling atoms by resonance optical radiation is described, which is based on the thermodynamic law of increasing the Renyi entropy in time. Our method is compared with the known methods for increasing the laser cooling efficiency such as the tuning of a laser frequency in time and a change of the atomic transition frequency in an inhomogeneous transverse field of a magnetic solenoid. (laser cooling)

  12. Laser cooling of a magnetically guided ultra cold atom beam

    Energy Technology Data Exchange (ETDEWEB)

    Aghajani-Talesh, Anoush

    2014-07-01

    This thesis examines two complimentary methods for the laser cooling of a magnetically guided ultra-cold atom beam. If combined, these methods could serve as a starting point for high-through put and possibly even continuous production of Bose-Einstein condensates. First, a mechanism is outlined to harvest ultra cold atoms from a magnetically guided atom beam into an optical dipole trap. A continuous loading scheme is described that dissipates the directed kinetic energy of a captured atom via deceleration by a magnetic potential barrier followed by optical pumping to the energetically lowest Zeeman sublevel. The application of this scheme to the transfer of ultra cold chromium atoms from a magnetically guided atom beam into a deep optical dipole trap is investigated via numerical simulations of the loading process. Based on the results of the theoretical studies the feasibility and the efficiency of our loading scheme, including the realisation of a suitable magnetic field configuration, are analysed. Second, experiments were conducted on the transverse laser cooling of a magnetically guided beam of ultra cold chromium atoms. Radial compression by a tapering of the guide is employed to adiabatically heat the beam. Inside the tapered section heat is extracted from the atom beam by a two-dimensional optical molasses perpendicular to it, resulting in a significant increase of atomic phase space density. A magnetic offset field is applied to prevent optical pumping to untrapped states. Our results demonstrate that by a suitable choice of the magnetic offset field, the cooling beam intensity and detuning, atom losses and longitudinal heating can be avoided. Final temperatures below 65 μK have been achieved, corresponding to an increase of phase space density in the guided beam by more than a factor of 30.

  13. Laser cooling of a magnetically guided ultra cold atom beam

    International Nuclear Information System (INIS)

    Aghajani-Talesh, Anoush

    2014-01-01

    This thesis examines two complimentary methods for the laser cooling of a magnetically guided ultra-cold atom beam. If combined, these methods could serve as a starting point for high-through put and possibly even continuous production of Bose-Einstein condensates. First, a mechanism is outlined to harvest ultra cold atoms from a magnetically guided atom beam into an optical dipole trap. A continuous loading scheme is described that dissipates the directed kinetic energy of a captured atom via deceleration by a magnetic potential barrier followed by optical pumping to the energetically lowest Zeeman sublevel. The application of this scheme to the transfer of ultra cold chromium atoms from a magnetically guided atom beam into a deep optical dipole trap is investigated via numerical simulations of the loading process. Based on the results of the theoretical studies the feasibility and the efficiency of our loading scheme, including the realisation of a suitable magnetic field configuration, are analysed. Second, experiments were conducted on the transverse laser cooling of a magnetically guided beam of ultra cold chromium atoms. Radial compression by a tapering of the guide is employed to adiabatically heat the beam. Inside the tapered section heat is extracted from the atom beam by a two-dimensional optical molasses perpendicular to it, resulting in a significant increase of atomic phase space density. A magnetic offset field is applied to prevent optical pumping to untrapped states. Our results demonstrate that by a suitable choice of the magnetic offset field, the cooling beam intensity and detuning, atom losses and longitudinal heating can be avoided. Final temperatures below 65 μK have been achieved, corresponding to an increase of phase space density in the guided beam by more than a factor of 30.

  14. Note: A versatile radio-frequency source for cold atom experiments

    Energy Technology Data Exchange (ETDEWEB)

    Li, Na; Wu, Yu-Ping; Min, Hao; Yang, Tao; Jiang, Xiao, E-mail: jiangx@ustc.edu.cn [Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2016-08-15

    A radio-frequency (RF) source designed for cold atom experiments is presented. The source uses AD9858, a direct digital synthesizer, to generate the sine wave directly, up to 400 MHz, with sub-Hz resolution. An amplitude control circuit consisting of wideband variable gain amplifier and high speed digital to analog converter is integrated into the source, capable of 70 dB off isolation and 4 ns on-off keying. A field programmable gate array is used to implement a versatile frequency and amplitude co-sweep logic. Owing to modular design, the RF sources have been used on many cold atom experiments to generate various complicated RF sequences, enriching the operation schemes of cold atoms, which cannot be done by standard RF source instruments.

  15. Light localization in cold and dense atomic ensemble

    International Nuclear Information System (INIS)

    Sokolov, Igor

    2017-01-01

    We report on results of theoretical analysis of possibilities of light strong (Anderson) localization in a cold atomic ensemble. We predict appearance of localization in dense atomic systems in strong magnetic field. We prove that in absence of the field the light localization is impossible. (paper)

  16. Trapping cold ground state argon atoms.

    Science.gov (United States)

    Edmunds, P D; Barker, P F

    2014-10-31

    We trap cold, ground state argon atoms in a deep optical dipole trap produced by a buildup cavity. The atoms, which are a general source for the sympathetic cooling of molecules, are loaded in the trap by quenching them from a cloud of laser-cooled metastable argon atoms. Although the ground state atoms cannot be directly probed, we detect them by observing the collisional loss of cotrapped metastable argon atoms and determine an elastic cross section. Using a type of parametric loss spectroscopy we also determine the polarizability of the metastable 4s[3/2](2) state to be (7.3±1.1)×10(-39)  C m(2)/V. Finally, Penning and associative losses of metastable atoms in the absence of light assisted collisions, are determined to be (3.3±0.8)×10(-10)  cm(3) s(-1).

  17. Velocity selection for ultra-cold atoms using bimodal mazer cavity

    International Nuclear Information System (INIS)

    Irshad, A.; Qamar, S.

    2009-04-01

    In this paper, we discuss the velocity selection of ultra-cold three-level atoms in Λ configuration using a micromazer. Our model is the same as discussed by Arun et al., for mazer action in a bimodal cavity. We have shown that significantly narrowed velocity distribution of ultra-cold atoms can be obtained in this system due to the presence of dark states. (author)

  18. Anisotropic Interactions between Cold Rydberg Atoms

    Science.gov (United States)

    2015-09-28

    AFRL-AFOSR-CL-TR-2015-0002 Anisotropic interactions between cold Rydberg atoms Luis Marcassa INSTITUTO DE FISICA DE SAO CARLOS Final Report 09/28...problem with the report +551633739806 Organization / Institution name Instituto de Fisica de Sao Carlos Grant/Contract Title The full title of the

  19. Formation of cold molecules through the photo-association of cold atoms of Cesium. Existence of long range forces between between cold excited atoms of Cesium; Formation de molecules froides par photoassociation d'atomes froids de cesium. Mise en evidence de forces a longue portee entre atomes froids excites de cesium

    Energy Technology Data Exchange (ETDEWEB)

    Comparat, D

    1999-09-01

    This thesis deals with the experimental study and the theoretical interpretation of the processes involved in photo-association and the formation of cold caesium molecules. It also presents a study of the dipolar forces between a pair of cold excited caesium atoms. We present here the first photo-association experiment on cold caesium atoms: two cold atoms absorb a photon to form an excited electronically excited molecules in a rotation-vibration level. The first production of cold molecules which was realised experimentally, after the spontaneous deexcitation of the photo-associated molecules, is described, stressing the role of the potential well of the molecular states O{sub g}{sup -}(6s+6p{sub 3/2}) or 1{sub u} (6s+6p{sub 3/2}) of caesium. The detection of the formed caesium molecules is based on a two-photons resonant ionisation that creates Cs{sub 2}{sup +} ions, afterwards selectively detected. Temperatures around 20-200 {mu}K have been measured. The photo-associative spectroscopy is described on the theoretical point of view: a detailed theoretical study allows to calculate precisely the asymptotic parts of the potential curves. On the experimental point of view, we present the spectroscopy of the extern potential well of the caesium state O{sub g}{sup -}(6s+6p{sub 3/2}) and the construction of an effective potential curve of the RKR type. A unified theory of photo-association in weak field, considered as a collision assisted by laser, is developed. The cold atoms experiments allow to study and control the collision between two atoms whose mutual interaction is of the dipole-dipole type. Two different physical systems are studied: a sample of Rydberg atoms, and the photo-association process which is a laser-assisted collision. A modification of the motion of one pair of atoms makes it possible to control the bipolar forces and to choose the atoms relative speeds. (author)

  20. Measurement of Local Gravity via a Cold Atom Interferometer

    International Nuclear Information System (INIS)

    Zhou Lin; Xiong Zong-Yuan; Yang Wei; Tang Biao; Peng Wen-Cui; Wang Yi-Bo; Xu Peng; Wang Jin; Zhan Ming-Sheng

    2011-01-01

    We demonstrate a precision measurement of local gravity acceleration g in Wuhan by a compact cold atom interferometer. The atom interferometer is in vertical Mach—Zehnder configuration realized using a π/2 - π - π/2 Raman pulse sequence. Cold atoms were prepared in a magneto-optical trap, launched upward to form an atom fountain, and then coherently manipulated to interfere by stimulated Raman transition. Population signal vs Raman laser phase was recorded as interference fringes, and the local gravity was deduced from the interference signal. We have obtained a resolution of 7 × 10 −9 g after an integration time of 236s under the best vibrational environment conditions. The absolute g value was derived from the chirp rate with a difference of 1.5 × 10 −7 g compared to the gravity reference value. The tidal phenomenon was observed by continuously monitoring the local gravity over 123 h. (atomic and molecular physics)

  1. STIR-Physics: Cold Atoms and Nanocrystals in Tapered Nanofiber and High-Q Resonator Potentials

    Science.gov (United States)

    2016-11-02

    STIR- Physics : Cold Atoms and Nanocrystals in Tapered Nanofiber and High-Q Resonator Potentials We worked on a tapered fiber in cold atomic cloud...reviewed journals: Number of Papers published in non peer-reviewed journals: Final Report: STIR- Physics : Cold Atoms and Nanocrystals in Tapered Nanofiber...other than abstracts): Number of Peer-Reviewed Conference Proceeding publications (other than abstracts): Books Number of Manuscripts: 0.00Number of

  2. Manipulating beams of ultra-cold atoms with a static magnetic field

    International Nuclear Information System (INIS)

    Rowlands, W.J.; Lau, D.C.; Opat, G.I.; Sidorov, A.I.; McLean, R.J.; Hannaford, P.

    1996-01-01

    The preliminary results on the deflection of a beam of ultra-cold atoms by a static magnetic field are presented. Caesium atoms trapped in a magneto-optical trap (MOT) are cooled using optical molasses, and then fall freely under gravity to form a beam of ultra-cold atoms. The atoms pass through a static inhomogeneous magnetic field produced by a single current-carrying wire, and are deflected by a force dependent on the magnetic substate of the atom. A schematical diagram of the experimental layout for laser trapping and cooling of cesium atom is given. The population of atoms in various magnetic substates can be altered by using resonant laser radiation to optically pump the atoms. The single-wire deflection experiment described can be considered as atomic reflexion from a cylindrical magnetic mirror; the underlying principles and techniques being relevant to the production of atomic mirrors and diffraction gratings. 16 refs., 10 figs

  3. Feshbach resonances in cold collisions of potassium atoms

    International Nuclear Information System (INIS)

    Bambini, A.; Geltman, S.

    2002-01-01

    In this paper we briefly review the basic steps that allow the calculation of the scattering length in the collision of two alkali-metal atoms in a well defined magnetic polarization state, and in the presence of a static magnetic field. Calculations are actually done for the low-field seeking state F=1, μ F =-1 of bosonic potassium atoms. The electrostatic potentials obtained through Rydberg-Klein-Rees data are connected to a dispersive, long range tail in which the dominant dipole-dipole C 6 term may take different values within a specified range. We show the occurrence of Feshbach resonances in the ultra cold collision of two identical atoms, belonging either to the bosonic species 39 K or 41 K. Our results demonstrate that there is a range of C 6 values for which the collision of two 39 K atoms displays a single resonance, while for other values of C 6 no resonance occurs. On the other hand, Feshbach resonances are present in the collision of two 41 K atoms for almost all values of the dispersion coefficient C 6 in that range. We also show the origin of the different types of Feshbach resonances that occur in the cold collision of two 41 K atoms. The detection of such resonances can help establish the actual value of the dispersive coefficient

  4. Quantum ratchets for periodically kicked cold atoms and Bose-Einstein condensates

    Energy Technology Data Exchange (ETDEWEB)

    Casati, Giulio [Center for Nonlinear and Complex Systems, Universita degli Studi dell' Insubria and Istituto Nazionale per la Fisica della Materia, Unita di Como, Via Valleggio 11, 22100 Como (Italy); Poletti, Dario [Center for Nonlinear and Complex Systems, Universita degli Studi dell' Insubria and Istituto Nazionale per la Fisica della Materia, Unita di Como, Via Valleggio 11, 22100 Como (Italy)

    2007-05-15

    We study cold atoms and Bose-Einstein condensates exposed to time-dependent standing waves of light. We first discuss a quantum chaotic dissipative ratchet using the method of quantum trajectories. This system is characterized by directed transport emerging from a quantum strange attractor. We then present a very simple model of directed transport with cold atoms in a pair of periodically flashed optical lattices. Finally we study the dynamics of a dilute Bose-Einstein condensate confined in a toroidal trap and exposed to a pair of periodically flashed optical lattices. We show that the many-body atom-atom interactions, treated within the mean-field approximation, can generate directed transport.

  5. Fuzzy Control of Cold Storage Refrigeration System with Dynamic Coupling Compensation

    Directory of Open Access Journals (Sweden)

    Xiliang Ma

    2018-01-01

    Full Text Available Cold storage refrigeration systems possess the characteristics of multiple input and output and strong coupling, which brings challenges to the optimize control. To reduce the adverse effects of the coupling and improve the overall control performance of cold storage refrigeration systems, a control strategy with dynamic coupling compensation was studied. First, dynamic model of a cold storage refrigeration system was established based on the requirements of the control system. At the same time, the coupling between the components was studied. Second, to reduce the adverse effects of the coupling, a fuzzy controller with dynamic coupling compensation was designed. As for the fuzzy controller, a self-tuning fuzzy controller was served as the primary controller, and an adaptive neural network was adopted to compensate the dynamic coupling. Finally, the proposed control strategy was employed to the cold storage refrigeration system, and simulations were carried out in the condition of start-up, variable load, and variable degree of superheat, respectively. The simulation results verify the effectiveness of the fuzzy control method with dynamic coupling compensation.

  6. Manipulating cold atoms for quantum information processing

    International Nuclear Information System (INIS)

    Knight, P.

    2005-01-01

    Full text: I will describe how cold atoms can be manipulated to realize arrays of addressable qbits as prototype quantum registers, focussing on how atom chips can be used in combination with cavity qed techniques to form such an array. I will discuss how the array can be generated and steered using optical lattices and the Mott transition, and describe the sources of noise and how these place limits on the use of such chips in quantum information processing. (author)

  7. Surface Plasmon Polaritons Probed with Cold Atoms

    DEFF Research Database (Denmark)

    Kawalec, Tomasz; Sierant, Aleksandra; Panas, Roman

    2017-01-01

    We report on an optical mirror for cold rubidium atoms based on a repulsive dipole potential created by means of a modified recordable digital versatile disc. Using the mirror, we have determined the absolute value of the surface plasmon polariton (SPP) intensity, reaching 90 times the intensity...

  8. Cold atoms near surfaces: designing potentials by sculpturing wires

    International Nuclear Information System (INIS)

    Della Pietra, Leonardo; Aigner, Simon; Hagen, Christoph vom; Lezec, Henri J; Schmiedmayer, Joerg

    2005-01-01

    The magnetic trapping potentials for atoms on atom chips are determined by the current flow pattern in the chip wires. By modifying the wire shape using focused ion beam nano-machining we can design specialized current flow patterns and therefore micro-design the magnetic trapping potentials. We give designs for a barrier, a quantum dot, and a double well or double barrier and show preliminary experiments with ultra cold atoms in these designed potentials

  9. Storage ring to investigate cold unidimensional atomic collisions

    International Nuclear Information System (INIS)

    Marcassa, L. G.; Caires, A. R. L.; Nascimento, V. A.; Dulieu, O.; Weiner, J.; Bagnato, V. S.

    2005-01-01

    In this paper we employ a circulating ring of trapped atoms, that we have named the atomotron, to study cold collisions. The atomotron is obtained from a conventional magneto-optical trap when the two pairs of normally retroreflecting Gaussian laser beams in the x-y plane are slightly offset. Circulating stable atomic orbits then form a racetrack geometry in this plane. The circulating atom flux behaves similarly to an atomic beam with an average tangential velocity much greater than the transverse components, and is therefore suitable for one-dimensional atomic collision studies. Using the atomotron, we have investigated the polarization dependence of ultracold photoassociation collisions between Rb atoms circulating in the racetrack. The ability to investigate collisions in ultracold circulating atomic rings reveals alignment and orientation properties that are averaged away in ordinary three-dimensional magneto-optical trap collision processes

  10. Dynamics of bad-cavity-enhanced interaction with cold Sr atoms for laser stabilization

    DEFF Research Database (Denmark)

    Schäffer, S. A.; Christensen, B. T.R.; Henriksen, M. R.

    2017-01-01

    Hybrid systems of cold atoms and optical cavities are promising systems for increasing the stability of laser oscillators used in quantum metrology and atomic clocks. In this paper we map out the atom-cavity dynamics in such a system and demonstrate limitations as well as robustness of the approach....... We investigate the phase response of an ensemble of cold Sr88 atoms inside an optical cavity for use as an error signal in laser frequency stabilization. With this system we realize a regime where the high atomic phase shift limits the dynamical locking range. The limitation is caused by the cavity...

  11. Atomic precision tests and light scalar couplings

    Energy Technology Data Exchange (ETDEWEB)

    Brax, Philippe [CEA, IPhT, CNRS, URA 2306, Gif-sur-Yvette (France). Inst. de Physique Theorique; Burrage, Clare [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Geneve Univ. (Switzerland). Dept. de Physique Theorique

    2010-10-15

    We calculate the shift in the atomic energy levels induced by the presence of a scalar field which couples to matter and photons. We find that a combination of atomic measurements can be used to probe both these couplings independently. A new and stringent bound on the matter coupling springs from the precise measurement of the 1s to 2s energy level difference in the hydrogen atom, while the coupling to photons is essentially constrained by the Lamb shift. Combining these constraints with current particle physics bounds we find that the contribution of a scalar field to the recently claimed discrepancy in the proton radius measured using electronic and muonic atoms is negligible. (orig.)

  12. The detection of cold antihydrogen atoms

    International Nuclear Information System (INIS)

    Zhang, Zhongdong

    2007-01-01

    The ATRAP experiment at CERN's antiproton decelerator (AD) aims for a test of CPT violation and Lorentz invariance by a comparison of hydrogen to antihydrogen atom spectroscopy and a measurement of the gravitational force on antimatter atoms. The experiment is divided into two parts: ATRAP-I, where successfully antihydrogen atoms were produced and intensive studies on the charged clouds of positrons and antiprotons were performed, and ATRAP-II which was commissioned during the beam-time 2006. ATRAP-II includes a much larger superconducting solenoid bore allowing the installation of an extended detection system as well as an optimized combined Penning-Ioffe trap. Another essential part is a new positron accumulator and delivery system which will increase the ATRAP-II efficiency drastically. Thus ATRAP-II now allows for much larger flexibility, increased performance, higher robustness, and better efficiency for the production and storage of cold antihydrogen atoms. A general overview of the experimental setup for the second phase of the ATRAP experiment will be presented in this thesis. The antiproton annihilation detector system, consisting of several layers of scintillating fibers, counts the antihydrogen atoms and determines the annihilation vertex of the atoms. This diagnostic element will allow to optimize the production of cold antihydrogen sufficiently to permit optical observations and measurements. Extensive Monte Carlo simulations concerning the track fitting and vertex reconstruction have been developed during the planned interruption of antiproton production at AD in the year 2005. Different event generators, magnetic field distributions as well as data reconstruction algorithms on simulated data were established and the results were compared to data in 2006. To improve the detector position resolution, a constraint-fit procedure was adopted. Further possible improvements, by applying certain cuts on the data, were investigated. Real-time measurements

  13. Experimental Investigation of the Influence of the Laser Beam Waist on Cold Atom Guiding Efficiency.

    Science.gov (United States)

    Song, Ningfang; Hu, Di; Xu, Xiaobin; Li, Wei; Lu, Xiangxiang; Song, Yitong

    2018-02-28

    The primary purpose of this study is to investigate the influence of the vertical guiding laser beam waist on cold atom guiding efficiency. In this study, a double magneto-optical trap (MOT) apparatus is used. With an unbalanced force in the horizontal direction, a cold atomic beam is generated by the first MOT. The cold atoms enter the second chamber and are then re-trapped and cooled by the second MOT. By releasing a second atom cloud, the process of transferring the cold atoms from MOT to the dipole trap, which is formed by a red-detuned converged 1064-nm laser, is experimentally demonstrated. And after releasing for 20 ms, the atom cloud is guided to a distance of approximately 3 mm. As indicated by the results, the guiding efficiency depends strongly on the laser beam waist; the efficiency reaches a maximum when the waist radius ( w ₀) of the laser is in the range of 15 to 25 μm, while the initial atom cloud has a radius of 133 μm. Additionally, the properties of the atoms inside the dipole potential trap, such as the distribution profile and lifetime, are deduced from the fluorescence images.

  14. Electrochemical generation of mercury cold vapor and its in-situ trapping in gold-covered graphite tube atomizers

    International Nuclear Information System (INIS)

    Cerveny, Vaclav; Rychlovsky, Petr; Netolicka, Jarmila; Sima, Jan

    2007-01-01

    The combination of more efficient flow-through electrochemical mercury cold vapor generation with its in-situ trapping in a graphite tube atomizer is described. This coupled technique has been optimized to attain the maximum sensitivity for Hg determination and to minimize the limits of detection and determination. A laboratory constructed thin-layer flow-through cell with a platinum cathode served as the cold vapor generator. Various cathode arrangements with different active surface areas were tested. Automated sampling equipment for the graphite atomizer with an untreated fused silica capillary was used for the introduction of the mercury vapor. The inner surface of the graphite tube was covered with a gold foil placed against the sampling hole. The results attained for the electrochemical mercury cold vapor generation (an absolute limit of detection of 80 pg; peak absorbance, 3σ criterion) were compared with the traditional vapor generation using NaBH 4 as the reducing agent (an absolute limit of detection of 124 pg; peak absorbance, 3σ criterion). The repeatability at the 5 ng ml -1 level was better than 4.1% (RSD) for electrochemical mercury vapor generation and better than 5.6% for the chemical cold vapor generation. The proposed method was applied to the determination the of Hg contents in a certified reference material and in spiked river water samples

  15. Anderson Transition of Cold Atoms with Synthetic Spin-Orbit Coupling in Two-Dimensional Speckle Potentials

    Science.gov (United States)

    Orso, Giuliano

    2017-03-01

    We investigate the metal-insulator transition occurring in two-dimensional (2D) systems of noninteracting atoms in the presence of artificial spin-orbit interactions and a spatially correlated disorder generated by laser speckles. Based on a high order discretization scheme, we calculate the precise position of the mobility edge and verify that the transition belongs to the symplectic universality class. We show that the mobility edge depends strongly on the mixing angle between Rashba and Dresselhaus spin-orbit couplings. For equal couplings a non-power-law divergence is found, signaling the crossing to the orthogonal class, where such a 2D transition is forbidden.

  16. Interplay of vacuum-mediated inter- and intra-atomic couplings in a pair of atoms

    International Nuclear Information System (INIS)

    Schmid, Sandra Isabelle; Evers, Joerg

    2010-01-01

    The resonance fluorescence emitted by a system of two dipole-dipole interacting nearby four-level atoms in a J=1/2↔J=1/2 configuration is studied. This setup is the simplest realistic model system which provides a complete description of the (inter-atomic) dipole-dipole interaction for arbitrary orientation of the inter-atomic distance vector, and at the same time allows for intra-atomic spontaneously generated coherences. Our main interest is the interplay of both these different coupling mechanisms. We discuss different methods to analyze the contribution of the various vacuum-induced coupling constants to the total resonance fluorescence spectrum. These allow us to find a dressed state interpretation of the contribution of the different inter-atomic dipole-dipole couplings to the total spectrum. We further study the role of the spontaneously generated coherences, and identify two different contributions to the single-particle vacuum-induced couplings. We show that they have a noticeable impact on the total resonance fluorescence spectrum down to small inter-atomic distances, even though the dipole-dipole coupling constants then are much larger in magnitude than the the single-particle coupling constants. Interestingly, we find that the inter-atomic couplings can induce an effect of the intra-atomic spontaneously generated coherences on the observed spectra which is not present in single-atom systems.

  17. Momentum diffusion for coupled atom-cavity oscillators

    International Nuclear Information System (INIS)

    Murr, K.; Maunz, P.; Pinkse, P. W. H.; Puppe, T.; Schuster, I.; Rempe, G.; Vitali, D.

    2006-01-01

    It is shown that the momentum diffusion of free-space laser cooling has a natural correspondence in optical cavities when the internal state of the atom is treated as a harmonic oscillator. We derive a general expression for the momentum diffusion, which is valid for most configurations of interest: The atom or the cavity or both can be probed by lasers, with or without the presence of traps inducing local atomic frequency shifts. It is shown that, albeit the (possibly strong) coupling between atom and cavity, it is sufficient for deriving the momentum diffusion to consider that the atom couples to a mean cavity field, which gives a first contribution, and that the cavity mode couples to a mean atomic dipole, giving a second contribution. Both contributions have an intuitive form and present a clear symmetry. The total diffusion is the sum of these two contributions plus the diffusion originating from the fluctuations of the forces due to the coupling to the vacuum modes other than the cavity mode (the so-called spontaneous emission term). Examples are given that help to evaluate the heating rates induced by an optical cavity for experiments operating at low atomic saturation. We also point out intriguing situations where the atom is heated although it cannot scatter light

  18. Cold collisions in dissipative optical lattices

    International Nuclear Information System (INIS)

    Piilo, J; Suominen, K-A

    2005-01-01

    The invention of laser cooling methods for neutral atoms allows optical and magnetic trapping of cold atomic clouds in the temperature regime below 1 mK. In the past, light-assisted cold collisions between laser cooled atoms have been widely studied in magneto-optical atom traps (MOTs). We describe here theoretical studies of dynamical interactions, specifically cold collisions, between atoms trapped in near-resonant, dissipative optical lattices. The extension of collision studies to the regime of optical lattices introduces several complicating factors. For the lattice studies, one has to account for the internal substates of atoms, position-dependent matter-light coupling, and position-dependent couplings between the atoms, in addition to the spontaneous decay of electronically excited atomic states. The developed one-dimensional quantum-mechanical model combines atomic cooling and collision dynamics in a single framework. The model is based on Monte Carlo wavefunction simulations and is applied when the lattice-creating lasers have frequencies both below (red-detuned lattice) and above (blue-detuned lattice) the atomic resonance frequency. It turns out that the radiative heating mechanism affects the dynamics of atomic cloud in a red-detuned lattice in a way that is not directly expected from the MOT studies. The optical lattice and position-dependent light-matter coupling introduces selectivity of collision partners. The atoms which are most mobile and energetic are strongly favoured to participate in collisions, and are more often ejected from the lattice, than the slow ones in the laser parameter region selected for study. Consequently, the atoms remaining in the lattice have a smaller average kinetic energy per atom than in the case of non-interacting atoms. For blue-detuned lattices, we study how optical shielding emerges as a natural part of the lattice and look for ways to optimize the effect. We find that the cooling and shielding dynamics do not mix

  19. Cold atoms in optical cavities and lattices

    International Nuclear Information System (INIS)

    Horak, P.

    1996-11-01

    The thesis is organized in three chapters covering different aspects of the interaction of atoms and light in the framework of theoretical quantum optics. In chapter 1 a special case of a microscopic laser where one or two atoms interact with several quantized cavity modes is discussed. In particular I investigate the properties of the light field created in one of the cavity modes. It is shown that a single-atom model already predicts average photon numbers in agreement with a semiclassical many-atom theory. The two-atom model exhibits additional collective features, such as superradiance and subradiance. In chapter 2 effects of the photon recoil on cold atoms in the limit of long-lived atomic transitions are investigated. First, I demonstrate that, in principle, relying on this scheme, a continuous-wave laser in the ultraviolet frequency domain could be established. Second, the splitting of an atomic beam into two coherent subbeams is discussed within the same scheme. Such beamsplitters play an important role in high-precision measurements using atomic interferometers. Finally, chapter 3 deals with cooling and trapping of atoms by the interaction with laser light. I discuss the properties and the light scattering of atoms trapped in a new light field configuration, a so-called dark optical superlattice. In principle, such systems allow the trapping of more than one atom in the ground state of a single optical potential well. This could give rise to the observation of e.g. atom-atom interactions and quantum statistical effects. (author)

  20. Production and detection of cold antihydrogen atoms

    CERN Multimedia

    Amoretti, M; Bonomi, G; Bouchta, A; Bowe, P; Carraro, C; Cesar, C L; Charlton, M; Collier, M; Doser, Michael; Filippini, V; Fine, K S; Fontana, A; Fujiwara, M C; Funakoshi, R; Genova, P; Hangst, J S; Hayano, R S; Holzscheiter, M H; Jørgensen, L V; Lagomarsino, V; Landua, Rolf; Landua, Rolf; Lindelöf, D; Lodi-Rizzini, E; Macri, M; Madsen, N; Manuzio, G; Marchesotti, M; Montagna, P; Pruys, H S; Regenfus, C; Riedler, P; Rochet, J; Rotondi, A; Rouleau, G; Testera, G; Van der Werf, D P; Variola, A; Watson, T L; CERN. Geneva

    2002-01-01

    A theoretical underpinning of the standard model of fundamental particles and interactions is CPT invariance, which requires that the laws of physics be invariant under the combined discrete operations of charge conjugation, parity and time reversal. Antimatter, the existence of which was predicted by Dirac, can be used to test the CPT theorem experimental investigations involving comparisons of particles with antiparticles are numerous. Cold atoms and anti-atoms, such as hydrogen and anti-hydrogen, could form the basis of a new precise test, as CPT invariance implies that they must have the same spectrum. Observations of antihydrogen in small quantities and at high energies have been reported at the European Organization for Nuclear Research (CERN) and at Fermilab, but were not suited to precision comparison measurements. Here we demonstrate the production of antihydrogen atoms at very low energy by mixing trapped antiprotons and positrons in a cryogenic environment. The neutral anti-atoms have been detected...

  1. Line splitting and modified atomic decay of atoms coupled with N quantized cavity modes

    Science.gov (United States)

    Zhu, Yifu

    1992-05-01

    We study the interaction of a two-level atom with N non-degenerate quantized cavity modes including dissipations from atomic decay and cavity damps. In the strong coupling regime, the absorption or emission spectrum of weakly excited atom-cavity system possesses N + 1 spectral peaks whose linewidths are the weighted averages of atomic and cavity linewidths. The coupled system shows subnatural (supernatural) atomic decay behavior if the photon loss rates from the N cavity modes are smaller (larger) than the atomic decay rate. If N cavity modes are degenerate, they can be treated effectively as a single mode. In addition, we present numerical calculations for N = 2 to characterize the system evolution from the weak coupling to strong coupling limits.

  2. A Many-Atom Cavity QED System with Homogeneous Atom-Cavity Coupling

    OpenAIRE

    Lee, Jongmin; Vrijsen, Geert; Teper, Igor; Hosten, Onur; Kasevich, Mark A.

    2013-01-01

    We demonstrate a many-atom-cavity system with a high-finesse dual-wavelength standing wave cavity in which all participating rubidium atoms are nearly identically coupled to a 780-nm cavity mode. This homogeneous coupling is enforced by a one-dimensional optical lattice formed by the field of a 1560-nm cavity mode.

  3. Reconstruction of a cold atom cloud by magnetic focusing

    International Nuclear Information System (INIS)

    Saba, C.V.

    1999-12-01

    Over the passed 15 years advances in laser cooling techniques have made it routinely possible to prepare cold clouds of atoms exhibiting temperatures of the order of several micro-Kelvin or less. Such low temperatures correspond to average atomic velocities of a few centimetres per second. Therefore, according to the de Broglie relationship p = h/λ, the atoms increasingly exhibit wave-like behaviour and can no longer be treated solely as particles. These advances in atom manipulation have renewed interest in the field of atom optics. One of the concerns of atom optics is the manipulation of atoms with optical elements analogous to those used in photon optics. The most basic of such elements is the mirror. This thesis presents a curved mirror for paramagnetic atoms fabricated from commercial video tape. It is the smoothest magnetic mirror to date and is the third generation of mirrors fabricated by our group using magnetic recording media. Previous designs used audio tape and 5 1/4 inch floppy disk. Using fluorescence imaging we have directly imaged atoms bouncing above the mirror and, owing to its smoothness, have observed the first ever reconstruction of a cold atom cloud above a curved reflector. The atoms were collected in a magneto optical trap (MOT), cooled to a temperature of 18 μK and then dropped onto the mirror. When released from a height of 13.5 mm we observed the collimation and refocusing of the cloud on consecutive bounces. Furthermore, we observed up to 14 bounces of the cloud, which corresponds to a time of ∼1.5 s. One of the factors that limited the number of observable bounces was the presence of some finite roughness in the reflecting surface. Using images of the focused cloud at the peak of even bounces we were able to measure this roughness and found it to be 5.9 mrads. By analysing magnetic force microscope (MFM) scans of the fields above the mirror we attributed this residual roughness to the spatial inhomogeneity of magnetic particles in

  4. Cold experiment of slag centrifugal granulation by rotary atomizer: Effect of atomizer configuration

    International Nuclear Information System (INIS)

    Wu, Jun-Jun; Wang, Hong; Zhu, Xun; Liao, Qiang; Li, Kai

    2017-01-01

    Centrifugal granulation has recently been employed to produce small blast furnace slag particles, so as to recover the waste heat from the high-temperature molten blast furnace slag. An appropriate atomizer enables centrifugal granulation to become a better cost-effective process for particle production. Thus, increasing emphasis has been placed on influence of atomizer configuration on granulation. In present study, three groups of atomizers were specially designed and the granulation performance of each atomizer was experimentally tested during cold experiments. The influences of atomizer configuration on granulation modes and droplet characteristics were investigated visually. Two modified correlations were proposed to predict the granulating droplet size by means of data fitting. The results indicated that the rotary cup atomizers can inhibit the film formation in contrast to rotary disc atomizer. Moreover, atomizers with outer angle of 90° was capable of producing smaller droplets. The revised correlation as well as the newly-developed correlation including the influence of atomizer configurations, presented in good agreement with the experiment data. In addition, an analysis on atomizer design was conducted to provide a good insight for industrialization. It was recommended to adopt cup-like atomizer in granulation for its ability to produce fine particles with smaller atomizer size.

  5. Trapping cold ground state argon atoms for sympathetic cooling of molecules

    OpenAIRE

    Edmunds, P. D.; Barker, P. F.

    2014-01-01

    We trap cold, ground-state, argon atoms in a deep optical dipole trap produced by a build-up cavity. The atoms, which are a general source for the sympathetic cooling of molecules, are loaded in the trap by quenching them from a cloud of laser-cooled metastable argon atoms. Although the ground state atoms cannot be directly probed, we detect them by observing the collisional loss of co-trapped metastable argon atoms using a new type of parametric loss spectroscopy. Using this technique we als...

  6. Physical replicas and the Bose glass in cold atomic gases

    International Nuclear Information System (INIS)

    Morrison, S; Kantian, A; Daley, A J; Zoller, P; Katzgraber, H G; Lewenstein, M; Buechler, H P

    2008-01-01

    We study cold atomic gases in a disorder potential and analyse the correlations between different systems subjected to the same disorder landscape. Such independent copies with the same disorder landscape are known as replicas. While, in general, these are not accessible experimentally in condensed matter systems, they can be realized using standard tools for controlling cold atomic gases in an optical lattice. Of special interest is the overlap function which represents a natural order parameter for disordered systems and is a correlation function between the atoms of two independent replicas with the same disorder. We demonstrate an efficient measurement scheme for the determination of this disorder-induced correlation function. As an application, we focus on the disordered Bose-Hubbard model and determine the overlap function within the perturbation theory and a numerical analysis. We find that the measurement of the overlap function allows for the identification of the Bose-glass phase in certain parameter regimes

  7. Physical replicas and the Bose glass in cold atomic gases

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, S; Kantian, A; Daley, A J; Zoller, P [Institute for Theoretical Physics, University of Innsbruck, Technikerstr. 25, A-6020 Innsbruck (Austria); Katzgraber, H G [Theoretische Physik, ETH Zurich, CH-8093 Zuerich (Switzerland); Lewenstein, M [ICAO-Institut de Ciencies Fotoniques, Parc Mediterrani de la Tecnologia, E-08860 Castelldefels, Barcelona (Spain); Buechler, H P [Institute for Theoretical Physics III, University of Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart (Germany)], E-mail: sarah.morrison@uibk.ac.at

    2008-07-15

    We study cold atomic gases in a disorder potential and analyse the correlations between different systems subjected to the same disorder landscape. Such independent copies with the same disorder landscape are known as replicas. While, in general, these are not accessible experimentally in condensed matter systems, they can be realized using standard tools for controlling cold atomic gases in an optical lattice. Of special interest is the overlap function which represents a natural order parameter for disordered systems and is a correlation function between the atoms of two independent replicas with the same disorder. We demonstrate an efficient measurement scheme for the determination of this disorder-induced correlation function. As an application, we focus on the disordered Bose-Hubbard model and determine the overlap function within the perturbation theory and a numerical analysis. We find that the measurement of the overlap function allows for the identification of the Bose-glass phase in certain parameter regimes.

  8. Cold pressor test on atomic bomb survivors, Nagasaki

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Tomoyoshi; Sweedler, D R; Okamoto, Akira

    1964-03-12

    Cold pressor test was performed on a sample of 1156 atomic bomb survivors and other persons (ages ranging between 15 to 81 years) residing in Nagasaki City. Response values differed according to such factors as age, sex, blood pressure and month of examination. The response in systolic pressure increased with age but no evidence was found to support an acceleration of aging by irradiation. The response in diastolic blood pressure showed no change with age, but differed between Comparison Groups during the summer months. However, this was apparently due to some other cause than exposure to the atomic bomb. 25 references, 8 tables.

  9. Development of the Science Data System for the International Space Station Cold Atom Lab

    Science.gov (United States)

    van Harmelen, Chris; Soriano, Melissa A.

    2015-01-01

    Cold Atom Laboratory (CAL) is a facility that will enable scientists to study ultra-cold quantum gases in a microgravity environment on the International Space Station (ISS) beginning in 2016. The primary science data for each experiment consists of two images taken in quick succession. The first image is of the trapped cold atoms and the second image is of the background. The two images are subtracted to obtain optical density. These raw Level 0 atom and background images are processed into the Level 1 optical density data product, and then into the Level 2 data products: atom number, Magneto-Optical Trap (MOT) lifetime, magnetic chip-trap atom lifetime, and condensate fraction. These products can also be used as diagnostics of the instrument health. With experiments being conducted for 8 hours every day, the amount of data being generated poses many technical challenges, such as downlinking and managing the required data volume. A parallel processing design is described, implemented, and benchmarked. In addition to optimizing the data pipeline, accuracy and speed in producing the Level 1 and 2 data products is key. Algorithms for feature recognition are explored, facilitating image cropping and accurate atom number calculations.

  10. Some applications of the Faddeev-Yakubovsky equations to the cold-atom physics

    International Nuclear Information System (INIS)

    Carbonell, J.; Deltuva, A.; Lazauskas, R.

    2011-01-01

    We present some recent applications of the Faddeev-Yakubovsky equations in describing atomic bound and scattering problems. We consider the scattering of a charged particle X by atomic hydrogen with special interest in X = p,e ± , systems of cold bosonic molecules and the bound and scattering properties of N=3 and N=4 atomic 4 He multimers. (authors)

  11. Spin-orbit coupling in ultracold Fermi gases of 173Yb atoms

    Science.gov (United States)

    Song, Bo; He, Chengdong; Hajiyev, Elnur; Ren, Zejian; Seo, Bojeong; Cai, Geyue; Amanov, Dovran; Zhang, Shanchao; Jo, Gyu-Boong

    2017-04-01

    Synthetic spin-orbit coupling (SOC) in cold atoms opens an intriguing new way to probe nontrivial topological orders beyond natural conditions. Here, we report the realization of the SOC physics both in a bulk system and in an optical lattice. First, we demonstrate two hallmarks induced from SOC in a bulk system, spin dephasing in the Rabi oscillation and asymmetric atomic distribution in the momentum space respectively. Then we describe the observation of non-trivial spin textures and the determination of the topological phase transition in a spin-dependent optical lattice dressed by the periodic Raman field. Furthermore, we discuss the quench dynamics between topological and trivial states by suddenly changing the band topology. Our work paves a new way to study non-equilibrium topological states in a controlled manner. Funded by Croucher Foundation and Research Grants Council (RGC) of Hong Kong (Project ECS26300014, GRF16300215, GRF16311516, and Croucher Innovation Grants).

  12. Cooled electronic system with thermal spreaders coupling electronics cards to cold rails

    Science.gov (United States)

    Chainer, Timothy J; Gaynes, Michael A; Graybill, David P; Iyengar, Madhusudan K; Kamath, Vinod; Kochuparambil, Bejoy J; Schmidt, Roger R; Schultz, Mark D; Simco, Daniel P; Steinke, Mark E

    2013-07-23

    Liquid-cooled electronic systems are provided which include an electronic assembly having an electronics card and a socket with a latch at one end. The latch facilitates securing of the card within the socket or removal of the card from the socket. A liquid-cooled cold rail is disposed at the one end of the socket, and a thermal spreader couples the electronics card to the cold rail. The thermal spreader includes first and second thermal transfer plates coupled to first and second surfaces on opposite sides of the card, and thermally conductive extensions extending from end edges of the plates, which couple the respective transfer plates to the liquid-cooled cold rail. The thermally conductive extensions are disposed to the sides of the latch, and the card is securable within or removable from the socket using the latch without removing the cold rail or the thermal spreader.

  13. Tunable atom-light beam splitter using electromagnetically induced transparency

    Science.gov (United States)

    Zhu, Xinyu; Wen, Rong; Chen, J. F.

    2018-06-01

    With electromagnetically induced transmission (EIT), an optical field can be converted into collective atomic excitation and stored in the atomic medium through switching off the strong-coupling field adiabatically. By varying the power of the coupling pulse, we can control the ratio between the transmitted optical field and the stored atomic mode. We use a cloud of cold 85Rb atoms prepared in magneto-optical trap as the experimental platform. Based on a model of EIT dark-state polariton, we consider the real case where the atomic medium has a finite length. The theoretical calculation gives numerical results that agree well with the experimental data. The results show that the ratio can be changed approximately from 0 to 100%, when the maximum power of the coupling pulse (the pulse length is 100 ns) varies from 0 to 20 mW, in the cold atomic ensemble with an optical depth of 40. This process can be used to achieve an atom-light hybrid beam splitter with tunable splitting ratio and thus find potential application in interferometric measurement and quantum information processing.

  14. A Molecular Dynamics of Cold Neutral Atoms Captured by Carbon Nanotube Under Electric Field and Thermal Effect as a Selective Atoms Sensor.

    Science.gov (United States)

    Santos, Elson C; Neto, Abel F G; Maneschy, Carlos E; Chen, James; Ramalho, Teodorico C; Neto, A M J C

    2015-05-01

    Here we analyzed several physical behaviors through computational simulation of systems consisting of a zig-zag type carbon nanotube and relaxed cold atoms (Rb, Au, Si and Ar). These atoms were chosen due to their different chemical properties. The atoms individually were relaxed on the outside of the nanotube during the simulations. Each system was found under the influence of a uniform electric field parallel to the carbon nanotube and under the thermal effect of the initial temperature at the simulations. Because of the electric field, the cold atoms orbited the carbon nanotube while increasing the initial temperature allowed the variation of the radius of the orbiting atoms. We calculated the following quantities: kinetic energy, potential energy and total energy and in situ temperature, molar entropy variation and average radius of the orbit of the atoms. Our data suggest that only the action of electric field is enough to generate the attractive potential and this system could be used as a selected atoms sensor.

  15. Cold-atom gravimetry with a Bose-Einstein condensate

    International Nuclear Information System (INIS)

    Debs, J. E.; Altin, P. A.; Barter, T. H.; Doering, D.; Dennis, G. R.; McDonald, G.; Close, J. D.; Robins, N. P.; Anderson, R. P.

    2011-01-01

    We present a cold-atom gravimeter operating with a sample of Bose-condensed 87 Rb atoms. Using a Mach-Zehnder configuration with the two arms separated by a two-photon Bragg transition, we observe interference fringes with a visibility of (83±6)% at T=3 ms. We exploit large momentum transfer (LMT) beam splitting to increase the enclosed space-time area of the interferometer using higher-order Bragg transitions and Bloch oscillations. We also compare fringes from condensed and thermal sources and observe a reduced visibility of (58±4)% for the thermal source. We suspect the loss in visibility is caused partly by wave-front aberrations, to which the thermal source is more susceptible due to its larger transverse momentum spread. Finally, we discuss briefly the potential advantages of using a coherent atomic source for LMT, and we present a simple mean-field model to demonstrate that with currently available experimental parameters, interaction-induced dephasing will not limit the sensitivity of inertial measurements using freely falling, coherent atomic sources.

  16. Decoherence for a quantum memory in an ensemble of cold atoms

    International Nuclear Information System (INIS)

    Riedmatten, H. de; Chou, C.W.; Felinto, D.; Plyakov, S.; Kimble, H.J.

    2005-01-01

    Full text: Atomic ensembles are a promising candidate for various applications in quantum information science. In particular, Duan, Lukin Cirac and Zoller (DLCZ) have proposed a protocol allowing scalable long distance quantum communication using atomic ensembles and linear optics. The DLCZ protocol is a probabilistic scheme based upon the entanglement of atomic ensembles via the detection of single photons. The detection of a single photon in the forward scattered direction is uniquely correlated with a collective atomic excitation in the sample, due to a collective enhancement effect. This collective excitation can be in principle stored for a time up to the coherence time of the system, and then released by conversion into a photon. This quantum memory is mandatory for the DLCZ scheme to be scalable. Hence, the coherence time is a critical parameter for this system. Our initial steps towards the realization of the DLCZ protocol have been by way of observations of non-classical correlations between the emitted single photons and the collective atomic excitations. However, in all the experiments reported so far using cold atomic ensembles, the coherence times were extremely short (of the order of 100 ns), thus preventing to take advantage of the quantum memory. In this contribution we explore the cause of this rather fast decoherence process and present an experimental scheme to overcome this problem. First results show an improvement of more than one order of magnitude in the coherence time. Future work includes the entanglement of two spatially separated cold atomic ensembles. (author)

  17. Effective field theory for cold atoms

    International Nuclear Information System (INIS)

    Hammer, H.-W.

    2005-01-01

    Effective Field Theory (EFT) provides a powerful framework that exploits a separation of scales in physical systems to perform systematically improvable, model-independent calculations. Particularly interesting are few-body systems with short-range interactions and large two-body scattering length. Such systems display remarkable universal features. In systems with more than two particles, a three-body force with limit cycle behavior is required for consistent renormalization already at leading order. We will review this EFT and some of its applications in the physics of cold atoms. Recent extensions of this approach to the four-body system and N-boson droplets in two spatial dimensions will also be discussed

  18. Fundamental symmetries studies with cold trapped francium atoms at ISAC

    International Nuclear Information System (INIS)

    Gwinner, G.; Gomez, E.; Orozco, L. A.; Perez Galvan, A.; Sheng, D.; Zhao, Y.; Sprouse, G. D.; Behr, J. A.; Jackson, K. P.; Pearson, M. R.; Aubin, S.; Flambaum, V. V.

    2006-01-01

    Francium combines a heavy nucleus (Z = 87) with the simple atomic structure of alkalis and is a very promising candidate for precision tests of fundamental symmetries such as atomic parity non-conservation measurements. Fr has no stable isotopes, and the ISAC radioactive beam facility at TRIUMF, equipped with an actinide target, promises to provide record quantities of Fr atoms, up to 10 10 /s for some isotopes. We discuss our plans for a Fr on-line laser trapping facility at ISAC and experiments with samples of cold Fr atoms. We outline our plans for a measurement of the nuclear anapole moment - a parity non-conserving, time-reversal conserving moment that arises from weak interactions between nucleons - in a chain of Fr isotopes. Its measurement is a unique probe for neutral weak interactions inside the nucleus.

  19. Strong Anderson localization in cold atom quantum quenches

    OpenAIRE

    Micklitz, T.; Müller, C. A.; Altland, A.

    2013-01-01

    Signatures of strong Anderson localization in the momentum distribution of a cold atom cloud after a quantum quench are studied. We consider a quasi one-dimensional cloud initially prepared in a well defined momentum state, and expanding for some time in a disorder speckle potential. Anderson localization leads to a formation of a coherence peak in the \\emph{forward} scattering direction (as opposed to the common weak localization backscattering peak). We present a microscopic, and fully time...

  20. Arbitrarily shaped high-coherence electron bunches from cold atoms

    Science.gov (United States)

    McCulloch, A. J.; Sheludko, D. V.; Saliba, S. D.; Bell, S. C.; Junker, M.; Nugent, K. A.; Scholten, R. E.

    2011-10-01

    Ultrafast electron diffractive imaging of nanoscale objects such as biological molecules and defects in solid-state devices provides crucial information on structure and dynamic processes: for example, determination of the form and function of membrane proteins, vital for many key goals in modern biological science, including rational drug design. High brightness and high coherence are required to achieve the necessary spatial and temporal resolution, but have been limited by the thermal nature of conventional electron sources and by divergence due to repulsive interactions between the electrons, known as the Coulomb explosion. It has been shown that, if the electrons are shaped into ellipsoidal bunches with uniform density, the Coulomb explosion can be reversed using conventional optics, to deliver the maximum possible brightness at the target. Here we demonstrate arbitrary and real-time control of the shape of cold electron bunches extracted from laser-cooled atoms. The ability to dynamically shape the electron source itself and to observe this shape in the propagated electron bunch provides a remarkable experimental demonstration of the intrinsically high spatial coherence of a cold-atom electron source, and the potential for alleviation of electron-source brightness limitations due to Coulomb explosion.

  1. Quantum control of ultra-cold atoms: uncovering a novel connection between two paradigms of quantum nonlinear dynamics

    DEFF Research Database (Denmark)

    Wang, Jiao; Mouritzen, Anders Sørrig; Gong, Jiangbin

    2009-01-01

    Controlling the translational motion of cold atoms using optical lattice potentials is of both theoretical and experimental interest. By designing two on-resonance time sequences of kicking optical lattice potentials, a novel connection between two paradigms of nonlinear mapping systems, i.e. the...... sequences of control fields. Extensions of this study are also discussed. The results are intended to open up a new generation of cold-atom experiments of quantum nonlinear dynamics.......Controlling the translational motion of cold atoms using optical lattice potentials is of both theoretical and experimental interest. By designing two on-resonance time sequences of kicking optical lattice potentials, a novel connection between two paradigms of nonlinear mapping systems, i...

  2. Photoionization and cold collision studies using trapped atoms

    International Nuclear Information System (INIS)

    Gould, P.L.

    1996-01-01

    The authors have used laser cooling and trapping techniques to investigate photoionization and cold collisions. With laser-trapped Rb, they have measured the photoionization cross section from the first excited (5P) level by observing the photoionization-induced loss rate of neutral atoms from the trap. This technique has the advantage that it directly measures the photoionization rate per atom. Knowing the ionizing laser intensity and the excited-state fraction, the measured loss rate gives the absolute cross section. Using this technique, the Rb 5P photoionization cross section at ∼400 nm has been determined with an uncertainty of 9%. The authors are currently attempting to extend this method to the 5D level. Using time-ordered pulses of diode-laser light (similar to the STIRAP technique), they have performed very efficient two-photon excitation of trapped Rb atoms to 5D. Finally, they will present results from a recent collaboration which combines measurements form conventional molecular spectroscopy (single photon and double resonance) with photoassociation collisions of ultracold Na atoms to yield a precise (≤1 ppm) value for the dissociation energy of the X Σ g+ ground state of the Na 2 molecule

  3. Dynamics and Thermodynamics of Many Particle Cold Atom Systems

    Science.gov (United States)

    2016-05-05

    simulate their dynamics far from equilibrium . It is likely that these ideas will find many applications in many areas of physics, quantum chemistry and...focus of this proposal was theoretical research on various non- equilibrium phenomena in isolated quantum systems and applications to experimental setups...theoretical research on various non- equilibrium phenomena in isolated quantum systems and applications to experimental setups largely to cold atoms

  4. Ultra-trace determination of methylmercuy in seafood by atomic fluorescence spectrometry coupled with electrochemical cold vapor generation

    Energy Technology Data Exchange (ETDEWEB)

    Zu, Wenchuan, E-mail: zuhongshuai@126.com [Beijing Institute of Technology, College of Chemistry, Beijing 100081 (China); Beijing Center for Physical & Chemical Analysis, Beijing 100089 (China); Wang, Zhenghao [Beijing Normal University, College of Chemistry, Beijing 100875 (China)

    2016-03-05

    Highlights: • Methylmercury detection by ECVG-AFS without pre-separation by HPLC is proposed. • Methylmercury is atomized by direct electrochemical reduction with no reductant. • Remarkably better sensitivity is obtained than the traditional HPLC-UV-AFS method. • Glassy carbon is the best cathode material to generate Hg vapor from methylmercury. - Abstract: A homemade electrochemical flow cell was adopted for the determination of methylmercury. The cold vapor of mercury atoms was generated from the surface of glassycarbon cathode through the method of electrolytic reduction and detected by atomic fluorescence spectroscopy subsequently. The operating conditions were optimized with 2 ng mL{sup −1} methylmercury standard solution. The caliberation curve was favorably linear when the concentrations of standard HgCH{sub 3}{sup +} solutions were in the range of 0.2–5 ng mL{sup −1}(as Hg). Under the optimized conditions, the limit of detection (LOD) for methylmercury was 1.88 × 10{sup −3} ng mL{sup −1} and the precision evaluated by relative standard deviation was 2.0% for six times 2 ng mL{sup −1} standard solution replicates. The terminal analytical results of seafood samples, available from local market, showed that the methylmercury content ranged within 3.7–45.8 ng g{sup −1}. The recoveries for methylmercury spiked samples were found to be in the range of 87.6–103.6% and the relative standard deviations below 5% (n = 6)were acquired, which showed this method was feasible for real sample analysis.

  5. Continuum-Coupling in Electron-Atom scattering

    International Nuclear Information System (INIS)

    Ballance, C.P.; Griffin, D.C.; Badnell, N.R.; Loch, S.D.; Pindzola, M.S.

    2004-01-01

    High quality fundamental atomic data provide the foundation of accurate collisional-radiative models of laboratory and astrophysical plasmas. In the SciDAC (Scientific Discovery through Advanced Computing) project entitled 'Terascale Computational Atomic Physics for the Edge Region in Controlled Fusion Plasmas', we employ an integrated approach from the calculation of basic atomic data to the modeling necessary for the interpretation of controlled nuclear fusion experiments. For example, helium electron-impact excitation results support helium puff experiments on the MAST (Mega Ampere Spherical Tokamak) at Culham to diagnose the radial variation in plasma density and temperature. Similarly, electron-impact excitation/ionization work for isonuclear beryllium will prove vital if beryllium is adopted as a surface material for the plasma-facing walls for ITER. Here we will discuss some examples of electron-impact excitation and ionization, where the effects of coupling to and between the target continuum states are large, and advanced close-coupling methods are required in order to generate data of sufficient accuracy

  6. Dimensional crossover and cold-atom realization of topological Mott insulators

    Science.gov (United States)

    Scheurer, Mathias S.; Rachel, Stephan; Orth, Peter P.

    2015-02-01

    Interacting cold-atomic gases in optical lattices offer an experimental approach to outstanding problems of many body physics. One important example is the interplay of interaction and topology which promises to generate a variety of exotic phases such as the fractionalized Chern insulator or the topological Mott insulator. Both theoretically understanding these states of matter and finding suitable systems that host them have proven to be challenging problems. Here we propose a cold-atom setup where Hubbard on-site interactions give rise to spin liquid-like phases: weak and strong topological Mott insulators. They represent the celebrated paradigm of an interacting and topological quantum state with fractionalized spinon excitations that inherit the topology of the non-interacting system. Our proposal shall help to pave the way for a controlled experimental investigation of this exotic state of matter in optical lattices. Furthermore, it allows for the investigation of a dimensional crossover from a two-dimensional quantum spin Hall insulating phase to a three-dimensional strong topological insulator by tuning the hopping between the layers.

  7. C-C Coupling on Single-Atom-Based Heterogeneous Catalyst.

    Science.gov (United States)

    Zhang, Xiaoyan; Sun, Zaicheng; Wang, Bin; Tang, Yu; Nguyen, Luan; Li, Yuting; Tao, Franklin Feng

    2018-01-24

    Compared to homogeneous catalysis, heterogeneous catalysis allows for ready separation of products from the catalyst and thus reuse of the catalyst. C-C coupling is typically performed on a molecular catalyst which is mixed with reactants in liquid phase during catalysis. This homogeneous mixing at a molecular level in the same phase makes separation of the molecular catalyst extremely challenging and costly. Here we demonstrated that a TiO 2 -based nanoparticle catalyst anchoring singly dispersed Pd atoms (Pd 1 /TiO 2 ) is selective and highly active for more than 10 Sonogashira C-C coupling reactions (R≡CH + R'X → R≡R'; X = Br, I; R' = aryl or vinyl). The coupling between iodobenzene and phenylacetylene on Pd 1 /TiO 2 exhibits a turnover rate of 51.0 diphenylacetylene molecules per anchored Pd atom per minute at 60 °C, with a low apparent activation barrier of 28.9 kJ/mol and no cost of catalyst separation. DFT calculations suggest that the single Pd atom bonded to surface lattice oxygen atoms of TiO 2 acts as a site to dissociatively chemisorb iodobenzene to generate an intermediate phenyl, which then couples with phenylacetylenyl bound to a surface oxygen atom. This coupling of phenyl adsorbed on Pd 1 and phenylacetylenyl bound to O ad of TiO 2 forms the product molecule, diphenylacetylene.

  8. Observation of modified radiative properties of cold atoms in vacuum near a dielectric surface

    International Nuclear Information System (INIS)

    Ivanov, V V; Cornelussen, R A; Heuvell, H B van Linden van den; Spreeuw, R J C

    2004-01-01

    We have observed a distance-dependent absorption linewidth of cold 87 Rb atoms close to a dielectric-vacuum interface. This is the first observation of modified radiative properties in vacuum near a dielectric surface. A cloud of cold atoms was created using a magneto-optical trap (MOT) and optical molasses cooling. Evanescent waves (EW) were used to observe the behaviour of the atoms near the surface. We observed an increase of the absorption linewidth by up to 25% with respect to the free-space value. Approximately half the broadening can be explained by cavity quantum electrodynamics (CQED) as an increase of the natural linewidth and inhomogeneous broadening. The remainder we attribute to local Stark shifts near the surface. By varying the characteristic EW length we have observed a distance dependence characteristic for CQED

  9. Dissipative Double-Well Potential for Cold Atoms: Kramers Rate and Stochastic Resonance.

    Science.gov (United States)

    Stroescu, Ion; Hume, David B; Oberthaler, Markus K

    2016-12-09

    We experimentally study particle exchange in a dissipative double-well potential using laser-cooled atoms in a hybrid trap. We measure the particle hopping rate as a function of barrier height, temperature, and atom number. Single-particle resolution allows us to measure rates over more than 4 orders of magnitude and distinguish the effects of loss and hopping. Deviations from the Arrhenius-law scaling at high barrier heights occur due to cold collisions between atoms within a well. By driving the system periodically, we characterize the phenomenon of stochastic resonance in the system response.

  10. Atomic fluorescence spectrometry with the inductively coupled plasma

    International Nuclear Information System (INIS)

    Omenetto, N.; Winefordner, J.D.

    1987-01-01

    Atomic fluorescence spectrometry (AFS) is based on the radiational activation of atoms and ions produced in a suitable atomizer (ionizer) and the subsequent measurement of the resulting radiational deactivation, called fluorescence. Atomic fluorescence spectrometry has been of considerable interest to researchers in atomic spectrometry because of its use for both analytical and diagnostic purposes. Unfortunately, the analytical applications of AFS have suffered from the lack of commercial instrumentation until the recent marketing of the Baird multiple-element, hollow cathode lamp-excited inductively coupled plasma system. This chapter is concerned strictly with the use of the inductively coupled plasma (ICP) as a cell and as a source for AFS. Many of the major references concerning the ICP in analytical AFS are categorized in Table 9.1, along with several reviews and diagnostical studies. For more detailed discussions of the fundamental aspects of AFS, the reader is referred to previous reviews

  11. Generation of maximally entangled mixed states of two atoms via on-resonance asymmetric atom-cavity couplings

    International Nuclear Information System (INIS)

    Li, Shang-Bin

    2007-01-01

    A scheme for generating the maximally entangled mixed state of two atoms on-resonance asymmetrically coupled to a single mode optical cavity field is presented. The part frontier of both maximally entangled mixed states and maximal Bell violating mixed states can be approximately reached by the evolving reduced density matrix of two atoms if the ratio of coupling strengths of two atoms is appropriately controlled. It is also shown that exchange symmetry of global maximal concurrence is broken if and only if coupling strength ratio lies between (√(3)/3) and √(3) for the case of one-particle excitation and asymmetric coupling, while this partial symmetry breaking cannot be verified by detecting maximal Bell violation

  12. Global land-atmosphere coupling associated with cold climate processes

    OpenAIRE

    Dutra, Emanuel, 1983-

    2011-01-01

    Tese de doutoramento, Ciências Geofísicas e da Geoinformação (Meteorologia), Universidade de Lisboa, Faculdade de Ciências, 2011 This dissertation constitutes an assessment of the role of cold processes, associated with snow cover, in controlling the land-atmosphere coupling. The work was based on model simulations, including offline simulations with the land surface model HTESSEL, and coupled atmosphere simulations with the EC-EARTH climate model. A revised snow scheme was developed and t...

  13. Subthermal linewidths in photoassociation spectra of cold alkaline-earth-metal atoms

    International Nuclear Information System (INIS)

    Machholm, Mette; Julienne, Paul S.; Suominen, Kalle-Antti

    2002-01-01

    Narrow s-wave features with subthermal widths are predicted for the 1 Π g photoassociation spectra of cold alkaline-earth-metal atoms. The phenomenon is explained by numerical and analytical calculations. These show that only a small subthermal range of collision energies near threshold contributes to the s-wave features that are excited when the atoms are very far apart. The resonances survive thermal averaging, and may be detectable for Ca cooled near the Doppler cooling temperature of the 4 1 P 1 S laser-cooling transition

  14. Evaporative cooling of cold atoms in a surface trap

    International Nuclear Information System (INIS)

    Hammes, M.; Rychtarik, D.; Grimm, R.

    2001-01-01

    Full text: Trapping cold atom close to a surface is a promising route for attaining a two-dimensional quantum gas. We present our gravito-optical surface trap (LOST), which consists of a horizontal evanescent-wave atom mirror in combination with a blue-detuned hollow beam for transverse confinement. Optical pre-cooling based on inelastic reflections from the evanescent wave provides good starting conditions for subsequent evaporative cooling, which can be realized by ramping down the optical potentials of the trap. Already our preliminary experiments (performed at the MPI fuer Kernphysik in Heidelberg) show a 100-fold increase in phase-space density and temperature reduction to 300 nK. Substantial further improvements can be expected in our greatly improved set-up after the recent transfer of the experiment to Innsbruck. By eliminating heating processes, optimizing the evaporation ramp, polarizing the atoms and by using an additional far red-detuned laser beam we expect to soon reach the conditions of quantum degeneracy and/or two-dimensionality. (author)

  15. Observation of Fano-Type Interference in a Coupled Cavity-Atom System

    International Nuclear Information System (INIS)

    Cheng Yong; Tan Zheng; Wang Jin; Zhan Ming-Sheng; Zhu Yi-Fu

    2016-01-01

    We present the experimental observation of the Fano-type interference in a coupled cavity-atom system by confining the laser-cooled "8"5Rb atoms in an optical cavity. The asymmetric Fano profile is obtained through quantum interference in a three-level atomic system coherently coupled to a single mode cavity field. The observed Fano profile can be explained by the interference between the intra-cavity dark state and the polariton state of the coupled cavity-atom system. The possible applications of our observations include all-optical switching, optical sensing and narrow band optical filters. (paper)

  16. Coherent generation and dynamic manipulation of double stationary light pulses in a five-level double-tripod system of cold atoms

    Energy Technology Data Exchange (ETDEWEB)

    Bao Qianqian; Zhang Xiaohang; Gao Junyan; Zhang Yan; Cui Cuili; Wu Jinhui [College of Physics, Jilin University, Changchun 130012 (China)

    2011-12-15

    We study a five-level double-tripod system of cold atoms for efficiently manipulating the dynamic propagation and evolution of a quantum probe field by modulating four classical control fields. Our numerical results show that it is viable to transform the quantum probe field into a pair of two-color stationary light pulses mutually coupled through two wave packets of atomic spin coherence. The pair of stationary light pulses can be released either from the sample entrance and exit synchronously or just from the sample exit with a controlled time delay. In addition, the two-color stationary light pulses are immune to the fast decay originating from the higher-order Fourier components of atomic spin and optical coherence, and may exhibit the quantum limited beating signals with their characteristic frequency determined by detunings of the four classical control fields. These results could be explored to design novel photonic devices, such as optical routing, beam splitter, and beat generator, for manipulating a quantum light field.

  17. Coherent generation and dynamic manipulation of double stationary light pulses in a five-level double-tripod system of cold atoms

    International Nuclear Information System (INIS)

    Bao Qianqian; Zhang Xiaohang; Gao Junyan; Zhang Yan; Cui Cuili; Wu Jinhui

    2011-01-01

    We study a five-level double-tripod system of cold atoms for efficiently manipulating the dynamic propagation and evolution of a quantum probe field by modulating four classical control fields. Our numerical results show that it is viable to transform the quantum probe field into a pair of two-color stationary light pulses mutually coupled through two wave packets of atomic spin coherence. The pair of stationary light pulses can be released either from the sample entrance and exit synchronously or just from the sample exit with a controlled time delay. In addition, the two-color stationary light pulses are immune to the fast decay originating from the higher-order Fourier components of atomic spin and optical coherence, and may exhibit the quantum limited beating signals with their characteristic frequency determined by detunings of the four classical control fields. These results could be explored to design novel photonic devices, such as optical routing, beam splitter, and beat generator, for manipulating a quantum light field.

  18. Hydrodynamics of Normal Atomic Gases with Spin-orbit Coupling.

    Science.gov (United States)

    Hou, Yan-Hua; Yu, Zhenhua

    2015-10-20

    Successful realization of spin-orbit coupling in atomic gases by the NIST scheme opens the prospect of studying the effects of spin-orbit coupling on many-body physics in an unprecedentedly controllable way. Here we derive the linearized hydrodynamic equations for the normal atomic gases of the spin-orbit coupling by the NIST scheme with zero detuning. We show that the hydrodynamics of the system crucially depends on the momentum susceptibilities which can be modified by the spin-orbit coupling. We reveal the effects of the spin-orbit coupling on the sound velocities and the dipole mode frequency of the gases by applying our formalism to the ideal Fermi gas. We also discuss the generalization of our results to other situations.

  19. A hybrid system of a membrane oscillator coupled to ultracold atoms

    Science.gov (United States)

    Kampschulte, Tobias

    2015-05-01

    The control over micro- and nanomechanical oscillators has recently made impressive progress. First experiments demonstrated ground-state cooling and single-phonon control of high-frequency oscillators using cryogenic cooling and techniques of cavity optomechanics. Coupling engineered mechanical structures to microscopic quantum system with good coherence properties offers new possibilities for quantum control of mechanical vibrations, precision sensing and quantum-level signal transduction. Ultracold atoms are an attractive choice for such hybrid systems: Mechanical can either be coupled to the motional state of trapped atoms, which can routinely be ground-state cooled, or to the internal states, for which a toolbox of coherent manipulation and detection exists. Furthermore, atomic collective states with non-classical properties can be exploited to infer the mechanical motion with reduced quantum noise. Here we use trapped ultracold atoms to sympathetically cool the fundamental vibrational mode of a Si3N4 membrane. The coupling of membrane and atomic motion is mediated by laser light over a macroscopic distance and enhanced by an optical cavity around the membrane. The observed cooling of the membrane from room temperature to 650 +/- 230 mK shows that our hybrid mechanical-atomic system operates at a large cooperativity. Our scheme could provide ground-state cooling and quantum control of low-frequency oscillators such as levitated nanoparticles, in a regime where purely optomechanical techniques cannot reach the ground state. Furthermore, we will present a scheme where an optomechanical system is coupled to internal states of ultracold atoms. The mechanical motion is translated into a polarization rotation which drives Raman transitions between atomic ground states. Compared to the motional-state coupling, the new scheme enables to couple atoms to high-frequency structures such as optomechanical crystals.

  20. Generation of a cold pulsed beam of Rb atoms by transfer from a 3D magneto-optic trap

    Energy Technology Data Exchange (ETDEWEB)

    Chanu, Sapam Ranjita; Rathod, Ketan D.; Natarajan, Vasant, E-mail: vasant@physics.iisc.ernet.in

    2016-08-26

    We demonstrate a technique for producing a cold pulsed beam of atoms by transferring a cloud of atoms trapped in a three dimensional magneto-optic trap (MOT). The MOT is loaded by heating a getter source of Rb atoms. We show that it is advantageous to transfer with two beams (with a small angle between them) compared to a single beam, because the atoms stop interacting with the beams in the two-beam technique, which results in a Gaussian velocity distribution. The atoms are further cooled in optical molasses by turning off the MOT magnetic field before the transfer beams are turned on. - Highlights: • Getter-source loaded magneto-optic trap (MOT). • Cold atomic beam generated by deflection from the MOT. • Use of two inclined beams for deflection.

  1. Cold Rydberg molecules

    Science.gov (United States)

    Raithel, Georg; Zhao, Jianming

    2017-04-01

    Cold atomic systems have opened new frontiers at the interface of atomic and molecular physics. These include research on novel types of Rydberg molecules. Three types of molecules will be reviewed. Long-range, homonuclear Rydberg molecules, first predicted in [1] and observed in [2], are formed via low-energy electron scattering of the Rydberg electron from a ground-state atom within the Rydberg atom's volume. The binding mostly arises from S- and P-wave triplet scattering. We use a Fermi model that includes S-wave and P-wave singlet and triplet scattering, the fine structure coupling of the Rydberg atom and the hyperfine structure coupling of the 5S1/2 atom (in rubidium [3]). The hyperfine structure gives rise to mixed singlet-triplet potentials for both low-L and high-L Rydberg molecules [3]. A classification into Hund's cases [3, 4, 5] will be discussed. The talk further includes results on adiabatic potentials and adiabatic states of Rydberg-Rydberg molecules in Rb and Cs. These molecules, which have even larger bonding length than Rydberg-ground molecules, are formed via electrostatic multipole interactions. The leading interaction term of neutral Rydberg-Rydberg molecules is between two dipoles, while for ionic Rydberg molecules it is between a dipole and a monopole. NSF (PHY-1506093), NNSF of China (61475123).

  2. First-principles many-body theory for ultra-cold atoms

    International Nuclear Information System (INIS)

    Drummond, Peter D.; Hu Hui; Liu Xiaji

    2010-01-01

    Recent breakthroughs in the creation of ultra-cold atoms in the laboratory have ushered in unprecedented changes in physical science. These enormous changes in the coldest temperatures available in the laboratory mean that many novel experiments are possible. There is unprecedented control and simplicity in these novel systems, meaning that quantum many-body theory is now facing severe challenges in quantitatively understanding these new results. We discuss some of the new experiments and recently developed theoretical techniques required to predict the results obtained.

  3. Strong Anderson localization in cold atom quantum quenches.

    Science.gov (United States)

    Micklitz, T; Müller, C A; Altland, A

    2014-03-21

    Signatures of Anderson localization in the momentum distribution of a cold atom cloud after a quantum quench are studied. We consider a quasi-one-dimensional cloud initially prepared in a well-defined momentum state, and expanding for some time in a disorder speckle potential. Quantum interference generates a peak in the forward scattering amplitude which, unlike the common weak localization backscattering peak, is a signature of strong Anderson localization. We present a nonperturbative, and fully time resolved description of the phenomenon, covering the entire diffusion-to-localization crossover. Our results should be observable by present day experiments.

  4. Trace mercury determination in drinking and natural water after preconcentration and separation by DLLME-SFO method coupled with cold vapor atomic absorption spectrometry

    OpenAIRE

    Abdollahi Atousa; Amirkavehei Mooud; Gheisari Mohammad Mehdi; Tadayon Fariba

    2014-01-01

    A novel dispersive liquid–liquid microextraction based on solidification of floating organic drop (DLLME-SFO) for simultaneous separation/preconcentration of ultra trace amounts of mercury was used. A method based on amalgamation was used for collection of gaseous mercury on gold coated sand (Gold trap). The concentration of mercury was determined by cold vapor atomic absorption spectrometry (CV-AAS). The DLLME-SFO behavior of mercury by using dithizone as complexing agent was systematically ...

  5. Enhancing optical nonreciprocity by an atomic ensemble in two coupled cavities

    Science.gov (United States)

    Song, L. N.; Wang, Z. H.; Li, Yong

    2018-05-01

    We study the optical nonreciprocal propagation in an optical molecule of two coupled cavities with one of them interacting with a two-level atomic ensemble. The effect of increasing the number of atoms on the optical isolation ratio of the system is studied. We demonstrate that the significant nonlinearity supplied by the coupling of the atomic ensemble with the cavity leads to the realization of greatly-enhanced optical nonreciprocity compared with the case of single atom.

  6. Einstein-Podolsky-Rosen Entanglement of Narrowband Photons from Cold Atoms

    OpenAIRE

    Lee, Jong-Chan; Park, Kwang-Kyoon; Zhao, Tian-Ming; Kim, Yoon-Ho

    2016-01-01

    Einstein-Podolsky-Rosen (EPR) entanglement introduced in 1935 deals with two particles that are entangled in their positions and momenta. Here we report the first experimental demonstration of EPR position-momentum entanglement of narrowband photon pairs generated from cold atoms. By using two-photon quantum ghost imaging and ghost interference, we demonstrate explicitly that the narrowband photon pairs violate the separability criterion, confirming EPR entanglement. We further demonstrate co...

  7. Realistic Rashba and Dresselhaus spin-orbit coupling for neutral atoms

    International Nuclear Information System (INIS)

    Campbell, D. L.; Spielman, I. B.; Juzeliunas, G.

    2011-01-01

    We describe a new class of atom-laser coupling schemes which lead to spin-orbit-coupled Hamiltonians for ultracold neutral atoms. By properly setting the optical phases, a pair of degenerate pseudospin (a linear combination of internal atomic) states emerge as the lowest-energy eigenstates in the spectrum and are thus immune to collisionally induced decay. These schemes use N cyclically coupled ground or metastable internal states. We focus on two situations: a three-level case and a four-level case, where the latter adds a controllable Dresselhaus contribution. We describe an implementation of the four-level scheme for 87 Rb and analyze its sensitivity to typical laboratory noise sources. Last, we argue that the Rashba Hamiltonian applies only in the large intensity limit since any laser coupling scheme will produce terms nonlinear in momentum that decline with intensity.

  8. Polarization-dependent spectra in the photoassociative ionization of cold atoms in a bright sodium beam

    International Nuclear Information System (INIS)

    Ramirez-Serrano, Jaime; DeGraffenreid, William; Weiner, John

    2002-01-01

    We report measurements of cold photoassociative ionization (PAI) spectra obtained from collisions within a slow, bright Na atomic beam. A high-brightness atom flux, obtained by optical cooling and focusing of the atom beam, permits a high degree of alignment and orientation of binary collisions with respect to the laboratory atom-beam axis. The results reveal features of PAI spectra not accessible in conventional magneto-optical trap studies. We take advantage of this high degree of alignment to selectively excite autoionizing doubly excited states of specific symmetry

  9. Intensity enhancement of cold neutrons from a coupled liquid-hydrogen moderator for pulsed cold neutron sources

    International Nuclear Information System (INIS)

    Ogawa, Y.; Kiyanagi, Y.; Kosugi, N.; Iwasa, H.; Furusaka, M.; Watanabe, N.

    1999-01-01

    In order to obtain higher cold neutron intensity from a coupled liquid-hydrogen moderator with a premoderator for pulsed cold neutron sources, we examined a partial enhancement method, namely, narrow beam extraction for both a flat liquid-hydrogen moderator and a single-groove one. Combined with the narrow beam extraction, which is especially suitable for small-angle scattering and neutron reflectometry experiments, a single-groove moderator provides higher intensity, by about 30%, than a flat-surface moderator at the region of interest on a viewed surface. The effect of double-side beam extraction from such moderators on the intensity gain factor is also discussed. (author)

  10. Intense source of cold cesium atoms based on a two-dimensional magneto–optical trap with independent axial cooling and pushing

    International Nuclear Information System (INIS)

    Huang Jia-Qiang; Wu Chen-Fei; Wang Li-Jun; Yan Xue-Shu; Zhang Jian-Wei

    2016-01-01

    We report our studies on an intense source of cold cesium atoms based on a two-dimensional (2D) magneto–optical trap (MOT) with independent axial cooling and pushing. The new-designed source, proposed as 2D-HP MOT, uses hollow laser beams for axial cooling and a thin pushing laser beam to extract a cold atomic beam. With the independent pushing beam, the atomic flux can be substantially optimized. The total atomic flux maximum obtained in the 2D-HP MOT is 4.02 × 10 10 atoms/s, increased by 60 percent compared to the traditional 2D + MOT in our experiment. Moreover, with the pushing power 10 μW and detuning 0 Γ , the 2D-HP MOT can generate a rather intense atomic beam with the concomitant light shift suppressed by a factor of 20. The axial velocity distribution of the cold cesium beams centers at 6.8 m/s with an FMHW of about 2.8 m/s. The dependences of the atomic flux on the pushing power and detuning are studied in detail. The experimental results are in good agreement with the theoretical model. (paper)

  11. Strong coupling effects between a meta-atom and MIM nanocavity

    Directory of Open Access Journals (Sweden)

    San Chen

    2012-09-01

    Full Text Available In this paper, we investigate the strong coupling effects between a meta-atom and a metal-insulator-metal (MIM nanocavity. By changing the meta-atom sizes, we achieve the meta-atomic electric dipole, quadrupole or multipole interaction with the plasmonic nanocavity, in which characteristic anticrossing behaviors demonstrate the occurrence of the strong coupling. The various interactions present obviously different splitting values and behaviors of dependence on the meta-atomic position. The largest Rabi-type splittings, about 360.0 meV and 306.1 meV, have been obtained for electric dipole and quadrupole interaction, respectively. We attribute the large splitting to the highly-confined cavity mode and the large transition dipole of the meta-atom. Also the Rabi-type oscillation in time domain is given.

  12. Detection of cold gas releases in space via low energy neutral atom imaging

    International Nuclear Information System (INIS)

    McComas, D.J.; Funsten, H.O.; Moore, K.R.; Scime, E.E.; Thomsen, M.F.

    1993-01-01

    Low energy neutral atoms (LENAs) are produced in space plasmas by charge exchange between the ambient magnetospheric plasma ions and cold neutral atoms. Under normal conditions these cold neutrals come from the terrestrial geocorona, a shroud of few-eV hydrogen atoms surrounding the Earth. As a consequence of this charge exchange, it has become possible to remotely image many regions of the magnetosphere for the first time utilizing recently developed LENA imaging technology. In addition to the natural hydrogen geocorona, conventional explosions and maneuvering thruster firings can also introduce large amounts of cold gas into the space environment. In this paper the authors examine whether such potentially clandestine activities could also be remotely observed for the first time via LENA imaging. First, they examine the fluxes of LENAs produced in the space environment from a conventional explosion. Then they review the present state of the art in the emerging field of LENA detection and imaging. Recent work has shown that LENAs can be imaged by first converting the neutrals to ions with ultra-thin (10s of angstrom) foils and then electrostatically analyzing these newly created ions to reject the large (> 10 10 cm -2 s -1 ) UV background to which the low energy detectors are sensitive. They conclude that the sensitivities for present LENA imager designs may be just adequate for detecting some man-made releases. With additional improvements in LENA detection capabilities, this technique could become an important new method for monitoring for conventional explosions, as well as other man-made neutral releases, in the space environment

  13. Simulation and detection of massive Dirac fermions with cold atoms in one-dimensional optical lattice

    Energy Technology Data Exchange (ETDEWEB)

    Yu Yafei, E-mail: yfyuks@hotmail.com [Laboratory of Nanophotonic Functional Materials and Devices, LQIT and SIPSE, South China Normal University, Guangzhou 510006 (China); Shan Chuanjia [Laboratory of Nanophotonic Functional Materials and Devices, LQIT and SIPSE, South China Normal University, Guangzhou 510006 (China); College of Physics and Electronic Science, Hubei Normal University, Huangshi 435002 (China); Mei Feng; Zhang Zhiming [Laboratory of Nanophotonic Functional Materials and Devices, LQIT and SIPSE, South China Normal University, Guangzhou 510006 (China)

    2012-09-15

    We propose a simple but feasible experimental scheme to simulate and detect Dirac fermions with cold atoms trapped in one-dimensional optical lattice. In our scheme, through tuning the laser intensity, the one-dimensional optical lattice can have two sites in each unit cell and the atoms around the low energy behave as massive Dirac fermions. Furthermore, we show that these relativistic quasiparticles can be detected experimentally by using atomic density profile measurements and Bragg scattering.

  14. Dynamic generation and coherent control of beating stationary light pulses by a microwave coupling field in five-level cold atoms

    Science.gov (United States)

    Bao, Qian-Qian; Zhang, Yan; Cui, Cui-Li; Meng, Shao-Ying; Fang, You-Wei; Tian, Xue-Dong

    2018-04-01

    We propose an efficient scheme for generating and controlling beating stationary light pulses in a five-level atomic sample driven into electromagnetically induced transparency condition. This scheme relies on an asymmetrical procedure of light storage and retrieval tuned by two counter-propagating control fields where an additional coupling field, such as the microwave field, is introduced in the retrieval stage. A quantum probe field, incident upon such an atomic sample, is first transformed into spin coherence excitation of the atoms and then retrieved as beating stationary light pulses exhibiting a series of maxima and minima in intensity due to the alternative constructive and destructive interference. It is convenient to control the beating stationary light pulses just by manipulating the intensity and detuning of the additional microwave field. This interesting phenomenon involves in fact the coherent manipulation of dark-state polaritons and could be explored to achieve the efficient temporal splitting of stationary light pulses and accurate measurement of the microwave intensity.

  15. Cold beam of isotopically pure Yb atoms by deflection using 1D ...

    Indian Academy of Sciences (India)

    Cold atoms [1], with their long measurement times, promise to revolutionize the field of precision measurements. In this respect, laser-cooled Yb constitutes a useful species because its spin-zero ground state obviates the need for a second re-pumping laser, as is required for laser cooling of the more common spin-half ...

  16. Destructive Interference in Coherent Backscattering of Light by an Ensemble of Cold Atoms

    International Nuclear Information System (INIS)

    Kupriyanov, D.V.; Larionov, N.V.; Sokolov, I.M.; Havey, M.D.

    2005-01-01

    The coherent backscattering of light by an ensemble of cold atoms located in a magneto-optical trap is investigated theoretically. The dependence of the gain coefficient on the probe frequency is analyzed in a wide spectral range covering the entire hyperfine structure of the excited state. The calculation is performed for 85 Rb atoms. It is found that destructive interference can be observed at certain frequencies, which results in gain coefficients smaller than unity. The angular distribution of scattered light is investigated for corresponding frequencies and the dependence of the shape of the cone of destructive interference on the size of the atomic cloud and its optical thickness is analyzed

  17. Cross-channel coupling in positron-atom scattering

    International Nuclear Information System (INIS)

    McAlinden, M.T.; Kernoghan, A.A.; Walters, H.R.J.

    1994-01-01

    Coupled-state calculations including positronium channels are reported for positron scattering by atomic hydrogen, lithium and sodium. Integrated cross sections and total cross sections are presented for all three atoms. For lithium differential cross sections are also given. Throughout, comparison is made between results calculated with and without inclusion of the positronium channels. S-wave cross sections for positron scattering by atomic hydrogen in the Ps(1s, 2s, 2p) + H(1s, 2s, 2p) approximation show the high energy resonance first observed by Higgins and Burke in the coupled-static approximation. This resonance has now moved up to 51.05 eV and narrowed in width to 2.92 eV. Other pronounced structure is seen in the S-wave cross sections between 10 and 20 eV; it is tentatively suggested that this structure may be due to the formation of a temporary pseudo-molecular collision complex. Results calculated in the Ps(1s, 2s, anti 3 anti s, anti 4 anti s, 2p, anti 3 anti p, anti 4 anti p, anti 3 anti d, anti 4 anti d) + H(1s, 2s, anti 3 anti s, anti 4 anti s, 2p, anti 3 anti p, anti 4 anti p, anti 3 anti d, anti 4 anti d) approximation show convergence towards accurate values in the energy region below and in the Ore gap. Contrary to previous work on lithium using only an atomic basis, it is found that coupling to the 3d state of lithium is not so important when positronium channels are included; this is because a mixed basis of atom and positronium states gives a more rapidly convergent approximation than an expansion based on atom states alone. The threshold behaviour of the elastic cross section and the Ps(1s) formation cross section for lithium is investigated. Results in the Ps(1s, 2s, 2p) + Na(3s, 3p) approximation for sodium show good agreement with the total cross section measurements of Kwan et al. (orig.)

  18. Three Dimensional Imaging of Cold Atoms in a Magneto Optical Trap with a Light Field Microscope

    Science.gov (United States)

    2017-09-14

    with a Light Field Microscope Gordon E. Lott Follow this and additional works at: https://scholar.afit.edu/etd Part of the Atomic, Molecular and......https://scholar.afit.edu/etd/774 THREE-DIMENSIONAL IMAGING OF COLD ATOMS IN A MAGNETO-OPTICAL TRAP WITH A LIGHT FIELD MICROSCOPE DISSERTATION Gordon E

  19. Speciation of methylmercury and ethylmercury by gas chromatography cold vapor atomic fluresence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Boggess, A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-09-28

    Existing models and simulants of tank disposition media at SRS have presumed the presence of high concentrations of inorganic mercury. However, recent quarterly tank analyses show that mercury is present as organomercurial species at concentrations that may present challenges to remediation and disposition and may exceed the Saltstone Waste Acceptance Criteria (WAC). To-date, methylmercury analysis for Savannah River Remediation (SRR) has been performed off-site by Eurofins Scientific (Lancaster, PA). A series of optimization and validation experiments has been performed at SRNL, which has resulted in the development of on-site organomercury speciation capabilities using purge and trap gas chromatography coupled with thermal desorption cold vapor atomic fluorescence spectroscopy (P&T GC/CVAFS). Speciation has been achieved for methylmercury, with a method reporting limit (MRL) values of 1.42 pg for methylmercury. Results obtained by SRNL from the analysis of past quarterly samples from tanks 21, 40, and 50 have demonstrated statistically indistinguishable concentration values compared with the concentration data obtained from Eurofins, while the data from SRNL has demonstrated significantly improved precision and processing time.

  20. Ultra-cold molecules in an atomic Bose-Einstein condensate

    Science.gov (United States)

    Wynar, Roahn Helden

    2000-08-01

    This thesis is about photoassociation of Bose-condensed 87Rb. Most importantly we report that state selected 87Rb2 molecules were created at rest in a condensate of 87Rb using two-photon photoassociation. Additionally, we have identified three weakly bound states of the 87Rb2 S+u3 , potential for the |1, -1> + |1, - 1> collisional channel. The binding energies of these states are 529.4 +/- .07, 636.0094 +/- .0012, and 24.24 +/- .01 MHz respectively. We have also carried out a detailed study of the density dependence of the shift and width of the two-photon lineshape. This shift and width is modeled using the theory of Bohn and Julienne [34] and in addition to the precise measurement of binding energy we also report the first measurement of an atom molecule scattering length, aam, which we conclude is -180 +/- 150 a0, and the inelastic collision rate, Kinel dependent coherent coupling between atoms and molecules. This theory yields two coupled equations, one for the evolution of atomic condensate amplitude and one for the evolution of molecular condensate amplitude. The nature of the atomic-molecular condensate evolution is shown to depend on six, model parameters including the coherent coupling, given by cn . The other five parameters can be interpreted as light-shifts and incoherent loss rates. We present a calculation intended to estimate the values of these six parameters for the 87Rb - 87Rb 2 system. Based on the results of this calculation we identify two locations in the 87Rb2 spectrum where coherent transfer of population from atomic condensate to molecular condensate is plausible. Finally, we examine the credibility of the theoretical model used to estimate the six parameters used by the mean field theory. By comparing the measured Stark shifts of two-color resonances with predictions based on our theoretical model we conclude that the model is satisfactory for the v = 37 level of the S+u3 potential. This work also describes the experimental details of

  1. Theory of the time orbiting potential (TOP) quadrupole magnetic trap for cold atoms

    Energy Technology Data Exchange (ETDEWEB)

    Minogin, V.G.; Richmond, J.A.; Opat, G.I.

    1997-12-31

    An analytical theory of the time orbiting potential (TOP) quadrupole magnetic trap for cold atoms is developed. It is shown that the rotating magnetic filed used to create the time-average harmonic potential is responsible for the formation of quasi-energy states of an atom in the trap. It is found that the motion of an atom near the origin of the trap can be represented as consisting of slow motion in the effective potential and fast oscillations with small amplitude. Dipole, quadrupole and higher order atomic transitions between quasi-energy states are shown to be responsible for an additional effective potential for slow atomic motion which is proportional to the fourth power of the atomic co-ordinate. Eigenstates and eigenfunctions are used to calculate the co-ordinate distribution for a single atom. It is concluded that at low temperature the quantum statistical co-ordinate distribution for a single atom exhibits a narrow central peak due to the ground state population, together with relatively broad wings due to the excited state population. (authors). 20 refs., 1 tab., 6 figs.

  2. Information entropy properties of the atoms in the system of coupled Λ-type three-level atoms interacting with coherent field in Kerr medium

    International Nuclear Information System (INIS)

    Li Ke; Ling Weijun

    2011-01-01

    The information entropy properties of the atoms of coupled Λ-type three-level atoms interacting with coherent field are studied by means of quantum theory, and discussed the time evolutions of the information entropy of the atoms via the average photon number, initial state of the atoms, detuning, coupling constant between the atoms and the coefficient of Kerr medium. Numerical calculation results show that the time evolutions of the information entropy properties of the atoms strongly dependent on the initial state of the system and the average photon number. Detuning, coupling constant between the atoms and the Kerr coefficient still make influence on the information entropy of the atoms. (authors)

  3. Engineering the Eigenstates of Coupled Spin-1/2 Atoms on a Surface.

    Science.gov (United States)

    Yang, Kai; Bae, Yujeong; Paul, William; Natterer, Fabian D; Willke, Philip; Lado, Jose L; Ferrón, Alejandro; Choi, Taeyoung; Fernández-Rossier, Joaquín; Heinrich, Andreas J; Lutz, Christopher P

    2017-12-01

    Quantum spin networks having engineered geometries and interactions are eagerly pursued for quantum simulation and access to emergent quantum phenomena such as spin liquids. Spin-1/2 centers are particularly desirable, because they readily manifest coherent quantum fluctuations. Here we introduce a controllable spin-1/2 architecture consisting of titanium atoms on a magnesium oxide surface. We tailor the spin interactions by atomic-precision positioning using a scanning tunneling microscope (STM) and subsequently perform electron spin resonance on individual atoms to drive transitions into and out of quantum eigenstates of the coupled-spin system. Interactions between the atoms are mapped over a range of distances extending from highly anisotropic dipole coupling to strong exchange coupling. The local magnetic field of the magnetic STM tip serves to precisely tune the superposition states of a pair of spins. The precise control of the spin-spin interactions and ability to probe the states of the coupled-spin network by addressing individual spins will enable the exploration of quantum many-body systems based on networks of spin-1/2 atoms on surfaces.

  4. Microfabricated Waveguide Atom Traps.

    Energy Technology Data Exchange (ETDEWEB)

    Jau, Yuan-Yu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-09-01

    A nanoscale , microfabricated waveguide structure can in - principle be used to trap atoms in well - defined locations and enable strong photon-atom interactions . A neutral - atom platform based on this microfabrication technology will be prealigned , which is especially important for quantum - control applications. At present, there is still no reported demonstration of evanescent - field atom trapping using a microfabricated waveguide structure. We described the capabilities established by our team for future development of the waveguide atom - trapping technology at SNL and report our studies to overcome the technical challenges of loading cold atoms into the waveguide atom traps, efficient and broadband optical coupling to a waveguide, and the waveguide material for high - power optical transmission. From the atomic - physics and the waveguide modeling, w e have shown that a square nano-waveguide can be utilized t o achieve better atomic spin squeezing than using a nanofiber for first time.

  5. Control of the dynamics of coupled atomic-molecular Bose-Einstein condensates: Modified Gross-Pitaevskii approach

    International Nuclear Information System (INIS)

    Gupta, Moumita; Dastidar, Krishna Rai

    2009-01-01

    We study the dynamics of the atomic and molecular Bose-Einstein condensates (BECs) of 87 Rb in a spherically symmetric trap coupled by stimulated Raman photoassociation process. Considering the higher order nonlinearity in the atom-atom interaction we analyze the dynamics of the system using coupled modified Gross-Pitaevskii (MGP) equations and compare it with mean-field coupled Gross-Pitaevskii (GP) dynamics. Considerable differences in the dynamics are obtained in these two approaches at large scattering length, i.e., for large values of peak-gas parameter x pk ≥10 -3 . We show how the dynamics of the coupled system is affected when the atom-molecule and molecule-molecule interactions are considered together with the atom-atom interaction and also when the strengths of these three interactions are increased. The effect of detuning on the efficiency of conversion of atomic fractions into molecules is demonstrated and the feasibility of maximum molecular BEC formation by varying the Raman detuning parameter at different values of time is explored. Thus by varying the Raman detuning and the scattering length for atom-atom interaction one can control the dynamics of the coupled atomic-molecular BEC system. We have also solved coupled Gross-Pitaevskii equations for atomic to molecular condensate formation through magnetic Feshbach resonance in a BEC of 85 Rb. We found similar features for oscillations between atomic and molecular condensates noted in previous theoretical study and obtained fairly good agreement with the evolution of total atomic condensate observed experimentally.

  6. Resonant atom-field interaction in large-size coupled-cavity arrays

    International Nuclear Information System (INIS)

    Ciccarello, Francesco

    2011-01-01

    We consider an array of coupled cavities with staggered intercavity couplings, where each cavity mode interacts with an atom. In contrast to large-size arrays with uniform hopping rates where the atomic dynamics is known to be frozen in the strong-hopping regime, we show that resonant atom-field dynamics with significant energy exchange can occur in the case of staggered hopping rates even in the thermodynamic limit. This effect arises from the joint emergence of an energy gap in the free photonic dispersion relation and a discrete frequency at the gap's center. The latter corresponds to a bound normal mode stemming solely from the finiteness of the array length. Depending on which cavity is excited, either the atomic dynamics is frozen or a Jaynes-Cummings-like energy exchange is triggered between the bound photonic mode and its atomic analog. As these phenomena are effective with any number of cavities, they are prone to be experimentally observed even in small-size arrays.

  7. Spontaneous excitation of a circularly accelerated atom coupled to electromagnetic vacuum fluctuations

    International Nuclear Information System (INIS)

    Jin, Yao; Hu, Jiawei; Yu, Hongwei

    2014-01-01

    We study, using the formalism proposed by Dalibard, Dupont-Roc and Cohen-Tannoudji, the contributions of the vacuum fluctuation and radiation reaction to the rate of change of the mean atomic energy for a circularly accelerated multilevel atom coupled to vacuum electromagnetic fields in the ultrarelativistic limit. We find that the balance between vacuum fluctuation and radiation reaction is broken, which causes spontaneous excitations of accelerated ground state atoms in vacuum. Unlike for a circularly accelerated atom coupled to vacuum scalar fields, the contribution of radiation reaction is also affected by acceleration, and this term takes the same form as that of a linearly accelerated atom coupled to vacuum electromagnetic fields. For the contribution of vacuum fluctuations, we find that in contrast to the linear acceleration case, terms proportional to the Planckian factor are replaced by those proportional to a non-Planck exponential term, and this indicates that the radiation perceived by a circularly orbiting observer is no longer thermal as is in the linear acceleration case. However, for an ensemble of two-level atoms, an effective temperature can be defined in terms of the atomic transition rates, which is found to be dependent on the transition frequency of the atom. Specifically, we calculate the effective temperature as a function of the transition frequency and find that in contrast to the case of circularly accelerated atoms coupled to the scalar field, the effective temperature in the current case is always larger than the Unruh temperature. -- Highlights: •We study the spontaneous excitation of a circularly accelerated atom. •Contribution of radiation reaction to the excitation is affected by acceleration. •The radiation perceived by a circularly orbiting observer is no longer thermal. •An effective temperature can be defined in terms of atomic transition rates. •Effective temperature is larger than Unruh temperature and frequency-dependent

  8. Hydrogen atom kinetics in capacitively coupled plasmas

    Science.gov (United States)

    Nunomura, Shota; Katayama, Hirotaka; Yoshida, Isao

    2017-05-01

    Hydrogen (H) atom kinetics has been investigated in capacitively coupled very high frequency (VHF) discharges at powers of 16-780 mW cm-2 and H2 gas pressures of 0.1-2 Torr. The H atom density has been measured using vacuum ultra violet absorption spectroscopy (VUVAS) with a micro-discharge hollow cathode lamp as a VUV light source. The measurements have been performed in two different electrode configurations of discharges: conventional parallel-plate diode and triode with an intermediate mesh electrode. We find that in the triode configuration, the H atom density is strongly reduced across the mesh electrode. The H atom density varies from ˜1012 cm-3 to ˜1010 cm-3 by crossing the mesh with 0.2 mm in thickness and 36% in aperture ratio. The fluid model simulations for VHF discharge plasmas have been performed to study the H atom generation, diffusion and recombination kinetics. The simulations suggest that H atoms are generated in the bulk plasma, by the electron impact dissociation (e + H2 \\to e + 2H) and the ion-molecule reaction (H2 + + H2 \\to {{{H}}}3+ + H). The diffusion of H atoms is strongly limited by a mesh electrode, and thus the mesh geometry influences the spatial distribution of the H atoms. The loss of H atoms is dominated by the surface recombination.

  9. Electromagnetically Induced Absorption (EIA) and a ``Twist'' on Nonlinear Magneto-optical Rotation (NMOR) with Cold Atoms

    Science.gov (United States)

    Kunz, Paul; Meyer, David; Quraishi, Qudsia

    2015-05-01

    Within the class of nonlinear optical effects that exhibit sub-natural linewidth features, electromagnetically induced transparency (EIT) and nonlinear magneto-optical rotation (NMOR) stand out as having made dramatic impacts on various applications including atomic clocks, magnetometry, and single photon storage. A related effect, known as electromagnetically induced absorption (EIA), has received less attention in the literature. Here, we report on the first observation of EIA in cold atoms using the Hanle configuration, where a single laser beam is used to both pump and probe the atoms while sweeping a magnetic field through zero along the beam direction. We find that, associated with the EIA peak, a ``twist'' appears in the corresponding NMOR signal. A similar twist has been previously noted by Budker et al., in the context of warm vapor optical magnetometry, and was ascribed to optical pumping through nearby hyperfine levels. By studying this feature through numerical simulations and cold atom experiments, thus rendering the hyperfine levels well resolved, we enhance the understanding of the optical pumping mechanism behind it, and elucidate its relation to EIA. Finally, we demonstrate a useful application of these studies through a simple and rapid method for nulling background magnetic fields within our atom chip apparatus.

  10. Coupling ultracold atoms to a superconducting coplanar waveguide resonator

    OpenAIRE

    Hattermann, H.; Bothner, D.; Ley, L. Y.; Ferdinand, B.; Wiedmaier, D.; Sárkány, L.; Kleiner, R.; Koelle, D.; Fortágh, J.

    2017-01-01

    We demonstrate coupling of magnetically trapped ultracold $^87$Rb ground state atoms to a coherently driven superconducting coplanar resonator on an integrated atom chip. We measure the microwave field strength in the cavity through observation of the AC shift of the hyperfine transition frequency when the cavity is driven off-resonance from the atomic transition. The measured shifts are used to reconstruct the field in the resonator, in close agreement with transmission measurements of the c...

  11. Two-body loss rates for reactive collisions of cold atoms

    Science.gov (United States)

    Cop, C.; Walser, R.

    2018-01-01

    We present an effective two-channel model for reactive collisions of cold atoms. It augments elastic molecular channels with an irreversible, inelastic loss channel. Scattering is studied with the distorted-wave Born approximation and yields general expressions for angular momentum resolved cross sections as well as two-body loss rates. Explicit expressions are obtained for piecewise constant potentials. A pole expansion reveals simple universal shape functions for cross sections and two-body loss rates in agreement with the Wigner threshold laws. This is applied to collisions of metastable 20Ne and 21Ne atoms, which decay primarily through exothermic Penning or associative ionization processes. From a numerical solution of the multichannel Schrödinger equation using the best currently available molecular potentials, we have obtained synthetic scattering data. Using the two-body loss shape functions derived in this paper, we can match these scattering data very well.

  12. Cold Atom Interferometers Used In Space (CAIUS) for Measuring the Earth's Gravity Field

    Science.gov (United States)

    Carraz, O.; Luca, M.; Siemes, C.; Haagmans, R.; Silvestrin, P.

    2016-12-01

    In the past decades, it has been shown that atomic quantum sensors are a newly emerging technology that can be used for measuring the Earth's gravity field. There are two ways of making use of that technology: One is a gravity gradiometer concept and the other is in a low-low satellite-to-satellite ranging concept. Whereas classical accelerometers typically suffer from high noise at low frequencies, Cold Atom Interferometers are highly accurate over the entire frequency range. We recently proposed a concept using cold atom interferometers for measuring all diagonal elements of the gravity gradient tensor and the full spacecraft angular velocity in order to achieve better performance than the GOCE gradiometer over a larger part of the spectrum, with the ultimate goals of determining the fine structures in the gravity field better than today. This concept relies on a high common mode rejection, which relaxes the drag free control compare to GOCE mission, and benefits from a long interaction time with the free falling clouds of atoms due to the micro gravity environment in space as opposed to the 1-g environment on-ground. Other concept is also being studied in the frame of NGGM, which relies on the hybridization between quantum and classical techniques to improve the performance of accelerometers. This could be achieved as it is realized in frequency measurements where quartz oscillators are phase locked on atomic or optical clocks. This technique could correct the spectrally colored noise of the electrostatic accelerometers in the lower frequencies. In both cases, estimation of the Earth gravity field model from the instruments has to be evaluated taking into account different system parameters such as attitude control, altitude of the satellite, time duration of the mission, etc. Miniaturization, lower consumptions and upgrading Technical Readiness Level are the key engineering challenges that have to be faced for these space quantum technologie.

  13. Generation of a cold pulsed beam of Rb atoms by transfer from a 3D magneto-optic trap

    OpenAIRE

    Chanu, Sapam Ranjita; Rathod, Ketan D.; Natarajan, Vasant

    2016-01-01

    We demonstrate a technique for producing a cold pulsed beam of atoms by transferring a cloud of atoms trapped in a three dimensional magneto-optic trap (MOT). The MOT is loaded by heating a getter source of Rb atoms. We show that it is advantageous to transfer with two beams (with a small angle between them) compared to a single beam, because the atoms stop interacting with the beams in the two-beam technique, which results in a Gaussian velocity distribution. The atoms are further cooled in ...

  14. Sensitive detection of individual neutral atoms in a strong coupling cavity QED system

    International Nuclear Information System (INIS)

    Zhang Pengfei; Zhang Yuchi; Li Gang; Du Jinjin; Zhang Yanfeng; Guo Yanqiang; Wang Junmin; Zhang Tiancai; Li Weidong

    2011-01-01

    We experimentally demonstrate real-time detection of individual cesium atoms by using a high-finesse optical micro-cavity in a strong coupling regime. A cloud of cesium atoms is trapped in a magneto-optical trap positioned at 5 mm above the micro-cavity center. The atoms fall down freely in gravitation after shutting off the magneto-optical trap and pass through the cavity. The cavity transmission is strongly affected by the atoms in the cavity, which enables the micro-cavity to sense the atoms individually. We detect the single atom transits either in the resonance or various detunings. The single atom vacuum-Rabi splitting is directly measured to be Ω = 2π × 23.9 MHz. The average duration of atom-cavity coupling of about 110 μs is obtained according to the probability distribution of the atom transits. (authors)

  15. Geneva University: Exploring Flatland with cold atoms

    CERN Document Server

    Université de Genève

    2012-01-01

    GENEVA UNIVERSITY École de physique Département de physique nucléaire et corspusculaire 24, quai Ernest-Ansermet 1211 Genève 4 Tél.: (022) 379 62 73 Fax: (022) 379 69 92   Lundi 12 mars 2012 17h00 - Ecole de Physique, Auditoire Stueckelberg « Exploring Flatland with cold atoms » Prof. Jean Dalibard Laboratoire Kastler Brossel, CNRS, Physics Department of Ecole Normale Supérieure, Paris In his world-famous novel "Flatland" published in 1884, the English writer Edwin Abbott imagined a social life in a two-dimensional world. With a very original use of geometrical notions, E. Abbott produced a unique satire of his own society. Long after Abbott's visionary allegory, Microscopic Physics has provided a practical path for the exploration of low-dimensional worlds. With the realization of quantum wells for example, it has been possible to produce two-dimensional gases of electrons. The prope...

  16. Green method for ultrasensitive determination of Hg in natural waters by electrothermal-atomic absorption spectrometry following sono-induced cold vapor generation and 'in-atomizer trapping'

    International Nuclear Information System (INIS)

    Gil, Sandra; Lavilla, Isela; Bendicho, Carlos

    2007-01-01

    Sono-induced cold vapor generation (SI-CVG) has been used for the first time in combination with a graphite furnace atomizer for determination of Hg in natural waters by electrothermal-atomic absorption spectrometry after in situ trapping onto a noble metal-pretreated platform (Pd, Pt or Rh) inserted into a graphite tube. The system allows 'in-atomizer trapping' of Hg without the use of conventional reduction reactions based on sodium borohydride or tin chloride in acid medium for cold vapor generation. The sono-induced reaction is accomplished by applying ultrasound irradiation to the sample solution containing Hg(II) in the presence of an organic compound such as formic acid. As this organic acid is partly degraded upon ultrasound irradiation to yield CO, CO 2 , H 2 and H 2 O, the amount of lab wastes is minimized and a green methodology is achieved. For this purpose, experimental variables influencing the generation/trapping process are fully investigated. The limit of detection for a 10 min trapping time and 10 mL sample volume was 0.03 μg L -1 (Integrated absorbance) and the repeatability expressed as relative standard deviation was about 3%. Carbonates and chlorides at 100 mg L -1 level caused a signal depression by 20-30%. The enhanced trapping efficiency observed with the sono-induced cold vapor generation as compared with 'in-atomizer trapping' methods employing chemical vapor generation is discussed. A reaction pathway for SI-CVG is proposed on the basis of the current knowledge for synthesis of noble metal nanoparticles by ultrasound

  17. Calculations of recombination rates for cold 4He atoms from atom-dimer phase shifts and determination of universal scaling functions

    International Nuclear Information System (INIS)

    Shepard, J. R.

    2007-01-01

    Three-body recombination rates for cold 4 He are calculated with a method which exploits the simple relationship between the imaginary part of the atom-dimer elastic scattering phase shift and the S-matrix for recombination. The elastic phase shifts are computed above breakup threshold by solving a three-body Faddeev equation in momentum space with inputs based on a variety of modern atom-atom potentials. Recombination coefficients for the HFD-B3-FCII potential agree very well with the only previously published results. Since the elastic scattering and recombination processes for 4 He are governed by 'Efimov physics', they depend on universal functions of a scaling variable. The computed recombination coefficients for potentials other than HFD-B3-FCII make it possible to determine these universal functions

  18. Unifying treatment of nonequilibrium and unstable dynamics of cold bosonic atom system with time-dependent order parameter in Thermo Field Dynamics

    International Nuclear Information System (INIS)

    Nakamura, Y.; Yamanaka, Y.

    2011-01-01

    Research highlights: → Cold atoms with time-dependent condensate in nonequilibrium Thermo Field Dynamics. → Coupled equations which describe the temporal evolution of the system are derived. → They are not the naive assemblages of presumable equations, but the self-consistently ones. → Valid even for systems with Landau or dynamical instability, and describing decays. → Transport equation has new collision term that is important in Landau instability. - Abstract: The coupled equations which describe the temporal evolution of the Bose-Einstein condensed system are derived in the framework of nonequilibrium Thermo Field Dynamics. The key element is that they are not the naive assemblages of assumed equations, but are the self-consistent ones derived by appropriate renormalization conditions. While the order parameter is time-dependent, an explicit quasiparticle picture is constructed by a time-dependent expansion. Our formulation is valid even for the system with a unstable condensate, and describes the condensate decay caused by the Landau instability as well as by the dynamical one.

  19. Charge breeding investigation in EBIS/T and collision study of ions with cold atoms for HITRAP

    Energy Technology Data Exchange (ETDEWEB)

    Sokolov, Alexey

    2010-01-29

    Highly charged ions (HCI) at low velocities or at rest are interesting systems for various atomic physics experiments. For investigations on HCI of heavy stable or radioactive nuclides the HITRAP (Highly charged Ion TRAP) decelerator facility has been set up at GSI to deliver cooled beams of HCI at an energy of 5 keV/q. The HCI are produced in a stripper foil at relativistic energies and are decelerated in several steps at ESR storage ring and HITRAP before they are delivered to experimental setups. One of the experiments is the investigation of multi-electron charge exchange in collisions of heavy HCI with cold atoms using novel MOTRIMS technique. Collision experiments on light ions from an ECR ion source colliding with cold atoms in a MOT have been performed and the results are described. An electron beam ion trap (EBIT) has been tested and optimized for commissioning of the HITRAP physics experiments. The process of charge breeding in the EBIT has been successfully studied with gaseous elements and with an alkaline element injected from an external ion source. (orig.)

  20. Charge breeding investigation in EBIS/T and collision study of ions with cold atoms for HITRAP

    International Nuclear Information System (INIS)

    Sokolov, Alexey

    2010-01-01

    Highly charged ions (HCI) at low velocities or at rest are interesting systems for various atomic physics experiments. For investigations on HCI of heavy stable or radioactive nuclides the HITRAP (Highly charged Ion TRAP) decelerator facility has been set up at GSI to deliver cooled beams of HCI at an energy of 5 keV/q. The HCI are produced in a stripper foil at relativistic energies and are decelerated in several steps at ESR storage ring and HITRAP before they are delivered to experimental setups. One of the experiments is the investigation of multi-electron charge exchange in collisions of heavy HCI with cold atoms using novel MOTRIMS technique. Collision experiments on light ions from an ECR ion source colliding with cold atoms in a MOT have been performed and the results are described. An electron beam ion trap (EBIT) has been tested and optimized for commissioning of the HITRAP physics experiments. The process of charge breeding in the EBIT has been successfully studied with gaseous elements and with an alkaline element injected from an external ion source. (orig.)

  1. Fifteen years of cold matter on the atom chip: promise, realizations, and prospects

    Science.gov (United States)

    Keil, Mark; Amit, Omer; Zhou, Shuyu; Groswasser, David; Japha, Yonathan; Folman, Ron

    2016-01-01

    Here we review the field of atom chips in the context of Bose–Einstein Condensates (BEC) as well as cold matter in general. Twenty years after the first realization of the BEC and 15 years after the realization of the atom chip, the latter has been found to enable extraordinary feats: from producing BECs at a rate of several per second, through the realization of matter-wave interferometry, and all the way to novel probing of surfaces and new forces. In addition, technological applications are also being intensively pursued. This review will describe these developments and more, including new ideas which have not yet been realized. PMID:27499585

  2. Nonlinear effects in optical pumping of a cold and slow atomic beam

    KAUST Repository

    Porfido, N.

    2015-10-12

    By photoionizing hyperfine (HF) levels of the Cs state 62P3/2 in a slow and cold atom beam, we find how their population depends on the excitation laser power. The long time (around 180μs) spent by the slow atoms inside the resonant laser beam is large enough to enable exploration of a unique atom-light interaction regime heavily affected by time-dependent optical pumping. We demonstrate that, under such conditions, the onset of nonlinear effects in the population dynamics and optical pumping occurs at excitation laser intensities much smaller than the conventional respective saturation values. The evolution of population within the HF structure is calculated by numerical integration of the multilevel optical Bloch equations. The agreement between numerical results and experiment outcomes is excellent. All main features in the experimental findings are explained by the occurrence of “dark” and “bright” resonances leading to power-dependent branching coefficients.

  3. Quantum phases of low-dimensional ultra-cold atom systems

    Science.gov (United States)

    Mathey, Ludwig G.

    2007-06-01

    In this thesis we derive and explore the quantum phases of various types of ultracold atom systems, as well as their experimental signature. The technology of cooling, trapping and manipulating ultracold atoms has advanced in an amazing fashion during the last decade, which has led to the study of many-body effects of atomic ensembles. We first consider atomic mixtures in one dimension, which show a rich structure of phases, using a Luttinger liquid description. We then go on to consider how noise correlations in time-of-flight images of one-dimensional systems can be used to draw conclusions about the many-body state that they're in. Thirdly, we consider the quantum phases of Bose-Fermi mixtures in optical lattices, either square lattices or triangular lattices, using the powerful method of functional renormalization group analysis. Lastly, we study the phases of two-coupled quasi-superfluids in two dimensions, which shows unusual phases, and which could be used to realize the Kibble-Zurek mechanism, i.e. the generation of topological defects by ramping across a phase transition, first proposed in the context of an early universe scenario.

  4. Dynamical Negative Differential Resistance in Antiferromagnetically Coupled Few-Atom Spin Chains

    Science.gov (United States)

    Rolf-Pissarczyk, Steffen; Yan, Shichao; Malavolti, Luigi; Burgess, Jacob A. J.; McMurtrie, Gregory; Loth, Sebastian

    2017-11-01

    We present the appearance of negative differential resistance (NDR) in spin-dependent electron transport through a few-atom spin chain. A chain of three antiferromagnetically coupled Fe atoms (Fe trimer) was positioned on a Cu2 N /Cu (100 ) surface and contacted with the spin-polarized tip of a scanning tunneling microscope, thus coupling the Fe trimer to one nonmagnetic and one magnetic lead. Pronounced NDR appears at the low bias of 7 mV, where inelastic electron tunneling dynamically locks the atomic spin in a long-lived excited state. This causes a rapid increase of the magnetoresistance between the spin-polarized tip and Fe trimer and quenches elastic tunneling. By varying the coupling strength between the tip and Fe trimer, we find that in this transport regime the dynamic locking of the Fe trimer competes with magnetic exchange interaction, which statically forces the Fe trimer into its high-magnetoresistance state and removes the NDR.

  5. Additive manufacturing of magnetic shielding and ultra-high vacuum flange for cold atom sensors.

    Science.gov (United States)

    Vovrosh, Jamie; Voulazeris, Georgios; Petrov, Plamen G; Zou, Ji; Gaber, Youssef; Benn, Laura; Woolger, David; Attallah, Moataz M; Boyer, Vincent; Bongs, Kai; Holynski, Michael

    2018-01-31

    Recent advances in the understanding and control of quantum technologies, such as those based on cold atoms, have resulted in devices with extraordinary metrological performance. To realise this potential outside of a lab environment the size, weight and power consumption need to be reduced. Here we demonstrate the use of laser powder bed fusion, an additive manufacturing technique, as a production technique relevant to the manufacture of quantum sensors. As a demonstration we have constructed two key components using additive manufacturing, namely magnetic shielding and vacuum chambers. The initial prototypes for magnetic shields show shielding factors within a factor of 3 of conventional approaches. The vacuum demonstrator device shows that 3D-printed titanium structures are suitable for use as vacuum chambers, with the test system reaching base pressures of 5 ± 0.5 × 10 -10 mbar. These demonstrations show considerable promise for the use of additive manufacturing for cold atom based quantum technologies, in future enabling improved integrated structures, allowing for the reduction in size, weight and assembly complexity.

  6. Nambu-Goldstone Fermion Mode in Quark-Gluon Plasma and Bose-Fermi Cold Atom System

    International Nuclear Information System (INIS)

    Satow, D.

    2015-01-01

    It was suggested that supersymmetry (SUSY) is broken at finite temperature, and as a result of the symmetry breaking, a Nambu-Goldstone fermion (goldstino) related to SUSY breaking appears. Since dispersion relations of quarks and gluons are almost degenerate at extremely high temperature, quasi-zero energy quark excitation was suggested to exist in quark-gluon plasma (QGP), though QCD does not have exact SUSY. On the other hand, in condensed matter system, a setup of cold atom system in which the Hamiltonian has SUSY was proposed, the goldstino was suggested to exist, and the dispersion relation of that mode at zero temperature was obtained recently. In this presentation, we obtain the expressions for the dispersion relation of the goldstino in cold atom system at finite temperature, and compare it with the dispersion of the quasi zero-mode in QGP. Furthermore, we show that the form of the dispersion relation of the goldstino can be understood by using an analogy with a magnon in ferromagnet. We also discuss on how the dispersion relation of the goldstino is reflected in observable quantities in experiment. (author)

  7. A compact micro-wave synthesizer for transportable cold-atom interferometers

    Energy Technology Data Exchange (ETDEWEB)

    Lautier, J.; Lours, M.; Landragin, A., E-mail: arnaud.landragin@obspm.fr [LNE-SYRTE, Observatoire de Paris, CNRS, UPMC, 61 avenue de l’Observatoire, 75014 Paris (France)

    2014-06-15

    We present the realization of a compact micro-wave frequency synthesizer for an atom interferometer based on stimulated Raman transitions, applied to transportable inertial sensing. Our set-up is intended to address the hyperfine transitions of {sup 87}Rb at 6.8 GHz. The prototype is evaluated both in the time and the frequency domain by comparison with state-of-the-art frequency references developed at Laboratoire national de métrologie et d'essais−Systémes de référence temps espace (LNE-SYRTE). In free-running mode, it features a residual phase noise level of −65 dB rad{sup 2} Hz{sup −1} at 10 Hz offset frequency and a white phase noise level in the order of −120 dB rad{sup 2} Hz{sup −1} for Fourier frequencies above 10 kHz. The phase noise effect on the sensitivity of the atomic interferometer is evaluated for diverse values of cycling time, interrogation time, and Raman pulse duration. To our knowledge, the resulting contribution is well below the sensitivity of any demonstrated cold atom inertial sensors based on stimulated Raman transitions. The drastic improvement in terms of size, simplicity, and power consumption paves the way towards field and mobile operations.

  8. Saturation spectroscopy of calcium atomic vapor in hot quartz cells with cold windows

    Science.gov (United States)

    Vilshanskaya, E. V.; Saakyan, S. A.; Sautenkov, V. A.; Murashkin, D. A.; Zelener, B. B.; Zelener, B. V.

    2018-01-01

    Saturation spectroscopy of calcium atomic vapor was performed in hot quartz cells with cold windows. The Doppler-free absorption resonances with spectral width near 50 MHz were observed. For these experiments and future applications long-lived quartz cells with buffer gas were designed and made. A cooling laser for calcium magneto-optical trap will be frequency locked to the saturation resonances in the long-lived cells.

  9. Automated dispersive liquid-liquid microextraction coupled to high performance liquid chromatography - cold vapour atomic fluorescence spectroscopy for the determination of mercury species in natural water samples.

    Science.gov (United States)

    Liu, Yao-Min; Zhang, Feng-Ping; Jiao, Bao-Yu; Rao, Jin-Yu; Leng, Geng

    2017-04-14

    An automated, home-constructed, and low cost dispersive liquid-liquid microextraction (DLLME) device that directly coupled to a high performance liquid chromatography (HPLC) - cold vapour atomic fluorescence spectroscopy (CVAFS) system was designed and developed for the determination of trace concentrations of methylmercury (MeHg + ), ethylmercury (EtHg + ) and inorganic mercury (Hg 2+ ) in natural waters. With a simple, miniaturized and efficient automated DLLME system, nanogram amounts of these mercury species were extracted from natural water samples and injected into a hyphenated HPLC-CVAFS for quantification. The complete analytical procedure, including chelation, extraction, phase separation, collection and injection of the extracts, as well as HPLC-CVAFS quantification, was automated. Key parameters, such as the type and volume of the chelation, extraction and dispersive solvent, aspiration speed, sample pH, salt effect and matrix effect, were thoroughly investigated. Under the optimum conditions, linear range was 10-1200ngL -1 for EtHg + and 5-450ngL -1 for MeHg + and Hg 2+ . Limits of detection were 3.0ngL -1 for EtHg + and 1.5ngL -1 for MeHg + and Hg 2+ . Reproducibility and recoveries were assessed by spiking three natural water samples with different Hg concentrations, giving recoveries from 88.4-96.1%, and relative standard deviations <5.1%. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. High-accuracy coupled cluster calculations of atomic properties

    Energy Technology Data Exchange (ETDEWEB)

    Borschevsky, A. [School of Chemistry, Tel Aviv University, 69978 Tel Aviv, Israel and Centre for Theoretical Chemistry and Physics, The New Zealand Institute for Advanced Study, Massey University Auckland, Private Bag 102904, 0745 Auckland (New Zealand); Yakobi, H.; Eliav, E.; Kaldor, U. [School of Chemistry, Tel Aviv University, 69978 Tel Aviv (Israel)

    2015-01-22

    The four-component Fock-space coupled cluster and intermediate Hamiltonian methods are implemented to evaluate atomic properties. The latter include the spectra of nobelium and lawrencium (elements 102 and 103) in the range 20000-30000 cm{sup −1}, the polarizabilities of elements 112-114 and 118, required for estimating their adsorption enthalpies on surfaces used to separate them in accelerators, and the nuclear quadrupole moments of some heavy atoms. The calculations on superheavy elements are supported by the very good agreement with experiment obtained for the lighter homologues.

  11. High-accuracy coupled cluster calculations of atomic properties

    International Nuclear Information System (INIS)

    Borschevsky, A.; Yakobi, H.; Eliav, E.; Kaldor, U.

    2015-01-01

    The four-component Fock-space coupled cluster and intermediate Hamiltonian methods are implemented to evaluate atomic properties. The latter include the spectra of nobelium and lawrencium (elements 102 and 103) in the range 20000-30000 cm −1 , the polarizabilities of elements 112-114 and 118, required for estimating their adsorption enthalpies on surfaces used to separate them in accelerators, and the nuclear quadrupole moments of some heavy atoms. The calculations on superheavy elements are supported by the very good agreement with experiment obtained for the lighter homologues

  12. Determination of mercury by multisyringe flow injection system with cold-vapor atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Leal, L.O.; Elsholz, O.; Forteza, R.; Cerda, V.

    2006-01-01

    A new software-controlled time-based multisyringe flow injection system for mercury determination by cold-vapor atomic absorption spectrometry is proposed. Precise known volumes of sample, reducing agent (1.1% SnCl 2 in 3% HCl) and carrier (3% HCl) are dispensed into a gas-liquid separation cell with a multisyringe burette coupled with one three-way solenoid valve. An argon flow delivers the reduced mercury to the spectrometer. The optimization of the system was carried out testing reaction coils and gas-liquid separators of different design as well as changing parameters, such as sample and reagents volumes, reagent concentrations and carrier gas flow rate, among others. The analytical curves were obtained within the range 50-5000 ng L -1 . The detection limit (3σ b /S) achieved is 5 ng L -1 . The relative standard deviation (R.S.D.) was 1.4%, evaluated from 16 successive injections of 250 ng L -1 Hg standard solution. The injection and sample throughput per hour were 44 and 11, respectively. This technique was validated by means of solid and water reference materials with good agreement with the certified values and was successfully applied to fish samples

  13. Transfer behavior of quantum states between atoms in photonic crystal coupled cavities

    International Nuclear Information System (INIS)

    Zhang Ke; Li Zhiyuan

    2010-01-01

    In this article, we discuss the one-excitation dynamics of a quantum system consisting of two two-level atoms each interacting with one of two coupled single-mode cavities via spontaneous emission. When the atoms and cavities are tuned into resonance, a wide variety of time-evolution behaviors can be realized by modulating the atom-cavity coupling strength g and the cavity-cavity hopping strength λ. The dynamics is solved rigorously via the eigenproblem of an ordinary coupled linear system and simple analytical solutions are derived at several extreme situations of g and λ. In the large hopping limit where g >λ, the time-evolution behavior of the system is characterized by the usual slowly varying carrier envelope superimposed upon a fast and violent oscillation. At a certain instant, the energy is fully transferred from the one quantum subsystem to the other. When the two interaction strengths are comparable in magnitude, the dynamics acts as a continuous pulse having irregular frequency and line shape of peaks and valleys, and the complicated time-evolution behaviors are ascribed to the violent competition between all the one-excitation quantum states. The coupled quantum system of atoms and cavities makes a good model to study cavity quantum electrodynamics with great freedoms of many-body interaction.

  14. Electromagnetically induced transparency and nonlinear pulse propagation in a combined tripod and Λ atom-light coupling scheme

    International Nuclear Information System (INIS)

    Hamedi, H R; Ruseckas, J; Juzeliūnas, G

    2017-01-01

    We consider propagation of a probe pulse in an atomic medium characterized by a combined tripod and Lambda (Λ) atom-light coupling scheme. The scheme involves three atomic ground states coupled to two excited states by five light fields. It is demonstrated that dark states can be formed for such an atom-light coupling. This is essential for formation of the electromagnetically induced transparency (EIT) and slow light. In the limiting cases the scheme reduces to conventional Λ- or N -type atom-light couplings providing the EIT or absorption, respectively. Thus, the atomic system can experience a transition from the EIT to the absorption by changing the amplitudes or phases of control lasers. Subsequently the scheme is employed to analyze the nonlinear pulse propagation using the coupled Maxwell–Bloch equations. It is shown that a generation of stable slow light optical solitons is possible in such a five-level combined tripod and Λ atomic system. (paper)

  15. Super-Coulombic atom-atom interactions in hyperbolic media

    Science.gov (United States)

    Cortes, Cristian L.; Jacob, Zubin

    2017-01-01

    Dipole-dipole interactions, which govern phenomena such as cooperative Lamb shifts, superradiant decay rates, Van der Waals forces and resonance energy transfer rates, are conventionally limited to the Coulombic near-field. Here we reveal a class of real-photon and virtual-photon long-range quantum electrodynamic interactions that have a singularity in media with hyperbolic dispersion. The singularity in the dipole-dipole coupling, referred to as a super-Coulombic interaction, is a result of an effective interaction distance that goes to zero in the ideal limit irrespective of the physical distance. We investigate the entire landscape of atom-atom interactions in hyperbolic media confirming the giant long-range enhancement. We also propose multiple experimental platforms to verify our predicted effect with phonon-polaritonic hexagonal boron nitride, plasmonic super-lattices and hyperbolic meta-surfaces as well. Our work paves the way for the control of cold atoms above hyperbolic meta-surfaces and the study of many-body physics with hyperbolic media.

  16. Transport and interaction blockade of cold bosonic atoms in a triple-well potential

    International Nuclear Information System (INIS)

    Schlagheck, P; Malet, F; Cremon, J C; Reimann, S M

    2010-01-01

    We theoretically investigate the transport properties of cold bosonic atoms in a quasi-one-dimensional (1D) triple-well potential that consists of two large outer wells, which act as microscopic source and drain reservoirs, and a small inner well, which represents a quantum-dot-like scattering region. Bias and gate 'voltages' introduce a time-dependent tilt of the triple-well configuration, and are used to shift the energetic level of the inner well with respect to the outer ones. By means of exact diagonalization considering a total number of six atoms in the triple-well potential, we find diamond-like structures for the occurrence of single-atom transport in the parameter space spanned by the bias and gate voltages. We discuss the analogy with Coulomb blockade in electronic quantum dots, and point out how one can infer the interaction energy in the central well from the distance between the diamonds.

  17. Strong enhancement of Penning ionization for asymmetric atom pairs in cold Rydberg gases: the Tom and Jerry effect

    KAUST Repository

    Efimov, D K

    2016-05-18

    We consider Penning ionization of Rydberg atom pairs as an Auger-type process induced by the dipole-dipole interaction and employ semiclassical formulae for dipole transitions to calculate the autoionization width as a function of the principal quantum numbers, n d, n i, of both atoms. While for symmetric atom pairs with the well-known increase of the autoionization width with increasing n 0 is obtained, the result for asymmetric pairs is counterintuitive - for a fixed n i of the ionizing atom of the pair, the autoionization width strongly increases with decreasing n d of the de-excited atom. For H Rydberg atoms this increase reaches two orders of magnitude at the maximum of the n d dependence, and the same type of counterintuitive behavior is exhibited also by Na, Rb and Cs atoms. This is a purely quantum-mechanical effect, which points towards existence of optimal (we call them \\'Tom\\' and \\'Jerry\\' for \\'big\\' and \\'small\\') pairs of Rydberg atoms with respect to autoionization efficiency. Building on the model of population redistribution in cold Rydberg gases proposed in [1], we demonstrate that population evolution following the initial laser excitation of Rydberg atoms in state n 0 would eventually lead to the formation of such Tom-Jerry pairs with which feature autoionization widths that are enhanced by several orders of magnitude compared to that of two atoms in the initial laser-excited state n 0. We also show that in the high-density regime of cold Rydberg gas experiments the ionization rate of Tom-Jerry pairs can be substantially larger than the blackbody radiation-induced photoionization rate. © 2016 IOP Publishing Ltd.

  18. The photonics collapse-revival's of intensity-dependent coupling of lambda atoms and fields

    International Nuclear Information System (INIS)

    Hajivandi, J.; Golshan, M. M.

    2007-01-01

    In this paper, we extend the intensity-dependent coupling of the interaction of two-level atoms and an electromagnetic field, originated by Sivakumar, to that of Λ-type atoms. In addition, we assume that the interaction occurs in a Kerr medium. In the present model we allow the Λ-type atom to interact with two quantized electromagnetic fields, one of which is initially coherent while the other one is not. We thus report the effect of such coupling and the medium on the collapse-revival's of the photonic mean numbers.

  19. CrossRef Large numbers of cold positronium atoms created in laser-selected Rydberg states using resonant charge exchange

    CERN Document Server

    McConnell, R; Kolthammer, WS; Richerme, P; Müllers, A; Walz, J; Grzonka, D; Zielinski, M; Fitzakerley, D; George, MC; Hessels, EA; Storry, CH; Weel, M

    2016-01-01

    Lasers are used to control the production of highly excited positronium atoms (Ps*). The laser light excites Cs atoms to Rydberg states that have a large cross section for resonant charge-exchange collisions with cold trapped positrons. For each trial with 30 million trapped positrons, more than 700 000 of the created Ps* have trajectories near the axis of the apparatus, and are detected using Stark ionization. This number of Ps* is 500 times higher than realized in an earlier proof-of-principle demonstration (2004 Phys. Lett. B 597 257). A second charge exchange of these near-axis Ps* with trapped antiprotons could be used to produce cold antihydrogen, and this antihydrogen production is expected to be increased by a similar factor.

  20. Dynamics of atom-field probability amplitudes in a coupled cavity system with Kerr non-linearity

    Energy Technology Data Exchange (ETDEWEB)

    Priyesh, K. V.; Thayyullathil, Ramesh Babu [Department of Physics, Cochin University of Science and Technology, Cochin (India)

    2014-01-28

    We have investigated the dynamics of two cavities coupled together via photon hopping, filled with Kerr non-linear medium and each containing a two level atom in it. The evolution of various atom (field) state probabilities of the coupled cavity system in two excitation sub space are obtained numerically. Detailed analysis has been done by taking different initial conditions of the system, with various coupling strengths and by varying the susceptibility of the medium. The role of susceptibility factor, on the dynamics atom field probability has been examined. In a coupled cavity system with strong photon hopping it is found that the susceptibility factor modifies the behaviour of probability amplitudes.

  1. Observation and measurement of interaction-induced dispersive optical nonlinearities in an ensemble of cold rydberg atoms

    DEFF Research Database (Denmark)

    Parigi, V.; Bimbard, E.; Stanojevic, J.

    2012-01-01

    We observe and measure dispersive optical nonlinearities in an ensemble of cold Rydberg atoms placed inside an optical cavity. The experimental results are in agreement with a simple model where the optical nonlinearities are due to the progressive appearance of a Rydberg blockaded volume within...

  2. px+ipy Superfluid from s-Wave Interactions of Fermionic Cold Atoms

    International Nuclear Information System (INIS)

    Zhang Chuanwei; Tewari, Sumanta; Lutchyn, Roman M.; Das Sarma, S.

    2008-01-01

    Two-dimensional (p x +ip y ) superfluids or superconductors offer a playground for studying intriguing physics such as quantum teleportation, non-Abelian statistics, and topological quantum computation. Creating such a superfluid in cold fermionic atom optical traps using p-wave Feshbach resonance is turning out to be challenging. Here we propose a method to create a p x +ip y superfluid directly from an s-wave interaction making use of a topological Berry phase, which can be artificially generated. We discuss ways to detect the spontaneous Hall mass current, which acts as a diagnostic for the chiral p-wave superfluid

  3. Spontaneous emergence of free-space optical and atomic patterns

    International Nuclear Information System (INIS)

    Schmittberger, Bonnie L; Gauthier, Daniel J

    2016-01-01

    The spontaneous formation of patterns in dynamical systems is a rich phenomenon that transcends scientific boundaries. Here, we report our observation of coupled optical–atomic pattern formation, which results in the creation of self-organized, multimode structures in free-space laser-driven cold atoms. We show that this process gives rise to spontaneous three-dimensional Sisyphus cooling even at very low light intensities and the emergence of self-organized structures on both sub- and super-wavelength scales. (paper)

  4. Diesel CPO for SOFC. Development of a cold-flame assisted CPO reactor coupled to a SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Van Dijk, H.A.J.; Ouweltjes, J.P.; Nyqvist, R.G. [ECN Hydrogen and Clean Fossil Fuels, Petten (Netherlands)

    2009-07-15

    Within the research program 'Reforming of liquid fuels for fuel-cells', ECN started a project on the development of a diesel CPO (catalytic partial oxidation) reformer for SOFC (solid oxide fuel cell) in 2005. The application in mind is a small scale (5kWe) diesel fed auxiliary power unit (APU). The goal of the project is to develop the technology required to transform a liquid logistic fuel into a reformat suitable for the operation of a SOFC. The emphasis of this work is on the development of a cold-flame assisted evaporator/mixer coupled to a catalytic CPO reformer. The application of cold-flame evaporation and mixing allows the reformat to be directly fed to the SOFC without further heating or cooling. Moreover, once cold-flames are ignited and stabilized, pre-heating of the air and fuel becomes obsolete. These aspects justify the development described in this report. In the cold-flame evaporator/mixer, the cold-flames are stabilized by means of a recirculation tube. The momentum of the fuel spray of the nozzle induces the required recirculation. The cold flame evaporator/mixer was coupled to a catalytic reformer reactor, transforming the hydrocarbon+air feed into a CO+H2 rich reformate. The reformer was coupled to a SOFC to be able to verify the quality of the reformat obtained with this reformer. The SOFC therefore served as an analysis tool. Characteristically, the reformat was held at 800C all the way towards the SOFC. For this, high temperature flange connections and steel-ceramic expansion connections were successfully applied. It is demonstrated that cold-flame evaporation of liquid fuels is a feasible means of feed preparation for a catalytic reforming reactor. The quality of the resulting reformat is adequate to be fed to the SOFC. The reformat quality, however, decreased with time-on-stream due to fouling of the reformer by carbon-depositions. These carbon-depositions were essentially located on the fuel injector, which is the coldest part

  5. Examination of a proposed phonon-coupling mechanism for cold fusion

    International Nuclear Information System (INIS)

    Crawford, O.H.

    1992-01-01

    In this paper the proposed nuclear energy in an atomic lattice (NEAL) mechanism for nuclear fusion in a cathode during electrolysis of D 2 O is examined. In this mechanism, coupled harmonic motion of deuterons is supposed to lead to a reduction in the width of the Coulomb barrier for proton-deuteron (p-d) fusion in palladium, thereby substantially increasing the fusion rate. Instead, it is argued that deuteron-deuteron coupling does not have an important effect and that interaction with phonons does not enhance the p-d fusion rate

  6. Lasing by driven atoms-cavity system in collective strong coupling regime.

    Science.gov (United States)

    Sawant, Rahul; Rangwala, S A

    2017-09-12

    The interaction of laser cooled atoms with resonant light is determined by the natural linewidth of the excited state. An optical cavity is another optically resonant system where the loss from the cavity determines the resonant optical response of the system. The near resonant combination of an optical Fabry-Pérot cavity with laser cooled and trapped atoms couples two distinct optical resonators via light and has great potential for precision measurements and the creation of versatile quantum optics systems. Here we show how driven magneto-optically trapped atoms in collective strong coupling regime with the cavity leads to lasing at a frequency red detuned from the atomic transition. Lasing is demonstrated experimentally by the observation of a lasing threshold accompanied by polarization and spatial mode purity, and line-narrowing in the outcoupled light. Spontaneous emission into the cavity mode by the driven atoms stimulates lasing action, which is capable of operating as a continuous wave laser in steady state, without a seed laser. The system is modeled theoretically, and qualitative agreement with experimentally observed lasing is seen. Our result opens up a range of new measurement possibilities with this system.

  7. Speciation analysis of organomercurial compounds in Fish Tissue by capillary gas chromatography coupled to microwave-induced plasma atomic emission detection

    Directory of Open Access Journals (Sweden)

    Dorfe Díaz

    Full Text Available This paper describes a novel approach for analysis of mercury speciation in fish using gas chromatography coupled with microwave-induced plasma optical emission spectrometry (GC-MIP-OES in surfatron resonant cavity. Sample treatment was based on quantitative leaching of mercury species from fish tissue with ultrasound-assisted acid-toluene extraction. The extracted mercury species analyzed with GC-MIP-OES attained detection limits of 5 and 9 pg for methylmercury (MeHg and ethylmercury (EtHg, respectively. A complete chromatogram could be completed in 1.5 min. MeHg values obtained with GC-MIP-OES were matched with organic mercury values obtained with selective reduction cold vapour- atomic absorption spectrometry (CV-AAS.

  8. Towards the production of an ultra cold antihydrogen beam with the AEGIS apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Storey, James William, E-mail: james.storey@cern.ch [University of Zurich, Physik-Institut (Switzerland); Collaboration: AEGIS Collaboration

    2012-12-15

    The AEGIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) experiment is an international collaboration, based at CERN, with the experimental goal of performing the first direct measurement of the Earth's gravitational acceleration on antihydrogen. In the first phase of the experiment, a gravity measurement with 1% precision will be performed by passing a beam of ultra cold antihydrogen atoms through a classical Moire deflectometer coupled to a position sensitive detector. The key requirements for this measurement are the production of ultra cold (T{approx}100 mK) Rydberg state antihydrogen and the subsequent Stark acceleration of these atoms. The aim is to produce Rydberg state antihydrogen by means of the charge exchange reaction between ultra cold antiprotons (T{approx}100 mK) and Rydberg state positronium. This paper will present details of the developments necessary for the successful production of the ultra cold antihydrogen beam, with emphasis on the detector that is required for the development of these techniques. Issues covered will include the detection of antihydrogen production and temperature, as well as detection of the effects of Stark acceleration.

  9. Atomic quantum simulation of the lattice gauge-Higgs model: Higgs couplings and emergence of exact local gauge symmetry.

    Science.gov (United States)

    Kasamatsu, Kenichi; Ichinose, Ikuo; Matsui, Tetsuo

    2013-09-13

    Recently, the possibility of quantum simulation of dynamical gauge fields was pointed out by using a system of cold atoms trapped on each link in an optical lattice. However, to implement exact local gauge invariance, fine-tuning the interaction parameters among atoms is necessary. In the present Letter, we study the effect of violation of the U(1) local gauge invariance by relaxing the fine-tuning of the parameters and showing that a wide variety of cold atoms is still a faithful quantum simulator for a U(1) gauge-Higgs model containing a Higgs field sitting on sites. The clarification of the dynamics of this gauge-Higgs model sheds some light upon various unsolved problems, including the inflation process of the early Universe. We study the phase structure of this model by Monte Carlo simulation and also discuss the atomic characteristics of the Higgs phase in each simulator.

  10. Tunable superconducting resonators with integrated trap structures for coupling with ultracold atomic gases

    Energy Technology Data Exchange (ETDEWEB)

    Ferdinand, Benedikt; Wiedmaier, Dominik; Koelle, Dieter; Kleiner, Reinhold [Physikalisches Institut and Center for Quantum Science in LISA+, Universitaet Tuebingen (Germany); Bothner, Daniel [Physikalisches Institut and Center for Quantum Science in LISA+, Universitaet Tuebingen (Germany); Kavli Institute of Nanoscience, Delft University of Technology, Delft (Netherlands)

    2016-07-01

    We intend to investigate a hybrid quantum system where ultracold atomic gases play the role of a long-living quantum memory, coupled to a superconducting qubit via a coplanar waveguide transmission line resonator. As a first step we developed a resonator chip containing a Z-shaped trapping wire for the atom trap. In order to suppress parasitic resonances due to stray capacitances, and to achieve good ground connection we use hybrid superconductor - normal conductor chips. As an additional degree of freedom we add a ferroelectric capacitor making the resonators voltage-tunable. We furthermore show theoretical results on the expected coupling strength between resonator and atomic cloud.

  11. Dependence of irradiation creep on temperature and atom displacements in 20% cold worked type 316 stainless steel

    International Nuclear Information System (INIS)

    Gilbert, E.R.

    1976-04-01

    Irradiation creep studies with pressurized tubes of 20 percent cold worked Type 316 stainless steel were conducted in EBR-2. Results showed that as atom displacements are extended above 5 dpa and temperatures are increased above 375 0 C, the irradiation induced creep rate increases with both increasing atom displacements and increasing temperature. The stress exponent for irradiation induced creep remained near unity. Irradiation-induced effective creep strains up to 1.8 percent were observed without specimen failure. 13 figures

  12. Cold atoms in microscopic traps: from wires to chips

    International Nuclear Information System (INIS)

    Cassettari, D.

    2000-05-01

    This thesis reports on the experimental demonstration of magnetic guides, traps and beam splitters for neutral atoms using current carrying wires. A straight wire allows to create two basic guide configurations: the magnetic field generated by the wire alone produces a guide where atoms in a strong field seeking state perform orbits around the wire (Kepler guide); by adding an external magnetic field, atoms in a weak field seeking state are guided at the location where the external field and the field generated by the wire cancel out (side guide). Furthermore, bending the wire in various shapes allows to modify the side guide potential and hence to create a large variety of three dimensional traps. A relevant property of these potentials is that higher trapping gradients are obtained by decreasing the current flowing in the wires. As the trap is compressed, it also moves closer to the wire. This feature has allowed us to create microscopic potentials by using thin wires designed on a surface (atom chip) by means of high resolution microfabrication techniques. Wires mounted on a surface have the advantage of being more robust and able to sustain larger currents due to their thermal coupling with the substrate. In our experiment we have developed methods to load these traps and guides with laser cooled atoms. Our first investigations have been performed with free standing wires which we have used to study the Kepler guide, the side guide and a three dimensional Ioffe-Pritchard trap. In the latter we have achieved the trapping parameters required in the experiments with Bose-Einstein condensates with much reduced power consumption. In a second time we have replaced the free standing wires with an atom chip, which we have used to compress the atomic cloud in potentials with trap frequencies above 100 kHz and ground state sizes below 100 nm. Such potentials are especially interesting for quantum information proposals of performing quantum gate operations with controlled

  13. A Simplified Digestion Protocol for the Analysis of Hg in Fish by Cold Vapor Atomic Absorption Spectroscopy

    Science.gov (United States)

    Kristian, Kathleen E.; Friedbauer, Scott; Kabashi, Donika; Ferencz, Kristen M.; Barajas, Jennifer C.; O'Brien, Kelly

    2015-01-01

    Analysis of mercury in fish is an interesting problem with the potential to motivate students in chemistry laboratory courses. The recommended method for mercury analysis in fish is cold vapor atomic absorption spectroscopy (CVAAS), which requires homogeneous analyte solutions, typically prepared by acid digestion. Previously published digestion…

  14. BEAM TRANSPORT AND STORAGE WITH COLD NEUTRAL ATOMS AND MOLECULES

    Energy Technology Data Exchange (ETDEWEB)

    Walstrom, Peter L. [Los Alamos National Laboratory

    2012-05-15

    A large class of cold neutral atoms and molecules is subject to magnetic field-gradient forces. In the presence of a field, hyperfine atomic states are split into several Zeeman levels. The slopes of these curves vs. field are the effective magnetic moments. By means of optical pumping in a field, Zeeman states of neutral lithium atoms and CaH molecules with effective magnetic moments of nearly {+-} one Bohr magneton can be selected. Particles in Zeeman states for which the energy increases with field are repelled by increasing fields; particles in states for which the energy decreases with field are attracted to increasing fields. For stable magnetic confinement, field-repelled states are required. Neutral-particle velocities in the present study are on the order of tens to hundreds of m/s and the magnetic fields needed for transport and injection are on the order of in the range of 0.01-1T. Many of the general concepts of charged-particle beam transport carry over into neutral particle spin-force optics, but with important differences. In general, the role of bending dipoles in charged particle optics is played by quadrupoles in neutral particle optics; the role of quadrupoles is played by sextupoles. The neutralparticle analog of charge-exchange injection into storage rings is the use of lasers to flip the state of particles from field-seeking to field-repelled. Preliminary tracking results for two neutral atom/molecule storage ring configurations are presented. It was found that orbit instabilities limit the confinment time in a racetrack-shaped ring with discrete magnetic elements with drift spaces between them; stable behavior was observed in a toroidal ring with a continuous sextupole field. An alternative concept using a linear sextupole or octupole channel with solenoids on the ends is presently being considered.

  15. Circuit QED with qutrits: Coupling three or more atoms via virtual-photon exchange

    Science.gov (United States)

    Zhao, Peng; Tan, Xinsheng; Yu, Haifeng; Zhu, Shi-Liang; Yu, Yang

    2017-10-01

    We present a model to describe a generic circuit QED system which consists of multiple artificial three-level atoms, namely, qutrits, strongly coupled to a cavity mode. When the state transition of the atoms disobeys the selection rules the process that does not conserve the number of excitations can happen determinatively. Therefore, we can realize coherent exchange interaction among three or more atoms mediated by the exchange of virtual photons. In addition, we generalize the one-cavity-mode mediated interactions to the multicavity situation, providing a method to entangle atoms located in different cavities. Using experimentally feasible parameters, we investigate the dynamics of the model including three cyclic-transition three-level atoms, for which the two lowest energy levels can be treated as qubits. Hence, we have found that two qubits can jointly exchange excitation with one qubit in a coherent and reversible way. In the whole process, the population in the third level of atoms is negligible and the cavity photon number is far smaller than 1. Our model provides a feasible scheme to couple multiple distant atoms together, which may find applications in quantum information processing.

  16. Dimensional crossover and cold-atom realization of gapless and semi-metallic Mott insulating phases

    Science.gov (United States)

    Orth, Peter P.; Scheurer, Mathias; Rachel, Stephan

    2014-03-01

    We propose a realistic cold-atom setup which allows for a dimensional crossover from a two-dimensional quantum spin Hall insulating phase to a three-dimensional strong topological insulator phase by simply tuning the hopping between the layers. We further employ cluster slave-rotor mean-field theory to study the effect of additional Hubbard onsite interactions that give rise to various spin liquid-like phases such as gapless and semi-metallic Mott insulating states.

  17. The Atoms for Peace USIS Films: Spreading the Gospel of the "Blessing" of Atomic Energy in the Early Cold War Era

    Directory of Open Access Journals (Sweden)

    Yuka Tsuchiya

    2014-08-01

    Full Text Available In 1955, the U.S. Information Service (USIS Tokyo produced a thirty-minute documentary film Blessing of Atomic Energy in commemoration of the tenth anniversary of the Atomic bombing of Hiroshima and Nagasaki. The film introduced how the Japanese government, researchers, and companies were using radioisotopes offered by the U.S. Argonne National Laboratory for the “peaceful” purposes in agriculture, medicine, hygiene, industry, and disaster prevention. The film also showed the mechanism of atomic power generation, and explained that it was already put into practice in the U.S. and Europe. The images of Japanese people enjoying the “blessing” of the “peaceful” use of atomic energy, ten years after the traumatic experience of A-bombs, were not only shown all over Japan, but also translated into different languages and shown in many countries, including the UK, Finland, Indonesia, Sudan, and Venezuela. The film was part of some fifty educational and documentary films produced for President Eisenhower’s “Atoms for Peace” campaign – a global information dissemination programs on the U.S. leadership in the civilian use of nuclear energy. This paper will explore the roles USIS films played in disseminating information on the “peaceful” use of nuclear energy in the early Cold War era.

  18. Photon-Induced Spin-Orbit Coupling in Ultracold Atoms inside Optical Cavity

    Directory of Open Access Journals (Sweden)

    Lin Dong

    2015-05-01

    Full Text Available We consider an atom inside a ring cavity, where a plane-wave cavity field together with an external coherent laser beam induces a two-photon Raman transition between two hyperfine ground states of the atom. This cavity-assisted Raman transition induces effective coupling between atom’s internal degrees of freedom and its center-of-mass motion. In the meantime, atomic dynamics exerts a back-action to cavity photons. We investigate the properties of this system by adopting a mean-field and a full quantum approach, and show that the interplay between the atomic dynamics and the cavity field gives rise to intriguing nonlinear phenomena.

  19. Quantum effects induced by a gap in the spectrum of atom-bath coupling constants: ''Freezing'' of atomic decay and monochromatic collective radiation

    International Nuclear Information System (INIS)

    Mogilevtsev, D.S.; Kilin, S.Ya.

    1994-08-01

    A specific kind of inhibition of atomic decay (''freezing of decay) and intense monochromatic collective radiation are predicted for a single two-level atom and for a system of atoms interacting with the field bath having the gap in the spectrum of coupling constants. (author). 10 refs, 5 figs

  20. Einstein-Podolsky-Rosen Entanglement of Narrow-Band Photons from Cold Atoms

    Science.gov (United States)

    Lee, Jong-Chan; Park, Kwang-Kyoon; Zhao, Tian-Ming; Kim, Yoon-Ho

    2016-12-01

    Einstein-Podolsky-Rosen (EPR) entanglement introduced in 1935 deals with two particles that are entangled in their positions and momenta. Here we report the first experimental demonstration of EPR position-momentum entanglement of narrow-band photon pairs generated from cold atoms. By using two-photon quantum ghost imaging and ghost interference, we demonstrate explicitly that the narrow-band photon pairs violate the separability criterion, confirming EPR entanglement. We further demonstrate continuous variable EPR steering for positions and momenta of the two photons. Our new source of EPR-entangled narrow-band photons is expected to play an essential role in spatially multiplexed quantum information processing, such as, storage of quantum correlated images, quantum interface involving hyperentangled photons, etc.

  1. Einstein-Podolsky-Rosen Entanglement of Narrow-Band Photons from Cold Atoms.

    Science.gov (United States)

    Lee, Jong-Chan; Park, Kwang-Kyoon; Zhao, Tian-Ming; Kim, Yoon-Ho

    2016-12-16

    Einstein-Podolsky-Rosen (EPR) entanglement introduced in 1935 deals with two particles that are entangled in their positions and momenta. Here we report the first experimental demonstration of EPR position-momentum entanglement of narrow-band photon pairs generated from cold atoms. By using two-photon quantum ghost imaging and ghost interference, we demonstrate explicitly that the narrow-band photon pairs violate the separability criterion, confirming EPR entanglement. We further demonstrate continuous variable EPR steering for positions and momenta of the two photons. Our new source of EPR-entangled narrow-band photons is expected to play an essential role in spatially multiplexed quantum information processing, such as, storage of quantum correlated images, quantum interface involving hyperentangled photons, etc.

  2. Magnetic atom optics: mirrors, guides, traps, and chips for atoms

    Energy Technology Data Exchange (ETDEWEB)

    Hinds, E.A.; Hughes, I.G. [Sussex Centre for Optical and Atomic Physics, University of Sussex, Brighton (United Kingdom)

    1999-09-21

    For the last decade it has been possible to cool atoms to microkelvin temperatures ({approx}1 cm s{sup -1}) using a variety of optical techniques. Light beams provide the very strong frictional forces required to slow atoms from room temperature ({approx}500 m s{sup -1}). However, once the atoms are cold, the relatively weak conservative forces of static electric and magnetic fields play an important role. In our group we have been studying the interaction of cold rubidium atoms with periodically magnetized data storage media. Here we review the underlying principles of the forces acting on atoms above a suitably magnetized substrate or near current-carrying wires. We also summarize the status of experiments. These structures can be used as smooth or corrugated reflectors for controlling the trajectories of cold atoms. Alternatively, they may be used to confine atoms to a plane, a line, or a dot and in some cases to reach the quantum limit of confinement. Atoms levitated above a magnetized surface can be guided electrostatically by wires deposited on the surface. The flow and interaction of atoms in such a structure may form the basis of a new technology, 'integrated atom optics' which might ultimately be capable of realizing a quantum computer. (author)

  3. Condensation of bosons with Rashba-Dresselhaus spin-orbit coupling

    International Nuclear Information System (INIS)

    Baym, Gordon; Ozawa, Tomoki

    2014-01-01

    Cold atomic Bose-Einstein systems in the presence of simulated Rashba- Dresselhaus spin-orbit coupling exhibit novel physical features. With pure in-plane Rashba coupling the system is predicted in Bogoliubov-Hartree-Fock to have a stable Bose condensate below a critical temperature, even though the effective density of states is two-dimensional. In addition the system has a normal state at all temperatures. We review here the new physics when the system has such spin-orbit coupling, and discuss the nature of the finite temperature condensation phase transition from the normal to condensed phases.

  4. Controllable optical bistability in a three-mode optomechanical system with atom-cavity-mirror couplings

    Science.gov (United States)

    Chen, Bin; Wang, Xiao-Fang; Yan, Jia-Kai; Zhu, Xiao-Fei; Jiang, Cheng

    2018-01-01

    We theoretically investigate the optical bistable behavior in a three-mode optomechanical system with atom-cavity-mirror couplings. The effects of the cavity-pump detuning and the pump power on the bistable behavior are discussed detailedly, the impacts of the atom-pump detuning and the atom-cavity coupling strength on the bistability of the system are also explored, and the influences of the cavity-resonator coupling strength and the cavity decay rate are also taken into consideration. The numerical results demonstrate that by tuning these parameters the bistable behavior of the system can be freely switched on or off, and the threshold of the pump power for the bistability as well as the bistable region width can also be effectively controlled. These results can find potential applications in optical bistable switch in the quantum information processing.

  5. Strong enhancement of Penning ionization for asymmetric atom pairs in cold Rydberg gases: the Tom and Jerry effect

    KAUST Repository

    Efimov, D K; Miculis, K; Bezuglov, N N; Ekers, Aigars

    2016-01-01

    with which feature autoionization widths that are enhanced by several orders of magnitude compared to that of two atoms in the initial laser-excited state n 0. We also show that in the high-density regime of cold Rydberg gas experiments the ionization rate

  6. Dynamics for a two-atom two-mode intensity-dependent Raman coupled model

    Energy Technology Data Exchange (ETDEWEB)

    Singh, S., E-mail: vasudha-rnc1@rediffmail.com, E-mail: sudhhasingh@gmail.com; Gilhare, K. [Ranchi University, Department of Physics (India)

    2016-06-15

    We study the quantum dynamics of a two-atom Raman coupled model interacting with a quantized bimodal field with intensity-dependent coupling terms in a lossless cavity. The unitary transformation method used to solve the time-dependent problem also gives the eigensolutions of the interaction Hamiltonian. We study the atomic-population dynamics and dynamics of the photon statistics in the two cavity modes, and present evidence of cooperative effects in the production of antibunching and anticorrelations between the modes. We also investigate the effect of detuning on the evolution of second-order correlation functions and observe that the oscillations become more rapid for large detuning.

  7. Emission Spectrum Property of Modulated Atom-Field Coupling System

    International Nuclear Information System (INIS)

    Gao Yun-Feng; Feng Jian; Li Yue-Ke

    2013-01-01

    The emission spectrum of a two-level atom interacting with a single mode radiation field in the case of periodic oscillation coupling coefficient is investigated. A general expression for the emission spectrum is derived. The numerical results for the initial field in pure number stare are calculated. It is found that the effect of the coupling coefficient modulation on the spectral structure is very obvious in the case of a low modulation frequency and larger amplitude when the initial field is vacuum, which is potentially useful for exploring a modulated light source. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  8. Magnetic-Field Dependence of Raman Coupling Strength in Ultracold "4"0K Atomic Fermi Gas

    International Nuclear Information System (INIS)

    Huang Liang-Hui; Wang Peng-Jun; Meng Zeng-Ming; Peng Peng; Chen Liang-Chao; Li Dong-Hao; Zhang Jing

    2016-01-01

    We experimentally demonstrate the relation of Raman coupling strength with the external bias magnetic field in degenerate Fermi gas of "4"0K atoms. Two Raman lasers couple two Zeeman energy levels, whose energy splitting depends on the external bias magnetic field. The Raman coupling strength is determined by measuring the Rabi oscillation frequency. The characteristics of the Rabi oscillation is to be damped after several periods due to Fermi atoms in different momentum states oscillating with different Rabi frequencies. The experimental results show that the Raman coupling strength will decrease as the external bias magnetic field increases, which is in good agreement with the theoretical prediction. (paper)

  9. The determination, by atomic-absorption spectrophotometry, of impurities in manganese dioxide

    International Nuclear Information System (INIS)

    Balaes, G.E.E.; Robert, R.V.D.

    1981-01-01

    This report describes various methods for the determination of impurities in electrolytic manganese dioxide by atomic-absorption spectrophotometry (AAS). The sample is dissolved in a mixture of acids, any residue being ignited and retreated with acid. Several AAS methods were applied so that the analysis required to meet the specifications could be attained. These involved conventional flame AAS, AAS with electrothermal atomization (ETA), hydride generation coupled with AAS, and cold-vapour AAS. Of the elements examined, copper, iron, zinc, and lead can be determined direct with confidence with or without corrections based on recoveries obtained from spiked solutions. Nickel can be determined direct by use of the method of standard additions, and copper, nickel, and lead by ETA with the method of standard additions. Arsenic and antimony are determined by hydride generation coupled with AAS, and mercury by cold-vapour AAS. The precision of analysis (relative standard deviation) is generally less than 0,050. Values were obtained for aluminium, molybdenum, magnesium, sodium, copper, chromium, and cadmium, but the accuracy of these determinations has not been fully established

  10. Relativistic Normal Coupled-Cluster Theory for Accurate Determination of Electric Dipole Moments of Atoms: First Application to the ^{199}Hg Atom.

    Science.gov (United States)

    Sahoo, B K; Das, B P

    2018-05-18

    Recent relativistic coupled-cluster (RCC) calculations of electric dipole moments (EDMs) of diamagnetic atoms due to parity and time-reversal violating (P,T-odd) interactions, which are essential ingredients for probing new physics beyond the standard model of particle interactions, differ substantially from the previous theoretical results. It is therefore necessary to perform an independent test of the validity of these results. In view of this, the normal coupled-cluster method has been extended to the relativistic regime [relativistic normal coupled-cluster (RNCC) method] to calculate the EDMs of atoms by simultaneously incorporating the electrostatic and P,T-odd interactions in order to overcome the shortcomings of the ordinary RCC method. This new relativistic method has been applied to ^{199}Hg, which currently has a lower EDM limit than that of any other system. The results of our RNCC and self-consistent RCC calculations of the EDM of this atom are found to be close. The discrepancies between these two results on the one hand and those of previous calculations on the other are elucidated. Furthermore, the electric dipole polarizability of this atom, which has computational similarities with the EDM, is evaluated and it is in very good agreement with its measured value.

  11. Relativistic Normal Coupled-Cluster Theory for Accurate Determination of Electric Dipole Moments of Atoms: First Application to the 199Hg Atom

    Science.gov (United States)

    Sahoo, B. K.; Das, B. P.

    2018-05-01

    Recent relativistic coupled-cluster (RCC) calculations of electric dipole moments (EDMs) of diamagnetic atoms due to parity and time-reversal violating (P ,T -odd) interactions, which are essential ingredients for probing new physics beyond the standard model of particle interactions, differ substantially from the previous theoretical results. It is therefore necessary to perform an independent test of the validity of these results. In view of this, the normal coupled-cluster method has been extended to the relativistic regime [relativistic normal coupled-cluster (RNCC) method] to calculate the EDMs of atoms by simultaneously incorporating the electrostatic and P ,T -odd interactions in order to overcome the shortcomings of the ordinary RCC method. This new relativistic method has been applied to 199Hg, which currently has a lower EDM limit than that of any other system. The results of our RNCC and self-consistent RCC calculations of the EDM of this atom are found to be close. The discrepancies between these two results on the one hand and those of previous calculations on the other are elucidated. Furthermore, the electric dipole polarizability of this atom, which has computational similarities with the EDM, is evaluated and it is in very good agreement with its measured value.

  12. Induced dipole-dipole coupling between two atoms at a migration resonance

    Science.gov (United States)

    Kaur, Maninder; Mian, Mahmood

    2018-05-01

    Results of numerical simulations for the resonant energy exchange phenomenon called Migration reaction between two cold Rydberg atoms are presented. The effect of spatial interatomic distance on the onset of peculiar coherent mechanism is investigated. Observation of Rabi-like population inversion oscillation at the resonance provides a clear signature of dipole induced exchange of electronic excitations between the atoms. Further we present the results for the dependence of expectation value of the interaction hamiltonian on the interatomic distance, which is responsible for energy exchange process. The results of this observation endorse the range of inter atomic distance within which the excitation exchange process occurs completely or partially. Migration process enhance the Rydberg-Rydberg interaction in the absence of an external field, under the condition of the zero permanent dipole moments. Our next observation sheds light on the fundamental mechanism of induced electric fields initiated by the oscillating dipoles in such energy exchange processes. We explore the dependence of induced electric field on the interatomic distance and angle between the dipoles highlighting the inverse power law dependence and anisotropic property of the field. We put forward an idea to utilise the coherent energy exchange process to build efficient and fast energy transfer channels by incorporating more atoms organised at successive distances with decreasing distance gradient.

  13. Optical coupling between atomically thin black phosphorus and a two dimensional photonic crystal nanocavity

    Science.gov (United States)

    Ota, Yasutomo; Moriya, Rai; Yabuki, Naoto; Arai, Miho; Kakuda, Masahiro; Iwamoto, Satoshi; Machida, Tomoki; Arakawa, Yasuhiko

    2017-05-01

    Atomically thin black phosphorus (BP) is an emerging two dimensional (2D) material exhibiting bright photoluminescence in the near infrared region. Coupling its radiation to photonic nanostructures will be an important step toward the realization of 2D material based nanophotonic devices that operate efficiently in the near infrared region, which includes the technologically important optical telecommunication wavelength bands. In this letter, we demonstrate the optical coupling between atomically thin BP and a 2D photonic crystal nanocavity. We employed a home-build dry transfer apparatus for placing a thin BP flake on the surface of the nanocavity. Their optical coupling was analyzed through measuring cavity mode emission under optical carrier injection at room temperature.

  14. Magnetic trapping of cold bromine atoms.

    Science.gov (United States)

    Rennick, C J; Lam, J; Doherty, W G; Softley, T P

    2014-01-17

    Magnetic trapping of bromine atoms at temperatures in the millikelvin regime is demonstrated for the first time. The atoms are produced by photodissociation of Br2 molecules in a molecular beam. The lab-frame velocity of Br atoms is controlled by the wavelength and polarization of the photodissociation laser. Careful selection of the wavelength results in one of the pair of atoms having sufficient velocity to exactly cancel that of the parent molecule, and it remains stationary in the lab frame. A trap is formed at the null point between two opposing neodymium permanent magnets. Dissociation of molecules at the field minimum results in the slowest fraction of photofragments remaining trapped. After the ballistic escape of the fastest atoms, the trapped slow atoms are lost only by elastic collisions with the chamber background gas. The measured loss rate is consistent with estimates of the total cross section for only those collisions transferring sufficient kinetic energy to overcome the trapping potential.

  15. Clean Floquet Time Crystals: Models and Realizations in Cold Atoms

    Science.gov (United States)

    Huang, Biao; Wu, Ying-Hai; Liu, W. Vincent

    2018-03-01

    Time crystals, a phase showing spontaneous breaking of time-translation symmetry, has been an intriguing subject for systems far away from equilibrium. Recent experiments found such a phase in both the presence and the absence of localization, while in theories localization by disorder is usually assumed a priori. In this work, we point out that time crystals can generally exist in systems without disorder. A series of clean quasi-one-dimensional models under Floquet driving are proposed to demonstrate this unexpected result in principle. Robust time crystalline orders are found in the strongly interacting regime along with the emergent integrals of motion in the dynamical system, which can be characterized by level statistics and the out-of-time-ordered correlators. We propose two cold atom experimental schemes to realize the clean Floquet time crystals, one by making use of dipolar gases and another by synthetic dimensions.

  16. xGASS: total cold gas scaling relations and molecular-to-atomic gas ratios of galaxies in the local Universe

    Science.gov (United States)

    Catinella, Barbara; Saintonge, Amélie; Janowiecki, Steven; Cortese, Luca; Davé, Romeel; Lemonias, Jenna J.; Cooper, Andrew P.; Schiminovich, David; Hummels, Cameron B.; Fabello, Silvia; Geréb, Katinka; Kilborn, Virginia; Wang, Jing

    2018-05-01

    We present the extended GALEX Arecibo SDSS Survey (xGASS), a gas fraction-limited census of the atomic hydrogen (H I) gas content of 1179 galaxies selected only by stellar mass (M⋆ = 109-1011.5 M⊙) and redshift (0.01 new Arecibo observations of 208 galaxies, for which we release catalogues and H I spectra. In addition to extending the GASS H I scaling relations by one decade in stellar mass, we quantify total (atomic+molecular) cold gas fractions and molecular-to-atomic gas mass ratios, Rmol, for the subset of 477 galaxies observed with the IRAM 30 m telescope. We find that atomic gas fractions keep increasing with decreasing stellar mass, with no sign of a plateau down to log M⋆/M⊙ = 9. Total gas reservoirs remain H I-dominated across our full stellar mass range, hence total gas fraction scaling relations closely resemble atomic ones, but with a scatter that strongly correlates with Rmol, especially at fixed specific star formation rate. On average, Rmol weakly increases with stellar mass and stellar surface density μ⋆, but individual values vary by almost two orders of magnitude at fixed M⋆ or μ⋆. We show that, for galaxies on the star-forming sequence, variations of Rmol are mostly driven by changes of the H I reservoirs, with a clear dependence on μ⋆. Establishing if galaxy mass or structure plays the most important role in regulating the cold gas content of galaxies requires an accurate separation of bulge and disc components for the study of gas scaling relations.

  17. Analyzing quantum jumps of one and two atoms strongly coupled to an optical cavity

    DEFF Research Database (Denmark)

    Reick, Sebastian; Mølmer, Klaus; Alt, Wolfgang

    2010-01-01

    We induce quantum jumps between the hyperfine ground states of one and two cesium atoms, strongly coupled to the mode of a high-finesse optical resonator, and analyze the resulting random telegraph signals. We identify experimental parameters to deduce the atomic spin state nondestructively from ...

  18. Critical evaluation of analytical performance of atomic absorption spectrometry and inductively coupled plasma mass spectrometry for mercury determination

    International Nuclear Information System (INIS)

    Krata, A.; Bulska, E.

    2005-01-01

    The analytical performance of cold vapor atomic absorption spectrometry (CV AAS), graphite furnace atomic absorption spectrometry (GF AAS) and inductively coupled plasma mass spectrometry (ICP-MS) for mercury determination have been investigated with the use of two reference materials SRM 2710 Montana I Soil and BCR-144R (sewage sludge from domestic origin). The digestion conditions and their influence on determination of mercury have been studied. Samples were decomposed by microwave digestion in closed vessels with the use of HCl alone or mixture of HCl+HNO 3 +HF. The digestion solutions were analyzed by CV AAS using NaBH 4 as a reducing agent, by GF AAS with Pd or mixture of Pd/Rh as modifiers and by ICP-MS with Rh as internal standard. In the case of CV AAS, results were not dependent on digestion conditions. In the case of GF AAS and ICP-MS, results depended significantly on digestion conditions; in both cases, the use of the mixture of acids as defined above suppressed the signal of mercury. Therefore, in those cases, the microwave digestion with HCl is recommended. Detection limits of 0.003, 0.01 and 0.2 μg g -1 were achieved by ICP-MS, CV AAS and GF AAS, respectively

  19. Coupling thermal atomic vapor to an integrated ring resonator

    International Nuclear Information System (INIS)

    Ritter, R; Kübler, H; Pfau, T; Löw, R; Gruhler, N; Pernice, W H P

    2016-01-01

    Strongly interacting atom–cavity systems within a network with many nodes constitute a possible realization for a quantum internet which allows for quantum communication and computation on the same platform. To implement such large-scale quantum networks, nanophotonic resonators are promising candidates because they can be scalably fabricated and interconnected with waveguides and optical fibers. By integrating arrays of ring resonators into a vapor cell we show that thermal rubidium atoms above room temperature can be coupled to photonic cavities as building blocks for chip-scale hybrid circuits. Although strong coupling is not yet achieved in this first realization, our approach provides a key step towards miniaturization and scalability of atom–cavity systems. (paper)

  20. Optical trapping of cold neutral atoms using a two-color evanescent light field around a carbon nanotube

    International Nuclear Information System (INIS)

    Nga, Do Thi; Viet, Nguyen Ai; Nga, Dao Thi Thuy; Lan, Nguyen Thi Phuong

    2014-01-01

    We suggest a new schema of trapping cold atoms using a two-color evanescent light field around a carbon nanotube. The two light fields circularly polarized sending through a carbon nanotube generates an evanescent wave around this nanotube. By evanescent effect, the wave decays away from the nanotube producing a set of trapping minima of the total potential in the transverse plane as a ring around the nanotube. This schema allows capture of atoms to a cylindrical shell around the nanotube. We consider some possible boundary conditions leading to the non-trivial bound state solution. Our result will be compared to some recent trapping models and our previous trapping models.

  1. Plasma arc and cold crucible furnace vitrification for medium level waste: a review

    International Nuclear Information System (INIS)

    Poitou, S.; Fiquet, O.; Bourdeloie, C.; Gramondi, P.; Rebollo, F.; Girold, C.; Charvillat, J.P.; Boen, R.; Jouan, A.; Ladirat, C.; Nabot, J.P.; Ochem, D.; Baronnet, J.M.

    2001-01-01

    Initially developed for high-level waste reprocessing, several vitrification processes have been under study since the 80's at the French Atomic Energy Commission (CEA) for other waste categories. According to the French law concerning waste management research passed on December 30, 1991, vitrification may be applied to mixed medium-level waste. A review of processes developed at CEA is presented: cold crucible furnace heated by induced current, refractory furnace heated by nitrogen transferred arc plasma torch, and coupling of cold crucible furnace with oxygen transferred plasma arc twin torch. Furthermore, gas post-combustion has been studied with an oxygen non-transferred plasma torch. (authors)

  2. Spectral analysis for systems of atoms and molecules coupled to the quantized radiation field

    International Nuclear Information System (INIS)

    Bach, V.; Sigal, I.M.

    1999-01-01

    We consider systems of static nuclei and electrons - atoms and molecules - coupled to the quantized radiation field. The interactions between electrons and the soft modes of the quantized electromagnetic field are described by minimal coupling, p→p-eA(x), where A(x) is the electromagnetic vector potential with an ultraviolet cutoff. If the interactions between the electrons and the quantized radiation field are turned off, the atom or molecule is assumed to have at least one bound state. We prove that, for sufficiently small values of the fine structure constant α, the interacting system has a ground state corresponding to the bottom of its energy spectrum. For an atom, we prove that its excited states above the ground state turn into metastable states whose life-times we estimate. Furthermore the energy spectrum is absolutely continuous, except, perhaps,in a small interval above the ground state energy and around the threshold energies of the atom or molecule. (orig.)

  3. Optics With Cold Atoms

    National Research Council Canada - National Science Library

    Hau, Lene

    2004-01-01

    .... And to test the novel atom sensor, we have built a moving-molasses magneto-optical trap in a geometry tailor-suited to the nanotube detector geometry, involving construction of a highly stable laser...

  4. Inductively coupled plasma as atomization, excitation and ionization sources in analytical atomic spectrometry

    International Nuclear Information System (INIS)

    Kawaguchi, Hiroshi

    1996-01-01

    Studies on inductively coupled plasma (ICP) for atomic emission and mass spectrometry accomplished in our laboratory since 1978 are reviewed. In emission spectrometry, the characteristics of the plasma are studied concerning the spatial profiles of spectral line intensity, axial profiles of gas and excitation temperatures, spectral line widths and matrix effect. The studies are particularly emphasized on the instrumentation such as developments of plasma generator, emission spectrometers, water-cooled torches and sample introduction methods. A slew-scan type spectrometer developed in these works represents a predecessor of the current commercial spectrometers. An ICP mass spectrometer was first developed in Japan in this laboratory in 1984. Non-spectroscopic interference of this method was found to have the correlation with the atomic weight of the matrix element. Plasma gases other than argon such as nitrogen and oxygen were used for the ICP to evaluate their performance in mass spectrometry as for the sensitivity and interferences. (author). 63 refs

  5. A Versatile Atom Transport Apparatus for Photonics

    NARCIS (Netherlands)

    Mussmann, B.O.

    2016-01-01

    This thesis describes and characterizes a setup to conduct experiments combining the fields of cold atoms and nanophotonics. Furthermore, a series of numerical simulations is employed to deepen of atom transport under experimentally realistic conditions. The study of cold atoms is usually

  6. Rabi dynamics of coupled atomic and molecular Bose-Einstein condensates

    International Nuclear Information System (INIS)

    Ishkhanyan, Artur; Chernikov, G.P.; Nakamura, Hiroki

    2004-01-01

    The dynamics of coherent Rabi oscillations in coupled atomic and molecular Bose-Einstein condensates is considered taking into account the atom-atom, atom-molecule, and molecule-molecule elastic interactions. The exact solution for the molecule formation probability is derived in terms of the elliptic functions. The two-dimensional space of the involved parameters intensity and detuning is analyzed and divided into two regions where the Rabi oscillations show different characteristics. A resonance curve is found, on which the molecular formation probability monotonically increases as a function of time. The maximum value of the final transition probability on this curve is 1/2 (i.e., total transition to the molecular state) and it is achieved at high field intensities starting from a minimal threshold defined by the interspecies interaction scattering lights. The explicit form of the resonance curve is determined, and it is shown that the resonance frequency position reveals a nonlinear dependence on the Rabi frequency of the applied field. A singular point is found on the resonance curve, where a power-law time evolution of the system is observed

  7. ''First evaluation of the accuracy of a cesium cold atom fountain, perspectives''

    International Nuclear Information System (INIS)

    Ghezali, S.

    1997-01-01

    The present PHD thesis is, at first, a detailed description of the atomic cesium fountain 'FO1' working as a frequency standard since more than three years at the Laboratoire Primaire du Temps et des Frequences. The 'FO1' has been included in the calculation of the TA1 in the CCDS 1996. Then, this manuscript holds on the different effects such as cold collisions, inhomogeneities of the static magnetic field... affecting the fountain's accuracy, limited at 2.10 -15 because of the hydrogen maser (few hours of integration). The traverse velocity selection via stimulated Raman transitions at two dimensions constitute an important part of the present work. The possible improvements are discussed at the end of the manuscript. (author)

  8. Cadmium, copper, lead, and zinc determination in precipitation: A comparison of inductively coupled plasma atomic emission spectrometry and graphite furnace atomization atomic absorption spectrometry

    Science.gov (United States)

    Reddy, M.M.; Benefiel, M.A.; Claassen, H.C.

    1987-01-01

    Selected trace element analysis for cadmium, copper, lead, and zinc in precipitation samples by inductively coupled plasma atomic emission Spectrometry (ICP) and by atomic absorption spectrometry with graphite furnace atomization (AAGF) have been evaluated. This task was conducted in conjunction with a longterm study of precipitation chemistry at high altitude sites located in remote areas of the southwestern United States. Coefficients of variation and recovery values were determined for a standard reference water sample for all metals examined for both techniques. At concentration levels less than 10 micrograms per liter AAGF analyses exhibited better precision and accuracy than ICP. Both methods appear to offer the potential for cost-effective analysis of trace metal ions in precipitation. ?? 1987 Springer-Verlag.

  9. Dipole and quadrupole forces exerted on atoms in laser fields: The nonperturbative approach

    International Nuclear Information System (INIS)

    Sindelka, Milan; Moiseyev, Nimrod; Cederbaum, Lorenz S.

    2006-01-01

    Manipulation of cold atoms by lasers has so far been studied solely within the framework of the conventional dipole approximation, and the atom-light interaction has been treated using low order perturbation theory. Laser control of atomic motions has been ascribed exclusively to the corresponding light-induced dipole forces. In this work, we present a general theory to derive the potential experienced by an atom in a monochromatic laser field in a context analogous to the Born-Oppenheimer approximation for molecules in the field-free case. The formulation goes beyond the dipole approximation and gives rise to the field-atom coupling potential terms which so far have not been taken into consideration in theoretical or experimental studies. Contrary to conventional approaches, our method is based upon the many electron Floquet theory and remains valid also for high intensity laser fields (i.e., for a strongly nonperturbative atom-light interaction). As an illustration of the developed theory, we investigate the trapping of cold atoms in optical lattices. We find that for some atoms for specific laser parameters, despite the absence of the dipole force, the laser trapping is still possible due to the electric quadrupole forces. Namely, we show that by using realistic laser parameters one can form a quadrupole optical lattice which is sufficiently strong to trap Ca and Na atoms

  10. Time-Dependent Close-Coupling Methods for Electron-Atom/Molecule Scattering

    International Nuclear Information System (INIS)

    Colgan, James

    2014-01-01

    The time-dependent close-coupling (TDCC) method centers on an accurate representation of the interaction between two outgoing electrons moving in the presence of a Coulomb field. It has been extensively applied to many problems of electrons, photons, and ions scattering from light atomic targets. Theoretical Description: The TDCC method centers on a solution of the time-dependent Schrödinger equation for two interacting electrons. The advantages of a time-dependent approach are two-fold; one treats the electron-electron interaction essentially in an exact manner (within numerical accuracy) and a time-dependent approach avoids the difficult boundary condition encountered when two free electrons move in a Coulomb field (the classic three-body Coulomb problem). The TDCC method has been applied to many fundamental atomic collision processes, including photon-, electron- and ion-impact ionization of light atoms. For application to electron-impact ionization of atomic systems, one decomposes the two-electron wavefunction in a partial wave expansion and represents the subsequent two-electron radial wavefunctions on a numerical lattice. The number of partial waves required to converge the ionization process depends on the energy of the incoming electron wavepacket and on the ionization threshold of the target atom or ion.

  11. Engineering and control of cold molecules. Making manipulating and exploiting ultra-cold polar molecules

    International Nuclear Information System (INIS)

    Bigelow, N.P.; Haimberger, C.; Kleinert, J.; Tscherneck, M.; Holmes, M.E.

    2005-01-01

    In the last 12 months several groups have demonstrated the use of photo association to create cold heteronuclear (polar) molecules. We report on the formation of translationally cold NaCs molecules starting from a laser-cooled atomic vapor of Na and Cs atoms. Colliding atoms are transferred into bound molecular states in a two-step photoactivated process. We find a translational temperature of T ≅ 260 mK. To increase the density and number of trapped atoms, dark-spot techniques are used on the MOT and a Zeeman slowed sodium beam is used to load the sodium atoms into the trap. Spectroscopy of these molecules is underway using time-of-flight ion detection and trap-loss. Initial REMPI measurements indicate that both singlet and triplet states are being populated by the spontaneous-decay driven process. We measure a rate constant for molecule formation of K NaCs = 7.43 · 10 15 cm 3 s -1 . (author)

  12. Trace mercury determination in drinking and natural water after preconcentration and separation by DLLME-SFO method coupled with cold vapor atomic absorption spectrometry

    Directory of Open Access Journals (Sweden)

    Abdollahi Atousa

    2014-07-01

    Full Text Available A novel dispersive liquid–liquid microextraction based on solidification of floating organic drop (DLLME-SFO for simultaneous separation/preconcentration of ultra trace amounts of mercury was used. A method based on amalgamation was used for collection of gaseous mercury on gold coated sand (Gold trap. The concentration of mercury was determined by cold vapor atomic absorption spectrometry (CV-AAS. The DLLME-SFO behavior of mercury by using dithizone as complexing agent was systematically investigated. The factors influencing, the complex formation and extraction of DLLME-SFO method such as type and volume of extraction and disperser solvents, pH, concentration of salt, centrifuging time and concentration of the chelating agent were optimized. The method was successfully applied to the determination of mercury in drinking and natural water and satisfactory relative recoveries (95–105% were achieved. The proposed procedure was based on very low consumption of organic solvents. The other benefits of the system were sensitive, simple, friendly to the environment, rejection of matrix constituent, low cost, the time consuming and high enrichment factor.

  13. Strong light-matter coupling from atoms to solid-state systems

    CERN Document Server

    2014-01-01

    The physics of strong light-matter coupling has been addressed in different scientific communities over the last three decades. Since the early eighties, atoms coupled to optical and microwave cavities have led to pioneering demonstrations of cavity quantum electrodynamics, Gedanken experiments, and building blocks for quantum information processing, for which the Nobel Prize in Physics was awarded in 2012. In the framework of semiconducting devices, strong coupling has allowed investigations into the physics of Bose gases in solid-state environments, and the latter holds promise for exploiting light-matter interaction at the single-photon level in scalable architectures. More recently, impressive developments in the so-called superconducting circuit QED have opened another fundamental playground to revisit cavity quantum electrodynamics for practical and fundamental purposes. This book aims at developing the necessary interface between these communities, by providing future researchers with a robust conceptu...

  14. Experiments with Rydberg atoms on a current-carrying atom chip

    NARCIS (Netherlands)

    Cisternas San Martín, N.V.

    2018-01-01

    On one side, atom-chip experiments have demonstrated to be a versatile tool to study quantum physics in cold atoms systems. On the other side, Rydberg atoms have exaggerated properties that makes them good candidates to study quantum information and quantum simulations protocols. In this thesis both

  15. Entanglement and quantum state transfer between two atoms trapped in two indirectly coupled cavities

    Science.gov (United States)

    Zheng, Bin; Shen, Li-Tuo; Chen, Ming-Feng

    2016-05-01

    We propose a one-step scheme for implementing entanglement generation and the quantum state transfer between two atomic qubits trapped in two different cavities that are not directly coupled to each other. The process is realized through engineering an effective asymmetric X-Y interaction for the two atoms involved in the gate operation and an auxiliary atom trapped in an intermediate cavity, induced by virtually manipulating the atomic excited states and photons. We study the validity of the scheme as well as the influences of the dissipation by numerical simulation and demonstrate that it is robust against decoherence.

  16. Casimir Forces and Quantum Friction from Ginzburg Radiation in Atomic Bose-Einstein Condensates.

    Science.gov (United States)

    Marino, Jamir; Recati, Alessio; Carusotto, Iacopo

    2017-01-27

    We theoretically propose an experimentally viable scheme to use an impurity atom in an atomic Bose-Einstein condensate, in order to realize condensed-matter analogs of quantum vacuum effects. In a suitable atomic level configuration, the collisional interaction between the impurity atom and the density fluctuations in the condensate can be tailored to closely reproduce the electric-dipole coupling of quantum electrodynamics. By virtue of this analogy, we recover and extend the paradigm of electromagnetic vacuum forces to the domain of cold atoms, showing in particular the emergence, at supersonic atomic speeds, of a novel power-law scaling of the Casimir force felt by the atomic impurity, as well as the occurrence of a quantum frictional force, accompanied by the Ginzburg emission of Bogoliubov quanta. Observable consequences of these quantum vacuum effects in realistic spectroscopic experiments are discussed.

  17. Continuous measurement of an atomic current

    Science.gov (United States)

    Laflamme, C.; Yang, D.; Zoller, P.

    2017-04-01

    We are interested in dynamics of quantum many-body systems under continuous observation, and its physical realizations involving cold atoms in lattices. In the present work we focus on continuous measurement of atomic currents in lattice models, including the Hubbard model. We describe a Cavity QED setup, where measurement of a homodyne current provides a faithful representation of the atomic current as a function of time. We employ the quantum optical description in terms of a diffusive stochastic Schrödinger equation to follow the time evolution of the atomic system conditional to observing a given homodyne current trajectory, thus accounting for the competition between the Hamiltonian evolution and measurement back action. As an illustration, we discuss minimal models of atomic dynamics and continuous current measurement on rings with synthetic gauge fields, involving both real space and synthetic dimension lattices (represented by internal atomic states). Finally, by "not reading" the current measurements the time evolution of the atomic system is governed by a master equation, where—depending on the microscopic details of our CQED setups—we effectively engineer a current coupling of our system to a quantum reservoir. This provides interesting scenarios of dissipative dynamics generating "dark" pure quantum many-body states.

  18. Phonon scattering and thermal conductance properties in two coupled graphene nanoribbons modulated with bridge atoms

    International Nuclear Information System (INIS)

    Tan, Shi-Hua; Tang, Li-Ming; Chen, Ke-Qiu

    2014-01-01

    The phonon scattering and thermal conductance properties have been studied in two coupled graphene nanoribbons connected by different bridge atoms by using density functional theory in combination with non-equilibrium Green's function approach. The results show that a wide range of thermal conductance tuning can be realized by changing the chemical bond strength and atom mass of the bridge atoms. It is found that the chemical bond strength (bridge atom mass) plays the main role in phonon scattering at low (high) temperature. A simple equation is presented to describe the relationship among the thermal conductance, bridge atom, and temperature.

  19. Scattering resonances in a low-dimensional Rashba-Dresselhaus spin-orbit coupled quantum gas

    Science.gov (United States)

    Wang, Su-Ju; Blume, D.

    2017-04-01

    Confinement-induced resonances allow for the tuning of the effective one-dimensional coupling constant. When the scattering state associated with the ground transverse mode is brought into resonance with the bound state attached to the energetically excited transverse modes, the atoms interact through an infinitely strong repulsion. This provides a route to realize the Tonks-Girardeau gas. On the other hand, the realization of synthetic gauge fields in cold atomic systems has attracted a lot of attention. For instance, bound-state formation is found to be significantly modified in the presence of spin-orbit coupling in three dimensions. This motivates us to study ultracold collisions between two Rashba-Dresselhaus spin-orbit coupled atoms in a quasi-one-dimensional geometry. We develop a multi-channel scattering formalism that accounts for the external transverse confinement and the spin-orbit coupling terms. The interplay between these two single-particle terms is shown to give rise to new scattering resonances. In particular, it is analyzed what happens when the scattering energy crosses the various scattering thresholds that arise from the single-particle confinement and the spin-orbit coupling. Support by the NSF is gratefully acknowledged.

  20. Electromagnetically induced transparency in a Zeeman-sublevels Λ-system of cold 87Rb atoms in free space

    International Nuclear Information System (INIS)

    Jiang Xiaojun; Zhang Haichao; Wang Yuzhu

    2016-01-01

    We report the experimental investigation of electromagnetically induced transparency (EIT) in a Zeeman-sublevels Λ-type system of cold 87 Rb atoms in free space. We use the Zeeman substates of the hyperfine energy states 5 2 S 1/2 , F = 2 and 5 2 P 3/2 , F′ = 2 of 87 Rb D 2 line to form a Λ-type EIT scheme. The EIT signal is obtained by scanning the probe light over 1 MHz in 4 ms with an 80 MHz arbitrary waveform generator. More than 97% transparency and 100 kHz EIT window are observed. This EIT scheme is suited for an application of pulsed coherent storage atom clock (Yan B, et al. 2009 Phys. Rev. A 79 063820). (paper)

  1. Theory and applications of atomic and ionic polarizabilities

    International Nuclear Information System (INIS)

    Mitroy, J; Safronova, M S; Clark, Charles W

    2010-01-01

    Atomic polarization phenomena impinge upon a number of areas and processes in physics. The dielectric constant and refractive index of any gas are examples of macroscopic properties that are largely determined by the dipole polarizability. When it comes to microscopic phenomena, the existence of alkaline-earth anions and the recently discovered ability of positrons to bind to many atoms are predominantly due to the polarization interaction. An imperfect knowledge of atomic polarizabilities is presently looming as the largest source of uncertainty in the new generation of optical frequency standards. Accurate polarizabilities for the group I and II atoms and ions of the periodic table have recently become available by a variety of techniques. These include refined many-body perturbation theory and coupled-cluster calculations sometimes combined with precise experimental data for selected transitions, microwave spectroscopy of Rydberg atoms and ions, refractive index measurements in microwave cavities, ab initio calculations of atomic structures using explicitly correlated wavefunctions, interferometry with atom beams and velocity changes of laser cooled atoms induced by an electric field. This review examines existing theoretical methods of determining atomic and ionic polarizabilities, and discusses their relevance to various applications with particular emphasis on cold-atom physics and the metrology of atomic frequency standards. (topical review)

  2. Theory and applications of atomic and ionic polarizabilities

    Energy Technology Data Exchange (ETDEWEB)

    Mitroy, J [School of Engineering, Charles Darwin University, Darwin NT 0909 (Australia); Safronova, M S [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Clark, Charles W, E-mail: jxm107@rsphysse.anu.edu.a, E-mail: msafrono@udel.ed, E-mail: charles.clark@nist.go [Joint Quantum Institute, National Institute of Standards and Technology and the University of Maryland, Gaithersburg, MD 20899-8410 (United States)

    2010-10-28

    Atomic polarization phenomena impinge upon a number of areas and processes in physics. The dielectric constant and refractive index of any gas are examples of macroscopic properties that are largely determined by the dipole polarizability. When it comes to microscopic phenomena, the existence of alkaline-earth anions and the recently discovered ability of positrons to bind to many atoms are predominantly due to the polarization interaction. An imperfect knowledge of atomic polarizabilities is presently looming as the largest source of uncertainty in the new generation of optical frequency standards. Accurate polarizabilities for the group I and II atoms and ions of the periodic table have recently become available by a variety of techniques. These include refined many-body perturbation theory and coupled-cluster calculations sometimes combined with precise experimental data for selected transitions, microwave spectroscopy of Rydberg atoms and ions, refractive index measurements in microwave cavities, ab initio calculations of atomic structures using explicitly correlated wavefunctions, interferometry with atom beams and velocity changes of laser cooled atoms induced by an electric field. This review examines existing theoretical methods of determining atomic and ionic polarizabilities, and discusses their relevance to various applications with particular emphasis on cold-atom physics and the metrology of atomic frequency standards. (topical review)

  3. Global land-atmosphere coupling associated with cold climate processes

    Science.gov (United States)

    Dutra, Emanuel

    This dissertation constitutes an assessment of the role of cold processes, associated with snow cover, in controlling the land-atmosphere coupling. The work was based on model simulations, including offline simulations with the land surface model HTESSEL, and coupled atmosphere simulations with the EC-EARTH climate model. A revised snow scheme was developed and tested in HTESSEL and EC-EARTH. The snow scheme is currently operational at the European Centre for Medium-Range Weather Forecasts integrated forecast system, and in the default configuration of EC-EARTH. The improved representation of the snowpack dynamics in HTESSEL resulted in improvements in the near surface temperature simulations of EC-EARTH. The new snow scheme development was complemented with the option of multi-layer version that showed its potential in modeling thick snowpacks. A key process was the snow thermal insulation that led to significant improvements of the surface water and energy balance components. Similar findings were observed when coupling the snow scheme to lake ice, where lake ice duration was significantly improved. An assessment on the snow cover sensitivity to horizontal resolution, parameterizations and atmospheric forcing within HTESSEL highlighted the role of the atmospheric forcing accuracy and snowpack parameterizations in detriment of horizontal resolution over flat regions. A set of experiments with and without free snow evolution was carried out with EC-EARTH to assess the impact of the interannual variability of snow cover on near surface and soil temperatures. It was found that snow cover interannual variability explained up to 60% of the total interannual variability of near surface temperature over snow covered regions. Although these findings are model dependent, the results showed consistency with previously published work. Furthermore, the detailed validation of the snow dynamics simulations in HTESSEL and EC-EARTH guarantees consistency of the results.

  4. Numerical and experimental modelling of back stream flow during close-coupled gas atomization

    OpenAIRE

    Motaman, S; Mullis, AM; Borman, DJ; Cochrane, RF; McCarthy, IN

    2013-01-01

    This paper reports the numerical and experimental investigation into the effects of different gas jet mis-match angles (for an external melt nozzle wall) on the back-stream flow in close coupled gas atomization. The Pulse Laser Imaging (PLI) technique was applied for visualising the back-stream melt flow phenomena with an analogue water atomizer and the associated PLI images compared with numerical results. In the investigation a Convergent–Divergent (C–D) discrete gas jet die at five differe...

  5. Helium clusters as cold, liquid matrix for the laser spectroscopy of silver atoms, silver clusters and C60 fullerenes

    International Nuclear Information System (INIS)

    Hoffmann, K.

    1999-01-01

    One of the main obstacles in the study of gas phase metal clusters is their high temperature. Even cooling in a seeded beam is only of limited used, since the condensation continuously releases energy into the system. As a consequence, spectroscopic studies of free metal clusters typically yield broad structures, which are interpreted as plasma resonances of a free electron gas. An experiment on ionic sodium clusters has shown that low temperatures lead to a narrowing of the absorption bands and the appearance of additional structure, that can not be explained within the free electron model. Thus the need for cold clusters is evident. In principle the deposition of metal clusters into inert matrices eliminates the temperature problem but it can also inflict strong changes on the electronic spectra. Droplets of liquid helium serve as a much more gentle matrix that avoids many of the above problems. In this thesis the new technique of helium droplet spectroscopy is presented as a tool for the study of extremely cold metal clusters. Clusters of silver up to a mass greater than 7000 amu have been produced by pickup of single atoms by a beam of helium droplets. The droplets are formed in a supersonic expansion. The cluster's binding energy is removed by evaporative cooling and the system remains at 0.4 K. The doped droplets are probed by laser spectroscopy with a depletion technique or resonant two photon ionization. We were able to measure the first UV absorption spectrum of metal atoms (silver) inside helium droplets. Another experiment shows that a small fraction of the captured silver atoms resides on the surface of the droplet like alkali atoms. In a two photon process previously unobserved s- and d-Rydberg states of the free silver atom (20 left angle n left angle 80) were excited. The silver atoms, initially embedded in the helium droplets, are found to move to the surface and desorb when excited to the broadened 5p level. This is the first result showing laser

  6. Dehalogenation and coupling of a polycyclic hydrocarbon on an atomically thin insulator.

    Science.gov (United States)

    Dienel, Thomas; Gómez-Díaz, Jaime; Seitsonen, Ari P; Widmer, Roland; Iannuzzi, Marcella; Radican, Kevin; Sachdev, Hermann; Müllen, Klaus; Hutter, Jürg; Gröning, Oliver

    2014-07-22

    Catalytic activity is of pivotal relevance in enabling efficient and selective synthesis processes. Recently, covalent coupling reactions catalyzed by solid metal surfaces opened the rapidly evolving field of on-surface chemical synthesis. Tailored molecular precursors in conjunction with the catalytic activity of the metal substrate allow the synthesis of novel, technologically highly relevant materials such as atomically precise graphene nanoribbons. However, the reaction path on the metal substrate remains unclear in most cases, and the intriguing question is how a specific atomic configuration between reactant and catalyst controls the reaction processes. In this study, we cover the metal substrate with a monolayer of hexagonal boron nitride (h-BN), reducing the reactivity of the metal, and gain unique access to atomistic details during the activation of a polyphenylene precursor by sequential dehalogenation and the subsequent coupling to extended oligomers. We use scanning tunneling microscopy and density functional theory to reveal a reaction site anisotropy, induced by the registry mismatch between the precursor and the nanostructured h-BN monolayer.

  7. Competition between the symmetry breaking and onset of collapse in weakly coupled atomic condensates

    International Nuclear Information System (INIS)

    Salasnich, L.; Toigo, F.; Malomed, B. A.

    2010-01-01

    We analyze the symmetry breaking of matter-wave solitons in a pair of cigar-shaped traps coupled by tunneling of atoms. The model is based on a system of linearly coupled nonpolynomial Schroedinger equations. Unlike the well-known spontaneous-symmetry-breaking (SSB) bifurcation in coupled cubic equations, in the present model the SSB competes with the onset of collapse in this system. Stability regions of symmetric and asymmetric solitons, as well as the collapse region, are identified in the system's parameter space.

  8. Production of cold antihydrogen in a nested trap

    International Nuclear Information System (INIS)

    Fujiwara, Makoto

    2004-01-01

    The ATHENA experiment at CERN produced and detected the first cold antihydrogen atoms. Antiprotons and positrons are mixed in a double Penning trap, known as a nested trap. The production of antihydrogen atoms was identified by detecting their annihilations signatures at trap wall. With the ATHENA results subsequently confirmed by another CERN experiment, ATRAP, cold antihydrogen research is entering an exciting era. (author)

  9. Coupled electronic and atomic effects on defect evolution in silicon carbide under ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yanwen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Xue, Haizhou [Univ. of Tennessee, Knoxville, TN (United States); Zarkadoula, Eva [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sachan, Ritesh [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Army Research Office, Triangle Park, NC (United States); Ostrouchov, Christopher [Univ. of Tennessee, Knoxville, TN (United States); Liu, Peng [Univ. of Tennessee, Knoxville, TN (United States); Shandong Univ., Jinan (China); Wang, Xue -lin [Shandong Univ., Jinan (China); Zhang, Shuo [Lanzhou Univ., Gansu Province (China); Wang, Tie Shan [Lanzhou Univ., Gansu Province (China); Weber, William J. [Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-10-16

    Understanding energy dissipation processes in electronic/atomic subsystems and subsequent non-equilibrium defect evolution is a long-standing challenge in materials science. In the intermediate energy regime, energetic particles simultaneously deposit a significant amount of energy to both electronic and atomic subsystems of silicon carbide (SiC). Here we show that defect evolution in SiC closely depends on the electronic-to-nuclear energy loss ratio (Se/Sn), nuclear stopping powers (dE/dxnucl), electronic stopping powers (dE/dxele), and the temporal and spatial coupling of electronic and atomic subsystem for energy dissipation. The integrated experiments and simulations reveal that: (1) increasing Se/Sn slows damage accumulation; (2) the transient temperatures during the ionization-induced thermal spike increase with dE/dxele, which causes efficient damage annealing along the ion trajectory; and (3) for more condensed displacement damage within the thermal spike, damage production is suppressed due to the coupled electronic and atomic dynamics. Ionization effects are expected to be more significant in materials with covalent/ionic bonding involving predominantly well-localized electrons. Here, insights into the complex electronic and atomic correlations may pave the way to better control and predict SiC response to extreme energy deposition

  10. Entanglement Criteria of Two Two-Level Atoms Interacting with Two Coupled Modes

    Science.gov (United States)

    Baghshahi, Hamid Reza; Tavassoly, Mohammad Kazem; Faghihi, Mohammad Javad

    2015-08-01

    In this paper, we study the interaction between two two-level atoms and two coupled modes of a quantized radiation field in the form of parametric frequency converter injecting within an optical cavity enclosed by a medium with Kerr nonlinearity. It is demonstrated that, by applying the Bogoliubov-Valatin canonical transformation, the introduced model is reduced to a well-known form of the generalized Jaynes-Cummings model. Then, under particular initial conditions for the atoms (in a coherent superposition of its ground and upper states) and the fields (in a standard coherent state) which may be prepared, the time evolution of state vector of the entire system is analytically evaluated. In order to understand the degree of entanglement between subsystems (atom-field and atom-atom), the dynamics of entanglement through different measures, namely, von Neumann reduced entropy, concurrence and negativity is evaluated. In each case, the effects of Kerr nonlinearity and detuning parameter on the above measures are numerically analyzed, in detail. It is illustrated that the amount of entanglement can be tuned by choosing the evolved parameters, appropriately.

  11. COUPLED ATOMIZATION AND SPRAY MODELLING IN THE SPRAY FORMING PROCESS USING OPENFOAM

    DEFF Research Database (Denmark)

    Gjesing, Rasmus; Hattel, Jesper Henri; Fritsching, Udo

    2009-01-01

    The paper presents a numerical model capable of simulating the atomization, break-up and in-flight spray phenomena in the spray forming process. The model is developed and implemented in the freeware code openFOAM. The focus is on studying the coupling effect of the melt break-up phenomena...

  12. Degenerate quantum gases with spin-orbit coupling: a review.

    Science.gov (United States)

    Zhai, Hui

    2015-02-01

    This review focuses on recent developments in synthetic spin-orbit (SO) coupling in ultracold atomic gases. Two types of SO coupling are discussed. One is Raman process induced coupling between spin and motion along one of the spatial directions and the other is Rashba SO coupling. We emphasize their common features in both single-particle and two-body physics and the consequences of both in many-body physics. For instance, single particle ground state degeneracy leads to novel features of superfluidity and a richer phase diagram; increased low-energy density-of-state enhances interaction effects; the absence of Galilean invariance and spin-momentum locking gives rise to intriguing behaviours of superfluid critical velocity and novel quantum dynamics; and the mixing of two-body singlet and triplet states yields a novel fermion pairing structure and topological superfluids. With these examples, we show that investigating SO coupling in cold atom systems can, enrich our understanding of basic phenomena such as superfluidity, provide a good platform for simulating condensed matter states such as topological superfluids and more importantly, result in novel quantum systems such as SO coupled unitary Fermi gas and high spin quantum gases. Finally we also point out major challenges and some possible future directions.

  13. The production and investigation of cold antihydrogen atoms

    International Nuclear Information System (INIS)

    Pittner, H.

    2005-04-01

    This work reports on experiments in which antihydrogen atoms have been produced in cryogenic Penning traps from antiproton and positron plasmas by two different methods and on experiments that have been carried out subsequently in order to investigate the antihydrogen atoms. By the first method antihydrogen atoms have been formed during the process of positron cooling of antiprotons in so called nested Penning traps and detected via a field ionization method. A measurement of the state distribution has revealed that the antihydrogen atoms are formed in highly excited states. This suggests along with the high production rate that the antihydrogen atoms are formed by three-body recombination processes and subsequent collisional deexcitations. However current theory cannot yet account for the measured state distribution. Typical radii of the detected antihydrogen atoms lie in the range between 0.4 μm and 0.15 μm. The deepest bound antihydrogen atoms have radii below 0.1 μm.The kinetic energy of the weakest bound antihydrogen atoms has been measured to about 200 meV. By the second method antihydrogen atoms have been synthesized in charge-exchange processes. Lasers are used to produce a Rydberg cesium beam within the cryogenic Penning trap that collides with trapped positrons so that Rydberg positronium atoms are formed via charge-exchange reactions. The Rydberg positronium atoms that collide with nearby stored antiprotons form antihydrogen atoms in charge-exchange reactions. So far, 14±4 antihydrogen atoms have been detected background-free via a field-ionization method. The antihydrogen atoms produced via the two-step charge-exchange mechanism are expected to have a temperature of 4.2 K, the temperature of the antiprotons from which they are formed

  14. Electromagnetically induced transparency in thermal Rydberg atoms: superatom model with finite Doppler broadening

    Science.gov (United States)

    Bai, Si-Yin; Bao, Qian-Qian; Tian, Xue-Dong; Liu, Yi-Mou; Wu, Jin-Hui

    2018-04-01

    We study the steady optical responses of a cold atomic ensemble driven into the three-level ladder configuration involving a Rydberg state at finite temperatures. By improving the superatom model with thermal movement included, we calculate relevant atomic coherence effects and find that the residual Doppler broadening at the mK-K temperatures will weaken the nonclassical properties of transmitted probe photons. Furthermore, propagation directions of the probe and coupling fields have a great influence on various properties related to electromagnetically induced transparency. That is, the residual Doppler effect is more destructive to relevant atomic coherence effects in the co-propagation case but can be partially eliminated in the counter-propagation case.

  15. Spontaneous emission spectrum of a four-level atom coupled by three kinds of reservoirs

    International Nuclear Information System (INIS)

    Yang Dong; Wang Jian; Zhang, Hanzhuang; Yao Jinbo

    2007-01-01

    A model of a four-level atom embedded in a double-band photonic crystal (PC) is presented. The atomic transitions from the upper two levels to the lower two levels are coupled by the same reservoir which is assumed in turn to be isotropic PC modes, anisotropic PC modes and free vacuum modes. The effects of the fine structure of the atomic ground state levels and the quantum interference on the spontaneous emission spectrum of an atom are investigated in detail. Most interestingly, it is shown for the first time that new spontaneous emission lines are produced from the fine splitting of atomic ground state levels in the isotropic PC case. Quantum interference induces additional narrow spontaneous lines near the transition from the empty upper level to the lower levels

  16. Progress with cold antihydrogen

    CERN Document Server

    Charlton, M; Amsler, C; Bonomi, G; Bowe, P D; Canali, C; Carraro, C; Cesar, C L; Doser, M; Fontana, A; Fujiwara, M C; Funakoshi, R; Genova, P; Hangst, J S; Hayano, R S; Johnson, I; Jørgensen, L V; Kellerbauer, A G; Lagomarsino, V; Landua, Rolf; Lodi-Rizzini, E; Macri, M; Madsen, N; Manuzio, G; Mitchard, D; Montagna, P; Pruys, H; Regenfus, C; Rotondi, A; Testera, G; Variola, A; Venturelli, L; Van der Werf, D P; Yamazaki, Y; Zurlo, N

    2006-01-01

    The creation of cold antihydrogen by the ATHENA and ATRAP collaborations, working at CERN's unique Antiproton Decelerator (AD) facility, has ushered in a new era in atomic physics. This contribution will briefly review recent results from the ATHENA experiment. These include discussions of antiproton slowing down in a cold positron gas during antihydrogen formation, information derived on the dependence of the antihydrogen formation rate upon the temperature of the stored positron plasma and, finally, upon the spatial distribution of the emitted anti-atoms. We will discuss the implications of these studies for the major outstanding goal of trapping samples of antihydrogen for precise spectroscopic comparisons with hydrogen. The physics motivations for undertaking these challenging experiments will be briefly recalled.

  17. Positron Plasma Control Techniques Applied to Studies of Cold Antihydrogen

    CERN Document Server

    Funakoshi, Ryo

    2003-01-01

    In the year 2002, two experiments at CERN succeeded in producing cold antihydrogen atoms, first ATHENA and subsequently ATRAP. Following on these results, it is now feasible to use antihydrogen to study the properties of antimatter. In the ATHENA experiment, the cold antihydrogen atoms are produced by mixing large amounts of antiprotons and positrons in a nested Penning trap. The complicated behaviors of the charged particles are controlled and monitored by plasma manipulation techniques. The antihydrogen events are studied using position sensitive detectors and the evidence of production of antihydrogen atoms is separated out with the help of analysis software. This thesis covers the first production of cold antihydrogen in the first section as well as the further studies of cold antihydrogen performed by using the plasma control techniques in the second section.

  18. Single-atom lasing induced atomic self-trapping

    International Nuclear Information System (INIS)

    Salzburger, T.; Ritsch, H.

    2004-01-01

    We study atomic center of mass motion and field dynamics of a single-atom laser consisting of a single incoherently pumped free atom moving in an optical high-Q resonator. For sufficient pumping, the system starts lasing whenever the atom is close to a field antinode. If the field mode eigenfrequency is larger than the atomic transition frequency, the generated laser light attracts the atom to the field antinode and cools its motion. Using quantum Monte Carlo wave function simulations, we investigate this coupled atom-field dynamics including photon recoil and cavity decay. In the regime of strong coupling, the generated field shows strong nonclassical features like photon antibunching, and the atom is spatially confined and cooled to sub-Doppler temperatures. (author)

  19. Note: Design and implementation of a home-built imaging system with low jitter for cold atom experiments

    Energy Technology Data Exchange (ETDEWEB)

    Hachtel, A. J.; Gillette, M. C.; Clements, E. R.; Zhong, S.; Weeks, M. R.; Bali, S., E-mail: balis@miamioh.edu [Department of Physics, Miami University, Oxford, Ohio 45056-1866 (United States)

    2016-05-15

    A novel home-built system for imaging cold atom samples is presented using a readily available astronomy camera which has the requisite sensitivity but no timing-control. We integrate the camera with LabVIEW achieving fast, low-jitter imaging with a convenient user-defined interface. We show that our system takes precisely timed millisecond exposures and offers significant improvements in terms of system jitter and readout time over previously reported home-built systems. Our system rivals current commercial “black box” systems in performance and user-friendliness.

  20. A fully coupled finite element framework for thermal fracturing simulation in subsurface cold CO2 injection

    Directory of Open Access Journals (Sweden)

    Shunde Yin

    2018-03-01

    Simulation of thermal fracturing during cold CO2 injection involves the coupled processes of heat transfer, mass transport, rock deforming as well as fracture propagation. To model such a complex coupled system, a fully coupled finite element framework for thermal fracturing simulation is presented. This framework is based on the theory of non-isothermal multiphase flow in fracturing porous media. It takes advantage of recent advances in stabilized finite element and extended finite element methods. The stabilized finite element method overcomes the numerical instability encountered when the traditional finite element method is used to solve the convection dominated heat transfer equation, while the extended finite element method overcomes the limitation with traditional finite element method that a model has to be remeshed when a fracture is initiated or propagating and fracturing paths have to be aligned with element boundaries.

  1. The effect of a coupling field on the entanglement dynamics of a three-level atom

    International Nuclear Information System (INIS)

    Mortezapour, Ali; Mahmoudi, Mohammad; Abedi, Majid; Khajehpour, M R H

    2011-01-01

    The effect of a coupling laser field on the entanglement of a three-level quantum system and its spontaneous emission is investigated via the reduced quantum entropy. We consider two schemes: the upper- and lower-level couplings. By calculating the degree of entanglement (DEM) for both systems, it is shown that the entanglement between the atom and its spontaneous emission can be controlled by the coupling laser field. This field, however, affects the entanglement differently in the two schemes; it is only the lower-level coupling scheme that shows a non-zero steady state DEM which can be controlled by the intensity and detuning of the coupling laser field.

  2. The effect of a coupling field on the entanglement dynamics of a three-level atom

    Energy Technology Data Exchange (ETDEWEB)

    Mortezapour, Ali; Mahmoudi, Mohammad [Physics Department, Zanjan University, PO Box 45195-313, Zanjan (Iran, Islamic Republic of); Abedi, Majid; Khajehpour, M R H, E-mail: mahmoudi@iasbs.ac.ir, E-mail: pour@iasbs.ac.ir [Institute for Advanced Studies in Basic Sciences, PO Box 45195-159, Zanjan (Iran, Islamic Republic of)

    2011-04-28

    The effect of a coupling laser field on the entanglement of a three-level quantum system and its spontaneous emission is investigated via the reduced quantum entropy. We consider two schemes: the upper- and lower-level couplings. By calculating the degree of entanglement (DEM) for both systems, it is shown that the entanglement between the atom and its spontaneous emission can be controlled by the coupling laser field. This field, however, affects the entanglement differently in the two schemes; it is only the lower-level coupling scheme that shows a non-zero steady state DEM which can be controlled by the intensity and detuning of the coupling laser field.

  3. Transport, atom blockade, and output coupling in a Tonks-Girardeau gas

    International Nuclear Information System (INIS)

    Rutherford, L.; McCann, J. F.; Goold, J.; Busch, Th.

    2011-01-01

    Recent experiments have demonstrated how quantum-mechanical impurities can be created within strongly correlated quantum gases and used to probe the coherence properties of these systems [S. Palzer, C. Zipkes, C. Sias, and M. Koehl, Phys. Rev. Lett. 103, 150601 (2009).]. Here we present a phenomenological model to simulate such an output coupler for a Tonks-Girardeau gas that shows qualitative agreement with the experimental results for atom transport and output coupling. Our model allows us to explore nonequilibrium transport phenomena in ultracold quantum gases and leads us to predict a regime of atom blockade, where the impurity component becomes localized in the parent cloud despite the presence of gravity. We show that this provides a stable mixed-species quantum gas in the strongly correlated limit.

  4. Delocalization of Relativistic Dirac Particles in Disordered One-Dimensional Systems and Its Implementation with Cold Atoms

    International Nuclear Information System (INIS)

    Zhu Shiliang; Zhang Danwei; Wang, Z. D.

    2009-01-01

    We study theoretically the localization of relativistic particles in disordered one-dimensional chains. It is found that the relativistic particles tend to delocalization in comparison with the nonrelativistic particles with the same disorder strength. More intriguingly, we reveal that the massless Dirac particles are entirely delocalized for any energy due to the inherent chiral symmetry, leading to a well-known result that particles are always localized in one-dimensional systems for arbitrary weak disorders to break down. Furthermore, we propose a feasible scheme to detect the delocalization feature of the Dirac particles with cold atoms in a light-induced gauge field.

  5. Simple and efficient absorption filter for single photons from a cold atom quantum memory.

    Science.gov (United States)

    Stack, Daniel T; Lee, Patricia J; Quraishi, Qudsia

    2015-03-09

    The ability to filter unwanted light signals is critical to the operation of quantum memories based on neutral atom ensembles. Here we demonstrate an efficient frequency filter which uses a vapor cell filled with (85)Rb and a buffer gas to attenuate both residual laser light and noise photons by nearly two orders of magnitude with little loss to the single photons associated with our cold (87)Rb quantum memory. This simple, passive filter provides an additional 18 dB attenuation of our pump laser and erroneous spontaneous emissions for every 1 dB loss of the single photon signal. We show that the addition of a frequency filter increases the non-classical correlations and the retrieval efficiency of our quantum memory by ≈ 35%.

  6. Laser-cooled atomic ions as probes of molecular ions

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Kenneth R.; Viteri, C. Ricardo; Clark, Craig R.; Goeders, James E.; Khanyile, Ncamiso B.; Vittorini, Grahame D. [Schools of Chemistry and Biochemistry, Computational Science and Engineering and Physics, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

    2015-01-22

    Trapped laser-cooled atomic ions are a new tool for understanding cold molecular ions. The atomic ions not only sympathetically cool the molecular ions to millikelvin temperatures, but the bright atomic ion fluorescence can also serve as a detector of both molecular reactions and molecular spectra. We are working towards the detection of single molecular ion spectra by sympathetic heating spectroscopy. Sympathetic heating spectroscopy uses the coupled motion of two trapped ions to measure the spectra of one ion by observing changes in the fluorescence of the other ion. Sympathetic heating spectroscopy is a generalization of quantum logic spectroscopy, but does not require ions in the motional ground state or coherent control of the ion internal states. We have recently demonstrated this technique using two isotopes of Ca{sup +} [Phys. Rev. A, 81, 043428 (2010)]. Limits of the method and potential applications for molecular spectroscopy are discussed.

  7. Many-body dynamics with cold atoms and molecules in optical lattices

    International Nuclear Information System (INIS)

    Schachenmayer, J.

    2012-01-01

    Systems of cold atoms or molecules, trapped in a periodic potential formed from standing waves of laser light, provide an experimental possibility to study strongly correlated many-body lattice models, which are traditionally used in condensed matter physics. Due to the relatively weak energy scales in these ''optical lattices'' (next-neighbor tunneling energies are typically on the order of tens of Hertz), the time-scales of the dynamics in these systems is relatively slow and can be observed in experiments. Furthermore, the microscopic parameters of the models can be very well controlled by lattice laser intensities and external fields. Thus, optical lattices provide an excellent framework to study many-body quantum non-equilibrium dynamics, which on the theoretical level is the topic of this thesis. This thesis contains a study of many-body dynamics in optical lattices for both idealized isolated models and realistic models with imperfections. It is centered around four main topics: The first two topics are studies of coherent many-body dynamics. This contains explicitly: (i) an analysis of the possibility to dynamically prepare crystalline states of Rydberg atoms or polar molecules by adiabatically tuning laser parameters; and (ii) a study of the collapses and revivals of the momentum-distribution of a Bose-Einstein condensate with a fixed number of atoms, which is suddenly loaded into a deep optical lattice. The third main topic is entanglement and specifically the dynamical growth of entanglement between portions of an optical lattice in quench experiments. A method to create and measure large-scale entanglement is presented in this thesis. The fourth main topic addresses classical noise. Specifically, a system of atoms in an optical lattice, which is created from lasers with intensity fluctuations, is analyzed in this work. The noisy evolution of many-body correlation functions is studied and a method to cancel this noise in a realistic experimental setup is

  8. New perspectives for Rashba spin–orbit coupling

    KAUST Repository

    Manchon, Aurelien; Koo, H. C.; Nitta, J.; Frolov, S. M.; Duine, R. A.

    2015-01-01

    In 1984, Bychkov and Rashba introduced a simple form of spin-orbit coupling to explain the peculiarities of electron spin resonance in two-dimensional semiconductors. Over the past 30 years, Rashba spin-orbit coupling has inspired a vast number of predictions, discoveries and innovative concepts far beyond semiconductors. The past decade has been particularly creative, with the realizations of manipulating spin orientation by moving electrons in space, controlling electron trajectories using spin as a steering wheel, and the discovery of new topological classes of materials. This progress has reinvigorated the interest of physicists and materials scientists in the development of inversion asymmetric structures, ranging from layered graphene-like materials to cold atoms. This Review discusses relevant recent and ongoing realizations of Rashba physics in condensed matter.

  9. New perspectives for Rashba spin–orbit coupling

    KAUST Repository

    Manchon, Aurelien

    2015-08-20

    In 1984, Bychkov and Rashba introduced a simple form of spin-orbit coupling to explain the peculiarities of electron spin resonance in two-dimensional semiconductors. Over the past 30 years, Rashba spin-orbit coupling has inspired a vast number of predictions, discoveries and innovative concepts far beyond semiconductors. The past decade has been particularly creative, with the realizations of manipulating spin orientation by moving electrons in space, controlling electron trajectories using spin as a steering wheel, and the discovery of new topological classes of materials. This progress has reinvigorated the interest of physicists and materials scientists in the development of inversion asymmetric structures, ranging from layered graphene-like materials to cold atoms. This Review discusses relevant recent and ongoing realizations of Rashba physics in condensed matter.

  10. Determination of Hg(II) as a pollutant in Karachi coastal waters by cold vapor atomic absorption spectroscopy

    International Nuclear Information System (INIS)

    Naqvi, I.I.; Shazli, J.; Ali, S.R.; Mohiuddin, S.; Zehra, I.

    2002-01-01

    Now a days, environmental monitoring has great importance and mercury is well known for its toxicity. Mercury (which is at trace level) is analyzed by cold vapor atomic absorption spectroscopy with amendments that are appropriate to the present laboratory need. The results are consistent with previous analysis, through other methods, two areas namely Ibrahim Hyderi and Fisheries were found to have mercury levels around 0.193 mu/L and 0.110 mu g/L, respectively. Whereas other areas have mercury levels similar to other places reported earlier. (author)

  11. Matterwave interferometric velocimetry of cold Rb atoms

    Science.gov (United States)

    Carey, Max; Belal, Mohammad; Himsworth, Matthew; Bateman, James; Freegarde, Tim

    2018-03-01

    We consider the matterwave interferometric measurement of atomic velocities, which forms a building block for all matterwave inertial measurements. A theoretical analysis, addressing both the laboratory and atomic frames and accounting for residual Doppler sensitivity in the beamsplitter and recombiner pulses, is followed by an experimental demonstration, with measurements of the velocity distribution within a 20 ?K cloud of rubidium atoms. Our experiments use Raman transitions between the long-lived ground hyperfine states, and allow quadrature measurements that yield the full complex interferometer signal and hence discriminate between positive and negative velocities. The technique is most suitable for measurement of colder samples.

  12. Ferruleless coupled-cavity traveling-wave tube cold-test characteristics simulated with micro-SOS

    Science.gov (United States)

    Schroeder, Dana L.; Wilson, Jeffrey D.

    1993-01-01

    The three-dimensional, electromagnetic circuit analysis code, Micro-SOS, can be used to reduce expensive and time consuming experimental 'cold-testing' of traveling-wave tube (TWT) circuits. The frequency-phase dispersion and beam interaction impedance characteristics of a ferruleless coupled-cavity traveling-wave tube slow-wave circuit were simulated using the code. Computer results agree closely with experimental data. Variations in the cavity geometry dimensions of period length and gap-to-period ratio were modeled. These variations can be used in velocity taper designs to reduce the radiofrequency (RF) phase velocity in synchronism with the decelerating electron beam. Such circuit designs can result in enhanced TWT power and efficiency.

  13. Absolute atomic oxygen and nitrogen densities in radio-frequency driven atmospheric pressure cold plasmas: Synchrotron vacuum ultra-violet high-resolution Fourier-transform absorption measurements

    International Nuclear Information System (INIS)

    Niemi, K.; O'Connell, D.; Gans, T.; Oliveira, N. de; Joyeux, D.; Nahon, L.; Booth, J. P.

    2013-01-01

    Reactive atomic species play a key role in emerging cold atmospheric pressure plasma applications, in particular, in plasma medicine. Absolute densities of atomic oxygen and atomic nitrogen were measured in a radio-frequency driven non-equilibrium plasma operated at atmospheric pressure using vacuum ultra-violet (VUV) absorption spectroscopy. The experiment was conducted on the DESIRS synchrotron beamline using a unique VUV Fourier-transform spectrometer. Measurements were carried out in plasmas operated in helium with air-like N 2 /O 2 (4:1) admixtures. A maximum in the O-atom concentration of (9.1 ± 0.7)×10 20 m −3 was found at admixtures of 0.35 vol. %, while the N-atom concentration exhibits a maximum of (5.7 ± 0.4)×10 19 m −3 at 0.1 vol. %

  14. Superconducting fluctuations in systems with Rashba-spin-orbit coupling

    Energy Technology Data Exchange (ETDEWEB)

    Beyl, Stefan [Institut fuer Theoretische Physik und Astrophysik, Universitaet Wuerzburg (Germany); Orth, Peter P.; Scheurer, Mathias; Schmalian, Joerg [Institut fuer Theorie der Kondensierten Materie, Karlsruher Institut fuer Technologie (Germany)

    2015-07-01

    We investigate the BEC-BCS crossover in a two-dimensional system with Rashba-spin-orbit coupling. To include the effects of phase and amplitude fluctuations of the superconducting order parameter we perform a loop expansion of the effective field theory. We analyze in particular the probability of a low density superconducting quantum phase transition. The theory is relevant to LaAlO{sub 3}/SrTiO{sub 3} interfaces and two-dimensional cold atom systems with synthetic gauge fields.

  15. Development of cold neutron spectrometers

    International Nuclear Information System (INIS)

    Lee, Changhee; Lee, C. H.; So, J. Y.; Park, S.; Han, Y. S.; Cho, S. J.; Moon, M. K.; Choi, Y. H.; Sun, G. M.

    2012-03-01

    Cold Neutron Triple Axsis Spectrometer (Cold-TAS) Development Ο Fabrication and Installation of the Major Cold-TAS Components Ο Performance Test of the Cold-TAS □ Cold Neutron Time-of-Flight Spectrometer(DC-TOF) Development Ο Fabrication of the Major DC-TOF Components Ο Development DC-TOF Data Reduction Software □ Expected Contribution The two world-class inelastic neutron scattering instruments measure atomic or molecular scale dynamics of meV energy range. This unprecedented measurement capability in the country will enable domestic and international scientists to observe new phenomena in their materials research to obtain world class results. Especially those who work in the fields of magnetic properties of superconductors and multiferroics, molecular dynamics, etc. will get more benefit from these two instruments

  16. Metabolomics coupled with similarity analysis advances the elucidation of the cold/hot properties of traditional Chinese medicines.

    Science.gov (United States)

    Jia, Yan; Zhang, Zheng-Zheng; Wei, Yu-Hai; Xue-Mei, Qin; Li, Zhen-Yu

    2017-08-01

    It recently becomes an important and urgent mission for modern scientific research to identify and explain the theory of traditional Chinese medicine (TCM), which has been utilized in China for more than four millennia. Since few works have been contributed to understanding the TCM theory, the mechanism of actions of drugs with cold/hot properties remains unclear. In the present study, six kinds of typical herbs with cold or hot properties were orally administered into mice, and serum and liver samples were analyzed using an untargeted nuclear magnetic resonance (NMR) based metabolomics approach coupled with similarity analysis. This approach was performed to identify and quantify changes in metabolic pathways to elucidate drug actions on the treated mice. Our results showed that those drugs with same property exerted similar effects on the metabolic alterations in mouse serum and liver samples, while drugs with different property showed different effects. The effects of herbal medicines with cold/hot properties were exerted by regulating the pathways linked to glycometabolism, lipid metabolism, amino acids metabolism and other metabolic pathways. The results elucidated the differences and similarities of drugs with cold/hot properties, providing useful information on the explanation of medicinal properties of these TCMs. Copyright © 2017 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

  17. In situ calibration of inductively coupled plasma-atomic emission and mass spectroscopy

    Science.gov (United States)

    Braymen, Steven D.

    1996-06-11

    A method and apparatus for in situ addition calibration of an inductively coupled plasma atomic emission spectrometer or mass spectrometer using a precision gas metering valve to introduce a volatile calibration gas of an element of interest directly into an aerosol particle stream. The present situ calibration technique is suitable for various remote, on-site sampling systems such as laser ablation or nebulization.

  18. Dynamics and applications of excited cold atoms

    NARCIS (Netherlands)

    Claessens, B.J.

    2006-01-01

    In a Magneto-Optical Trap (MOT), realized for the first time in 1987, one can trap and cool neutral atoms to temperatures below a mK. The invention of this device caused a revolution in atomic physics. With an MOT collision and spectroscopy experiments could be performed with unprecedented accuracy.

  19. Entropy squeezing for a two-level atom in the Jaynes-Cummings model with an intensity-depend coupling

    Institute of Scientific and Technical Information of China (English)

    李春先; 方卯发

    2003-01-01

    We study the squeezing for a two-level atom in the Jaynes-Cummings model with intensity-dependent coupling using quantum information entropy, and examine the influences of the initial state of the system on the squeezed component number and direction of the information entropy squeezing. Our results show that, the squeezed component number depends on the atomic initial distribution angle, while the squeezed direction is determined by both the phases of the atom and the field for the information entropy squeezing. Quantum information entropy is shown to be a remarkable precision measure for atomic squeezing.

  20. Entropy squeezing for a two—level atom in the Jaynes—Cummings model with an intensity—depend coupling

    Institute of Scientific and Technical Information of China (English)

    李春先; 方卯发; 等

    2003-01-01

    We study the squeezing for a two-level atom in the Jaynes-Cumings model with intensity-dependent coupling using quantum information entropy,and examine the influences of the initial state of the system on the squeezed component number and direction of the information entropy squeezing.Our results show that,the squeezed component number depends on the atomic initial distribution angle,while the squeezed direction is determined by both the phases of the atom and the field for the information entropy squeezing.Quantum information entropy is shown to be a remarkable precision measure for atomic squeezing.

  1. Two atoms scattering at low and cold energies

    Indian Academy of Sciences (India)

    A modified static-exchange model is developed to study the collision of an atom with another atom. It includes the effect of long-range dipole–dipole van der Waals interaction between two atoms in addition to the exact effect of short-range force due to Coulomb exchange between two system electrons. Both these ...

  2. Production and detection of cold anti-hydrogen atoms A first step towards high precision CPT test

    CERN Document Server

    Variola, A; Bonomi, G; Boutcha, A; Bowe, P; Carraro, C; Cesar, C L; Charlton, M; Doser, Michael; Filippini, V; Fontana, A; Fujiwara, M C; Funakoshi, R; Genova, P; Hangst, J S; Hayano, R S; Jørgensen, L V; Lagomarsino, V; Landua, Rolf; Lindelöf, D; Lodi-Rizzini, E; Macri, M; Madsen, N; Manuzio, G; Montagna, P; Pruys, H S; Regenfus, C; Rotondi, A; Riedler, P; Testera, G; Van der Werf, D P

    2003-01-01

    Observations of anti-hydrogen in small quantities have been reported at CERN and at FermiLab, but these experiments were not suited to spectroscopy experiments. In 2002 the ATHENA collaboration reported the production and detection of very low energy anti-hydrogen atoms produced in cryogenic environment. This is the first major step in the study of antiatom's internal structure and it can lead to a high precision test of the CPT fundamental symmetry. The method of production and detection of cold anti-hydrogen will be introduced. The absolute rate of anti-hydrogen production and the signal to background ratio in the ATHENA experiment will be discussed. (7 refs) .

  3. Van der Waals enhancement of optical atom potentials via resonant coupling to surface polaritons.

    Science.gov (United States)

    Kerckhoff, Joseph; Mabuchi, Hideo

    2009-08-17

    Contemporary experiments in cavity quantum electrodynamics (cavity QED) with gas-phase neutral atoms rely increasingly on laser cooling and optical, magneto-optical or magnetostatic trapping methods to provide atomic localization with sub-micron uncertainty. Difficult to achieve in free space, this goal is further frustrated by atom-surface interactions if the desired atomic placement approaches within several hundred nanometers of a solid surface, as can be the case in setups incorporating monolithic dielectric optical resonators such as microspheres, microtoroids, microdisks or photonic crystal defect cavities. Typically in such scenarios, the smallest atom-surface separation at which the van der Waals interaction can be neglected is taken to be the optimal localization point for associated trapping schemes, but this sort of conservative strategy generally compromises the achievable cavity QED coupling strength. Here we suggest a new approach to the design of optical dipole traps for atom confinement near surfaces that exploits strong surface interactions, rather than avoiding them, and present the results of a numerical study based on (39)K atoms and indium tin oxide (ITO). Our theoretical framework points to the possibility of utilizing nanopatterning methods to engineer novel modifications of atom-surface interactions. (c) 2009 Optical Society of America

  4. Transporting, splitting and merging of atomic ensembles in a chip trap

    International Nuclear Information System (INIS)

    Hommelhoff, P; Haensel, W; Steinmetz, T; Haensch, T W; Reichel, J

    2005-01-01

    We present a toolbox for cold atom manipulation with time-dependent magnetic fields generated by an atom chip. Wire layouts, detailed experimental procedures and results are presented for the following experiments: use of a magnetic conveyor belt for positioning of cold atoms and Bose-Einstein condensates (BECs) with a potential resolution of 2 nm; splitting of thermal clouds and BECs in adjustable magnetic double-well potentials; and controlled splitting of a cold reservoir. The devices that enable these manipulations can be combined with each other. We demonstrate this by combining reservoir splitter and conveyor belt to obtain a cold atom dispenser. We discuss the importance of these devices for quantum information processing, atom interferometry and Josephson junction physics on the chip. For all devices, absorption-image video sequences are provided to demonstrate their time-dependent behaviour

  5. Controllability in tunable chains of coupled harmonic oscillators

    DEFF Research Database (Denmark)

    Buchmann, Lukas Filip; Mølmer, Klaus; Petrosyan, David

    2018-01-01

    any desired Gaussian state requires at most 3 N ( N −1)/2 operations. We illustrate this capability by engineering squeezed pseudo-phonon states—highly nonlocal, strongly correlated states that may result from various nonlinear processes. Tunable chains of coupled harmonic oscillators can......We prove that temporal control of the strengths of springs connecting N harmonic oscillators in a chain provides complete access to all Gaussian states of N −1 collective modes. The proof relies on the construction of a suitable basis of cradle modes for the system. An iterative algorithm to reach...... be implemented by a number of current state-of-the-art experimental platforms, including cold atoms in lattice potentials, arrays of mechanical micro-oscillators, and coupled optical waveguides....

  6. Controllability in tunable chains of coupled harmonic oscillators

    Science.gov (United States)

    Buchmann, L. F.; Mølmer, K.; Petrosyan, D.

    2018-04-01

    We prove that temporal control of the strengths of springs connecting N harmonic oscillators in a chain provides complete access to all Gaussian states of N -1 collective modes. The proof relies on the construction of a suitable basis of cradle modes for the system. An iterative algorithm to reach any desired Gaussian state requires at most 3 N (N -1 )/2 operations. We illustrate this capability by engineering squeezed pseudo-phonon states—highly nonlocal, strongly correlated states that may result from various nonlinear processes. Tunable chains of coupled harmonic oscillators can be implemented by a number of current state-of-the-art experimental platforms, including cold atoms in lattice potentials, arrays of mechanical micro-oscillators, and coupled optical waveguides.

  7. Controllability in tunable chains of coupled harmonic oscillators

    DEFF Research Database (Denmark)

    Buchmann, Lukas Filip; Mølmer, Klaus; Petrosyan, David

    2018-01-01

    We prove that temporal control of the strengths of springs connecting N harmonic oscillators in a chain provides complete access to all Gaussian states of N −1 collective modes. The proof relies on the construction of a suitable basis of cradle modes for the system. An iterative algorithm to reach...... any desired Gaussian state requires at most 3 N ( N −1)/2 operations. We illustrate this capability by engineering squeezed pseudo-phonon states—highly nonlocal, strongly correlated states that may result from various nonlinear processes. Tunable chains of coupled harmonic oscillators can...... be implemented by a number of current state-of-the-art experimental platforms, including cold atoms in lattice potentials, arrays of mechanical micro-oscillators, and coupled optical waveguides....

  8. Ultra-cold molecule production

    International Nuclear Information System (INIS)

    Ramirez-Serrano, Jamie; Chandler, David W.; Strecker, Kevin; Rahn, Larry A.

    2005-01-01

    The production of Ultra-cold molecules is a goal of many laboratories through out the world. Here we are pursuing a unique technique that utilizes the kinematics of atomic and molecular collisions to achieve the goal of producing substantial numbers of sub Kelvin molecules confined in a trap. Here a trap is defined as an apparatus that spatially localizes, in a known location in the laboratory, a sample of molecules whose temperature is below one degree absolute Kelvin. Further, the storage time for the molecules must be sufficient to measure and possibly further cool the molecules. We utilize a technique unique to Sandia to form cold molecules from near mass degenerate collisions between atoms and molecules. This report describes the progress we have made using this novel technique and the further progress towards trapping molecules we have cooled

  9. Superradiant cascade emissions in an atomic ensemble via four-wave mixing

    Energy Technology Data Exchange (ETDEWEB)

    Jen, H.H., E-mail: sappyjen@gmail.com

    2015-09-15

    We investigate superradiant cascade emissions from an atomic ensemble driven by two-color classical fields. The correlated pair of photons (signal and idler) is generated by adiabatically driving the system with large-detuned light fields via four-wave mixing. The signal photon from the upper transition of the diamond-type atomic levels is followed by the idler one which can be superradiant due to light-induced dipole–dipole interactions. We then calculate the cooperative Lamb shift (CLS) of the idler photon, which is a cumulative effect of interaction energy. We study its dependence on a cylindrical geometry, a conventional setup in cold atom experiments, and estimate the maximum CLS which can be significant and observable. Manipulating the CLS of cascade emissions enables frequency qubits that provide alternative robust elements in quantum network. - Highlights: • Superradiance from a cascade atomic transition. • Correlated photon pair generation via four-wave mixing. • Dynamical light–matter couplings in a phased symmetrical state. • Cooperative Lamb shift in a cylindrical atomic ensemble.

  10. Absolute Gravity Datum in the Age of Cold Atom Gravimeters

    Science.gov (United States)

    Childers, V. A.; Eckl, M. C.

    2014-12-01

    The international gravity datum is defined today by the International Gravity Standardization Net of 1971 (IGSN-71). The data supporting this network was measured in the 1950s and 60s using pendulum and spring-based gravimeter ties (plus some new ballistic absolute meters) to replace the prior protocol of referencing all gravity values to the earlier Potsdam value. Since this time, gravimeter technology has advanced significantly with the development and refinement of the FG-5 (the current standard of the industry) and again with the soon-to-be-available cold atom interferometric absolute gravimeters. This latest development is anticipated to provide improvement in the range of two orders of magnitude as compared to the measurement accuracy of technology utilized to develop ISGN-71. In this presentation, we will explore how the IGSN-71 might best be "modernized" given today's requirements and available instruments and resources. The National Geodetic Survey (NGS), along with other relevant US Government agencies, is concerned about establishing gravity control to establish and maintain high order geodetic networks as part of the nation's essential infrastructure. The need to modernize the nation's geodetic infrastructure was highlighted in "Precise Geodetic Infrastructure, National Requirements for a Shared Resource" National Academy of Science, 2010. The NGS mission, as dictated by Congress, is to establish and maintain the National Spatial Reference System, which includes gravity measurements. Absolute gravimeters measure the total gravity field directly and do not involve ties to other measurements. Periodic "intercomparisons" of multiple absolute gravimeters at reference gravity sites are used to constrain the behavior of the instruments to ensure that each would yield reasonably similar measurements of the same location (i.e. yield a sufficiently consistent datum when measured in disparate locales). New atomic interferometric gravimeters promise a significant

  11. Reactor cold neutron source facility, the first in Japan

    International Nuclear Information System (INIS)

    Utsuro, Masahiko; Maeda, Yutaka; Kawai, Takeshi; Tashiro, Tameyoshi; Sakakibara, Shoji; Katada, Minoru.

    1986-01-01

    In the Research Reactor Institute, Kyoto University, the first cold neutron source facility for the reactor in Japan was installed, and various tests are carried out outside the reactor. Nippon Sanso K.K. had manufactured it. After the prescribed tests outside the reactor, this facility will be installed soon in the reactor, and its outline is described on this occasion. Cold neutrons are those having very small energy by being cooled to about-250 deg C. Since the wavelength of the material waves of cold neutrons is long, and their energy is small, they are very advantageous as an experimental means for clarifying the structure of living body molecules and polymers, the atom configuration in alloys, and atomic and molecular movements by neutron scattering and neutron diffraction. The basic principle of the cold neutron source facility is to irradiate thermal neutrons on a cold moderator kept around 20 K, and to moderate and cool the neutrons by nuclear scattering to convert to cold neutrons. The preparatory research on cold neutrons and hydrogen liquefaction, the basic design to put the cold neutron source facility in the graphite moderator facility, the safety countermeasures, the manufacture and quality control, the operation outside the reactor and the performance are reported. The cold neutron source facility comprises a cold moderator tank and other main parts, a deuterium gas tank, a helium refrigerator and instrumentation. (Kako, I.)

  12. Convergent close-coupling calculations of low-energy positron-atomic-hydrogen scattering

    International Nuclear Information System (INIS)

    Bray, I.; Stelbovics, A.T.

    1993-07-01

    The convergent close coupling approach developed by the authors is applied to positron scattering from atomic hydrogen below the first excitation threshold. In this approach the multi-channel expansion one-electron states are obtained by diagonalizing the target Hamiltonian in a large Laguerre basis. It is demonstrated that this expansion of the scattering wave function is sufficient to reproduce the very accurate low-energy variational results, provided target states with l≤ 15 are included in the expansions. 10 refs., 1 tab

  13. Inductively coupled plasma for atomic emission spectroscopy at the Savannah River Plant

    International Nuclear Information System (INIS)

    Coleman, J.T.

    1986-01-01

    The Savannah River Plant atomic emission spectroscopy laboratory has been in operation for over 30 years. Routine analytical methods and instrumentation are being replaced with current technology. Laboratory renovation will include the installation of contained dual excitation sources (inductively coupled plasma and d-c arc) with a direct reading spectrometer. The instrument will be used to provide impurity analyses of plutonium, uranium, and other nuclear fuel cycle materials

  14. Characterisation of an Ar-H2-O2 ICP by OES: Measurement of the atomic concentrations of H and O

    International Nuclear Information System (INIS)

    Altenberend J; Majchrzak M; Delannoy Y; Chichignoud G

    2011-01-01

    In order to characterize an inductively coupled plasma torch used in refining of metallurgical silicon, we have developed a spectroscopic method based on absolute emissivity measurements and Abel inversion. This method permitted to measure the concentrations of atomic hydrogen and atomic oxygen, which are among the reactive species involved in the purification process. Assuming LTE, the temperature profiles are deduced from the emissivity of the Argon lines. The concentration of atomic oxygen is deduced from the intensity ratio O/Ar. The hydrogen concentration measurement has to take into account the Stark broadening and the Doppler broadening of the hydrogen lines. The comparison between experimental and simulated line profiles permits to determine this concentration. The method has been tested on 2 kW and 30 kW inductively coupled plasma torches at atmospheric pressure. The results show that the concentrations of atomic oxygen and atomic hydrogen can be measured with an accuracy of 25%. The main disadvantage of this method is that, using emission, it does not permit to measure the concentration in the 'cold' zone of the plasma, i.e. at the edges.

  15. Multiple ionization and coupling effects in L-subshell ionization of heavy atoms by oxygen ions

    International Nuclear Information System (INIS)

    Pajek, M.; Banas, D.; Semaniak, J.; Braziewicz, J.; Majewska, U.; Chojnacki, S.; Czyzewski, T.; Fijal, I.; Jaskola, M.; Glombik, A.; Kretschmer, W.; Trautmann, D.; Lapicki, G.; Mukoyama, T.

    2003-01-01

    The multiple-ionization and coupling effects in L-shell ionization of atoms by heavy-ion impact have been studied by measuring the L x-ray production cross sections in solid targets of Au, Bi, Th, and U bombarded by oxygen ions in the energy range 6.4-70 MeV. The measured L x-ray spectra were analyzed using the recently proposed method accounting for the multiple-ionization effects, such as x-ray line shifting and broadening, which enables one to obtain the ionization probabilities for outer shells. The L-subshell ionization cross sections have been obtained from measured x-ray production cross sections for resolved Lα 1,2 , Lγ 1 , and Lγ 2,3 transitions using the L-shell fluorescence and Coster-Kronig yields being substantially modified by the multiple ionization in the M and N shells. In particular, the effect of closing of strong L 1 -L 3 M 4,5 Coster-Kronig transitions in multiple-ionized atoms was evidenced and discussed. The experimental ionization cross sections for the L 1 , L 2 , and L 3 subshells have been compared with the predictions of the semiclassical approximation (SCA) and the ECPSSR theory that includes the corrections for the binding-polarization effect within the perturbed stationary states approximation, the projecticle energy loss, and Coulomb deflection effects as well as the relativistic description of inner-shell electrons. These approaches were further modified to include the L-subshell couplings within the ''coupled-subshell model'' (CSM). Both approaches, when modified for the coupling effects, are in better agreement with the data. Particularly, the predictions of the SCA-CSM calculations reproduce the experimental L-subshell ionization cross section reasonably well. Remaining discrepancies are discussed qualitatively, in terms of further modifications of the L-shell decay rates caused by a change of electronic wave functions in multiple-ionized atoms

  16. Ionization Spectroscopic Measurement of nP Rydberg Levels of 87Rb Cold Atoms

    Science.gov (United States)

    Li, Yufan; Zaheeruddin, Syed; Zhao, Dongmei; Ma, Xinwen; Yang, Jie

    2018-05-01

    We created an ultracold plasma via the spontaneous ionization of cold dense Rydberg atoms of 87Rb in a magneto-optical trap (MOT), and measured the nS1/2 (n = 50-80), nP1/2 (n = 16-23), nP3/2 (n = 16-98), and nD5/2 (n = 49-96) Rydberg levels by detecting the electrons in the ultracold plasma. By fitting the energy levels of Rydberg states, the first ionization potential of 33690.950(11) cm-1 and the quantum defects of S, P, and D orbitals were obtained. The absolute transition energies of nS1/2 (n = 66-80), nP1/2 (n = 16-23), nP3/2 (n = 16-98), and nD5/2 (n = 58-96) states of 87Rb, as well as the quantum defects for p1/2 and p3/2 series, are given for the first time.

  17. Computational Fluid Dynamics Analysis of Cold Plasma Plume Mixing with Blood Using Level Set Method Coupled with Heat Transfer

    Directory of Open Access Journals (Sweden)

    Mehrdad Shahmohammadi Beni

    2017-06-01

    Full Text Available Cold plasmas were proposed for treatment of leukemia. In the present work, conceptual designs of mixing chambers that increased the contact between the two fluids (plasma and blood through addition of obstacles within rectangular-block-shaped chambers were proposed and the dynamic mixing between the plasma and blood were studied using the level set method coupled with heat transfer. Enhancement of mixing between blood and plasma in the presence of obstacles was demonstrated. Continuous tracking of fluid mixing with determination of temperature distributions was enabled by the present model, which would be a useful tool for future development of cold plasma devices for treatment of blood-related diseases such as leukemia.

  18. Fabrication of Al doped ZnO films using atmospheric pressure cold plasma

    International Nuclear Information System (INIS)

    Suzaki, Yoshifumi; Miyagawa, Hayato; Yamaguchi, Kenzo; Kim, Yoon-Kee

    2012-01-01

    Under atmospheric pressure, homogeneous non-equilibrium cold plasma was generated stably by high voltage pulsed power (1 kV, 20 kHz, 38 W) excitation of a mixture of He and O 2 gases produced by a dielectric barrier discharge setup. By feeding Bis (2 methoxy‐6-methyl‐3, 5-heptanedione) Zn (Zn-MOPD, C 18 H 3 O 6 Zn) and Tris (2-methoxy‐6‐methy l‐3, 5-heptanedione) Al (Al-MOPD, C 27 H 45 O 9 Al) into this plasma with He carrier gas, transparent flat Al-doped ZnO (ZnO:Al) films about 120–240 nm thick were prepared on glass substrates directly under the slit made into the cathode. Deposition rates of the films were about 20–40 nm/min. The concentration of Al was measured by inductively coupled plasma atomic emission spectroscopy. The composition ratio of Al to Zn was 7.8 mol% when the carrier He gas flow rate of Al-MOPD was 30 cm 3 . The average transmittance of all films was more than 85% in the wavelength range from 400 to 800 nm. When the composition ratio of Al/Zn was between 1.1 and 7.8 mol%, the optical band gap of the film increased from 3.28 to 3.40 eV. The resistivity of ZnO:Al film was 2.96 Ω cm at 1.3 mol% of Al/Zn. In addition, the microstructure of the films was studied by X-ray diffraction measurement and field emission scanning electron microscope observation. It was revealed that doped Al is substituted onto the Zn site of the ZnO crystalline structure in ZnO:Al films. - Highlights: ► An atmospheric pressure cold plasma generator generated stable glow discharge. ► We fabricated Al doped ZnO films on glass substrates using cold plasma. ► Al concentration measured by inductively coupled plasma atomic emission spectroscopy. ► The transmission spectrum and the resistivity of the films were measured. ► The microstructure of the films was studied.

  19. Influence of driving frequency on oxygen atom density in O2 radio frequency capacitively coupled plasma

    International Nuclear Information System (INIS)

    Kitajima, Takeshi; Noro, Kouichi; Nakano, Toshiki; Makabe, Toshiaki

    2004-01-01

    The influence of the driving frequency on the absolute oxygen atom density in an O 2 radio frequency (RF) capacitively coupled plasma (CCP) was investigated using vacuum ultraviolet absorption spectroscopy with pulse modulation of the main plasma. A low-power operation of a compact inductively coupled plasma light source was enabled to avoid the significant measurement errors caused by self-absorption in the light source. The pulse modulation of the main plasma enabled accurate absorption measurement for high plasma density conditions by eliminating background signals due to light emission from the main plasma. As for the effects of the driving frequency, the effect of VHF (100 MHz) drive on oxygen atom production was small because of the modest increase in plasma density of electronegative O 2 in contrast to the significant increase in electron density previously observed for electropositive Ar. The recombination coefficient of oxygen atoms on the electrode surface was obtained from a decay rate in the afterglow by comparison with a diffusion model, and it showed agreement with previously reported values for several electrode materials

  20. Atomic Quantum Simulations of Abelian and non-Abelian Gauge Theories

    CERN Multimedia

    CERN. Geneva

    2014-01-01

    Using a Fermi-Bose mixture of ultra-cold atoms in an optical lattice, in a collaboration of atomic and particle physicists, we have constructed a quantum simulator for a U(1) gauge theory coupled to fermionic matter. The construction is based on quantum link models which realize continuous gauge symmetry with discrete quantum variables. At low energies, quantum link models with staggered fermions emerge from a Hubbard-type model which can be quantum simulated. This allows investigations of string breaking as well as the real-time evolution after a quench in gauge theories, which are inaccessible to classical simulation methods. Similarly, using ultracold alkaline-earth atoms in optical lattices, we have constructed a quantum simulator for U(N) and SU(N) lattice gauge theories with fermionic matter based on quantum link models. These systems share qualitative features with QCD, including chiral symmetry breaking and restoration at non-zero temperature or baryon density. Unlike classical simulations, a quantum ...

  1. Coupled dynamics of interacting spin-1 bosons in a double-well potential

    Science.gov (United States)

    Carvalho, D. W. S.; Foerster, A.; Gusmão, M. A.

    2018-03-01

    We present a detailed analysis of dynamical processes involving two or three particles in a double-well potential. Motivated by experimental realizations of such a system with optically trapped cold atoms, we focus on spin-1 bosons with special attention on the effects of a spin-dependent interaction in addition to the usual Hubbard-like repulsive one. For a sufficiently weak tunneling amplitude in comparison to the dominant Hubbard coupling, particle motion is strongly correlated, occurring only under fine-tuned relationships between well-depth asymmetry and interactions. We highlight processes involving tunneling of coupled particle pairs and triads, emphasizing the role of the spin-dependent interaction in resonance conditions.

  2. Measurements of diffusion resonances for the atom optics quantum kicked rotor

    International Nuclear Information System (INIS)

    Williams, M E K; Sadgrove, M P; Daley, A J; Gray, R N C; Tan, S M; Parkins, A S; Christensen, N; Leonhardt, R

    2004-01-01

    We present experimental observations of diffusion resonances for the quantum kicked rotor with weak decoherence. Cold caesium atoms are subject to a pulsed standing wave of near-resonant light, with spontaneous emission providing environmental coupling. The mean energy as a function of the pulse period is determined during the late-time diffusion period for a constant probability of spontaneous emission. Structure in the late-time energy is seen to increase with physical kicking strength. The observed structure is related to Shepelyansky's predictions for the initial quantum diffusion rates

  3. Sub-Doppler temperature measurements of laser-cooled atoms using optical nanofibres

    International Nuclear Information System (INIS)

    Russell, Laura; Daly, Mark J; Chormaic, Síle Nic; Deasy, Kieran; Morrissey, Michael J

    2012-01-01

    We present a method for measuring the average temperature of a cloud of cold 85 Rb atoms in a magneto-optical trap using an optical nanofibre. A periodic spatial variation is applied to the magnetic fields generated by the trapping coils and this causes the trap centre to oscillate, which, in turn, causes the cloud of cold atoms to oscillate. The optical nanofibre is used to collect the fluorescence emitted by the cold atoms, and the frequency response between the motion of the centre of the oscillating trap and the cloud of atoms is determined. This allows us to make measurements of cloud temperature both above and below the Doppler limit, thereby paving the way for nanofibres to be integrated with ultracold atoms for hybrid quantum devices

  4. Development of asymptotic methods for the study of interactions between cold atoms: determination of scattering lengths of sodium and cesium; Developpement de methodes asymptotiques pour l'etude des interactions entre atomes froids: determination de longueurs de diffusion du sodium et du cesium

    Energy Technology Data Exchange (ETDEWEB)

    T' Jampens, B

    2002-12-15

    Precise knowledge of cold-atom collision properties is essential for the studies of Bose-Einstein condensation or cold molecule formation. In such experiments, the interaction mainly occurs at rather large interatomic distance, in the so-called asymptotic region. We have developed a purely asymptotic method which allows us to fully describe the collision properties of cold alkali atoms without using the inner part of the molecular potentials, which is often known with a poor precision. The key point of the method is the setting of nodal lines, which are the lines connecting the nodes of successive radial wavefunctions near the ground state threshold. Within the framework of Born-Oppenheimer approximation, computing such nodal lines, by numerical integration of the radial Schroedinger equation in the asymptotic region only, provides a very simple way to derive scattering lengths from observed bound level positions. The method has been extended to the multichannel case and appears now as a genuine parametric method, in which a few parameters (some chosen nodal lines) replace the inner part of the potentials. These nodal lines are used as fitting parameters, which are adjusted on experimental results. Once these parameters have been determined, any collision property such as scattering lengths, clock shifts or magnetic field induced Feshbach resonances can be deduced in principle. This method has been applied to obtain the collision properties of ultracold sodium and cesium atoms. (author)

  5. Precision spectroscopy of the 2S-4P{sub 1/2} transition in atomic hydrogen on a cold thermal beam of optically excited 2S atoms

    Energy Technology Data Exchange (ETDEWEB)

    Beyer, Axel; Kolachevsky, Nikolai; Alnis, Janis; Yost, Dylan C.; Matveev, Arthur; Parthey, Christian G.; Pohl, Randolf; Udem, Thomas [Max-Planck-Institut fuer Quantenoptik, 85748 Garching (Germany); Khabarova, Ksenia [FSUE ' VNIIFTRI' , 141570 Moscow (Russian Federation); Haensch, Theodor W. [Max-Planck-Institut fuer Quantenoptik, 85748 Garching (Germany); Ludwig-Maximilians-Universitaet, 80799 Muenchen (Germany)

    2013-07-01

    The 'proton size puzzle', i.e. the discrepancy between the values for the proton r.m.s. charge radius deduced from precision spectroscopy of atomic hydrogen and electron-proton-scattering on one side and the value deduced from muonic hydrogen spectroscopy on the other side, has been persisting for more than two years now. Although huge efforts have been put into trying to resolve this discrepancy from experimental and theoretical side, no convincing argument could be found so far. In this talk, we report on a unique precision spectroscopy experiment on atomic hydrogen, which is aiming to bring some light to the hydrogen part of the puzzle: In contrast to any previous high resolution experiment probing a transition frequency between the meta-stable 2S state and a higher lying nL state (n=3,4,6,8,12, L=S,P,D), our measurement of the 2S-4P{sub 1/2} transition frequency is the first experiment being performed on a cold thermal beam of hydrogen atoms optically excited to the 2S state. We will discuss how this helps to efficiently suppresses leading systematic effects of previous measurements and present the preliminary results we obtained so far.

  6. Coupled-channels calculations of excitation and ionization in ion-atom collisions

    International Nuclear Information System (INIS)

    Martir, M.H.

    1981-01-01

    A numerical method has been used to compute excitation and ionization cross sections for ion-atom collisions. The projectile is treated classically and follows a straight line, constant velocity path (unless indicated otherwise). The wave function that describes the atom is expanded about the target in a truncated Hilbert space. The interaction between the projectile and the target atom is treated as a time dependent perturbation. A unitary time development operator, U, propagates the wave function from a time prior to the collision to a time after the collision in small time steps. Contrary to first-order theories, coupling between states is allowed. This method has been improved so that any number of partial waves can be included in the wave function expansion. This method has been applied to study negatively charged projectiles. Cross sections are obtained for collisions of antiprotons on atomic hydrogen (30 keV to 372 keV) and compared with cross sections of protons on atomic hydrogen to explore the Z/sub P/ dependence. The antiproton-hydrogen results were converted into electron-hydrogen values with E/sub e/ = E/sub P/(m/sub e//m/sub P/) (15 eV to 200 eV) and compared to experimental values. The method is then applied to study vacancy production from the L-shell. The partial wave convergence of the cross sections was carefully studied for s through g waves. Collisions between protons (and alpha-particles) and argon are studied to explore the Z/sub P/ dependence of the cross sections. The cross section ratio sigma(α)/(4sigma(p)) is compared to experiment

  7. Control and manipulation of cold atoms in optical tweezers

    International Nuclear Information System (INIS)

    Muldoon, Cecilia; Brandt, Lukas; Dong Jian; Stuart, Dustin; Brainis, Edouard; Himsworth, Matthew; Kuhn, Axel

    2012-01-01

    Neutral atoms trapped by laser light are among the most promising candidates for storing and processing information in a quantum computer or simulator. The application certainly calls for a scalable and flexible scheme for addressing and manipulating the atoms. We have now made this a reality by implementing a fast and versatile method to dynamically control the position of neutral atoms trapped in optical tweezers. The tweezers result from a spatial light modulator (SLM) controlling and shaping a large number of optical dipole-force traps. Trapped atoms adapt to any change in the potential landscape, such that one can rearrange and randomly access individual sites within atom-trap arrays. (paper)

  8. EDITORIAL: Focus on Cold and Ultracold Molecules FOCUS ON COLD AND ULTRACOLD MOLECULES

    Science.gov (United States)

    Carr, Lincoln D.; Ye, Jun

    2009-05-01

    Cold and ultracold molecules are the next wave of ultracold physics, giving rise to an exciting array of scientific opportunities, including many body physics for novel quantum phase transitions, new states of matter, and quantum information processing. Precision tests of fundamental physical laws benefit from the existence of molecular internal structure with exquisite control. The study of novel collision and reaction dynamics will open a new chapter of quantum chemistry. Cold molecules bring together researchers from a variety of fields, including atomic, molecular, and optical physics, chemistry and chemical physics, quantum information science and quantum simulations, condensed matter physics, nuclear physics, and astrophysics, a truly remarkable synergy of scientific explorations. For the past decade there have been steady advances in direct cooling techniques, from buffer-gas cooling to cold molecular beams to electro- and magneto-molecular decelerators. These techniques have allowed a large variety of molecules to be cooled for pioneering studies. Recent amazing advances in experimental techniques combining the ultracold and the ultraprecise have furthermore brought molecules to the point of quantum degeneracy. These latter indirect cooling techniques magnetically associate atoms from a Bose-Einstein condensate and/or a quantum degenerate Fermi gas, transferring at 90% efficiency highly excited Fano-Feshbach molecules, which are on the order of 10 000 Bohr radii in size, to absolute ground state molecules just a few Bohr across. It was this latter advance, together with significant breakthroughs in internal state manipulations, which inspired us to coordinate this focus issue now, and is the reason why we say the next wave of ultracold physics has now arrived. Whether directly or indirectly cooled, heteronuclear polar molecules offer distinct new features in comparison to cold atoms, while sharing all of their advantages (purity, high coherence

  9. Decreased expression of G-protein coupled receptor kinase 2 in cold thyroid nodules.

    Science.gov (United States)

    Voigt, C; Holzapfel, H-P; Paschke, R

    2005-02-01

    G-protein coupled receptor kinases (GRKs) have been shown to regulate the homologous desensitization of different G-protein coupled receptors. We have previously demonstrated that the expression of GRK 3 and 4 is increased in hyperfunctioning thyroid nodules (HTNs) and that GRKs 2, 3, 5 and 6 are able to desensitize the TSHR in vitro. Since cold thyroid nodules (CTNs) and HTNs show different molecular and functional properties, different expression patterns of GRKs in these nodules can be expected. The comparison of GRK expression between CTNs and HTNs could give additional insight into the regulation mechanisms of these nodules. We therefore examined the expression of GRKs in CTNs and analyzed the differences to HTNs. The expression of the different GRKs in CTNs was measured by Western blot followed by chemiluminescence imaging. We found a decreased expression of GRK 2 in CTNs compared to their surrounding tissues and an increased expression of GRK 3 and 4 in CTNs, which is similar to HTNs. The decreased GRK 2 expression most likely results from reduced cAMP stimulation in CTNs. However, the increased GRK 3 and 4 expression in CTNs remains unclear and requires further investigations.

  10. Determination of thiomersal by flow injection coupled with microwave-assisted photochemical online oxidative decomposition of organic mercury and cold vapor atomic fluorescence spectroscopy

    International Nuclear Information System (INIS)

    Campanella, Beatrice; Onor, Massimo; Mascherpa, Marco Carlo; D’Ulivo, Alessandro; Ferrari, Carlo; Bramanti, Emilia

    2013-01-01

    Graphical abstract: -- Highlights: •Thiomersal was determined on line using FI-MW/UV-CVGAFS. •MW/UV allows a “green” on line oxidation of organic mercury to Hg II . •Each measure requires less than 5 min with a LOD of 3 ng mL −1 (as mercury). •Hg concentration in commercial ophthalmic solutions ranges between 7.5 and 59.0 μg mL −1 . -- Abstract: We developed a flow injection (FI) method for the determination of thiomersal (sodium ethylmercurithiosalicylate, C 9 H 9 HgNaO 2 S) based on the UV/microwave (MW) photochemical, online oxidation of organic mercury, followed by cold vapor generation atomic fluorescence spectrometry (CVG-AFS) detection. Thiomersal was quantitatively converted in the MW/UV process to Hg(II), with a yield of 97 ± 3%. This reaction was followed by the reduction of Hg(II) to Hg(0) performed in a knotted reaction coil with NaBH 4 solution, and AFS detection in an Ar/H 2 miniaturized flame. The method was linear in the 0.01–2 μg mL −1 range, with a LOD of 0.003 μg mL −1 . This method has been applied to the determination of thiomersal in ophthalmic solutions, with recoveries ranging between 97% and 101%. We found a mercury concentration in commercial ophthalmic solutions ranging between 7.5 and 59.0 μg mL −1

  11. Recent advances in on-line coupling of capillary electrophoresis to atomic absorption and fluorescence spectrometry for speciation analysis and studies of metal-biomolecule interactions

    International Nuclear Information System (INIS)

    Li Yan; Yin Xuebo; Yan Xiuping

    2008-01-01

    Speciation information is vital for the understanding of the toxicity, mobility and bioavailability of elements in environmental or biological samples. Hyphenating high resolving power of separation techniques and element-selective detectors provides powerful tools for studying speciation of trace elements in environmental and biological systems. During the last five years several novel hybrid techniques based on capillary electrophoresis (CE) and atomic spectrometry have been developed for speciation analysis and metal-biomolecule interaction study in our laboratory. These techniques include CE on-line coupled with atomic fluorescence spectrometry (AFS), chip-CE on-line coupled with AFS, CE on-line coupled with flame heated quartz furnace atomic absorption spectrometry (FHF-AAS), and CE on-line coupled with electrothermal atomic absorption spectrometry (ETAAS). The necessity for the development of these techniques, their interface design, and applications in speciation analysis and metal-biomolecule interaction study are reviewed. The advantages and limitations of the developed hybrid techniques are critically discussed, and further development is also prospected

  12. A quantum trampoline for ultra-cold atoms

    Science.gov (United States)

    Robert-de-Saint-Vincent, M.; Brantut, J.-P.; Bordé, Ch. J.; Aspect, A.; Bourdel, T.; Bouyer, P.

    2010-01-01

    We have observed the interferometric suspension of a free-falling Bose-Einstein condensate periodically submitted to multiple-order diffraction by a vertical 1D standing wave. This scheme permits simultaneously the compensation of gravity and coherent splitting/recombination of the matter waves. It results in high-contrast interference in the number of atoms detected at constant height. For long suspension times, multiple-wave interference is revealed through a sharpening of the fringes. We characterize our atom interferometer and use it to measure the acceleration of gravity.

  13. Optical lattice clock with strontium atoms: a second generation of cold atom clocks

    International Nuclear Information System (INIS)

    Le Targat, R.

    2007-07-01

    Atomic fountains, based on a microwave transition of Cesium or Rubidium, constitute the state of the art atomic clocks, with a relative accuracy close to 10 -16 . It nevertheless appears today that it will be difficult to go significantly beyond this level with this kind of device. The use of an optical transition, the other parameters being unchanged, gives hope for a 4 or 5 orders of magnitude improvement of the stability and of the relative uncertainty on most systematic effects. As for motional effects on the atoms, they can be controlled on a very different manner if they are trapped in an optical lattice instead of experiencing a free ballistic flight stage, characteristic of fountains. The key point of this approach lies in the fact that the trap can be operated in such a way that a well chosen, weakly allowed, J=0 → J=0 clock transition can be free from light shift effects. In this respect, the strontium atom is one of the most promising candidate, the 1S 0 → 3P 0 transition has a natural width of 1 mHz, and several other easily accessible transitions can be used to efficiently laser cool atoms down to 10 μK. This thesis demonstrates the experimental feasibility of an optical lattice clock based on the strontium atom, and reports on a preliminary evaluation of the relative accuracy with the fermionic isotope 87 Sr, at a level of a few 10 -15 . (author)

  14. A minimalistic and optimized conveyor belt for neutral atoms.

    Science.gov (United States)

    Roy, Ritayan; Condylis, Paul C; Prakash, Vindhiya; Sahagun, Daniel; Hessmo, Björn

    2017-10-20

    Here we report of a design and the performance of an optimized micro-fabricated conveyor belt for precise and adiabatic transportation of cold atoms. A theoretical model is presented to determine optimal currents in conductors used for the transportation. We experimentally demonstrate a fast adiabatic transportation of Rubidium ( 87 Rb) cold atoms with minimal loss and heating with as few as three conveyor belt conductors. This novel design of a multilayered conveyor belt structure is fabricated in aluminium nitride (AlN) because of its outstanding thermal and electrical properties. This demonstration would pave a way for a compact and portable quantum device required for quantum information processing and sensors, where precise positioning of cold atoms is desirable.

  15. Development of inductively coupled plasma atomic emission spectrometry for palladium and Rhodium determination in platinum-based alloy

    International Nuclear Information System (INIS)

    Kovacevic, R.; Todorovic, M.; Manojlovic, D.; Mutic, J.

    2008-01-01

    Inductively coupled plasma atomic emission spectroscopy with internal standardization was applied for the analysis of an in-house reference platinum alloy containing palladium and rhodium (approximately 5% by weight). In order to compensate for variations in signal recovery due to matrix interferences, and therefore to improve the precision, platinum. the major component, was chosen as an internal standard. Quantitative analysis was based on calibration using a set of matrix-matched calibration standards with and without employing the internal standard. These results were compared with those obtained by X-ray fluorescence spectroscopy. The results for both techniques were in a good agreement, although the precision was slightly better in the inductively coupled plasma atomic emission spectroscopy technique, with or without the internal standard

  16. Self-consistent coupling of atomic orbitals to a moving charge

    International Nuclear Information System (INIS)

    Da Costa, H.F.M.; Micha, D.A.

    1994-01-01

    The authors describe the time evolution of hydrogenic orbitals perturbed by a moving charge. Starting with the equation for an atom interacting with a charge, the authors use an eikonal representation of the total wave-function, followed by an eikonal approximation, to derive coupled differential equations for the temporal change of the orbitals and the charge's trajectory. The orbitals are represented by functions with complex exponents changing with time, describing electronic density and flux changes. For each orbital, they solve a set of six coupled differential equations; two of them are derived with a time-dependent variational procedure for the real and imaginary parts of the exponents, and the other four are the Hamilton equations of the positions and momenta of the moving charge. The molecular potentials are derived from the exact expressions for the electronic energies. Results of calculations for 1s and 2s orbitals show large variation of the real exponent parts over time, with respect to asymptotic values, and that imaginary parts remain small

  17. Ultrafast Coulomb-Induced Intervalley Coupling in Atomically Thin WS2.

    Science.gov (United States)

    Schmidt, Robert; Berghäuser, Gunnar; Schneider, Robert; Selig, Malte; Tonndorf, Philipp; Malić, Ermin; Knorr, Andreas; Michaelis de Vasconcellos, Steffen; Bratschitsch, Rudolf

    2016-05-11

    Monolayers of semiconducting transition metal dichalcogenides hold the promise for a new paradigm in electronics by exploiting the valley degree of freedom in addition to charge and spin. For MoS2, WS2, and WSe2, valley polarization can be conveniently initialized and read out by circularly polarized light. However, the underlying microscopic processes governing valley polarization in these atomically thin equivalents of graphene are still not fully understood. Here, we present a joint experiment-theory study on the ultrafast time-resolved intervalley dynamics in monolayer WS2. Based on a microscopic theory, we reveal the many-particle mechanisms behind the observed spectral features. We show that Coulomb-induced intervalley coupling explains the immediate and prominent pump-probe signal in the unpumped valley and the seemingly low valley polarization degrees typically observed in pump-probe measurements compared to photoluminescence studies. The gained insights are also applicable to other light-emitting monolayer transition metal dichalcogenides, such as MoS2 and WSe2, where the Coulomb-induced intervalley coupling also determines the initial carrier dynamics.

  18. Effects of doping in 25-atom bimetallic nanocluster catalysts for carbon–carbon coupling reaction of iodoanisole and phenylacetylene

    Directory of Open Access Journals (Sweden)

    Zhimin Li

    2016-10-01

    Full Text Available We here report the catalytic effects of foreign atoms (Cu, Ag, and Pt doped into well-defined 25-gold-atom nanoclusters. Using the carbon-carbon coupling reaction of p-iodoanisole and phenylacetylene as a model reaction, the gold-based bimetallic MxAu25−x(SR18 (–SR=–SCH2CH2Ph nanoclusters (supported on titania were found to exhibit distinct effects on the conversion of p-iodoanisole as well as the selectivity for the Sonogashira cross-coupling product, 1-methoxy-4-(2-phenylethynylbenzene. Compared to Au25(SR18, the centrally doped Pt1Au24(SR18 causes a drop in catalytic activity but with the selectivity retained, while the AgxAu25−x(SR18 nanoclusters gave an overall performance comparable to Au25(SR18. Interestingly, CuxAu25−x(SR18 nanoclusters prefer the Ullmann homo-coupling pathway and give rise to product 4,4′-dimethoxy-1,1′-biphenyl, which is in opposite to the other three nanocluster catalysts. Our overall conclusion is that the conversion of p-iodoanisole is largely affected by the electronic effect in the bimetallic nanoclusters’ 13-atom core (i.e., Pt1Au12, CuxAu13−x, and Au13, with the exception of Ag doping, and that the selectivity is primarily determined by the type of atoms on the MxAu12−x shell (M=Ag, Cu, and Au in the nanocluster catalysts.

  19. Determination of rare earth elements in aluminum by inductively coupled plasma-atomic emission spectroscopy

    International Nuclear Information System (INIS)

    Mahanti, H.S.; Barnes, R.M.

    1983-01-01

    Inductively coupled plasma-atomic emission spectroscopy is evaluated for the determination of 14 rare earth elements in aluminum. Spectral line interference, limit of detection, and background equivalent concentration values are evaluated, and quantitative recovery is obtained from aluminum samples spiked with rare earth elements. The procedure is simple and suitable for routine process control analysis. 20 references, 5 tables

  20. Key technologies and applications of laser cooling and trapping "8"7Rb atomic system

    International Nuclear Information System (INIS)

    Ru, Ning; Zhang, Li; Wang, Yu; Fan, Shangchun

    2016-01-01

    Atom Interferometry is proved to be a potential method for measuring the acceleration of atoms due to Gravity, we are now building a feasible system of cold atom gravimeter. In this paper development and the important applications of laser cooling and trapping atoms are introduced, some key techniques which are used to obtain "8"7Rb cold atoms in our experiments are also discussed.

  1. The dynamics of coupled atom and field assisted by continuous external pumping

    International Nuclear Information System (INIS)

    Burlak, G.; Hernandez, J.A.; Starostenko, O.

    2006-01-01

    The dynamics of a coupled system comprising a two-level atom and cavity field assisted by a continuous external classical field (driving Jaynes-Cummings model) is studied. When the initial field is prepared in a coherent state, the dynamics strongly depends on the algebraic sum of both fields. If this sum is zero (the compensative case) in the system, only the vacuum Rabi oscillations occur. The results with dissipation and external field detuning from the cavity field are also discussed. (Author)

  2. The dynamics of coupled atom and field assisted by continuous external pumping

    Energy Technology Data Exchange (ETDEWEB)

    Burlak, G.; Hernandez, J.A. [Centro de Investigacion en Ingenieria y Ciencias Aplicadas, Universidad Autonoma de Morelos, Cuernavaca, Morelos (Mexico); Starostenko, O. [Departamento de Fisica, Electronica, Sistemas y Mecatronica, Universidad de las Americas, 72820 Puebla (Mexico)

    2006-07-01

    The dynamics of a coupled system comprising a two-level atom and cavity field assisted by a continuous external classical field (driving Jaynes-Cummings model) is studied. When the initial field is prepared in a coherent state, the dynamics strongly depends on the algebraic sum of both fields. If this sum is zero (the compensative case) in the system, only the vacuum Rabi oscillations occur. The results with dissipation and external field detuning from the cavity field are also discussed. (Author)

  3. Stimulated cold fusion by positronium atoms, cross sections, and wall interactions in plasmas, used to diagnostics

    International Nuclear Information System (INIS)

    Emami, Z.

    2005-01-01

    Because of the technical complexities, involved in the controlled thermonuclear, reactions, a simple vicegerent agent cold plasma, stimulated by positronium atoms (achieved through a ring storage) as stimulus, introduced by this author in ITC 12 conference. In the present paper, the interaction between γ rays emitted through positronium atoms annihilation (in the forms of doublet and triplet electromagnetic photonic radiation) with plasma particles (including electrons, ions and neutral particles) investigated. Proper lifetime of singlet γ rays τs are about 100 ns and from that of triplet γ rays, i.e τt about 100 fems, reside in the following transition times in Ne and Argon elements in He-Ne and Ar lasers respectively: Ne*(3S2) [transition time τ = 105 ns] -> Ne*(2P4); Ar+*(3P4 4S) [transition time τ = 105 fems] -> Ar+(3P5). Then the interactions of γ rays with mater in plasma could follow up as treated from that of the laser and mater in one extreme while the comparison of this situation with normal plasmas in other extreme could serve as diagnostics key role in magnetically confined plasmas reactors. Collisions between charge and neutral species in plasma with electromagnetic radiation (γ photonic radiation) including the energy loss and scattering lead to different consequences. Light electrons can take up appreciably amounts of energy from the incident rays, lead to heating cold plasma, whereas massive ions absorb very little energy. Thus loss of incident energy in radiation occurs almost entirely in collisions with electrons , which, referred to the γ rays energy this would led to plasma heating about thermonuclear reaction ( Eγ = hν = 0.5 MeV). The heavy ions and neutral species in interaction with electromagnetic γ radiation, result on the other hand in scattering, in turn may increase the ionization level of the cold plasma, toward fully ionized plasma. Although all the essential features of these different interaction cross sections deduced

  4. Optical properties of an atomic ensemble coupled to a band edge of a photonic crystal waveguide

    Science.gov (United States)

    Munro, Ewan; Kwek, Leong Chuan; Chang, Darrick E.

    2017-08-01

    We study the optical properties of an ensemble of two-level atoms coupled to a 1D photonic crystal waveguide (PCW), which mediates long-range coherent dipole-dipole interactions between the atoms. We show that the long-range interactions can dramatically alter the linear and nonlinear optical behavior, as compared to a typical atomic ensemble. In particular, in the linear regime, we find that the transmission spectrum contains multiple transmission dips, whose properties we characterize. Moreover, we show how the linear spectrum may be used to infer the number of atoms present in the system, constituting an important experimental tool in a regime where techniques for conventional ensembles break down. We also show that some of the transmission dips are associated with an effective ‘two-level’ resonance that forms due to the long-range interactions. In particular, under strong global driving and appropriate conditions, we find that the atomic ensemble is only capable of absorbing and emitting single collective excitations at a time. Our results are of direct relevance to atom-PCW experiments that should soon be realizable.

  5. Determination of thiomersal by flow injection coupled with microwave-assisted photochemical online oxidative decomposition of organic mercury and cold vapor atomic fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Campanella, Beatrice; Onor, Massimo; Mascherpa, Marco Carlo; D’Ulivo, Alessandro [National Research Council of Italy, C.N.R., Istituto di Chimica dei Composti Organo Metallici-ICCOM-UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy); Ferrari, Carlo [National Research Council of Italy, C.N.R., Istituto Nazionale di Ottica, INO–UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy); Bramanti, Emilia, E-mail: bramanti@pi.iccom.cnr.it [National Research Council of Italy, C.N.R., Istituto di Chimica dei Composti Organo Metallici-ICCOM-UOS Pisa, Area di Ricerca, Via G. Moruzzi 1, 56124 Pisa (Italy)

    2013-12-04

    Graphical abstract: -- Highlights: •Thiomersal was determined on line using FI-MW/UV-CVGAFS. •MW/UV allows a “green” on line oxidation of organic mercury to Hg{sup II}. •Each measure requires less than 5 min with a LOD of 3 ng mL{sup −1} (as mercury). •Hg concentration in commercial ophthalmic solutions ranges between 7.5 and 59.0 μg mL{sup −1}. -- Abstract: We developed a flow injection (FI) method for the determination of thiomersal (sodium ethylmercurithiosalicylate, C{sub 9}H{sub 9}HgNaO{sub 2}S) based on the UV/microwave (MW) photochemical, online oxidation of organic mercury, followed by cold vapor generation atomic fluorescence spectrometry (CVG-AFS) detection. Thiomersal was quantitatively converted in the MW/UV process to Hg(II), with a yield of 97 ± 3%. This reaction was followed by the reduction of Hg(II) to Hg(0) performed in a knotted reaction coil with NaBH{sub 4} solution, and AFS detection in an Ar/H{sub 2} miniaturized flame. The method was linear in the 0.01–2 μg mL{sup −1} range, with a LOD of 0.003 μg mL{sup −1}. This method has been applied to the determination of thiomersal in ophthalmic solutions, with recoveries ranging between 97% and 101%. We found a mercury concentration in commercial ophthalmic solutions ranging between 7.5 and 59.0 μg mL{sup −1}.

  6. Investigation of multi-stage cold forward extrusion process using coupled thermo-mechanical finite element analysis

    Science.gov (United States)

    Görtan, Mehmet Okan

    2018-05-01

    Cold extrusion processes are distinguished by their low material usage as well as great efficiency in the production of mid-range and large component series. Although majority of the cold extruded parts are produced using die systems containing multiple forming stages, this subject has rarely been investigated so far. Therefore, the characteristics of multi-stage cold forward rod extrusion is studied in the current work using thermo-mechanically coupled finite element (FE) analysis. A case hardening steel, 16MnCr5 (1.7131) was used as experimental material. Its strain, strain rate and temperature dependent mechanical characteristics were determined using compression testing and modeled in FE simulations via a Johnson-Cook material model. Friction coefficients for the same material while in contact with a tool steel (1.2379) were determined dependent on temperature and contact pressure using sliding compression test (SCT) and modeled by an adaptive friction model developed by the author. In the first set of simulations, rod material with a diameter of 14.9 mm was extruded down to a diameter of 9.6 mm in a single step using three different die opening angles (2α); 20°, 40° and 60°. In the second set of investigations, the same rod was reduced first to 12 mm and then to 9.6 mm in two steps within the same forming die. Press forces, contact normal stresses between extruded material and forming die, material temperature and axial stresses are compared in these two set of simulations and the differences are discussed.

  7. Coherent and radiative couplings through two-dimensional structured environments

    Science.gov (United States)

    Galve, F.; Zambrini, R.

    2018-03-01

    We study coherent and radiative interactions induced among two or more quantum units by coupling them to two-dimensional (2D) lattices acting as structured environments. This model can be representative of atoms trapped near photonic crystal slabs, trapped ions in Coulomb crystals, or to surface acoustic waves on piezoelectric materials, cold atoms on state-dependent optical lattices, or even circuit QED architectures, to name a few. We compare coherent and radiative contributions for the isotropic and directional regimes of emission into the lattice, for infinite and finite lattices, highlighting their differences and existing pitfalls, e.g., related to long-time or large-lattice limits. We relate the phenomenon of directionality of emission with linear-shaped isofrequency manifolds in the dispersion relation, showing a simple way to disrupt it. For finite lattices, we study further details such as the scaling of resonant number of lattice modes for the isotropic and directional regimes, and relate this behavior with known van Hove singularities in the infinite lattice limit. Furthermore, we export the understanding of emission dynamics with the decay of entanglement for two quantum, atomic or bosonic, units coupled to the 2D lattice. We analyze in some detail completely subradiant configurations of more than two atoms, which can occur in the finite lattice scenario, in contrast with the infinite lattice case. Finally, we demonstrate that induced coherent interactions for dark states are zero for the finite lattice.

  8. A metastable helium trap for atomic collision physics

    International Nuclear Information System (INIS)

    Colla, M.; Gulley, R.; Uhlmann, L.; Hoogerland, M.D.; Baldwin, K.G.H.; Buckman, S.J.

    1999-01-01

    Full text: Metastable helium in the 2 3 S state is an important species for atom optics and atomic collision physics. Because of its large internal energy (20eV), long lifetime (∼8000s) and large collision cross section for a range of processes, metastable helium plays an important role in atmospheric physics, plasma discharges and gas laser physics. We have embarked on a program of studies on atom-atom and electron-atom collision processes involving cold metastable helium. We confine metastable helium atoms in a magneto-optic trap (MOT), which is loaded by a transversely collimated, slowed and 2-D focussed atomic beam. We employ diode laser tuned to the 1083 nm (2 3 S 1 - 2 3 P2 1 ) transition to generate laser cooling forces in both the loading beam and the trap. Approximately 10 million helium atoms are trapped at temperatures of ∼ 1mK. We use phase modulation spectroscopy to measure the trapped atomic density. The cold, trapped atoms can collide to produce either atomic He + or molecular He 2 + ions by Penning Ionisation (PI) or Associative Ionisation (AI). The rate of formation of these ions is dependant upon the detuning of the trapping laser from resonance. A further laser can be used to connect the 2 3 S 1 state to another higher lying excited state, and variation of the probe laser detuning used to measure interatomic collision potential. Electron-atom collision processes are studied using a monochromatic electron beam with a well defined spatial current distribution. The total trap loss due to electron collisions is measured as a function of electron energy. Results will be presented for these atomic collision physics measurements involving cold, trapped metastable helium atoms. Copyright (1999) Australian Optical Society

  9. All-optical 3D atomic loops generated with Bessel light fields

    International Nuclear Information System (INIS)

    Volke-Sepulveda, Karen; Jauregui, RocIo

    2009-01-01

    The propagation invariance of Bessel beams as well as their transversal structure is used to perform a comparative analysis of their effect on cold atoms for four different configurations and combinations thereof. We show that, even at temperatures for which the classical description of the atom's centre-of-mass motion is valid, the interchange of momentum, energy and orbital angular momentum between light and atoms yields efficient tools for all-optical trapping, transporting and, in general, manipulating the state of motion of cold atoms.

  10. Inductively coupled plasma-atomic emission spectroscopy

    International Nuclear Information System (INIS)

    Winge, R.K.; Fassel, V.A.; Peterson, V.J.; Floyd, M.A.

    1985-01-01

    This atlas of inductively coupled plasma-atomic emission spectroscopy records the spectra of the elements in a way that would reveal the general nature of the spectra, in all their simplicity or complexity; and offers a definitive summary of the most prominent spectral lines of the elements, i.e., those most likely to be useful for the determination of trace and ultratrace concentrations; it provides reliable estimates, based on the recorded experimental spectra, of the powers of detection of the listed prominent lines; and assesses the very important problem of spectral interferences. The atlas is composed of three main sections. Part I is concerned with the historical aspects of compilations of spectral information. Part II is based on 232 wavelength scans of 70 elements. Each of the wavelength scans covers an 80 nm spectral region. These scans allow a rapid comparison of the background and spectral line intensities emitted in the ICP and provide a ready means for identification of the most prominent lines of each element and for estimation of the trace element analytical capabilities of these lines. A listing of 973 prominent lines with associated detection limits is also presented. Part III addresses the problem of spectral interferences. On this topic a detailed collection of coincidence profiles is presented for 281 of the most prominent lines, each with profiles of ten of the most prevalent concomitants superimposed. (Auth.)

  11. Light-induced gauge fields for ultracold atoms

    Science.gov (United States)

    Goldman, N.; Juzeliūnas, G.; Öhberg, P.; Spielman, I. B.

    2014-12-01

    Gauge fields are central in our modern understanding of physics at all scales. At the highest energy scales known, the microscopic universe is governed by particles interacting with each other through the exchange of gauge bosons. At the largest length scales, our Universe is ruled by gravity, whose gauge structure suggests the existence of a particle—the graviton—that mediates the gravitational force. At the mesoscopic scale, solid-state systems are subjected to gauge fields of different nature: materials can be immersed in external electromagnetic fields, but they can also feature emerging gauge fields in their low-energy description. In this review, we focus on another kind of gauge field: those engineered in systems of ultracold neutral atoms. In these setups, atoms are suitably coupled to laser fields that generate effective gauge potentials in their description. Neutral atoms ‘feeling’ laser-induced gauge potentials can potentially mimic the behavior of an electron gas subjected to a magnetic field, but also, the interaction of elementary particles with non-Abelian gauge fields. Here, we review different realized and proposed techniques for creating gauge potentials—both Abelian and non-Abelian—in atomic systems and discuss their implication in the context of quantum simulation. While most of these setups concern the realization of background and classical gauge potentials, we conclude with more exotic proposals where these synthetic fields might be made dynamical, in view of simulating interacting gauge theories with cold atoms.

  12. Light-induced gauge fields for ultracold atoms

    International Nuclear Information System (INIS)

    Goldman, N; Juzeliūnas, G; Öhberg, P; Spielman, I B

    2014-01-01

    Gauge fields are central in our modern understanding of physics at all scales. At the highest energy scales known, the microscopic universe is governed by particles interacting with each other through the exchange of gauge bosons. At the largest length scales, our Universe is ruled by gravity, whose gauge structure suggests the existence of a particle—the graviton—that mediates the gravitational force. At the mesoscopic scale, solid-state systems are subjected to gauge fields of different nature: materials can be immersed in external electromagnetic fields, but they can also feature emerging gauge fields in their low-energy description. In this review, we focus on another kind of gauge field: those engineered in systems of ultracold neutral atoms. In these setups, atoms are suitably coupled to laser fields that generate effective gauge potentials in their description. Neutral atoms ‘feeling’ laser-induced gauge potentials can potentially mimic the behavior of an electron gas subjected to a magnetic field, but also, the interaction of elementary particles with non-Abelian gauge fields. Here, we review different realized and proposed techniques for creating gauge potentials—both Abelian and non-Abelian—in atomic systems and discuss their implication in the context of quantum simulation. While most of these setups concern the realization of background and classical gauge potentials, we conclude with more exotic proposals where these synthetic fields might be made dynamical, in view of simulating interacting gauge theories with cold atoms. (review article)

  13. Second CERN group produces cold atoms of antihydrogen

    CERN Document Server

    Levi-Goss, Barbara

    2003-01-01

    A new experiment, by CERN's ATRAP collaboration, which introduced a technique for determining the quantum state in which antihydrogen atoms are formed was discussed. To make antihydrogen, antiprotons were taken from CERN's Antiproton Decelerator, further slowed down, and trapped with a configuration of electric fields. The evidence gathered confirmed that the H over bar atoms formed in the experiment occupy highly excited Rydberg states. (Edited abstract) 5 Refs.

  14. Spontaneous emission spectra and simulating multiple spontaneous generation coherence in a five-level atomic medium

    International Nuclear Information System (INIS)

    Li Jiahua; Liu Jibing; Qi Chunchao; Chen Aixi

    2006-01-01

    We investigate the features of the spontaneous emission spectra in a coherently driven cold five-level atomic system by means of a radio frequency (rf) or microwave field driving a hyperfine transition within the ground state. It is shown that a few interesting phenomena such as spectral-line narrowing, spectral-line enhancement, spectral-line suppression, and spontaneous emission quenching can be realized by modulating the frequency and intensity of the rf-driving field in our system. In the dressed-state picture of the coupling and rf-driving fields, we find that this coherently driven atomic system has three close-lying levels so that multiple spontaneously generated coherence (SGC) arises. Our considered atomic model can be found in real atoms, such as rubidium or sodium, so a corresponding experiment can be done to observe the expected phenomena related to SGC reported by Fountoulakis et al. [Phys. Rev. A 73, 033811 (2006)], since no rigorous conditions are required

  15. Steady-state properties of coupled hot and cold Ising chains

    International Nuclear Information System (INIS)

    Lavrentovich, Maxim O

    2012-01-01

    Recently, the present author and Zia (2011 Europhys. Lett. 91 50003) reported on exact results for a far-from-equilibrium system in which two coupled semi-infinite Ising chains at temperatures T h and T c , with T h > T c , establish a flux of energy across their junction. This paper provides a complete derivation of those results, more explicit expressions for the energy flux, and a more detailed characterization of the system at arbitrary T c and T h . We consider the two-point correlation functions and the energy flux F(x) between each spin, located at integer position x, and its associated heat bath. In the T h → ∞ limit, the flux F(x) decays exponentially into the cold bath (spins with x = 1, 2, …) for all T c > 0 and transitions into a power-law decay as T c → 0. We find an asymptotic expansion for large x in terms of modified Bessel functions that captures both of these behaviors. We perform Monte Carlo simulations that give excellent agreement with both the exact and asymptotic results for F(x). The simulations are also used to study the system at arbitrary T h and T c . (paper)

  16. Connection of off-diagonal radiative-decay coupling to electromagnetically induced transparency and amplification without inversion in a three-level atomic system

    International Nuclear Information System (INIS)

    Cardimona, D.A.; Huang Danhong

    2002-01-01

    The equivalence between the off-diagonal radiative-decay coupling (ODRDC) effect in the bare-atom picture of a three-level atomic system [see Cardimona et al., J. Phys. B 15, 55 (1982)] and the electromagnetically induced transparency (EIT) effect in the dressed-atom picture [see Imamoglu et al., Opt. Lett. 14, 1344 (1989)] is uncovered and a full comparison of their physical origins is given. The mechanism for both ODRDC and Harris' EIT is found to be a consequence of the quantum interference between a direct absorption path and an indirect absorption path mediated by either a self absorption of spontaneous photons or a Fano-type coupling. A connection is then pointed out between the effects of probe-field gain (PFG) based on an ODRDC process [see Huang et al., Phys. Rev. A 64, 013822 (2001)] and amplification without inversion (AWI) [see Fearn et al., Opt. Commun. 87, 323 (1992)] in the bare-atom picture of a three-level atomic system. The PFG effect is found as a result of transferring electrons between the two upper levels due to the phase-sensitive coherence provided by a laser-induced ODRDC process, while the AWI effect to one of the two probe fields is attributed to its coupling to a strong laser field generating an off-resonant gain through an induced nonlinearity in the other probe field. Both the advantages and disadvantages as well as the limitations of the ODRDC, EIT, PFG, and AWI effects are discussed and compared

  17. Demonstration of spatial-light-modulation-based four-wave mixing in cold atoms

    Science.gov (United States)

    Juo, Jz-Yuan; Lin, Jia-Kang; Cheng, Chin-Yao; Liu, Zi-Yu; Yu, Ite A.; Chen, Yong-Fan

    2018-05-01

    Long-distance quantum optical communications usually require efficient wave-mixing processes to convert the wavelengths of single photons. Many quantum applications based on electromagnetically induced transparency (EIT) have been proposed and demonstrated at the single-photon level, such as quantum memories, all-optical transistors, and cross-phase modulations. However, EIT-based four-wave mixing (FWM) in a resonant double-Λ configuration has a maximum conversion efficiency (CE) of 25% because of absorptive loss due to spontaneous emission. An improved scheme using spatially modulated intensities of two control fields has been theoretically proposed to overcome this conversion limit. In this study, we first demonstrate wavelength conversion from 780 to 795 nm with a 43% CE by using this scheme at an optical density (OD) of 19 in cold 87Rb atoms. According to the theoretical model, the CE in the proposed scheme can further increase to 96% at an OD of 240 under ideal conditions, thereby attaining an identical CE to that of the previous nonresonant double-Λ scheme at half the OD. This spatial-light-modulation-based FWM scheme can achieve a near-unity CE, thus providing an easy method of implementing an efficient quantum wavelength converter for all-optical quantum information processing.

  18. Single atom oscillations

    International Nuclear Information System (INIS)

    Wiorkowski, P.; Walther, H.

    1990-01-01

    Modern methods of laser spectroscopy allow the study of single atoms or ions in an unperturbed environment. This has opened up interesting new experiments, among them the detailed study of radiation-atom coupling. In this paper, the following two experiments dealing with this problem are reviewed: the single-atom maser and the study of the resonance fluorescence of a single stored ion. The simplest and most fundamental system for studying radiation-matter coupling is a single two-level atom interacting with a single mode of an electromagnetic field in a cavity. This problem received a great deal of attention shortly after the maser was invented

  19. Entropy squeezing for a two-level atom in two-mode Raman coupled model with intrinsic decoherence

    Institute of Scientific and Technical Information of China (English)

    Zhang Jian; Shao Bin; Zou Jian

    2009-01-01

    In this paper,we investigate the entropy squeezing for a two-level atom interacting with two quantized fields through Raman coupling.We obtain the dynamical evolution of the total system under the influence of intrinsic decoherence when the two quantized fields are prepared in a two-mode squeezing vacuum state initially.The effects of the field squeezing factor,the two-level atomic transition frequency,the second field frequency and the intrinsic decoherence on the entropy squeezing are discussed.Without intrinsic decoherence,the increase of field squeezing factor can break the entropy squeezing.The two-level atomic transition frequency changes only the period of oscillation but not the strength of entropy squeezing.The influence of the second field frequency is complicated.With the intrinsic decoherence taken into consideration,the results show that the stronger the intrinsic decoherence is,the more quickly the entropy squeezing will disappear.The increase of the atomic transition frequency can hasten the disappearance of entropy squeezing.

  20. Entropy squeezing for a two-level atom in two-mode Raman coupled model with intrinsic decoherence

    International Nuclear Information System (INIS)

    Jian, Zhang; Bin, Shao; Jian, Zou

    2009-01-01

    In this paper, we investigate the entropy squeezing for a two-level atom interacting with two quantized fields through Raman coupling. We obtain the dynamical evolution of the total system under the influence of intrinsic decoherence when the two quantized fields are prepared in a two-mode squeezing vacuum state initially. The effects of the field squeezing factor, the two-level atomic transition frequency, the second field frequency and the intrinsic decoherence on the entropy squeezing are discussed. Without intrinsic decoherence, the increase of field squeezing factor can break the entropy squeezing. The two-level atomic transition frequency changes only the period of oscillation but not the strength of entropy squeezing. The influence of the second field frequency is complicated. With the intrinsic decoherence taken into consideration, the results show that the stronger the intrinsic decoherence is, the more quickly the entropy squeezing will disappear. The increase of the atomic transition frequency can hasten the disappearance of entropy squeezing. (classical areas of phenomenology)

  1. Matter-wave localization in disordered cold atom lattices.

    Science.gov (United States)

    Gavish, Uri; Castin, Yvan

    2005-07-08

    We propose to observe Anderson localization of ultracold atoms in the presence of a random potential made of atoms of another species or spin state and trapped at the nodes of an optical lattice, with a filling factor less than unity. Such systems enable a nearly perfect experimental control of the disorder, while the possibility of modeling the scattering potentials by a set of pointlike ones allows an exact theoretical analysis. This is illustrated by a detailed analysis of the one-dimensional case.

  2. CERN experiment provides first glimpse inside cold antihydrogen

    CERN Multimedia

    2002-01-01

    "The ATRAP experiment at the Antiproton Decelerator at CERN has detected and measured large numbers of cold antihydrogen atoms. Relying on ionization of the cold antiatoms when they pass through a strong electric field gradient, the ATRAP measurement provides the first glimpse inside an antiatom, and the first information about the physics of antihydrogen. The results have been accepted for publication in Physical Review Letters" (1 page).

  3. Convergent Close-Coupling Calculations for Electron-Atom and Electron-Molecule Scattering

    International Nuclear Information System (INIS)

    Fursa, Dmitry; Zammit, M.C.; Bostock, C.J.; Bray, I.

    2014-01-01

    The Convergent Close-Coupling (CCC) method developed in our group has been applied extensively to study electron-atom/ion collisions and recently has been extended to electron collisions with diatomic molecules. This approach relies on the ability to represent the infinite number of target bound states and its continuum via a finite number of states obtained by a diagonalization of the target in a square-integrable (Sturmian) one-electron basis. We normally use a Laguerre basis though other choices are possible, for example a boxed-based basis or a B-spline basis. The choice of the basis is governed by the physical problem under consideration. As the size of a Sturmian basis increases the calculated negative energy states (relative to the corresponding ionization stage of the target) converge to the target true bound states and the positive energy states provide an increasingly dense representation of the target continuum. We then perform a multichannel expansion of the total (projectile plus target electrons) wave function and formulate a set of close-coupling equations. These equations are transformed into momentum space where they take the form of the Lippmann-Schwinger equations for the T-matrix. A solution of the T-matrix equations is obtained at each total energy E by converting them into a set of linear equations that are solved by standard techniques. We perform a partial-wave expansion of the projectile wave function and take into account the symmetry of the scattering system (e.g, total spin, parity, etc.) in order to reduce the size of the coupled equations and make calculations feasible. As soon as the T-matrix is obtained we can evaluate scattering amplitudes and cross sections for the transitions of interest. For the case of molecular targets the formulation is done within the fixed-nuclei approximation. We adopt a single-centre approach in CCC calculations. This allows us to utilize a great deal of computational development thoroughly tested for

  4. Tunneling couplings in discrete lattices, single-particle band structure, and eigenstates of interacting atom pairs

    International Nuclear Information System (INIS)

    Piil, Rune; Moelmer, Klaus

    2007-01-01

    By adjusting the tunneling couplings over longer than nearest-neighbor distances, it is possible in discrete lattice models to reproduce the properties of the lowest energy band of a real, continuous periodic potential. We propose to include such terms in problems with interacting particles, and we show that they have significant consequences for scattering and bound states of atom pairs in periodic potentials

  5. WISPy cold dark matter

    Energy Technology Data Exchange (ETDEWEB)

    Arias, Paola [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Pontificia Univ. Catolica de Chile, Santiago (Chile). Facultad de Fisica; Cadamuro, Davide; Redondo, Javier [Max-Planck-Institut fuer Physik, Muenchen (Germany); Goodsell, Mark [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); European Organization for Nuclear Research (CERN), Geneva (Switzerland); Jaeckel, Joerg [Durham Univ. (United Kingdom). Inst. for Particle Physics Phenomenology; Ringwald, Andreas [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2012-01-15

    Very weakly interacting slim particles (WISPs), such as axion-like particles (ALPs) or hidden photons (HPs), may be non-thermally produced via the misalignment mechanism in the early universe and survive as a cold dark matter population until today. We find that, both for ALPs and HPs whose dominant interactions with the standard model arise from couplings to photons, a huge region in the parameter spaces spanned by photon coupling and ALP or HP mass can give rise to the observed cold dark matter. Remarkably, a large region of this parameter space coincides with that predicted in well motivated models of fundamental physics. A wide range of experimental searches - exploiting haloscopes (direct dark matter searches exploiting microwave cavities), helioscopes (searches for solar ALPs or HPs), or light-shining-through-a-wall techniques - can probe large parts of this parameter space in the foreseeable future. (orig.)

  6. The coupling of rapidly synergistic cloud point extraction with thermospray flame furnace atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Wen, X.; Deng, Q.; Guo, J.; Zhao, X.; Zhao, Y.; Ji, S.

    2012-01-01

    Rapidly synergistic cloud point extraction (RS-CPE) was coupled with thermospray flame furnace atomic absorption spectrometry (TS-FF-AAS) to result in new CPE patterns and accelerated (1 min) protocols. It is demonstrated, for the case of copper (II) ion, that TS-FF-AAS improves the sampling efficiency and the sensitivity of FAAS determinations. Problems of nebulization associated with previous methods based on the coupling of FAAS and RS-CPE are overcome. TS-FF-AAS also improves sensitivity and gives a limit of detection for copper of 0.20 μg L -1 , which is better by a factor of 32. Compared to direct FAAS, the factor is 114. (author)

  7. Entanglement and Other Nonclassical Properties of Two Two-Level Atoms Interacting with a Two-Mode Binomial Field: Constant and Intensity-Dependent Coupling Regimes

    International Nuclear Information System (INIS)

    Tavassoly, M.K.; Hekmatara, H.

    2015-01-01

    In this paper, we consider the interaction between two two-level atoms and a two-mode binomial field with a general intensity-dependent coupling regime. The outlined dynamical problem has explicit analytical solution, by which we can evaluate a few of its physical features of interest. To achieve the purpose of the paper, after choosing a particular nonlinearity function, we investigate the quantum statistics, atomic population inversion and at last the linear entropy of the atom-field system which is a good measure for the degree of entanglement. In detail, the effects of binomial field parameters, in addition to different initial atomic states on the temporal behavior of the mentioned quantities have been analyzed. The results show that, the values of binomial field parameters and the initial state of the two atoms influence on the nonclassical effects in the obtained states through which one can tune the nonclassicality criteria appropriately. Setting intensity-dependent coupling function equal to 1 reduces the results to the constant coupling case. By comparing the latter case with the nonlinear regime, we will observe that the nonlinearity disappears the pattern of collapse-revival phenomenon in the evolution of Mandel parameter and population inversion (which can be seen in the linear case with constant coupling), however, more typical collapse-revivals will be appeared for the cross-correlation function in the nonlinear case. Finally, in both linear and nonlinear regime, the entropy remains less than (but close to) 0.5. In other words the particular chosen nonlinearity does not critically affect on the entropy of the system. (paper)

  8. Determination of mercury in rice by cold vapor atomic fluorescence spectrometry after microwave-assisted digestion

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Maria Jose da [Department of Analytical Chemistry, Edificio de Investigacion, University of Valencia, 50 Dr. Moliner Street, E-46100 Burjassot, Valencia (Spain); Departamento de Quimica Fundamental, Universidade Federal de Pernambuco, Cidade Universitaria, 50740-550 Recife, PE (Brazil); Paim, Ana Paula S. [Departamento de Quimica Fundamental, Universidade Federal de Pernambuco, Cidade Universitaria, 50740-550 Recife, PE (Brazil); Pimentel, Maria Fernanda [Departamento de Engenharia Quimica, Universidade Federal de Pernambuco, Recife, PE (Brazil); Cervera, M. Luisa, E-mail: m.luisa.cervera@uv.es [Department of Analytical Chemistry, Edificio de Investigacion, University of Valencia, 50 Dr. Moliner Street, E-46100 Burjassot, Valencia (Spain); Guardia, Miguel de la [Department of Analytical Chemistry, Edificio de Investigacion, University of Valencia, 50 Dr. Moliner Street, E-46100 Burjassot, Valencia (Spain)

    2010-05-14

    A cold vapor atomic fluorescence spectrometry method (CV-AFS) has been developed for the determination of Hg in rice samples at a few ng g{sup -1} concentration level. The method is based on the previous digestion of samples in a microwave oven with HNO{sub 3} and H{sub 2}O{sub 2} followed by dilution with water containing KBr/KBrO{sub 3} and hydroxylamine and reduction with SnCl{sub 2} in HCl using external calibration. The matrix interferences and the effect of nitrogen oxide vapors have been evaluated and the method validated using a certified reference material. The limit of detection of the method was 0.9 ng g{sup -1} with a recovery percentage of 95 {+-} 4% at an added concentration of 5 ng g{sup -1}. The concentration level of Hg found in 24 natural rice samples from different origin ranged between 1.3 and 7.8 ng g{sup -1}.

  9. Quantum simulation of transverse Ising models with Rydberg atoms

    Science.gov (United States)

    Schauss, Peter

    2018-04-01

    Quantum Ising models are canonical models for the study of quantum phase transitions (Sachdev 1999 Quantum Phase Transitions (Cambridge: Cambridge University Press)) and are the underlying concept for many analogue quantum computing and quantum annealing ideas (Tanaka et al Quantum Spin Glasses, Annealing and Computation (Cambridge: Cambridge University Press)). Here we focus on the implementation of finite-range interacting Ising spin models, which are barely tractable numerically. Recent experiments with cold atoms have reached the interaction-dominated regime in quantum Ising magnets via optical coupling of trapped neutral atoms to Rydberg states. This approach allows for the tunability of all relevant terms in an Ising spin Hamiltonian with 1/{r}6 interactions in transverse and longitudinal fields. This review summarizes the recent progress of these implementations in Rydberg lattices with site-resolved detection. Strong correlations in quantum Ising models have been observed in several experiments, starting from a single excitation in the superatom regime up to the point of crystallization. The rapid progress in this field makes spin systems based on Rydberg atoms a promising platform for quantum simulation because of the unmatched flexibility and strength of interactions combined with high control and good isolation from the environment.

  10. Self-alignment of a compact large-area atomic Sagnac interferometer

    International Nuclear Information System (INIS)

    Tackmann, G; Berg, P; Schubert, C; Abend, S; Gilowski, M; Ertmer, W; Rasel, E M

    2012-01-01

    We report on the realization of a compact atomic Mach-Zehnder-type Sagnac interferometer of 13.7 cm length, which covers an area of 19 mm 2 previously reported only for large thermal beam interferometers. According to Sagnac's formula, which holds for both light and atoms, the sensitivity for rotation rates increases linearly with the area enclosed by the interferometer. The use of cold atoms instead of thermal atoms enables miniaturization of Sagnac interferometers without sacrificing large areas. In comparison with thermal beams, slow atoms offer better matching of the initial beam velocity and the velocity with which the matter waves separate. In our case, the area is spanned by a cold atomic beam of 2.79 m s -1 , which is split, deflected and combined by driving a Raman transition between the two hyperfine ground states of 87 Rb in three spatially separated light zones. The use of cold atoms requires a precise angular alignment and high wave front quality of the three independent light zones over the cloud envelope. We present a procedure for mutually aligning the beam splitters at the microradian level by making use of the atom interferometer itself in different configurations. With this method, we currently achieve a sensitivity of 6.1×10 -7 rad s -1 Hz -1/2 . (paper)

  11. Spontaneous emission by moving atoms

    International Nuclear Information System (INIS)

    Meystre, P.; Wilkens, M.

    1994-01-01

    It is well known that spontaneous emission is not an intrinsic atomic property, but rather results from the coupling of the atom to the vacuum modes of the electromagnetic field. As such, it can be modified by tailoring the electromagnetic environment into which the atom can radiate. This was already realized by Purcell, who noted that the spontaneous emission rate can be enhanced if the atom placed inside a cavity is resonant with one of the cavity is resonant with one of the cavity modes, and by Kleppner, who discussed the opposite case of inhibited spontaneous emission. It has also been recognized that spontaneous emission need not be an irreversible process. Indeed, a system consisting of a single atom coupled to a single mode of the electromagnetic field undergoes a periodic exchange of excitation between the atom and the field. This periodic exchange remains dominant as long as the strength of the coupling between the atom and a cavity mode is itself dominant. 23 refs., 6 figs

  12. Frequency shift, damping, and tunneling current coupling with quartz tuning forks in noncontact atomic force microscopy

    Science.gov (United States)

    Nony, Laurent; Bocquet, Franck; Para, Franck; Loppacher, Christian

    2016-09-01

    A combined experimental and theoretical approach to the coupling between frequency-shift (Δ f ) , damping, and tunneling current (It) in combined noncontact atomic force microscopy/scanning tunneling microscopy using quartz tuning forks (QTF)-based probes is reported. When brought into oscillating tunneling conditions, the tip located at the QTF prong's end radiates an electromagnetic field which couples to the QTF prong motion via its piezoelectric tensor and loads its electrodes by induction. Our approach explains how those It-related effects ultimately modify the Δ f and the damping measurements. This paradigm to the origin of the coupling between It and the nc-AFM regular signals relies on both the intrinsic piezoelectric nature of the quartz constituting the QTF and its electrodes design.

  13. Entanglement manipulation via Coulomb interaction in an optomechanical cavity assisted by two-level cold atoms

    Science.gov (United States)

    Wang, Jing; Tian, Xue-Dong; Liu, Yi-Mou; Cui, Cui-Li; Wu, Jin-Hui

    2018-06-01

    We investigate the stationary entanglement properties in a hybrid system consisting of an optical cavity, a mechanical resonator, a charged object, and an atomic ensemble. Numerical results show that this hybrid system exhibits three kinds of controllable bipartite entanglements in an experimentally accessible parameter regime with the help of the charged object. More importantly, it is viable to enhance on demand each bipartite entanglement at the expense of reducing others by modulating the Coulomb coupling strength. Last but not least, these bipartite entanglements seem more robust against on the environmental temperature for the positive Coulomb interaction.

  14. Laser-cooling and electromagnetic trapping of neutral atoms

    International Nuclear Information System (INIS)

    Phillips, W.D.; Migdall, A.L.; Metcalf, H.J.

    1986-01-01

    Until recently it has been impossible to confine and trap neutral atoms using electromagnetic fields. While many proposals for such traps exist, the small potential energy depth of the traps and the high kinetic energy of available atoms prevented trapping. We review various schemes for atom trapping, the advances in laser cooling of atomic beams which have now made trapping possible, and the successful magnetic trapping of cold sodium atoms

  15. Optimization of atomic beam sources for polarization experiments

    Energy Technology Data Exchange (ETDEWEB)

    Gaisser, Martin; Nass, Alexander; Stroeher, Hans [IKP, Forschungszentrum Juelich (Germany)

    2013-07-01

    For experiments with spin-polarized protons and neutrons a dense target is required. In current atomic beam sources an atomic hydrogen or deuterium beam is expanded through a cold nozzle and a system of sextupole magnets and RF-transition units selects a certain hyperfine state. The achievable flux seems to be limited to about 10{sup 17} particles per second with a high nuclear polarization. A lot of experimental and theoretical effort has been undertaken to understand all effects and to increase the flux. However, improvements have remained marginal. Now, a Monte Carlo simulation based on the DSMC part of the open source C++ library OpenFOAM is set up in order to get a better understanding of the flow and to optimize the various elements. It is intended to include important effects like deflection from magnetic fields, recombination on the walls and spin exchange collisions in the simulation and make quantitative predictions of changes in the experimental setup. The goal is to get a tool that helps to further increase the output of an atomic beam source. So far, a new binary collision model, magnetic fields, RF-transition units and a tool to measure the collision age are included. The next step will be to couple the whole simulation with an optimization algorithm implementing Adaptive Simulated Annealing (ASA) in order to automatically optimize the atomic beam source.

  16. Integration of fiber-coupled high-Q SiNx microdisks with atom chips

    International Nuclear Information System (INIS)

    Barclay, Paul E.; Srinivasan, Kartik; Painter, Oskar; Lev, Benjamin; Mabuchi, Hideo

    2006-01-01

    Micron scale silicon nitride (SiN x ) microdisk optical resonators are demonstrated with Q=3.6x10 6 and an effective mode volume of 15(λ/n) 3 at near-visible wavelengths. A hydrofluoric acid wet etch provides sensitive tuning of the microdisk resonances, and robust mounting of a fiber taper provides efficient fiber optic coupling to the microdisks while allowing unfettered optical access for laser cooling and trapping of atoms. Measurements indicate that cesium adsorption on the SiN x surfaces significantly red detunes the microdisk resonances. Parallel integration of multiple (10) microdisks with a single fiber taper is also demonstrated

  17. Athermalization in atomic force microscope based force spectroscopy using matched microstructure coupling.

    Science.gov (United States)

    Torun, H; Finkler, O; Degertekin, F L

    2009-07-01

    The authors describe a method for athermalization in atomic force microscope (AFM) based force spectroscopy applications using microstructures that thermomechanically match the AFM probes. The method uses a setup where the AFM probe is coupled with the matched structure and the displacements of both structures are read out simultaneously. The matched structure displaces with the AFM probe as temperature changes, thus the force applied to the sample can be kept constant without the need for a separate feedback loop for thermal drift compensation, and the differential signal can be used to cancel the shift in zero-force level of the AFM.

  18. Modulational Instability and Quantum Discrete Breather States of Cold Bosonic Atoms in a Zig-Zag Optical Lattice

    Science.gov (United States)

    Chang, Xia; Xie, Jiayu; Wu, Tianle; Tang, Bing

    2018-07-01

    A theoretical study on modulational instability and quantum discrete breather states in a system of cold bosonic atoms in zig-zag optical lattices is presented in this work. The time-dependent Hartree approximation is employed to deal with the multiple body problem. By means of a linear stability analysis, we analytically study the modulational instability, and estimate existence conditions of the bright stationary localized solutions for different values of the second-neighbor hopping constant. On the other hand, we get analytical bright stationary localized solutions, and analyze the influence of the second-neighbor hopping on their existence conditions. The predictions of the modulational instability analysis are shown to be reliable. Using these stationary localized single-boson wave functions, the quantum breather states corresponding to the system with different types of nonlinearities are constructed.

  19. Modulational Instability and Quantum Discrete Breather States of Cold Bosonic Atoms in a Zig-Zag Optical Lattice

    Science.gov (United States)

    Chang, Xia; Xie, Jiayu; Wu, Tianle; Tang, Bing

    2018-04-01

    A theoretical study on modulational instability and quantum discrete breather states in a system of cold bosonic atoms in zig-zag optical lattices is presented in this work. The time-dependent Hartree approximation is employed to deal with the multiple body problem. By means of a linear stability analysis, we analytically study the modulational instability, and estimate existence conditions of the bright stationary localized solutions for different values of the second-neighbor hopping constant. On the other hand, we get analytical bright stationary localized solutions, and analyze the influence of the second-neighbor hopping on their existence conditions. The predictions of the modulational instability analysis are shown to be reliable. Using these stationary localized single-boson wave functions, the quantum breather states corresponding to the system with different types of nonlinearities are constructed.

  20. Cold crucible induction melter test for crystalline ceramic waste form fabrication: A feasibility assessment

    Energy Technology Data Exchange (ETDEWEB)

    Amoroso, Jake W., E-mail: jake.amoroso@srnl.doe.gov [Savannah River National Laboratory, Aiken, SC 29808 (United States); Marra, James; Dandeneau, Christopher S. [Savannah River National Laboratory, Aiken, SC 29808 (United States); Brinkman, Kyle; Xu, Yun [Clemson University, Clemson, SC 29634 (United States); Tang, Ming [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Maio, Vince [Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Webb, Samuel M. [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94086 (United States); Chiu, Wilson K.S. [University of Connecticut, Storrs, Connecticut 06269-3139 (United States)

    2017-04-01

    The first scaled proof-of-principle cold crucible induction melter (CCIM) test to process a multiphase ceramic waste form from a simulated combined (Cs/Sr, lanthanide and transition metal fission products) commercial used nuclear fuel waste stream was recently conducted in the United States. X-ray diffraction, 2-D X-ray absorption near edge structure (XANES), electron microscopy, inductively coupled plasma-atomic emission spectroscopy (and inductively coupled plasma-mass spectroscopy for Cs), and product consistency tests were used to characterize the fabricated CCIM material. Characterization analyses confirmed that a crystalline ceramic with a desirable phase assemblage was produced from a melt using a CCIM. Primary hollandite, pyrochlore/zirconolite, and perovskite phases were identified in addition to minor phases rich in Fe, Al, or Cs. The material produced in the CCIM was chemically homogeneous and displayed a uniform phase assemblage with acceptable aqueous chemical durability.

  1. The Cold War legacy of regulatory risk analysis: The Atomic Energy Commission and radiation safety

    Science.gov (United States)

    Boland, Joseph B.

    From its inception in 1946 the Atomic Energy Commission pioneered the use of risk analysis as a mode of regulatory rationality and political rhetoric, yet historical treatments of risk analysis nearly always overlook the important role it played in the administration of atomic energy during the early Cold War. How this absence from history has been achieved and why it characterizes most historical accounts are the subjects of Chapter II. From there, this study goes on to develop the thesis that the advent of the atomic bomb was a world-shattering event that forced the Truman administration to choose between two novel alternatives: (1) movement towards global governance based initially on cooperative control of atomic energy or (2) unsparing pursuit of nuclear superiority. I refer to these as nuclear internationalism and nuclear nationalism, respectively. Each defined a social risk hierarchy. With the triumph of nuclear nationalism, nuclear annihilation was designated the greatest risk and a strong nuclear defense the primary means of prevention. The AEC's mission in the 1950s consisted of the rapid development of a nuclear arsenal, continual improvements in weapons technologies, and the promotion of nuclear power. The agency developed a risk-based regulatory framework through its dominant position within the National Committee on Radiation Protection. It embraced a technocratic model of risk analysis whose articulation and application it controlled, largely in secret. It used this to undergird a public rhetoric of reassurance and risk minimization. In practice, safety officials adjusted exposure levels within often wide parameters and with considerable fluidity in order to prevent safety concerns from interfering with operations. Secrecy, the political climate of the time, and a lack of accountability enabled the agency to meld technical assessments with social value judgments in a manner reflective of nuclear nationalism's risk hierarchy. In the late fifties

  2. Determination of trace elements in Egyptian cane sugar (Deshna Factories) by neutron activation, atomic absorption spectrophotometric and inductively coupled plasma-atomic emission spectrometric analysis

    International Nuclear Information System (INIS)

    Awadallah, R.M.; Sherif, M.K.; Mohamed, A.E.; Grass, F.

    1986-01-01

    Multielement instrumental neutron activation (INAA), inductively coupled plasma-atomic emission spectrometric (ICP-AES) and atomic absorption spectrophotometric (AAS) analyses were utilized for the determination of Ag, Al, As, Au, Ba, Be, Br, Ca, Cd, Ce, Cl, Co, Cr, Cu, Eu, Fe, Ga, Hf, K, La, Li, Lu, Mg, Mn, Na, Nb, Ni, P, Pb, Sb, Sc, Se, Sm, Sn, Sr, Ta, Th, Ti, U, V, W and Zn in sugar cane plant, raw juice, juice in different stages, syrup, deposits, molasses, A, B and C sugar, refinery 1 and 2 sugar, and in soil samples picked up from the immediate vicinity of the cane plant roots at surface, 30 and 60 cm depth, respectively. (author)

  3. Inductively coupled plasma-atomic emission spectroscopy glovebox assembly system at the West Valley Demonstration Project

    International Nuclear Information System (INIS)

    Marlow, J.H.; McCarthy, K.M.; Tamul, N.R.

    1999-01-01

    The inductively coupled plasma/atomic emission spectroscopy [ICP/AES (ICP)] system for elemental analyses in support of vitrification processing was first installed in 1986. The initial instrument was a Jobin Yvon (JY) Model JY-70 ICP that consisted of sequential and simultaneous spectrometers for analysis of nonradioactive samples as radioactive surrogates. The JY-70 ICP continued supporting nonradioactive testing during the Functional and Checkout Testing of Systems (FACTS) using the full-scale melter with ''cold'' (nonradioactive) testing campaigns. As a result, the need for another system was identified to allow for the analysis of radioactive samples. The Mass Spec (Spectrometry) Lab was established for the installation of the modified ICP system for handling radioactive samples. The conceptual setup of another ICP was predicated on the use of a hood to allow ease of accessibility of the torch, nebulizer, and spray chamber, and the minimization of air flow paths. However, reconsideration of the radioactive sample dose rate and contamination levels led to the configuration of the glovebox system with a common transfer interface box for the ICP and the inductively coupled plasma-mass spectrometer (ICP-MS) glovebox assemblies. As a result, a simultaneous Model JY-50P ICP with glovebox was installed in 1990 as a first generation ICP glovebox system. This was one of the first ICP glovebox assemblies connected with an ICP-MS glovebox system. Since the economics of processing high-level radioactive waste (HLW) required the availability of an instrument to operate 24 hours a day throughout the year without any downtime, a second generation ICP glovebox assembly was designed, manufactured, and installed in 1995 using a Model JY-46P ICP. These two ICP glovebox systems continue to support vitrification of the HLW into canisters for storage. The ICP systems have been instrumental in monitoring vitrification batch processing. To date, remote sample preparation and

  4. Efficient atom localization via probe absorption in an inverted-Y atomic system

    Science.gov (United States)

    Wu, Jianchun; Wu, Bo; Mao, Jiejian

    2018-06-01

    The behaviour of atom localization in an inverted-Y atomic system is theoretically investigated. For the atoms interacting with a weak probe field and several orthogonal standing-wave fields, their position information can be obtained by measuring the probe absorption. Compared with the traditional scheme, we couple the probe field to the transition between the middle and top levels. It is found that the probe absorption sensitively depends on the detuning and strength of the relevant light fields. Remarkably, the atom can be localized at a particular position in the standing-wave fields by coupling a microwave field to the transition between the two ground levels.

  5. Nanofabrication for On-Chip Optical Levitation, Atom-Trapping, and Superconducting Quantum Circuits

    Science.gov (United States)

    Norte, Richard Alexander

    a final value of Qm = 5.8(1.1) x 105, representing more than an order of magnitude improvement over the conventional limits of SiO2 for a pendulum geometry. Our technique may enable new opportunities for mechanical sensing and facilitate observations of quantum behavior in this class of mechanical systems. We then give a detailed overview of the techniques used to produce high-aspect-ratio nanostructures with applications in a wide range of quantum optics experiments. The ability to fabricate such nanodevices with high precision opens the door to a vast array of experiments which integrate macroscopic optical setups with lithographically engineered nanodevices. Coupled with atom-trapping experiments in the Kimble Lab, we use these techniques to realize a new waveguide chip designed to address ultra-cold atoms along lithographically patterned nanobeams which have large atom-photon coupling and near 4pi Steradian optical access for cooling and trapping atoms. We describe a fully integrated and scalable design where cold atoms are spatially overlapped with the nanostring cavities in order to observe a resonant optical depth of d0 ≈ 0.15. The nanodevice illuminates new possibilities for integrating atoms into photonic circuits and engineering quantum states of atoms and light on a microscopic scale. We then describe our work with superconducting microwave resonators coupled to a phononic cavity towards the goal of building an integrated device for quantum-limited microwave-to-optical wavelength conversion. We give an overview of our characterizations of several types of substrates for fabricating a low-loss high-frequency electromechanical system. We describe our electromechanical system fabricated on a SiN membrane which consists of a 12 GHz superconducting LC resonator coupled capacitively to the high frequency localized modes of a phononic nanobeam. Using our suspended membrane geometry we isolate our system from substrates with significant loss tangents

  6. Cold atomic gas in the inner Galaxy

    International Nuclear Information System (INIS)

    Garwood, R.W.; Dickey, J.M.

    1989-01-01

    A new set of 21 cm H I absorption spectra were obtained toward 21 compact continuum sources in the Galactic plane is presented. The 21 cm line velocity-averaged absorption coefficient as a function of Galactocentric distance is calculated. The result for distances within 2 kpc of the sun agrees with the local value found from absorption toward pulsars of 5-7 km/s/kpc. Overall, the absorption coefficient decreases to about half of its local value inside a Galactocentric radius of about 4 kpc. This decrease is shown to be primarily due to an increase in the mean line-of-sight distance between absorbing atomic clouds. Thus, the cool phase of the atomic gas is less abundant in the inner Galaxy than at the solar circle. The absorption spectra are similar in appearance to existing (C-12)O spectra. The spectral regions which show H I absorption also show CO emission. 43 references

  7. Average and extreme multi-atom Van der Waals interactions: Strong coupling of multi-atom Van der Waals interactions with covalent bonding

    Directory of Open Access Journals (Sweden)

    Finkelstein Alexei V

    2007-07-01

    Full Text Available Abstract Background The prediction of ligand binding or protein structure requires very accurate force field potentials – even small errors in force field potentials can make a 'wrong' structure (from the billions possible more stable than the single, 'correct' one. However, despite huge efforts to optimize them, currently-used all-atom force fields are still not able, in a vast majority of cases, even to keep a protein molecule in its native conformation in the course of molecular dynamics simulations or to bring an approximate, homology-based model of protein structure closer to its native conformation. Results A strict analysis shows that a specific coupling of multi-atom Van der Waals interactions with covalent bonding can, in extreme cases, increase (or decrease the interaction energy by about 20–40% at certain angles between the direction of interaction and the covalent bond. It is also shown that on average multi-body effects decrease the total Van der Waals energy in proportion to the square root of the electronic component of dielectric permittivity corresponding to dipole-dipole interactions at small distances, where Van der Waals interactions take place. Conclusion The study shows that currently-ignored multi-atom Van der Waals interactions can, in certain instances, lead to significant energy effects, comparable to those caused by the replacement of atoms (for instance, C by N in conventional pairwise Van der Waals interactions.

  8. Non-local coupled-channels optical calculation of electron scattering by atomic hydrogen at 54.42 eV

    International Nuclear Information System (INIS)

    Ratnavelu, K.; McCarthy, I.E.

    1990-01-01

    The present study incorporates the non-local optical potentials for the continuum within the coupled-channels optical framework to study electron scattering from atomic hydrogen at 54.42 eV. Nine-state coupled-channels calculations with non-local and local continuum optical potentials were performed. The results for differential, total and ionization cross sections as well as the 2p angular correlation parameters λ and R are comparable with other non-perturbative calculations. There are still discrepancies between theory and experiment, particularly for λ and R at larger angles. (author)

  9. Study on biodiesel heat transfer through self-temperature limit injector during vehicle cold start

    Directory of Open Access Journals (Sweden)

    Wang Jun

    2015-01-01

    Full Text Available A type of Self-Temperature Limit-Injector (STL- injector is proposed to reduce the biodiesel consumption and emission in vehicle cold start process. The STL-injector is capable of fast raising fuel temperature, which helps improve the quality of diesel spray and its combustion efficiency. A STL-injector model is established with consideration of electro-mechanic coupling and fluid-structure interaction. A transient simulation is conducted using dynamic grid technology. The results show that STL-injector can effectively raise biodiesel temperature to 350K from 300K in 32 seconds. That is to say, adding STL-injector to existing biodiesel combustion system is an environment-friendly solution due to improving atomization and spray quality quickly.

  10. Hybrid quantum systems of ions and atoms

    OpenAIRE

    Sias, Carlo; Köhl, Michael

    2014-01-01

    In this chapter we review the progress in experiments with hybrid systems of trapped ions and ultracold neutral atoms. We give a theoretical overview over the atom-ion interactions in the cold regime and give a summary of the most important experimental results. We conclude with an overview of remaining open challenges and possible applications in hybrid quantum systems of ions and neutral atoms.

  11. Atomic polarizabilities

    International Nuclear Information System (INIS)

    Safronova, M. S.; Mitroy, J.; Clark, Charles W.; Kozlov, M. G.

    2015-01-01

    The atomic dipole polarizability governs the first-order response of an atom to an applied electric field. Atomic polarization phenomena impinge upon a number of areas and processes in physics and have been the subject of considerable interest and heightened importance in recent years. In this paper, we will summarize some of the recent applications of atomic polarizability studies. A summary of results for polarizabilities of noble gases, monovalent, and divalent atoms is given. The development of the CI+all-order method that combines configuration interaction and linearized coupled-cluster approaches is discussed

  12. Atomic polarizabilities

    Energy Technology Data Exchange (ETDEWEB)

    Safronova, M. S. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Mitroy, J. [School of Engineering, Charles Darwin University, Darwin NT 0909 (Australia); Clark, Charles W. [Joint Quantum Institute, National Institute of Standards and Technology and the University of Maryland, Gaithersburg, Maryland 20899-8410 (United States); Kozlov, M. G. [Petersburg Nuclear Physics Institute, Gatchina 188300 (Russian Federation)

    2015-01-22

    The atomic dipole polarizability governs the first-order response of an atom to an applied electric field. Atomic polarization phenomena impinge upon a number of areas and processes in physics and have been the subject of considerable interest and heightened importance in recent years. In this paper, we will summarize some of the recent applications of atomic polarizability studies. A summary of results for polarizabilities of noble gases, monovalent, and divalent atoms is given. The development of the CI+all-order method that combines configuration interaction and linearized coupled-cluster approaches is discussed.

  13. Three-body recombination of cold fermionic atoms

    International Nuclear Information System (INIS)

    Suno, H; Esry, B D; Greene, Chris H

    2003-01-01

    Recombination of identical, spin-polarized fermions in cold three-body collisions is investigated. We parametrize the mechanisms for recombination in terms of the 'scattering volume' V p and another length scale r 0 . Model two-body interactions were used within the framework of the adiabatic hyperspherical representation. We examine the recombination rate K 3 as a function of the collision energy E for various values of V p . Not only do we consider the dominant J Π = 1 + case, but also the next-leading order contributions from J Π = 1 - and 3 - . We discuss the behaviour near a two-body resonance and the expected universality of fermionic recombination. Comparisons with boson recombination are considered in detail

  14. Coexistence of photonic and atomic Bose-Einstein condensates in ideal atomic gases

    Directory of Open Access Journals (Sweden)

    N. Boichenko

    2015-12-01

    Full Text Available We have studied conditions of photon Bose-Einstein condensate formation that is in thermodynamic equilibrium with ideal gas of two-level Bose atoms below the degeneracy temperature. Equations describing thermodynamic equilibrium in the system were formulated; critical temperatures and densities of photonic and atomic gas subsystems were obtained analytically. Coexistence conditions of these photonic and atomic Bose-Einstein condensates were found. There was predicted the possibility of an abrupt type of photon condensation in the presence of Bose condensate of ground-state atoms: it was shown that the slightest decrease of the temperature could cause a significant gathering of photons in the condensate. This case could be treated as a simple model of the situation known as "stopped light" in cold atomic gas. We also showed how population inversion of atomic levels can be created by lowering the temperature. The latter situation looks promising for light accumulation in atomic vapor at very low temperatures.

  15. Laser Cooling and Trapping of Atoms and Particles

    Science.gov (United States)

    1992-01-16

    magnitude. The creation of an atom trampoline , where cold atoms were dropped onto a evanescent wave of light extending out of a totally internally reflected...Staff, Electromagnetic Phenomena Research Bell Laboratories, Murray Hill, 1978-1983 Head , Quantum Electronics Research Department AT&T Bell

  16. Theoretical atomic physics

    CERN Document Server

    Friedrich, Harald

    2017-01-01

    This expanded and updated well-established textbook contains an advanced presentation of quantum mechanics adapted to the requirements of modern atomic physics. It includes topics of current interest such as semiclassical theory, chaos, atom optics and Bose-Einstein condensation in atomic gases. In order to facilitate the consolidation of the material covered, various problems are included, together with complete solutions. The emphasis on theory enables the reader to appreciate the fundamental assumptions underlying standard theoretical constructs and to embark on independent research projects. The fourth edition of Theoretical Atomic Physics contains an updated treatment of the sections involving scattering theory and near-threshold phenomena manifest in the behaviour of cold atoms (and molecules). Special attention is given to the quantization of weakly bound states just below the continuum threshold and to low-energy scattering and quantum reflection just above. Particular emphasis is laid on the fundamen...

  17. Synthesis of Well-Defined Three-Arm Star-Branched Polystyrene through Arm-First Coupling Approach by Atom Transfer Radical Polymerization

    OpenAIRE

    Shahabuddin, Syed; Hamime Ismail, Fatem; Mohamad, Sharifah; Muhamad Sarih, Norazilawati

    2015-01-01

    Here we describe a simple route to synthesize three-arm star-branched polystyrene. Atom transfer radical polymerization technique has been utilized to yield branched polystyrene involving Williamson coupling strategy. Initially a linear polymeric chain of predetermined molecular weight has been synthesized which is further end-functionalized into a primary alkyl bromide moiety, a prime requisition for Williamson reaction. The end-functionalized polymer is then coupled using 1,1,1-tris(4-hydro...

  18. Self-consistent collisional-radiative model for hydrogen atoms: Atom–atom interaction and radiation transport

    International Nuclear Information System (INIS)

    Colonna, G.; Pietanza, L.D.; D’Ammando, G.

    2012-01-01

    Graphical abstract: Self-consistent coupling between radiation, state-to-state kinetics, electron kinetics and fluid dynamics. Highlight: ► A CR model of shock-wave in hydrogen plasma has been presented. ► All equations have been coupled self-consistently. ► Non-equilibrium electron and level distributions are obtained. ► The results show non-local effects and non-equilibrium radiation. - Abstract: A collisional-radiative model for hydrogen atom, coupled self-consistently with the Boltzmann equation for free electrons, has been applied to model a shock tube. The kinetic model has been completed considering atom–atom collisions and the vibrational kinetics of the ground state of hydrogen molecules. The atomic level kinetics has been also coupled with a radiative transport equation to determine the effective adsorption and emission coefficients and non-local energy transfer.

  19. Generation of Exotic Quantum States of a Cold Atomic Ensemble

    DEFF Research Database (Denmark)

    Christensen, Stefan Lund

    Over the last decades quantum effects have become more and more controllable, leading to the implementations of various quantum information protocols. These protocols are all based on utilizing quantum correlation. In this thesis we consider how states of an atomic ensemble with such correlations...... can be created and characterized. First we consider a spin-squeezed state. This state is generated by performing quantum non-demolition measurements of the atomic population difference. We show a spectroscopically relevant noise reduction of -1.7dB, the ensemble is in a many-body entangled state...... — a nanofiber based light-atom interface. Using a dual-frequency probing method we measure and prepare an ensemble with a sub-Poissonian atom number distribution. This is a first step towards the implementation of more exotic quantum states....

  20. Storage of Quantum Variables in Atomic Media

    DEFF Research Database (Denmark)

    Cviklinski, J.; Ortalo, J.; Josse, V.

    2007-01-01

    Storage and read-out of non classical states of light is a critical element for quantum information networks. Simultaneous storage of two non-commuting variables carried by light and subsequent read-out is shown to be possible in atomic ensembles. Interaction of light fields with three-level syst......-level systems allows direct mapping the quantum state of light into long lived coherences in the atomic ground state. We show that excess noise linked to atomic transitions can be made negligible. Experimental developments are discussed for atomic vapours and cold atoms....

  1. Microwave-to-optical frequency conversion using a cesium atom coupled to a superconducting resonator

    Science.gov (United States)

    Gard, Bryan T.; Jacobs, Kurt; McDermott, R.; Saffman, M.

    2017-07-01

    A candidate for converting quantum information from microwave to optical frequencies is the use of a single atom that interacts with a superconducting microwave resonator on one hand and an optical cavity on the other. The large electric dipole moments and microwave transition frequencies possessed by Rydberg states allow them to couple strongly to superconducting devices. Lasers can then be used to connect a Rydberg transition to an optical transition to realize the conversion. Since the fundamental source of noise in this process is spontaneous emission from the atomic levels, the resulting control problem involves choosing the pulse shapes of the driving lasers so as to maximize the transfer rate while minimizing this loss. Here we consider the concrete example of a cesium atom, along with two specific choices for the levels to be used in the conversion cycle. Under the assumption that spontaneous emission is the only significant source of errors, we use numerical optimization to determine the likely rates for reliable quantum communication that could be achieved with this device. These rates are on the order of a few megaqubits per second.

  2. Trapped atoms along nanophotonic resonators

    Science.gov (United States)

    Fields, Brian; Kim, May; Chang, Tzu-Han; Hung, Chen-Lung

    2017-04-01

    Many-body systems subject to long-range interactions have remained a very challenging topic experimentally. Ultracold atoms trapped in extreme proximity to the surface of nanophotonic structures provides a dynamic system combining the strong atom-atom interactions mediated by guided mode photons with the exquisite control implemented with trapped atom systems. The hybrid system promises pair-wise tunability of long-range interactions between atomic pseudo spins, allowing studies of quantum magnetism extending far beyond nearest neighbor interactions. In this talk, we will discuss our current status developing high quality nanophotonic ring resonators, engineered on CMOS compatible optical chips with integrated nanostructures that, in combination with a side illuminating beam, can realize stable atom traps approximately 100nm above the surface. We will report on our progress towards loading arrays of cold atoms near the surface of these structures and studying atom-atom interaction mediated by photons with high cooperativity.

  3. Reflection-type hologram for atoms

    International Nuclear Information System (INIS)

    Shimizu, Fujio; Fujita, Jun-ichi

    2002-01-01

    A cold metastable neon atomic beam was manipulated with a reflective amplitude hologram that was encoded on a silicon surface. A black-and-white pattern of atoms was reconstructed on a microchannel plate detector. The hologram used the enhanced quantum reflection developed by authors and was made of a two-dimensional array of rectangular low and high reflective cells. The surface of the high reflective cell was composed of regularly spaced roof-shaped ridges, while the low reflective cell was simply a flat surface. The hologram was the first demonstration of reflective atom-optical elements that used universal interaction between a neutral atom and solid surface

  4. Magnetic-field-driven localization of light in a cold-atom gas.

    Science.gov (United States)

    Skipetrov, S E; Sokolov, I M

    2015-02-06

    We discover a transition from extended to localized quasimodes for light in a gas of immobile two-level atoms in a magnetic field. The transition takes place either upon increasing the number density of atoms in a strong field or upon increasing the field at a high enough density. It has many characteristic features of a disorder-driven (Anderson) transition but is strongly influenced by near-field interactions between atoms and the anisotropy of the atomic medium induced by the magnetic field.

  5. Optical atomic phase reference and timing

    Science.gov (United States)

    Hollberg, L.; Cornell, E. H.; Abdelrahmann, A.

    2017-06-01

    Atomic clocks based on laser-cooled atoms have made tremendous advances in both accuracy and stability. However, advanced clocks have not found their way into widespread use because there has been little need for such high performance in real-world/commercial applications. The drive in the commercial world favours smaller, lower-power, more robust compact atomic clocks that function well in real-world non-laboratory environments. Although the high-performance atomic frequency references are useful to test Einstein's special relativity more precisely, there are not compelling scientific arguments to expect a breakdown in special relativity. On the other hand, the dynamics of gravity, evidenced by the recent spectacular results in experimental detection of gravity waves by the LIGO Scientific Collaboration, shows dramatically that there is new physics to be seen and understood in space-time science. Those systems require strain measurements at less than or equal to 10-20. As we discuss here, cold atom optical frequency references are still many orders of magnitude away from the frequency stability that should be achievable with narrow-linewidth quantum transitions and large numbers of very cold atoms, and they may be able to achieve levels of phase stability, ΔΦ/Φtotal ≤ 10-20, that could make an important impact in gravity wave science. This article is part of the themed issue 'Quantum technology for the 21st century'.

  6. Cooled electronic system with liquid-cooled cold plate and thermal spreader coupled to electronic component

    Science.gov (United States)

    Chainer, Timothy J.; Graybill, David P.; Iyengar, Madhusudan K.; Kamath, Vinod; Kochuparambil, Bejoy J.; Schmidt, Roger R.; Steinke, Mark E.

    2018-03-27

    Apparatus and method are provided for facilitating cooling of an electronic component. The apparatus includes a liquid-cooled cold plate and a thermal spreader associated with the cold plate. The cold plate includes multiple coolant-carrying channel sections extending within the cold plate, and a thermal conduction surface with a larger surface area than a surface area of the component to be cooled. The thermal spreader includes one or more heat pipes including multiple heat pipe sections. One or more heat pipe sections are partially aligned to a first region of the cold plate, that is, where aligned to the surface to be cooled, and partially aligned to a second region of the cold plate, which is outside the first region. The one or more heat pipes facilitate distribution of heat from the electronic component to coolant-carrying channel sections of the cold plate located in the second region of the cold plate.

  7. Generation of atom-photon entangled states in atomic Bose-Einstein condensate via electromagnetically induced transparency

    International Nuclear Information System (INIS)

    Kuang Leman; Zhou Lan

    2003-01-01

    In this paper, we present a method to generate continuous-variable-type entangled states between photons and atoms in atomic Bose-Einstein condensate (BEC). The proposed method involves an atomic BEC with three internal states, a weak quantized probe laser, and a strong classical coupling laser, which form a three-level Λ-shaped BEC system. We consider a situation where the BEC is in electromagnetically induced transparency with the coupling laser being much stronger than the probe laser. In this case, the upper and intermediate levels are unpopulated, so that their adiabatic elimination enables an effective two-mode model involving only the atomic field at the lowest internal level and the quantized probe laser field. Atom-photon quantum entanglement is created through laser-atom and interatomic interactions, and two-photon detuning. We show how to generate atom-photon entangled coherent states and entangled states between photon (atom) coherent states and atom-(photon-) macroscopic quantum superposition (MQS) states, and between photon-MQS and atom-MQS states

  8. Superradiators created atom by atom

    Science.gov (United States)

    Meschede, Dieter

    2018-02-01

    High radiation rates are usually associated with macroscopic lasers. Laser radiation is “coherent”—its amplitude and phase are well-defined—but its generation requires energy inputs to overcome loss. Excited atoms spontaneously emit in a random and incoherent fashion, and for N such atoms, the emission rate simply increases as N. However, if these atoms are in close proximity and coherently coupled by a radiation field, this microscopic ensemble acts as a single emitter whose emission rate increases as N2 and becomes “superradiant,” to use Dicke's terminology (1). On page 662 of this issue, Kim et al. (2) show the buildup of coherent light fields through collective emission from atomic radiators injected one by one into a resonator field. There is only one atom ever in the cavity, but the emission is still collective and superradiant. These results suggest another route toward thresholdless lasing.

  9. Highly versatile atomic micro traps generated by multifrequency magnetic field modulation

    International Nuclear Information System (INIS)

    Courteille, Ph W; Deh, B; Fortagh, J; Guenther, A; Kraft, S; Marzok, C; Slama, S; Zimmermann, C

    2006-01-01

    We propose the realization of custom-designed adiabatic potentials for cold atoms based on multimode radio frequency radiation in combination with static inhomogeneous magnetic fields. For example, the use of radio frequency combs gives rise to periodic potentials acting as gratings for cold atoms. In strong magnetic field gradients, the lattice constant can be well below 1 μm. By changing the frequencies of the comb in time the gratings can easily be propagated in space, which may prove useful for Bragg scattering atomic matter waves. Furthermore, almost arbitrarily shaped potentials are possible such as disordered potentials on a scale of several 100 nm or lattices with a spatially varying lattice constant. The potentials can be made state selective and, in the case of atomic mixtures, also species selective. This opens new perspectives for generating tailored quantum systems based on ultracold single atoms or degenerate atomic and molecular quantum gases

  10. Submicron Positioning of Single Atoms in a Microcavity

    International Nuclear Information System (INIS)

    Nussmann, Stefan; Hijlkema, Markus; Weber, Bernhard; Rohde, Felix; Rempe, Gerhard; Kuhn, Axel

    2005-01-01

    The coupling of individual atoms to a high-finesse optical cavity is precisely controlled and adjusted using a standing-wave dipole-force trap, a challenge for strong atom-cavity coupling. Ultracold Rubidium atoms are first loaded into potential minima of the dipole trap in the center of the cavity. Then we use the trap as a conveyor belt that we set into motion perpendicular to the cavity axis. This allows us to repetitively move atoms out of and back into the cavity mode with a repositioning precision of 135 nm. This makes it possible to either selectively address one atom of a string of atoms by the cavity, or to simultaneously couple two precisely separated atoms to a higher mode of the cavity

  11. Incorporating Cold Cap Behavior in a Joule-heated Waste Glass Melter Model

    Energy Technology Data Exchange (ETDEWEB)

    Varija Agarwal; Donna Post Guillen

    2013-08-01

    In this paper, an overview of Joule-heated waste glass melters used in the vitrification of high level waste (HLW) is presented, with a focus on the cold cap region. This region, in which feed-to-glass conversion reactions occur, is critical in determining the melting properties of any given glass melter. An existing 1D computer model of the cold cap, implemented in MATLAB, is described in detail. This model is a standalone model that calculates cold cap properties based on boundary conditions at the top and bottom of the cold cap. Efforts to couple this cold cap model with a 3D STAR-CCM+ model of a Joule-heated melter are then described. The coupling is being implemented in ModelCenter, a software integration tool. The ultimate goal of this model is to guide the specification of melter parameters that optimize glass quality and production rate.

  12. Tunable spin-orbit coupling for ultracold atoms in two-dimensional optical lattices

    Science.gov (United States)

    Grusdt, Fabian; Li, Tracy; Bloch, Immanuel; Demler, Eugene

    2017-06-01

    Spin-orbit coupling (SOC) is at the heart of many exotic band structures and can give rise to many-body states with topological order. Here we present a general scheme based on a combination of microwave driving and lattice shaking for the realization of two-dimensional SOC with ultracold atoms in systems with inversion symmetry. We show that the strengths of Rashba and Dresselhaus SOC can be independently tuned in a spin-dependent square lattice. More generally, our method can be used to open gaps between different spin states without breaking time-reversal symmetry. We demonstrate that this allows for the realization of topological insulators with nontrivial spin textures closely related to the Kane-Mele model.

  13. On- and off-resonance radiation-atom-coupling matrix elements involving extended atomic wave functions

    Science.gov (United States)

    Komninos, Yannis; Mercouris, Theodoros; Nicolaides, Cleanthes A.

    2014-01-01

    In continuation of our earlier works, we present results concerning the computation of matrix elements of the multipolar Hamiltonian (MPH) between extended wave functions that are obtained numerically. The choice of the MPH is discussed in connection with the broader issue of the form of radiation-atom (or -molecule) interaction that is appropriate for the systematic solution of various problems of matter-radiation interaction. We derive analytic formulas, in terms of the sine-integral function and spherical Bessel functions of various orders, for the cumulative radial integrals that were obtained and calculated by Komninos, Mercouris, and Nicolaides [Phys. Rev. A 71, 023410 (2005), 10.1103/PhysRevA.71.023410]. This development allows the much faster and more accurate computation of such matrix elements, a fact that enhances the efficiency with which the time-dependent Schrödinger equation is solved nonperturbatively, in the framework of the state-specific expansion approach. The formulas are applicable to the general case where a pair of orbitals with angular parts |ℓ1,m1> and |ℓ2,m2> are coupled radiatively. As a test case, we calculate the matrix elements of the electric field and of the paramagnetic operators for on- and off-resonance transitions, between hydrogenic circular states of high angular momentum, whose quantum numbers are chosen so as to satisfy electric dipole and electric quadrupole selection rules. Because of the nature of their wave function (they are nodeless and the large centrifugal barrier keeps their overwhelming part at large distances from the nucleus), the validity of the electric dipole approximation in various applications where the off-resonance couplings must be considered becomes precarious. For example, for the transition from the circular state with n = 20 to that with n = 21, for which ≈400 a.u., the dipole approximation starts to fail already at XUV wavelengths (λ <125nm).

  14. Analysis of off-axis solenoid fields using the magnetic scalar potential: An application to a Zeeman-slower for cold atoms

    Science.gov (United States)

    Muniz, Sérgio R.; Bagnato, Vanderlei S.; Bhattacharya, M.

    2015-06-01

    In a region free of currents, magnetostatics can be described by the Laplace equation of a scalar magnetic potential, and one can apply the same methods commonly used in electrostatics. Here, we show how to calculate the general vector field inside a real (finite) solenoid, using only the magnitude of the field along the symmetry axis. Our method does not require integration or knowledge of the current distribution and is presented through practical examples, including a nonuniform finite solenoid used to produce cold atomic beams via laser cooling. These examples allow educators to discuss the nontrivial calculation of fields off-axis using concepts familiar to most students, while offering the opportunity to introduce themes of current modern research.

  15. Thousands of cold anti-atoms produced at CERN

    CERN Multimedia

    2002-01-01

    The antimatter factory delivers its first major results. ATHENA has just produced thousands of anti-atoms. This is the result of techniques developed by ATRAP and ATHENA, the two collaborations aiming to study antihydrogen.

  16. Optimal control of complex atomic quantum systems.

    Science.gov (United States)

    van Frank, S; Bonneau, M; Schmiedmayer, J; Hild, S; Gross, C; Cheneau, M; Bloch, I; Pichler, T; Negretti, A; Calarco, T; Montangero, S

    2016-10-11

    Quantum technologies will ultimately require manipulating many-body quantum systems with high precision. Cold atom experiments represent a stepping stone in that direction: a high degree of control has been achieved on systems of increasing complexity. However, this control is still sub-optimal. In many scenarios, achieving a fast transformation is crucial to fight against decoherence and imperfection effects. Optimal control theory is believed to be the ideal candidate to bridge the gap between early stage proof-of-principle demonstrations and experimental protocols suitable for practical applications. Indeed, it can engineer protocols at the quantum speed limit - the fastest achievable timescale of the transformation. Here, we demonstrate such potential by computing theoretically and verifying experimentally the optimal transformations in two very different interacting systems: the coherent manipulation of motional states of an atomic Bose-Einstein condensate and the crossing of a quantum phase transition in small systems of cold atoms in optical lattices. We also show that such processes are robust with respect to perturbations, including temperature and atom number fluctuations.

  17. Quantum-coherent coupling of a mechanical oscillator to an optical cavity mode.

    Science.gov (United States)

    Verhagen, E; Deléglise, S; Weis, S; Schliesser, A; Kippenberg, T J

    2012-02-01

    Optical laser fields have been widely used to achieve quantum control over the motional and internal degrees of freedom of atoms and ions, molecules and atomic gases. A route to controlling the quantum states of macroscopic mechanical oscillators in a similar fashion is to exploit the parametric coupling between optical and mechanical degrees of freedom through radiation pressure in suitably engineered optical cavities. If the optomechanical coupling is 'quantum coherent'--that is, if the coherent coupling rate exceeds both the optical and the mechanical decoherence rate--quantum states are transferred from the optical field to the mechanical oscillator and vice versa. This transfer allows control of the mechanical oscillator state using the wide range of available quantum optical techniques. So far, however, quantum-coherent coupling of micromechanical oscillators has only been achieved using microwave fields at millikelvin temperatures. Optical experiments have not attained this regime owing to the large mechanical decoherence rates and the difficulty of overcoming optical dissipation. Here we achieve quantum-coherent coupling between optical photons and a micromechanical oscillator. Simultaneously, coupling to the cold photon bath cools the mechanical oscillator to an average occupancy of 1.7 ± 0.1 motional quanta. Excitation with weak classical light pulses reveals the exchange of energy between the optical light field and the micromechanical oscillator in the time domain at the level of less than one quantum on average. This optomechanical system establishes an efficient quantum interface between mechanical oscillators and optical photons, which can provide decoherence-free transport of quantum states through optical fibres. Our results offer a route towards the use of mechanical oscillators as quantum transducers or in microwave-to-optical quantum links.

  18. [Improvement of the method for methylmercury determination in aquatic products using liquid chromatography online coupled with atomic fluorescence spectrometry].

    Science.gov (United States)

    Shang, Xiaohong; Zhao, Yunfeng; Zhang, Lei; Li, Xiaowei; Wu, Yongning

    2011-07-01

    The improvement method was developed for methylmercury determination using liquid chromatography online coupled with cold vapor atomic fluorescence spectrometry (LC-CV-AFS). Cysteine was used as complexing agent in mobile phase instead of mercaptoethanol. Under the optimized conditions, baseline separation of mercury species could be achieved within 8 min on a C18 column with a mobile phase of 5% (v/v) acetonitrile-1 g/L L-cysteine-50 mmol/L ammonium acetate aqueous solution. The linear range of calibration curve of methylmercury was 1-50 microg/L and the limit of detection (S/N = 3) for methylmercury was 0.3 microg/L. Ultrasonication assisted hydrochloric acid extraction was used to extract methylmercury from seafood samples. The sample extract was cleaned up by a C18 solid phase extraction (SPE) cartridge. For validation of the method, certified reference materials and spiked seafood samples were analyzed. The determined methylmercury contents of certified reference materials NIST1566b, BCR464 and GBW10029 agreed well with the certified values. The determined methylmercury values for Food Analysis Performance Assessment Scheme (FAPAS) sample 07115 were satisfied. The recoveries of methylmercury in seafood samples at three spiked levels (10, 50 and 500 microg/kg) ranged from 89% to 112%, including cooked seafood food. The precision of the method based on relative standard deviation (RSD) was not more than 7%. The present method of LC-CV-AFS is accurate, sensitive, simple, and can meet the demand of methylmercury determination in seafood.

  19. A coupled diffusion-transport computational method and its application for the determination of space dependent angular flux distributions at a cold neutron source

    International Nuclear Information System (INIS)

    Turgut, M.H.

    1985-01-01

    A fast calculation program ''BRIDGE'' was developed for the calculation of a Cold Neutron Source (CNS) at a radial beam tube of the FRG-I reactor, which couples a total assembly diffusion calculation to a transport calculation for a certain subregion. For the coupling flux and current boundary values at the common surfaces are taken from the diffusion calculation and are used as driving conditions in the transport calculation. 'Equivalence Theorie' is used for the transport feedback effect on the diffusion calculation to improve the consistency of the boundary values. The optimization of a CNS for maximizing the subthermal flux in the wavelength range 4 - 6 A is discussed. (orig.) [de

  20. Two atoms scattering at low and cold energies

    Indian Academy of Sciences (India)

    terms exactly with exchange/antisymmetry between the system electrons. ... Figure 1a presents the picture of two atoms with nuclei A and B attached with electrons ..... Physical Chemistry Dept. of IACS, Kolkata, India, Private Communication.

  1. EPA Method 245.2: Mercury (Automated Cold Vapor Technique)

    Science.gov (United States)

    Method 245.2 describes procedures for preparation and analysis of drinking water samples for analysis of mercury using acid digestion and cold vapor atomic absorption. Samples are prepared using an acid digestion technique.

  2. Trapping hydrogen atoms from a neon-gas matrix: a theoretical simulation.

    Science.gov (United States)

    Bovino, S; Zhang, P; Kharchenko, V; Dalgarno, A

    2009-08-07

    Hydrogen is of critical importance in atomic and molecular physics and the development of a simple and efficient technique for trapping cold and ultracold hydrogen atoms would be a significant advance. In this study we simulate a recently proposed trap-loading mechanism for trapping hydrogen atoms released from a neon matrix. Accurate ab initio quantum calculations are reported of the neon-hydrogen interaction potential and the energy- and angular-dependent elastic scattering cross sections that control the energy transfer of initially cold atoms are obtained. They are then used to construct the Boltzmann kinetic equation, describing the energy relaxation process. Numerical solutions of the Boltzmann equation predict the time evolution of the hydrogen energy distribution function. Based on the simulations we discuss the prospects of the technique.

  3. The Brazilian time and frequency atomic standards program

    Directory of Open Access Journals (Sweden)

    Mushtaq Ahmed

    2008-06-01

    Full Text Available Cesium atomic beam clocks have been the workhorse for many demanding applications in science and technology for the past four decades. Tests of the fundamental laws of physics and the search for minute changes in fundamental constants, the synchronization of telecommunication networks, and realization of the satellite-based global positioning system would not be possible without atomic clocks. The adoption of optical cooling and trapping techniques, has produced a major advance in atomic clock precision. Cold-atom fountain and compact cold-atom clocks have also been developed. Measurement precision of a few parts in 10(15 has been demonstrated for a cold-atom fountain clock. We present here an overview of the time and frequency metrology program based on cesium atoms under development at USP São Carlos. This activity consists of construction and characterization of atomic-beam, and several variations of cold-atom clocks. We discuss the basic working principles, construction, evaluation, and important applications of atomic clocks in the Brazilian program.Relógios atômicos de feixe de Césio têm sido a base para diversas aplicações em ciência e tecnologia nas últimas quatro décadas. Testes de leis fundamentais de física, buscas por mínimas variações em constantes fundamentais, sincronização de redes de telecomunicações e o funcionamento do sistema de posicionamento global, baseado em satélites de navegação, não seriam possíveis sem os relógios atômicos. A adoção de técnicas de aprisionamento e resfriamento ópticos tem permitido um grande avanço na precisão dos relógios atômicos. Chafarizes de átomos frios e relógios compactos de átomos frios também têm sido desenvolvidos. Precisões de medida de algumas partes em 1015 foram demonstradas para relógios do tipo chafariz de átomos frios. Apresentamos uma visão geral do programa de metrologia de tempo e freqüência baseado em átomos de césio, em

  4. Coupling of (ultra- relativistic atomic nuclei with photons

    Directory of Open Access Journals (Sweden)

    M. Apostol

    2013-11-01

    Full Text Available The coupling of photons with (ultra- relativistic atomic nuclei is presented in two particular circumstances: very high electromagnetic fields and very short photon pulses. We consider a typical situation where the (bare nuclei (fully stripped of electrons are accelerated to energies ≃ 1 TeV per nucleon (according to the state of the art at LHC, for instance and photon sources like petawatt lasers ≃ 1 eV-radiation (envisaged by ELI-NP project, for instance, or free-electron laser ≃ 10 keV-radiation, or synchrotron sources, etc. In these circumstances the nuclear scale energy can be attained, with very high field intensities. In particular, we analyze the nuclear transitions induced by the radiation, including both one- and two-photon proceses, as well as the polarization-driven transitions which may lead to giant dipole resonances. The nuclear (electrical polarization concept is introduced. It is shown that the perturbation theory for photo-nuclear reactions is applicable, although the field intensity is high, since the corresponding interaction energy is low and the interaction time (pulse duration is short. It is also shown that the description of the giant nuclear dipole resonance requires the dynamics of the nuclear electrical polarization degrees of freedom.

  5. Forward and backward scattering experiments in ultra-cold Rubidium atoms

    DEFF Research Database (Denmark)

    Kampel, Nir Shlomo

    project, we have studied coherent forward scattering in the form of a memory experiment. In such an experiment we convert the input light pulse to an atomic excitation, and at a later time convert back the atomic excitation into the retrieved light pulse. In the first project, we investigate the source...

  6. Experimental evidence of state-selective charge transfer in inductively coupled plasma-atomic emission spectrometry

    International Nuclear Information System (INIS)

    Chan, George C.-Y.; Hieftje, Gary M.

    2004-01-01

    State-selective charge-transfer behavior was observed for Fe, Cr, Mn and Cu in inductively coupled plasma (ICP)-atomic emission spectrometry. Charge transfer from Ar + to Fe, Cr and Mn is state-selective because of inefficient collisional mixing of the quasiresonant charge-transfer energy levels with nearby levels. This low efficiency is the consequence of differences in electronic configuration of the core electrons. The reason for state-selective charge-transfer behavior to Cu is not clear, although a tentative explanation based on efficiency of intramultiplet and intermultiplet mixing for this special case is offered

  7. Internal Spin Control, Squeezing and Decoherence in Ensembles of Alkali Atomic Spins

    Science.gov (United States)

    Norris, Leigh Morgan

    Large atomic ensembles interacting with light are one of the most promising platforms for quantum information processing. In the past decade, novel applications for these systems have emerged in quantum communication, quantum computing, and metrology. Essential to all of these applications is the controllability of the atomic ensemble, which is facilitated by a strong coupling between the atoms and light. Non-classical spin squeezed states are a crucial step in attaining greater ensemble control. The degree of entanglement present in these states, furthermore, serves as a benchmark for the strength of the atom-light interaction. Outside the broader context of quantum information processing with atomic ensembles, spin squeezed states have applications in metrology, where their quantum correlations can be harnessed to improve the precision of magnetometers and atomic clocks. This dissertation focuses upon the production of spin squeezed states in large ensembles of cold trapped alkali atoms interacting with optical fields. While most treatments of spin squeezing consider only the case in which the ensemble is composed of two level systems or qubits, we utilize the entire ground manifold of an alkali atom with hyperfine spin f greater than or equal to 1/2, a qudit. Spin squeezing requires non-classical correlations between the constituent atomic spins, which are generated through the atoms' collective coupling to the light. Either through measurement or multiple interactions with the atoms, the light mediates an entangling interaction that produces quantum correlations. Because the spin squeezing treated in this dissertation ultimately originates from the coupling between the light and atoms, conventional approaches of improving this squeezing have focused on increasing the optical density of the ensemble. The greater number of internal degrees of freedom and the controllability of the spin-f ground hyperfine manifold enable novel methods of enhancing squeezing. In

  8. Advances in atomic, molecular, and optical physics

    CERN Document Server

    Berman, Paul R; Arimondo, Ennio

    2006-01-01

    Volume 54 of the Advances Series contains ten contributions, covering a diversity of subject areas in atomic, molecular and optical physics. The article by Regal and Jin reviews the properties of a Fermi degenerate gas of cold potassium atoms in the crossover regime between the Bose-Einstein condensation of molecules and the condensation of fermionic atom pairs. The transition between the two regions can be probed by varying an external magnetic field. Sherson, Julsgaard and Polzik explore the manner in which light and atoms can be entangled, with applications to quantum information processing

  9. Electromagnetic modes in cold magnetized strongly coupled plasmas

    OpenAIRE

    Tkachenko, I. M.; Ortner, J.; Rylyuk, V. M.

    1999-01-01

    The spectrum of electromagnetic waves propagating in a strongly coupled magnetized fully ionized hydrogen plasma is found. The ion motion and damping being neglected, the influence of the Coulomb coupling on the electromagnetic spectrum is analyzed.

  10. Coherent Microwave-to-Optical Conversion via Six-Wave Mixing in Rydberg Atoms

    Science.gov (United States)

    Han, Jingshan; Vogt, Thibault; Gross, Christian; Jaksch, Dieter; Kiffner, Martin; Li, Wenhui

    2018-03-01

    We present an experimental demonstration of converting a microwave field to an optical field via frequency mixing in a cloud of cold 87Rb atoms, where the microwave field strongly couples to an electric dipole transition between Rydberg states. We show that the conversion allows the phase information of the microwave field to be coherently transferred to the optical field. With the current energy level scheme and experimental geometry, we achieve a photon-conversion efficiency of ˜0.3 % at low microwave intensities and a broad conversion bandwidth of more than 4 MHz. Theoretical simulations agree well with the experimental data, and they indicate that near-unit efficiency is possible in future experiments.

  11. Matrix digestion of soil and sediment samples for extraction of lead, cadmium and antimony and their direct determination by inductively coupled plasma-mass spectrometry and atomic emission spectrometry

    International Nuclear Information System (INIS)

    Chattopadhyay, P.; Fisher, A.S.; Henon, D.N.; Hill, S.J.

    2004-01-01

    An environmentally friendly and simple method has been developed for complete digestion of lead, cadmium and antimony from soil samples using a magnesium nitrate assisted dry ashing procedure. Statistical data for a series of experiments with standard reference materials are presented, and precision values are found to be comparable for inductively coupled plasma-mass spectrometry and for inductively coupled plasma-atomic emission spectrometry. From a single digest solution all analytes are quantified without involving any preconcentration routes. Inter-method comparison of inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES) shows that the probability of the results being different is less than 99 %. (author)

  12. Continuous loading of cold atoms into a Ioffe-Pritchard magnetic trap

    International Nuclear Information System (INIS)

    Schmidt, Piet O; Hensler, Sven; Werner, Joerg; Binhammer, Thomas; Goerlitz, Axel; Pfau, Tilman

    2003-01-01

    We present a robust continuous optical loading scheme for a Ioffe-Pritchard (IP) type magnetic trap (MT). Chromium atoms are cooled and trapped in a modified magneto-optical trap (MOT) consisting of a conventional 2D-MOT in the radial direction and an axial molasses. The MOT and IP trap share the same magnetic field configuration. Continuous loading of atoms into the IP trap is provided by radiative leakage from the MOT to a metastable level which is magnetically trapped and decoupled from the MOT light. We are able to accumulate 30 times more atoms in the MT than in the MOT. The absolute number of 2 x 10 8 atoms is limited by inelastic collisions. A model based on rate equations shows good agreement with the data. Our scheme can also be applied to other atoms with similar level structure like alkaline earth metals

  13. Versatile element for free-space dividing and redirecting neutral-atom clouds

    International Nuclear Information System (INIS)

    Arakelyan, I. V.; Chattrapiban, N.; Mitra, S.; Hill, W. T. III

    2007-01-01

    We introduce a tunnel lock that can be exploited to divide, delay, and alter the direction of traveling clouds of cold atoms. This versatile free-space element is implemented by crossing two atom tunnels formed by low-intensity, blue-detuned dark-hollow (Bessel mode) laser beams. We show that clouds of cold Rb atoms initially moving within one tunnel can be transferred to the other without heating by gating the intensities of the two tunnels--a tunnel lock--with an efficiency limited by the overlap volume. The element also can be used to divide a single cloud into smaller clouds, each having a distinct momentum

  14. Consequences of atomic layer etching on wafer scale uniformity in inductively coupled plasmas

    Science.gov (United States)

    Huard, Chad M.; Lanham, Steven J.; Kushner, Mark J.

    2018-04-01

    Atomic layer etching (ALE) typically divides the etching process into two self-limited reactions. One reaction passivates a single layer of material while the second preferentially removes the passivated layer. As such, under ideal conditions the wafer scale uniformity of ALE should be independent of the uniformity of the reactant fluxes onto the wafers, provided all surface reactions are saturated. The passivation and etch steps should individually asymptotically saturate after a characteristic fluence of reactants has been delivered to each site. In this paper, results from a computational investigation are discussed regarding the uniformity of ALE of Si in Cl2 containing inductively coupled plasmas when the reactant fluxes are both non-uniform and non-ideal. In the parameter space investigated for inductively coupled plasmas, the local etch rate for continuous processing was proportional to the ion flux. When operated with saturated conditions (that is, both ALE steps are allowed to self-terminate), the ALE process is less sensitive to non-uniformities in the incoming ion flux than continuous etching. Operating ALE in a sub-saturation regime resulted in less uniform etching. It was also found that ALE processing with saturated steps requires a larger total ion fluence than continuous etching to achieve the same etch depth. This condition may result in increased resist erosion and/or damage to stopping layers using ALE. While these results demonstrate that ALE provides increased etch depth uniformity, they do not show an improved critical dimension uniformity in all cases. These possible limitations to ALE processing, as well as increased processing time, will be part of the process optimization that includes the benefits of atomic resolution and improved uniformity.

  15. Circuit-quantum electrodynamics with direct magnetic coupling to single-atom spin qubits in isotopically enriched 28Si

    Directory of Open Access Journals (Sweden)

    Guilherme Tosi

    2014-08-01

    Full Text Available Recent advances in silicon nanofabrication have allowed the manipulation of spin qubits that are extremely isolated from noise sources, being therefore the semiconductor equivalent of single atoms in vacuum. We investigate the possibility of directly coupling an electron spin qubit to a superconducting resonator magnetic vacuum field. By using resonators modified to increase the vacuum magnetic field at the qubit location, and isotopically purified 28Si substrates, it is possible to achieve coupling rates faster than the single spin dephasing. This opens up new avenues for circuit-quantum electrodynamics with spins, and provides a pathway for dispersive read-out of spin qubits via superconducting resonators.

  16. Radiofrequency-dressed-state potentials for neutral atoms

    DEFF Research Database (Denmark)

    Hofferberth, S.; Lesanovsky, Igor; Fischer, B.

    2006-01-01

    Potentials for atoms can be created by external fields acting on properties such as magnetic moment, charge, polarizability, or by oscillating fields that couple internal states. The most prominent realization of the latter is the optical dipole potential formed by coupling ground and electronica......Potentials for atoms can be created by external fields acting on properties such as magnetic moment, charge, polarizability, or by oscillating fields that couple internal states. The most prominent realization of the latter is the optical dipole potential formed by coupling ground...... and electronically excited states of an atom with light. Here, we present an extensive experimental analysis of potentials derived from radiofrequency (RF) coupling of electronic ground states. The coupling is magnetic and the vector character allows the design of versatile microscopic state-dependent potential...... landscapes. Compared with standard magnetic trapping, we find no additional heating or (collisional) loss up to densities of 1015 atoms cm-3. We demonstrate robust evaporative cooling in RF potentials, which allows easy production of Bose-Einstein condensates in complex potentials. Altogether, this makes RF...

  17. Coherence Phenomena in Coupled Optical Resonators

    Science.gov (United States)

    Smith, D. D.; Chang, H.

    2004-01-01

    We predict a variety of photonic coherence phenomena in passive and active coupled ring resonators. Specifically, the effective dispersive and absorptive steady-state response of coupled resonators is derived, and used to determine the conditions for coupled-resonator-induced transparency and absorption, lasing without gain, and cooperative cavity emission. These effects rely on coherent photon trapping, in direct analogy with coherent population trapping phenomena in atomic systems. We also demonstrate that the coupled-mode equations are formally identical to the two-level atom Schrodinger equation in the rotating-wave approximation, and use this result for the analysis of coupled-resonator photon dynamics. Notably, because these effects are predicted directly from coupled-mode theory, they are not unique to atoms, but rather are fundamental to systems of coherently coupled resonators.

  18. Optical atomic phase reference and timing.

    Science.gov (United States)

    Hollberg, L; Cornell, E H; Abdelrahmann, A

    2017-08-06

    Atomic clocks based on laser-cooled atoms have made tremendous advances in both accuracy and stability. However, advanced clocks have not found their way into widespread use because there has been little need for such high performance in real-world/commercial applications. The drive in the commercial world favours smaller, lower-power, more robust compact atomic clocks that function well in real-world non-laboratory environments. Although the high-performance atomic frequency references are useful to test Einstein's special relativity more precisely, there are not compelling scientific arguments to expect a breakdown in special relativity. On the other hand, the dynamics of gravity, evidenced by the recent spectacular results in experimental detection of gravity waves by the LIGO Scientific Collaboration, shows dramatically that there is new physics to be seen and understood in space-time science. Those systems require strain measurements at less than or equal to 10 -20 As we discuss here, cold atom optical frequency references are still many orders of magnitude away from the frequency stability that should be achievable with narrow-linewidth quantum transitions and large numbers of very cold atoms, and they may be able to achieve levels of phase stability, Δ Φ / Φ total  ≤ 10 -20 , that could make an important impact in gravity wave science.This article is part of the themed issue 'Quantum technology for the 21st century'. © 2017 The Author(s).

  19. Determination of Ar metastable atom densities in Ar and Ar/H2 inductively coupled low-temperature plasmas

    International Nuclear Information System (INIS)

    Fox-Lyon, N; Knoll, A J; Oehrlein, G S; Franek, J; Demidov, V; Koepke, M; Godyak, V

    2013-01-01

    Ar metastable atoms are important energy carriers and surface interacting species in low-temperature plasmas that are difficult to quantify. Ar metastable atom densities (N Ar,m ) in inductively coupled Ar and Ar/H 2 plasmas were obtained using a model combining electrical probe measurements of electron density (N e ) and temperature (T e ), with analysis of spectrally resolved Ar plasma optical emission based on 3p → 1s optical emission ratios of the 419.8 nm line to the 420.1 nm line. We present the variation of N Ar,m as the Ar pressure and the addition of H 2 to Ar are changed comparatively to recent adsorption spectroscopy measurements. (paper)

  20. Role of atomic spin-mechanical coupling in the problem of a magnetic biocompass

    Science.gov (United States)

    Cao, Yunshan; Yan, Peng

    2018-04-01

    It is a well established notion that animals can detect the Earth's magnetic field, while the biophysical origin of such magnetoreception is still elusive. Recently, a magnetic receptor Drosophila CG8198 (MagR) with a rodlike protein complex is reported [S. Qin et al., Nat. Mater. 15, 217 (2016), 10.1038/nmat4484] to act like a compass needle to guide the magnetic orientation of animals. This view, however, is challenged [M. Meister, Elife 5, e17210 (2016), 10.7554/eLife.17210] by arguing that thermal fluctuations beat the Zeeman coupling of the proteins's magnetic moment with the rather weak geomagnetic field (˜25 -65 μ T ). In this work, we show that the spin-mechanical interaction at the atomic scale gives rise to a high blocking temperature which allows a good alignment of the protein's magnetic moment with the Earth's magnetic field at room temperature. Our results provide a promising route to resolve the debate on the thermal behaviors of MagR, and may stimulate a broad interest in spin-mechanical couplings down to atomistic levels.

  1. Single atoms on demand for cavity QED experiments

    International Nuclear Information System (INIS)

    Dotsenko, I.

    2007-01-01

    Cavity quantum electrodynamics (cavity QED) describes electromagnetic fields in a confined space and the radiative properties of atoms in such fields. The simplest example of such system is a single atom interacting with one mode of a high-finesse resonator. Besides observation and exploration of fundamental quantum mechanical effects, this system bears a high potential for applications quantum information science such as, e.g., quantum logic gates, quantum communication and quantum teleportation. In this thesis I present an experiment on the deterministic coupling of a single neutral atom to the mode of a high-finesse optical resonator. In Chapter 1 I describe our basic techniques for trapping and observing single cesium atoms. As a source of single atoms we use a high-gradient magneto-optical trap, which captures the atoms from background gas in a vacuum chamber and cools them down to millikelvin temperatures. The atoms are then transferred without loss into a standing-wave dipole trap, which provides a conservative potential required for experiments on atomic coherence such as quantum information processing and metrology on trapped atoms. Moreover, shifting the standing-wave pattern allows us to deterministically transport the atoms (Chapter 2). In combination with nondestructive fluorescence imaging of individual trapped atoms, this enables us to control their position with submicrometer precision over several millimeters along the dipole trap. The cavity QED system can distinctly display quantum behaviour in the so-called strong coupling regime, i.e., when the coherent atom-cavity coupling rate dominates dissipation in the system. This sets the main requirements on the resonator's properties: small mode volume and high finesse. Chapter 3 is devoted to the manufacturing, assembling, and testing of an ultra-high finesse optical Fabry-Perot resonator, stabilized to the atomic transition. In Chapter 4 I present the transportation of single atoms into the cavity

  2. Single atoms on demand for cavity QED experiments

    Energy Technology Data Exchange (ETDEWEB)

    Dotsenko, I.

    2007-09-06

    Cavity quantum electrodynamics (cavity QED) describes electromagnetic fields in a confined space and the radiative properties of atoms in such fields. The simplest example of such system is a single atom interacting with one mode of a high-finesse resonator. Besides observation and exploration of fundamental quantum mechanical effects, this system bears a high potential for applications quantum information science such as, e.g., quantum logic gates, quantum communication and quantum teleportation. In this thesis I present an experiment on the deterministic coupling of a single neutral atom to the mode of a high-finesse optical resonator. In Chapter 1 I describe our basic techniques for trapping and observing single cesium atoms. As a source of single atoms we use a high-gradient magneto-optical trap, which captures the atoms from background gas in a vacuum chamber and cools them down to millikelvin temperatures. The atoms are then transferred without loss into a standing-wave dipole trap, which provides a conservative potential required for experiments on atomic coherence such as quantum information processing and metrology on trapped atoms. Moreover, shifting the standing-wave pattern allows us to deterministically transport the atoms (Chapter 2). In combination with nondestructive fluorescence imaging of individual trapped atoms, this enables us to control their position with submicrometer precision over several millimeters along the dipole trap. The cavity QED system can distinctly display quantum behaviour in the so-called strong coupling regime, i.e., when the coherent atom-cavity coupling rate dominates dissipation in the system. This sets the main requirements on the resonator's properties: small mode volume and high finesse. Chapter 3 is devoted to the manufacturing, assembling, and testing of an ultra-high finesse optical Fabry-Perot resonator, stabilized to the atomic transition. In Chapter 4 I present the transportation of single atoms into the

  3. Ultracold Atoms in a Square Lattice with Spin-Orbit Coupling: Charge Order, Superfluidity, and Topological Signatures

    Science.gov (United States)

    Rosenberg, Peter; Shi, Hao; Zhang, Shiwei

    2017-12-01

    We present an ab initio, numerically exact study of attractive fermions in square lattices with Rashba spin-orbit coupling. The ground state of this system is a supersolid, with coexisting charge and superfluid order. The superfluid is composed of both singlet and triplet pairs induced by spin-orbit coupling. We perform large-scale calculations using the auxiliary-field quantum Monte Carlo method to provide the first full, quantitative description of the charge, spin, and pairing properties of the system. In addition to characterizing the exotic physics, our results will serve as essential high-accuracy benchmarks for the intense theoretical and especially experimental efforts in ultracold atoms to realize and understand an expanding variety of quantum Hall and topological superconductor systems.

  4. Searching for an Oscillating Massive Scalar Field as a Dark Matter Candidate Using Atomic Hyperfine Frequency Comparisons.

    Science.gov (United States)

    Hees, A; Guéna, J; Abgrall, M; Bize, S; Wolf, P

    2016-08-05

    We use 6 yrs of accurate hyperfine frequency comparison data of the dual rubidium and caesium cold atom fountain FO2 at LNE-SYRTE to search for a massive scalar dark matter candidate. Such a scalar field can induce harmonic variations of the fine structure constant, of the mass of fermions, and of the quantum chromodynamic mass scale, which will directly impact the rubidium/caesium hyperfine transition frequency ratio. We find no signal consistent with a scalar dark matter candidate but provide improved constraints on the coupling of the putative scalar field to standard matter. Our limits are complementary to previous results that were only sensitive to the fine structure constant and improve them by more than an order of magnitude when only a coupling to electromagnetism is assumed.

  5. Sample Preprocessing For Atomic Spectrometry

    International Nuclear Information System (INIS)

    Kim, Sun Tae

    2004-08-01

    This book gives descriptions of atomic spectrometry, which deals with atomic absorption spectrometry such as Maxwell-Boltzmann equation and Beer-Lambert law, atomic absorption spectrometry for solvent extraction, HGAAS, ETASS, and CVAAS and inductively coupled plasma emission spectrometer, such as basic principle, generative principle of plasma and device and equipment, and interferences, and inductively coupled plasma mass spectrometry like device, pros and cons of ICP/MS, sample analysis, reagent, water, acid, flux, materials of experiments, sample and sampling and disassembling of sample and pollution and loss in open system and closed system.

  6. Cold - an underrated risk factor for health

    International Nuclear Information System (INIS)

    Mercer, James B.

    2003-01-01

    Cardiovascular diseases (CVD) are responsible for around 20% of all deaths worldwide (approximately 14 million) and are the principal cause of death in all developed countries, accounting for 50% of all deaths. Variations in the annual per capita death rates in different countries are well documented. Less well known are seasonal variations in death rates, with the highest levels occurring during the colder winter months, which have been described in many countries. This phenomenon is referred to as excess winter mortality. CVD-related deaths account for the majority of excess winter deaths (up to 70% in some countries), while about half of the remaining are due to increases in respiratory diseases. Paradoxically, CVD mortality increases to a greater extent with a given fall in temperature in regions with warm winters. While much of the indirect evidence points to the notion that cold is somehow involved in explaining excess winter deaths, the mechanism by which seemingly mild exposure to cold ambient conditions can increase the risk of death remains unclear. The strong indirect epidemiological evidence coupling cold climate to mortality may be related to indoor rather than outdoor climatic conditions (e.g., cold/damp houses versus arm/dry houses) coupled with a plethora of factors including health status, ageing-related deterioration in physiological and behavioral thermoregulation, toxicology, and socioeconomic factors

  7. Lorentz-Symmetry Test at Planck-Scale Suppression With a Spin-Polarized 133Cs Cold Atom Clock.

    Science.gov (United States)

    Pihan-Le Bars, H; Guerlin, C; Lasseri, R-D; Ebran, J-P; Bailey, Q G; Bize, S; Khan, E; Wolf, P

    2018-06-01

    We present the results of a local Lorentz invariance (LLI) test performed with the 133 Cs cold atom clock FO2, hosted at SYRTE. Such a test, relating the frequency shift between 133 Cs hyperfine Zeeman substates with the Lorentz violating coefficients of the standard model extension (SME), has already been realized by Wolf et al. and led to state-of-the-art constraints on several SME proton coefficients. In this second analysis, we used an improved model, based on a second-order Lorentz transformation and a self-consistent relativistic mean field nuclear model, which enables us to extend the scope of the analysis from purely proton to both proton and neutron coefficients. We have also become sensitive to the isotropic coefficient , another SME coefficient that was not constrained by Wolf et al. The resulting limits on SME coefficients improve by up to 13 orders of magnitude the present maximal sensitivities for laboratory tests and reach the generally expected suppression scales at which signatures of Lorentz violation could appear.

  8. On-line preconcentration and determination of mercury in biological and environmental samples by cold vapor-atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Ferrua, N.; Cerutti, S.; Salonia, J.A.; Olsina, R.A.; Martinez, L.D.

    2007-01-01

    An on-line procedure for the determination of traces of total mercury in environmental and biological samples is described. The present methodology combines cold vapor generation associated to atomic absorption spectrometry (CV-AAS) with preconcentration of the analyte on a minicolumn packed with activated carbon. The retained analyte was quantitatively eluted from the minicolumn with nitric acid. After that, volatile specie of mercury was generated by merging the acidified sample and sodium tetrahydroborate(III) in a continuous flow system. The gaseous analyte was subsequently introduced via a stream of Ar carrier into the atomizer device. Optimizations of both, preconcentration and mercury volatile specie generation variables were carried out using two level full factorial design (2 3 ) with 3 replicates of the central point. Considering a sample consumption of 25 mL, an enrichment factor of 13-fold was obtained. The detection limit (3σ) was 10 ng L -1 and the precision (relative standard deviation) was 3.1% (n = 10) at the 5 μg L -1 level. The calibration curve using the preconcentration system for mercury was linear with a correlation coefficient of 0.9995 at levels near the detection limit up to at least 1000 μg L -1 . Satisfactory results were obtained for the analysis of mercury in tap water and hair samples

  9. Computer simulation and cold model testing of CCL cavities

    International Nuclear Information System (INIS)

    Chang, C.R.; Yao, C.G.; Swenson, D.A.; Funk, L.W.

    1993-01-01

    The SSC coupled-cavity-linac (CCL) consists of nine modules with eight tanks in each module. Multicavity magnetically coupled bridge couplers are used to couple the eight tanks within a module into one RF resonant chain. The operating frequency is 1282.851 MHz. In this paper the authors discuss both computer calculations and cold model measurements to determine the geometry dimension of the RF structure

  10. Synthesis of Well-Defined Three-Arm Star-Branched Polystyrene through Arm-First Coupling Approach by Atom Transfer Radical Polymerization

    Directory of Open Access Journals (Sweden)

    Syed Shahabuddin

    2015-01-01

    Full Text Available Here we describe a simple route to synthesize three-arm star-branched polystyrene. Atom transfer radical polymerization technique has been utilized to yield branched polystyrene involving Williamson coupling strategy. Initially a linear polymeric chain of predetermined molecular weight has been synthesized which is further end-functionalized into a primary alkyl bromide moiety, a prime requisition for Williamson reaction. The end-functionalized polymer is then coupled using 1,1,1-tris(4-hydroxyphenylethane, a trifunctional core molecule, to give well-defined triple-arm star-branched polystyrene.

  11. A Rotating-Bears Optical Dipole Trap for Cold Aatoms

    International Nuclear Information System (INIS)

    Friedman, N.; Ozeri, R.; Khaykovich, L.; Davidson, N.

    1999-01-01

    In the last few years, several optical dipole traps for cold atoms were demonstrated and used to study cold atomic collisions, long atomic coherence times and quantum collective effects. Blue-detuned dipole traps, where repulsive light forces confines atoms mostly in dark, offer long storage, and photon-scattering times, combined with strong confinement forces. Unfortunately, such blue-detuned dipole traps involve complicated light intensity distributions that require either multiple laser beams or complicated phase elements. Here, we propose and demonstrate a novel configuration for a single-beam blue-detuned dipole trap, which enables larger trapping volume, and fast temporal changes in the trap size and shape. Our trap consists of a tightly-focused laser beam which is rapidly rotated (with rotation frequency up to 400 khz) with two orthogonal acousto optical scanners. For very high rotation frequencies the atoms feel a time-averaged static dipole potential. Therefore, when the radius of rotation is larger than the beam size, a dark volume which is completely surrounded by light is obtained around the focal region. By changing the rotation radius and the trapping laser intensity and detuning, the trap dimensions and oscillation frequency could be changed over a large parameter range. In particular trap diameters were changed between 50 to 220 microns and trap length was changed between 3.5 to 16 mm. ∼10 6 atoms were loaded into the rotating-beam dipole trap from a magneto optical trap. The density of the trapped atoms was 4x10 10 atoms/cm 3 ,their temperature was -6 pK. and the trap (1/e) lifetime was 0.65 sec, limited by collisions with background atoms. When the rotation frequency was decreased below the oscillation frequency of the atoms in the trap, the trap became unstable, and a sharp reduction of the trap lifetime was observed, in agreement with our theoretical analysis. Finally, we demonstrated adiabatic compression of atoms in the trap by decreasing

  12. Optical angular momentum and atoms.

    Science.gov (United States)

    Franke-Arnold, Sonja

    2017-02-28

    Any coherent interaction of light and atoms needs to conserve energy, linear momentum and angular momentum. What happens to an atom's angular momentum if it encounters light that carries orbital angular momentum (OAM)? This is a particularly intriguing question as the angular momentum of atoms is quantized, incorporating the intrinsic spin angular momentum of the individual electrons as well as the OAM associated with their spatial distribution. In addition, a mechanical angular momentum can arise from the rotation of the entire atom, which for very cold atoms is also quantized. Atoms therefore allow us to probe and access the quantum properties of light's OAM, aiding our fundamental understanding of light-matter interactions, and moreover, allowing us to construct OAM-based applications, including quantum memories, frequency converters for shaped light and OAM-based sensors.This article is part of the themed issue 'Optical orbital angular momentum'. © 2017 The Author(s).

  13. Atom chip gravimeter

    Science.gov (United States)

    Schubert, Christian; Abend, Sven; Gebbe, Martina; Gersemann, Matthias; Ahlers, Holger; Müntinga, Hauke; Matthias, Jonas; Sahelgozin, Maral; Herr, Waldemar; Lämmerzahl, Claus; Ertmer, Wolfgang; Rasel, Ernst

    2016-04-01

    Atom interferometry has developed into a tool for measuring rotations [1], accelerations [2], and testing fundamental physics [3]. Gravimeters based on laser cooled atoms demonstrated residual uncertainties of few microgal [2,4] and were simplified for field applications [5]. Atomic gravimeters rely on the interference of matter waves which are coherently manipulated by laser light fields. The latter can be interpreted as rulers to which the position of the atoms is compared. At three points in time separated by a free evolution, the light fields are pulsed onto the atoms. First, a coherent superposition of two momentum states is produced, then the momentum is inverted, and finally the two trajectories are recombined. Depending on the acceleration the atoms experienced, the number of atoms detected in the output ports will change. Consequently, the acceleration can be determined from the output signal. The laser cooled atoms with microkelvin temperatures used in state-of-the-art gravimeters impose limits on the accuracy [4]. Therefore, ultra-cold atoms generated by Bose-Einstein condensation and delta-kick collimation [6,7] are expected to be the key for further improvements. These sources suffered from a low flux implying an incompatible noise floor, but a competitive performance was demonstrated recently with atom chips [8]. In the compact and robust setup constructed for operation in the drop tower [6] we demonstrated all steps necessary for an atom chip gravimeter with Bose-Einstein condensates in a ground based operation. We will discuss the principle of operation, the current performance, and the perspectives to supersede the state of the art. The authors thank the QUANTUS cooperation for contributions to the drop tower project in the earlier stages. This work is supported by the German Space Agency (DLR) with funds provided by the Federal Ministry for Economic Affairs and Energy (BMWi) due to an enactment of the German Bundestag under grant numbers DLR 50WM

  14. Development of a high efficient conventional type cold neutron source using a non-explosive material

    International Nuclear Information System (INIS)

    Kiyanagi, Y.; Satoh, S.

    1999-01-01

    An efficient cold moderator that can be used easily at a small neutron source would be useful for neutron radiography, prompt gamma ray analysis and so on. Non-explosive materials are chosen for a cold moderator since explosive materials such as hydrogen and methane require a safety system. Neutronic performances of coupled moderators of various non-explosive materials are studied so as to develop such a cold moderator since the coupled moderator system is the best to obtain high intensity of cold neutrons. Effect of premoderator is studied and neutron spectra from methanol, ethanol, benzene, mesitylene and benzene methanol are measured around 20 K. The premoderator increased the cold neutron intensity by about 50∼70%. Methanol and mesitylene gave the highest cold neutron intensity. Effect of Be filter-reflector is also studied and a intensity gain of about 20% was obtained below about 5 MeV. (author)

  15. High-Flux Ultracold-Atom Chip Interferometers, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — ColdQuanta's ultimate objective is to produce a compact, turnkey, ultracold-atom system specifically designed for performing interferometry with Bose-Einstein...

  16. How to cool down cold atoms using laser light? Principles and techniques

    International Nuclear Information System (INIS)

    Guellati-Khelifa, Saida; Clade, Pierre

    2012-01-01

    This article is devoted to the description of various mechanisms of the laser cooling of neutral atoms. These mechanisms are all based on the interaction between a photon, an entity of light, and an atom, an entity of matter. One of the macroscopic manifestations of this interaction is the pressure of radiation force. The effect of this force is strongly amplified when the source of photon is a laser. We will describe how it is possible to use this force with the Doppler effect in order to slow an atomic beam and also to reduce considerably the thermal agitation of atoms. We will explain how by shaping the light potentials and magnetic fields it is possible to reach extremely low temperatures of some nano-kelvin. At these temperatures, very near to the absolute zero, it is possible for certain kind of atoms, called bosons, to achieve a new state of matter, where quantum behaviour of atoms became apparent on a macroscopic scale. (authors)

  17. Coupled processes and the tropical climatology : part III : instabilities of the fully coupled climatology

    NARCIS (Netherlands)

    Dijkstra, H.A.; Neelin, J.D.

    1998-01-01

    Coupled processes between the equatorial ocean and atmosphere control the spatial structure of the annual mean state in the Pacific region,in particular the warm-pool/cold- tongue structure.At the same time,coupled processes are known to be responsible for the variability about this mean state,in

  18. Atom Interferometry for Dark Contents of the Vacuum Searches

    Energy Technology Data Exchange (ETDEWEB)

    Burrow, O. [Liverpool U.; Carroll, A. [Liverpool U.; Chattopadhyay, S. [Northern Illinois U.; Coleman, J. [Liverpool U.; Elertas, G. [Teddington, Natl. Phys. Lab; Heffer, J. [Liverpool U.; Metelko, C. [Liverpool U.; Moore, R. [Teddington, Natl. Phys. Lab; Morris, D. [Liverpool U.; Perl, M. [SLAC; Ralph, J. [Liverpool U.; Tinsley, J. [Teddington, Natl. Phys. Lab

    2017-05-25

    A cold atom interferometer is being developed using 85Rb atoms towards a search for the dark contents of the vacuum, and as a test stand for inertial sensing applications. Here we outline the current status of the experiment and report the observation of Ramsey interference fringes in the apparatus.

  19. Evolution Properties of Atomic Fidelity in the Combined Multi-Atom-Cavity Field System

    International Nuclear Information System (INIS)

    Wang Ju-Xia; Zhang Xiao-Juan; Zhang Xiu-Xing

    2015-01-01

    The atom fidelity is investigated in a system consisting of Mtwo-level atoms and M single-mode fields by use of complete quantum theory and numerical evaluation method. The influences of various system parameters on the evolution of atomic fidelity are studied. The results show that the atomic fidelity evolves in a Rabi oscillation manner. The oscillation frequency is mainly modulated by the coupling strength between atoms and light field, the atomic transition probabilities and the average photon numbers. Other factors hardly impact on the atomic fidelity. The present results may provide a useful approach to the maintenance of the atomic fidelity in the atom cavity field systems. (paper)

  20. Synthetic Unruh effect in cold atoms

    Science.gov (United States)

    Rodríguez-Laguna, Javier; Tarruell, Leticia; Lewenstein, Maciej; Celi, Alessio

    2017-01-01

    We propose to simulate a Dirac field near an event horizon using ultracold atoms in an optical lattice. Such a quantum simulator allows for the observation of the celebrated Unruh effect. Our proposal involves three stages: (1) preparation of the ground state of a massless two-dimensional Dirac field in Minkowski space-time; (2) quench of the optical lattice setup to simulate how an accelerated observer would view that state; (3) measurement of the local quantum fluctuation spectra by one-particle excitation spectroscopy in order to simulate a De Witt detector. According to Unruh's prediction, fluctuations measured in such a way must be thermal. Moreover, following Takagi's inversion theorem, they will obey the Bose-Einstein distribution, which will smoothly transform into the Fermi-Dirac as one of the dimensions of the lattice is reduced.

  1. A theoretical study of cold nuclear fusion using barrier penetration approach

    International Nuclear Information System (INIS)

    Gupta, S.K.; Gupta, R.K.

    1989-06-01

    The cold nuclear fusion process is investigated in terms of barrier penetration calculations by considering both the deuteron-molecule and colliding deuteron-deuteron atoms. Atomic collisions with strongly screened interatomic potential and the resonant state formation can bring agreement with present experimental results. Analysis of the data in terms of the reaction rates is also discussed. (author). 13 refs, 1 tab

  2. Elemental analysis using instrumental neutron activation analysis and inductively coupled plasma atomic emission spectrometry: a comparative study

    International Nuclear Information System (INIS)

    Chung, Yong Sam; Choi, Kwang Soon; Moon, Jong Hwa; Kim, Sun Ha; Lim, Jong Myoung; Kim, Young Jin; Quraishi, Shamshad Begum

    2003-05-01

    Elemental analyses for certified reference materials were carried out using instrumental neutron activation analysis and inductively coupled plasma-atomic emission spectrometry. Five Certified Reference Materials (CRM) were selected for the study on comparative analysis of environmental samples. The CRM are Soil (NIST SRM 2709), Coal fly ash (NIST SRM 1633a), urban dust (NIST SRM 1649a) and air particulate on filter media (NIST SRM 2783 and human hair (GBW 09101)

  3. Inelastic collisions between an atom and a diatomic molecule. I. Theoretical and numerical considerations for the close coupling approximation

    International Nuclear Information System (INIS)

    Choi, B.H.; Tang, K.T.

    1975-01-01

    The close coupled differential equations for rotational excitation in collisions between an atom and a diatomic molecule are reformulated. Although it is equivalent to other formulations, it is computationally more convenient and gives a simpler expression for differential cross sections. Questions concerning real boundary conditions and the unitarity of the S matrix are discussed. Stormer's algorithm for solving coupled differential equations is introduced for molecular scatterings. This numerical procedure, which is known to be very useful in nuclear scattering problems, has to be modified for molecular systems. It is capable of treating the case where all channels are open as well as the case where some of the channels are closed. This algorithm is compared with other typical procedures of solving coupled differential equations

  4. Pharao: study of an atomic clock using laser-cooled atoms and realization of a prototype

    International Nuclear Information System (INIS)

    Lemonde, P.

    1997-01-01

    Thermal jets and atomic fountains are two different principles on which atomic clocks are based. In atomic fountains the velocity of atoms can be reduced to a few cm/s so the classical limitations of thermal jets such as phase shift between two Ramsey impulses, second order Doppler effect become negligible. The new limitations set by atomic fountain clocks are now collisions between cold atoms and the radiation emitted by the black body. Weightlessness leads to a different running of the atomic clock and can imply an enhancement of its performances. In micro-gravity an interatomic interaction time of several seconds can be reached. The application of such atomic clocks can go beyond time or frequency metrology. This work is dedicated to the development of a spatial atomic clock to fully use the extremely low velocity of laser-cooled atoms and to quantify what can be expected of weightlessness. This study has involved the realization of a prototype and its testing in a zero-g plane. The experimental results are presented and it is highlighted that an accuracy and a one-day stability of 10 -16 are within reach with an optimized version of this atomic clock. (A.C.)

  5. Use of magnesium as a test element for inductively coupled plasma atomic emission spectrometry diagnosis

    International Nuclear Information System (INIS)

    Mermet, J.M.

    1991-01-01

    To optimize atomization and ionization processes in an inductively coupled plasma used as a source in atomic emission spectrometry, the Mg II 280.270-nm/Mg I 285-213-nm line intensity ratio is used. A theoretic ratio is calculated assuming a local thermodynamic equilibrium.A review of previously published experimental values of the ratio is given as a function of the parameters influencing the energy transfer between the plasma and injected species. In particular, the effects of the power, the carrier gas flow-rate, the i.d. of the torch injector, the use of a sheathing gas and the presence of hydrogen are described. Values of the ratio close to the theoretical values are obtained with a high power (>1.4 kW), a lower carrier gas flow-rate ( -1 ) and a large i.d. of the injector (>2 mm). This optimization can also be applied to the minimization of interference effects due to the presence of sodium. (author). 64 refs.; 9 figs.; 1 tab

  6. Quantum Phases of Atom-Molecule Mixtures of Fermionic Atoms

    Science.gov (United States)

    Lopez, Nicolas; Tsai, Shan-Wen

    2009-11-01

    Cold atom experiments have observed atom-molecule mixtures by tuning the interactions between particles.footnotetextM.L. Olsen, J. D. Perreault, T. D. Cumby, and D. S. Jin, Phys. Rev. A 80, 030701(R) (2009) We study many particle interactions by examaning a simple model that describes the destruction of fermionic atom pairs to form single bosonic molecules and vice versa. A set of functional Renomalization Group equationsfootnotetextR. Shankar, Rev. Mod. Phys., Vol 66 No. 1, January 1994^,footnotetextS.W. Tsai, A.H. Castro Neto, R. Shankar, D.K. Campbell, Phys. Rev. B 72, 054531 (2005) describing these processes are set up and solved numerically. The Self Energy of the fermions are attained as a function of frequency and we search for frequency dependent instabilities that could denote a transition from a disordered liquid to a BCS phase. (Financial support from NSF DMR-084781 and UC-Lab Fees Research Program.)

  7. Decoherence-Free Interaction between Giant Atoms in Waveguide Quantum Electrodynamics.

    Science.gov (United States)

    Kockum, Anton Frisk; Johansson, Göran; Nori, Franco

    2018-04-06

    In quantum-optics experiments with both natural and artificial atoms, the atoms are usually small enough that they can be approximated as pointlike compared to the wavelength of the electromagnetic radiation with which they interact. However, superconducting qubits coupled to a meandering transmission line, or to surface acoustic waves, can realize "giant artificial atoms" that couple to a bosonic field at several points which are wavelengths apart. Here, we study setups with multiple giant atoms coupled at multiple points to a one-dimensional (1D) waveguide. We show that the giant atoms can be protected from decohering through the waveguide, but still have exchange interactions mediated by the waveguide. Unlike in decoherence-free subspaces, here the entire multiatom Hilbert space (2^{N} states for N atoms) is protected from decoherence. This is not possible with "small" atoms. We further show how this decoherence-free interaction can be designed in setups with multiple atoms to implement, e.g., a 1D chain of atoms with nearest-neighbor couplings or a collection of atoms with all-to-all connectivity. This may have important applications in quantum simulation and quantum computing.

  8. Decoherence-Free Interaction between Giant Atoms in Waveguide Quantum Electrodynamics

    Science.gov (United States)

    Kockum, Anton Frisk; Johansson, Göran; Nori, Franco

    2018-04-01

    In quantum-optics experiments with both natural and artificial atoms, the atoms are usually small enough that they can be approximated as pointlike compared to the wavelength of the electromagnetic radiation with which they interact. However, superconducting qubits coupled to a meandering transmission line, or to surface acoustic waves, can realize "giant artificial atoms" that couple to a bosonic field at several points which are wavelengths apart. Here, we study setups with multiple giant atoms coupled at multiple points to a one-dimensional (1D) waveguide. We show that the giant atoms can be protected from decohering through the waveguide, but still have exchange interactions mediated by the waveguide. Unlike in decoherence-free subspaces, here the entire multiatom Hilbert space (2N states for N atoms) is protected from decoherence. This is not possible with "small" atoms. We further show how this decoherence-free interaction can be designed in setups with multiple atoms to implement, e.g., a 1D chain of atoms with nearest-neighbor couplings or a collection of atoms with all-to-all connectivity. This may have important applications in quantum simulation and quantum computing.

  9. The formation and interactions of cold and ultracold molecules: new challenges for interdisciplinary physics

    Energy Technology Data Exchange (ETDEWEB)

    Dulieu, O [Laboratoire Aime Cotton, CNRS, Bat. 505, Univ Paris-Sud 11, F-91405 Orsay Cedex (France); Gabbanini, C [Istituto per i processi chimico-fisici del C.N.R., Via Moruzzi 1, 56124 Pisa (Italy)], E-mail: olivier.dulieu@lac.u-psud.fr, E-mail: carlo@ipcf.cnr.it

    2009-08-15

    Progress on research in the field of molecules at cold and ultracold temperatures is reported in this review. It covers extensively the experimental methods to produce, detect and characterize cold and ultracold molecules including association of ultracold atoms, deceleration by external fields and kinematic cooling. Confinement of molecules in different kinds of traps is also discussed. The basic theoretical issues related to the knowledge of the molecular structure, the atom-molecule and molecule-molecule mutual interactions, and to their possible manipulation and control with external fields, are reviewed. A short discussion on the broad area of applications completes the review.

  10. Multiphysics Integrated Coupling Environment (MICE) User Manual

    Energy Technology Data Exchange (ETDEWEB)

    Varija Agarwal; Donna Post Guillen

    2013-08-01

    The complex, multi-part nature of waste glass melters used in nuclear waste vitrification poses significant modeling challenges. The focus of this project has been to couple a 1D MATLAB model of the cold cap region within a melter with a 3D STAR-CCM+ model of the melter itself. The Multiphysics Integrated Coupling Environment (MICE) has been developed to create a cohesive simulation of a waste glass melter that accurately represents the cold cap. The one-dimensional mathematical model of the cold cap uses material properties, axial heat, and mass fluxes to obtain a temperature profile for the cold cap, the region where feed-to-glass conversion occurs. The results from Matlab are used to update simulation data in the three-dimensional STAR-CCM+ model so that the cold cap is appropriately incorporated into the 3D simulation. The two processes are linked through ModelCenter integration software using time steps that are specified for each process. Data is to be exchanged circularly between the two models, as the inputs and outputs of each model depend on the other.

  11. Fermionic Hubbard model with Rashba or Dresselhaus spin-orbit coupling

    Science.gov (United States)

    Sun, Fadi; Ye, Jinwu; Liu, Wu-Ming

    2017-06-01

    In this work, we investigate the possible dramatic effects of Rashba or Dresselhaus spin-orbit coupling (SOC) on the fermionic Hubbard model in a two-dimensional square lattice. In the strong coupling limit, it leads to the rotated antiferromagnetic Heisenberg model which is a new class of quantum spin model. For a special equivalent class, we identify a new spin-orbital entangled commensurate ground (Y-y) state subject to strong quantum fluctuations at T = 0. We evaluate the quantum fluctuations by the spin wave expansion up to order 1/{S}2. In some SOC parameter regimes, the Y-y state supports a massive relativistic incommensurate magnon (C-IC) with its two gap minima positions continuously tuned by the SOC parameters. The C-IC magnons dominate all the low temperature thermodynamic quantities and also lead to the separation of the peak positions between the longitudinal and the transverse spin structure factors. In the weak coupling limit, any weak repulsive interaction also leads to a weak Y-y state. There is only a crossover from the weak to the strong coupling. High temperature expansions of the specific heats in both weak and strong coupling are presented. The dramatic roles to be played by these C-IC magnons at generic SOC parameters or under various external probes are hinted at. Experimental applications to both layered noncentrosymmetric materials and cold atoms are discussed.

  12. Coherent Radiation in Atomic Systems

    Science.gov (United States)

    Sutherland, Robert Tyler

    Over the last century, quantum mechanics has dramatically altered our understanding of light and matter. Impressively, exploring the relationship between the two continues to provide important insights into the physics of many-body systems. In this thesis, we add to this still growing field of study. Specifically, we discuss superradiant line-broadening and cooperative dipole-dipole interactions for cold atom clouds in the linear-optics regime. We then discuss how coherent radiation changes both the photon scattering properties and the excitation distribution of atomic arrays. After that, we explore the nature of superradiance in initially inverted clouds of multi-level atoms. Finally, we explore the physics of clouds with degenerate Zeeman ground states, and show that this creates quantum effects that fundamentally change the photon scattering of atomic ensembles.

  13. A control approach to cross-coupling compensation of piezotube scanners in tapping-mode atomic force microscope imaging.

    Science.gov (United States)

    Wu, Ying; Shi, Jian; Su, Chanmin; Zou, Qingze

    2009-04-01

    In this article, an approach based on the recently developed inversion-based iterative control (IIC) to cancel the cross-axis coupling effect of piezoelectric tube scanners (piezoscanners) in tapping-mode atomic force microscope (AFM) imaging is proposed. Cross-axis coupling effect generally exists in piezoscanners used for three-dimensional (x-y-z axes) nanopositioning in applications such as AFM, where the vertical z-axis movement can be generated by the lateral x-y axes scanning. Such x/y-to-z cross-coupling becomes pronounced when the scanning is at large range and/or at high speed. In AFM applications, the coupling-caused position errors, when large, can generate various adverse effects, including large imaging and topography distortions, and damage of the cantilever probe and/or the sample. This paper utilizes the IIC technique to obtain the control input to precisely track the coupling-caused x/y-to-z displacement (with sign-flipped). Then the obtained input is augmented as a feedforward control to the existing feedback control in tapping-mode imaging, resulting in the cancellation of the coupling effect. The proposed approach is illustrated through two exemplary applications in industry, the pole-tip recession examination, and the nanoasperity measurement on hard-disk drive. Experimental results show that the x/y-to-z coupling effect in large-range (20 and 45 microm) tapping-mode imaging at both low to high scan rates (2, 12.2 to 24.4 Hz) can be effectively removed.

  14. Theoretical study of electromagnetically induced transparency in a five-level atom and application to Doppler-broadened and Doppler-free Rb atoms

    International Nuclear Information System (INIS)

    Bhattacharyya, Dipankar; Ray, Biswajit; Ghosh, Pradip N

    2007-01-01

    We report theoretical studies of a Λ-type five-level atomic system. The density matrix equations are set up and solved numerically to obtain the probe absorption line shape of Rb D 2 transitions for cold (Doppler-free) and room temperature (Doppler-broadened) atoms. Simulated spectra for Doppler-broadened systems lead to four velocity-selective dips along with an electromagnetic induced transparency (EIT) peak as observed earlier from the co-propagating pump-probe spectroscopy of Rb D 2 transitions. Effects of pump power and spontaneous decay rate from the upper levels on the simulated spectra are also studied. For cold atoms a very pronounced EIT peak is observed when the pump frequency is on resonance with one allowed transition. We find that lower pump power leads to a much sharper EIT signal in this case. A simulated dispersion curve shows a rapid variation of the refractive index that may lead to a sharp reduction of the group velocity of photons

  15. Assessment and Risk Mitigation Strategies for the Atom Interferometer Gravity Gradiometer Seed Lasers

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA GSFC has been working on an ESTO IIP - Cold Atom Gravity Gradiometer (CAGG)/Atom Interferometer Gravity Gradiometer (AIGG) for Geodesy since 2014 (Saif/551 –...

  16. Optical angular momentum and atoms

    Science.gov (United States)

    2017-01-01

    Any coherent interaction of light and atoms needs to conserve energy, linear momentum and angular momentum. What happens to an atom’s angular momentum if it encounters light that carries orbital angular momentum (OAM)? This is a particularly intriguing question as the angular momentum of atoms is quantized, incorporating the intrinsic spin angular momentum of the individual electrons as well as the OAM associated with their spatial distribution. In addition, a mechanical angular momentum can arise from the rotation of the entire atom, which for very cold atoms is also quantized. Atoms therefore allow us to probe and access the quantum properties of light’s OAM, aiding our fundamental understanding of light–matter interactions, and moreover, allowing us to construct OAM-based applications, including quantum memories, frequency converters for shaped light and OAM-based sensors. This article is part of the themed issue ‘Optical orbital angular momentum’. PMID:28069766

  17. Manipulating collective quantum states of ultracold atoms by probing

    DEFF Research Database (Denmark)

    Wade, Andrew Christopher James

    2015-01-01

    The field of cold gases has grown dramatically over the past few decades. The exquisite experimental control of their environment and properties has lead to landmark achievements, and has motivated the pursuit of quantum technologies with ultracold atoms. At the same time, the theory of measureme......The field of cold gases has grown dramatically over the past few decades. The exquisite experimental control of their environment and properties has lead to landmark achievements, and has motivated the pursuit of quantum technologies with ultracold atoms. At the same time, the theory...... of measurements on quantum systems has grown into a well established field. Experimental demonstrations of nondestructive continuous measurements on individual quantum systems now occur in many laboratories. Such experiments with ultracold atoms have shown great progress, but the exploitation of the quantum...... nature of the measurement interaction and backaction is yet to be realised. This dissertation is concerned with ultracold atoms and their control via fully quantum mechanical probes. Nonclassical, squeezed and entangled states of matter and single photon sources are important for fundamental studies...

  18. Collapse–revival of squeezing of two atoms in dissipative cavities

    International Nuclear Information System (INIS)

    Zou Hong-Mei; Fang Mao-Fa

    2016-01-01

    Based on the time-convolutionless master-equation approach, we investigate the squeezing dynamics of two atoms in dissipative cavities. We find that the atomic squeezing is related to initial atomic states, atom–cavity couplings, non-Markovian effects and resonant frequencies of an atom and its cavity. The results show that a collapse–revival phenomenon will occur in the atomic squeezing and this process is accompanied by the buildup and decay of entanglement between two atoms. Enhancing the atom–cavity coupling can increase the frequency of the collapse–revival of the atomic squeezing. The stronger the non-Markovian effect is, the more obvious the collapse–revival phenomenon is. In particular, if the atom–cavity coupling or the non-Markovian effect is very strong, the atomic squeezing will tend to a stably periodic oscillation in a long time. The oscillatory frequency of the atomic squeezing is dependent on the resonant frequency of the atom and its cavity. (paper)

  19. First-Order Quantum Phase Transition for Dicke Model Induced by Atom-Atom Interaction

    International Nuclear Information System (INIS)

    Zhao Xiu-Qin; Liu Ni; Liang Jiu-Qing

    2017-01-01

    In this article, we use the spin coherent state transformation and the ground state variational method to theoretically calculate the ground function. In order to consider the influence of the atom-atom interaction on the extended Dicke model’s ground state properties, the mean photon number, the scaled atomic population and the average ground energy are displayed. Using the self-consistent field theory to solve the atom-atom interaction, we discover the system undergoes a first-order quantum phase transition from the normal phase to the superradiant phase, but a famous Dicke-type second-order quantum phase transition without the atom-atom interaction. Meanwhile, the atom-atom interaction makes the phase transition point shift to the lower atom-photon collective coupling strength. (paper)

  20. Cold molecules: formation, trapping and spectroscopy. - Piling up of cesium dimers in a quadrupolar magnetic trap. - Spectroscopy by lack of photo-association

    International Nuclear Information System (INIS)

    Vanhaecke, N.

    2003-10-01

    This thesis deals with the study of cold molecules obtained through the cold atom photo-association technique. Our study is focused both on manipulating external degrees of freedom of these Cs 2 molecules and on studying their internal interactions. A quadrupolar magnetic trap of about 2.10 5 cold Cs 2 molecules is demonstrated. The trap lifetime is on the order of 600 ms, mainly limited by the background gas pressure. The trapped molecules are identified, which allows the determination of the trapped molecule cloud temperature, which is about 35 μK. A dipolar trap is set up by the use of a focused CO 2 laser beam. Moreover, this thesis describes a two-photon photo-association spectroscopy. We report the first study of two-photon photo-association line shapes, which exhibit typical Fano profiles. Taking advantage of the detailed understanding of these line shapes, we measure over one hundred high-lying level energies with an accuracy on the order of 10 MHz. Then we interpret theoretically these energies. The huge hyperfine structure of the Cesium atom binds us to solve a coupled channel Schroedinger equation for internuclear distances above 15 a 0 . Hence we use an asymptotic theory to fit the potential parameters of the Cs 2 dimer. We adjust those parameters by the mean of both evolutionary strategies and deterministic optimum seeking. This is followed by a careful statistics study, which leads to a very accurate determination of the Vander Waals coefficient. Moreover we report the first experimental determination of the exchange interaction amplitude. (author)

  1. Observation of the spin-orbit activated interchannel coupling in the 3d photoionization of caesium atoms

    International Nuclear Information System (INIS)

    Farrokhpour, H; Alagia, M; Amusia, M Ya

    2006-01-01

    The ionization cross-section of the 3d spin-orbit components of the Cs atom has been measured from about 12 to 70 eV above their respective thresholds. The measured relative ionization cross-section of the 3d 5/2 channel exhibits a pronounced minimum above threshold followed by a second maximum near the 3d 3/2 ionization onset and thus qualitatively confirms the theoretical predictions of a spin-orbit activated interchannel coupling (Amusia et al 2002 Phys. Rev. Lett 88 093002)

  2. Observation of the spin-orbit activated interchannel coupling in the 3d photoionization of caesium atoms

    Energy Technology Data Exchange (ETDEWEB)

    Farrokhpour, H [Chemistry Department, Isfahan University of Technology, Isfahan 84154 (Iran, Islamic Republic of); Abdus Salam International Centre for Theoretical Physics, I-34014 Trieste (Italy); Alagia, M [CNR-ISMN Sez.Roma1, P.le A Moro 5, I-00185 Rome (Italy) and CNR-Lab. Naz. TASC-INFM, Gas Phase Beamline at Elettra, Area Science Park, I-34012 Basovizza, Trieste (Italy); Amusia, M Ya [Racah Institute of Physics, Hebrew University, Jerusalem 91904 (Israel); A F Ioffe Physical-Technical Institute, St Petersburg 194021 (Russian Federation)] (and others)

    2006-02-21

    The ionization cross-section of the 3d spin-orbit components of the Cs atom has been measured from about 12 to 70 eV above their respective thresholds. The measured relative ionization cross-section of the 3d{sub 5/2} channel exhibits a pronounced minimum above threshold followed by a second maximum near the 3d{sub 3/2} ionization onset and thus qualitatively confirms the theoretical predictions of a spin-orbit activated interchannel coupling (Amusia et al 2002 Phys. Rev. Lett 88 093002)

  3. Proton-coupled electron transfer versus hydrogen atom transfer: generation of charge-localized diabatic states.

    Science.gov (United States)

    Sirjoosingh, Andrew; Hammes-Schiffer, Sharon

    2011-03-24

    The distinction between proton-coupled electron transfer (PCET) and hydrogen atom transfer (HAT) mechanisms is important for the characterization of many chemical and biological processes. PCET and HAT mechanisms can be differentiated in terms of electronically nonadiabatic and adiabatic proton transfer, respectively. In this paper, quantitative diagnostics to evaluate the degree of electron-proton nonadiabaticity are presented. Moreover, the connection between the degree of electron-proton nonadiabaticity and the physical characteristics distinguishing PCET from HAT, namely, the extent of electronic charge redistribution, is clarified. In addition, a rigorous diabatization scheme for transforming the adiabatic electronic states into charge-localized diabatic states for PCET reactions is presented. These diabatic states are constructed to ensure that the first-order nonadiabatic couplings with respect to the one-dimensional transferring hydrogen coordinate vanish exactly. Application of these approaches to the phenoxyl-phenol and benzyl-toluene systems characterizes the former as PCET and the latter as HAT. The diabatic states generated for the phenoxyl-phenol system possess physically meaningful, localized electronic charge distributions that are relatively invariant along the hydrogen coordinate. These diabatic electronic states can be combined with the associated proton vibrational states to generate the reactant and product electron-proton vibronic states that form the basis of nonadiabatic PCET theories. Furthermore, these vibronic states and the corresponding vibronic couplings may be used to calculate rate constants and kinetic isotope effects of PCET reactions.

  4. Cold nuclear fusion

    Energy Technology Data Exchange (ETDEWEB)

    Tsyganov, E.N., E-mail: edward.tsyganov@coldfusion-power.com [Cold Fusion Power, International (United States); Bavizhev, M.D. [LLC “Radium”, Moscow (Russian Federation); Buryakov, M.G. [Joint Institute for Nuclear Research (JINR), Dubna (Russian Federation); Dabagov, S.B. [RAS P.N. Lebedev Physical Institute, Leninsky pr. 53, 119991 Moscow (Russian Federation); National Research Nuclear University MEPhI, Kashirskoe shosse 31, 115409 Moscow (Russian Federation); Golovatyuk, V.M.; Lobastov, S.P. [Joint Institute for Nuclear Research (JINR), Dubna (Russian Federation)

    2015-07-15

    If target deuterium atoms were implanted in a metal crystal in accelerator experiments, a sharp increase in the probability of DD-fusion reaction was clearly observed when compared with the reaction’s theoretical value. The electronic screening potential, which for a collision of free deuterium atoms is about 27 eV, reached 300–700 eV in the case of the DD-fusion in metallic crystals. These data leads to the conclusion that a ban must exist for deuterium atoms to be in the ground state 1s in a niche filled with free conduction electrons. At the same time, the state 2p whose energy level is only 10 eV above that of state 1s is allowed in these conditions. With anisotropy of 2p, 3p or above orbitals, their spatial positions are strictly determined in the lattice coordinate system. When filling out the same potential niches with two deuterium atoms in the states 2p, 3p or higher, the nuclei of these atoms can be permanently positioned without creating much Coulomb repulsion at a very short distance from each other. In this case, the transparency of the potential barrier increases dramatically compared to the ground state 1s for these atoms. The probability of the deuterium nuclei penetrating the Coulomb barrier by zero quantum vibration of the DD-system also increases dramatically. The so-called cold nuclear DD-fusion for a number of years was registered in many experiments, however, was still rejected by mainstream science for allegedly having no consistent scientific explanation. Finally, it received the validation. Below, we outline the concept of this explanation and give the necessary calculations. This paper also considers the further destiny of the formed intermediate state of {sup 4}He{sup ∗}.

  5. Determination of trace amounts of cerium in paint by inductively coupled plasma atomic emission spectrometry

    International Nuclear Information System (INIS)

    Wong, K.L.

    1981-01-01

    The determination of Ce in paint by inductively coupled plasma atomic emission spectrometry (ICP-OES) is described, and the detection limit of ICP-OES of 0.0004 ppM is compared with that of other methods. The effects of the major elemental components of paint, Si, Pb, Cr, and Na on the ICP-OES determination of Ce were studied. The interference of 400 ppM of the other ions on the determination of 10 ppM Ce was small (0 to 3% error). The method is applicable to the range of 0.2 to 700 ppM Ce

  6. Optical ferris wheel for ultracold atoms

    Science.gov (United States)

    Franke-Arnold, S.; Leach, J.; Padgett, M. J.; Lembessis, V. E.; Ellinas, D.; Wright, A. J.; Girkin, J. M.; Ohberg, P.; Arnold, A. S.

    2007-07-01

    We propose a versatile optical ring lattice suitable for trapping cold and quantum degenerate atomic samples. We demonstrate the realisation of intensity patterns from pairs of Laguerre-Gauss (exp(iℓө) modes with different ℓ indices. These patterns can be rotated by introducing a frequency shift between the modes. We can generate bright ring lattices for trapping atoms in red-detuned light, and dark ring lattices suitable for trapping atoms with minimal heating in the optical vortices of blue-detuned light. The lattice sites can be joined to form a uniform ring trap, making it ideal for studying persistent currents and the Mott insulator transition in a ring geometry.

  7. Oscillatory exchange coupling in magnetic molecules

    International Nuclear Information System (INIS)

    Sevincli, H; Senger, R T; Durgun, E; Ciraci, S

    2007-01-01

    Recently, first-principles calculations based on the spin-dependent density functional theory (DFT) have revealed that the magnetic ground state of a finite linear carbon chain capped by two transition metal (TM) atoms alternates between ferromagnetic and antiferromagnetic configurations depending on the number of carbon atoms. The character of indirect exchange coupling in this nanoscale, quasi-zero-dimensional system is different from those analogous extended structures consisting of magnetic layers separated by a non-magnetic spacer (or magnetic impurities in a non-magnetic host material) and a formulation based on an atomic picture is needed. We present a tight-binding model which provides a theoretical framework to the underlying mechanism of the exchange coupling in molecular structures. The model calculations are capable of reproducing the essential features of the DFT results for the indirect exchange coupling and the atomic magnetic moments in the TM-C n -TM structures as functions of the number of carbon atoms. In nanostructures consisting of a few atoms the concepts of extended wavefunctions and the band theory lose their validity, and hence the oscillatory exchange coupling turns out to be a consequence of quantum interference effects due to the spin-dependent onsite and hopping energies

  8. Evaluation of an inductively-coupled plasma with an extended-sleeve torch as an atomization cell for laser-excited fluorescence spectrometry.

    Science.gov (United States)

    Kosinski, M A; Uchida, H; Winefordner, J D

    1983-05-01

    An inductively-coupled plasma (ICP) with an extended-sleeve torch has been evaluated as an atomization cell for laser-excited fluorescence spectrometry. Limits of detection for 20 lines are given. The detection power is almost equivalent to that obtained by excitation with a hollow-cathode lamp. Interelement effects and spectral interferences are discussed.

  9. Fluidized bed coupled rotary reactor for nanoparticles coating via atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Chen-Long; Liu, Xiao; Chen, Rong, E-mail: rongchen@mail.hust.edu.cn, E-mail: bshan@mail.hust.edu.cn [State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074 (China); Shan, Bin, E-mail: rongchen@mail.hust.edu.cn, E-mail: bshan@mail.hust.edu.cn [State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, Hubei 430074 (China)

    2015-07-15

    A fluidized bed coupled rotary reactor has been designed for coating on nanoparticles (NPs) via atomic layer deposition. It consists of five major parts: reaction chamber, dosing and fluidizing section, pumping section, rotary manipulator components, as well as a double-layer cartridge for the storage of particles. In the deposition procedure, continuous fluidization of particles enlarges and homogenizes the void fraction in the particle bed, while rotation enhances the gas-solid interactions to stabilize fluidization. The particle cartridge presented here enables both the fluidization and rotation acting on the particle bed, demonstrated by the analysis of pressure drop. Moreover, enlarged interstitials and intense gas–solid contact under sufficient fluidizing velocity and proper rotation speed facilitate the precursor delivery throughout the particle bed and consequently provide a fast coating process. The cartridge can ensure precursors flowing through the particle bed exclusively to achieve high utilization without static exposure operation. By optimizing superficial gas velocities and rotation speeds, minimum pulse time for complete coating has been shortened in experiment, and in situ mass spectrometry showed the precursor usage can reach 90%. Inductively coupled plasma-optical emission spectroscopy results suggested a saturated growth of nanoscale Al{sub 2}O{sub 3} films on spherical SiO{sub 2} NPs. Finally, the uniformity and composition of the shells were characterized by high angle annular dark field-transmission electron microscopy and energy dispersive X-ray spectroscopy.

  10. Artificial Atoms: from Quantum Physics to Applications

    International Nuclear Information System (INIS)

    2014-01-01

    The primary objective of this workshop is to survey the most recent advances of technologies enabling single atom- and artificial atom-based devices. These include the assembly of artificial molecular structures with magnetic dipole and optical interactions between engineered atoms embedded in solid-state lattices. The ability to control single atoms in diamond or similar solids under ambient operating conditions opens new perspectives for technologies based on nanoelectronics and nanophotonics. The scope of the workshop is extended towards the physics of strong coupling between atoms and radiation field modes. Beyond the traditional atom-cavity systems, artificial dipoles coupled to microwave radiation in circuit quantum electrodynamics is considered. All these technologies mutually influence each other in developing novel devices for sensing at the quantum level and for quantum information processing.

  11. Studies and modeling of cold neutron sources

    International Nuclear Information System (INIS)

    Campioni, G.

    2004-11-01

    With the purpose of updating knowledge in the fields of cold neutron sources, the work of this thesis has been run according to the 3 following axes. First, the gathering of specific information forming the materials of this work. This set of knowledge covers the following fields: cold neutron, cross-sections for the different cold moderators, flux slowing down, different measurements of the cold flux and finally, issues in the thermal analysis of the problem. Secondly, the study and development of suitable computation tools. After an analysis of the problem, several tools have been planed, implemented and tested in the 3-dimensional radiation transport code Tripoli-4. In particular, a module of uncoupling, integrated in the official version of Tripoli-4, can perform Monte-Carlo parametric studies with a spare factor of Cpu time fetching 50 times. A module of coupling, simulating neutron guides, has also been developed and implemented in the Monte-Carlo code McStas. Thirdly, achieving a complete study for the validation of the installed calculation chain. These studies focus on 3 cold sources currently functioning: SP1 from Orphee reactor and 2 other sources (SFH and SFV) from the HFR at the Laue Langevin Institute. These studies give examples of problems and methods for the design of future cold sources

  12. Coherent control of the formation of cold heteronuclear molecules by photoassociation

    Science.gov (United States)

    de Lima, Emanuel F.

    2017-01-01

    We consider the formation of cold diatomic molecules in the electronic ground state by photoassociation of atoms of dissimilar species. A combination of two transition pathways from the free colliding pair of atoms to a bound vibrational level of the electronic molecular ground state is envisioned. The first pathway consists of a pump-dump scheme with two time-delayed laser pulses in the near-infrared frequency domain. The pump pulse drives the transition to a bound vibrational level of an excited electronic state, while the dump pulse transfers the population to a bound vibrational level of the electronic ground state. The second pathway takes advantage of the existing permanent dipole moment and employs a single pulse in the far-infrared domain to drive the transition from the unbound atoms directly to a bound vibrational level in the electronic ground state. We show that this scheme offers the possibility to coherently control the photoassociation yield by manipulating the relative phase and timing of the pulses. The photoassociation mechanism is illustrated for the formation of cold LiCs molecules.

  13. Tapered optical fibers as tools for probing magneto-optical trap characteristics

    International Nuclear Information System (INIS)

    Morrissey, Michael J.; Deasy, Kieran; Wu Yuqiang; Nic Chormaic, Sile; Chakrabarti, Shrabana

    2009-01-01

    We present a novel technique for measuring the characteristics of a magneto-optical trap (MOT) for cold atoms by monitoring the spontaneous emission from trapped atoms coupled into the guided mode of a tapered optical nanofiber. We show that the nanofiber is highly sensitive to very small numbers of atoms close to its surface. The size and shape of the MOT, determined by translating the cold atom cloud across the tapered fiber, is in excellent agreement with measurements obtained using the conventional method of fluorescence imaging using a charge coupled device camera. The coupling of atomic fluorescence into the tapered fiber also allows us to monitor the loading and lifetime of the trap. The results are compared to those achieved by focusing the MOT fluorescence onto a photodiode and it was seen that the tapered fiber gives slightly longer loading and lifetime measurements due to the sensitivity of the fiber, even when very few atoms are present.

  14. Methylmercury determination using a hyphenated high performance liquid chromatography ultraviolet cold vapor multipath atomic absorption spectrometry system

    Energy Technology Data Exchange (ETDEWEB)

    Campos, Reinaldo C. [Department of Chemistry, Pontifical Catholic University of Rio de Janeiro, Rua Marques de S Vicente 225, 22453-900 Rio de Janeiro (Brazil)], E-mail: rccampos@puc-rio.br; Goncalves, Rodrigo A.; Brandao, Geisamanda P.; Azevedo, Marlo S. [Department of Chemistry, Pontifical Catholic University of Rio de Janeiro, Rua Marques de S Vicente 225, 22453-900 Rio de Janeiro (Brazil); Oliveira, Fabiana; Wasserman, Julio [Institut of Geosciences, Fluminense Federal University, Av. Gal. Milton Tavares de Souza, s/n, 24.210-340, Niteroi, Rio de Janeiro (Brazil)

    2009-06-15

    The present work investigates the use of a multipath cell atomic absorption mercury detector for mercury speciation analysis in a hyphenated high performance liquid chromatography assembly. The multipath absorption cell multiplies the optical path while energy losses are compensated by a very intense primary source. Zeeman-effect background correction compensates for non-specific absorption. For the separation step, the mobile phase consisted in a 0.010% m/v mercaptoethanol solution in 5% methanol (pH = 5), a C{sub 18} column was used as stationary phase, and post column treatment was performed by UV irradiation (60 deg. C, 13 W). The eluate was then merged with 3 mol L{sup -1} HCl, reduction was performed by a NaBH{sub 4} solution, and the Hg vapor formed was separated at the gas-liquid separator and carried through a desiccant membrane to the detector. The detector was easily attached to the system, since an external gas flow to the gas-liquid separator was provided. A multivariate approach was used to optimize the procedure and peak area was used for measurement. Instrumental limits of detection of 0.05 {mu}g L{sup -1} were obtained for ionic (Hg{sup 2+}) and HgCH{sub 3}{sup +}, for an injection volume of 200 {mu}L. The multipath atomic absorption spectrometer proved to be a competitive mercury detector in hyphenated systems in relation to the most commonly used atomic fluorescence and inductively coupled plasma mass spectrometric detectors. Preliminary application studies were performed for the determination of methyl mercury in sedi0011men.

  15. Methylmercury determination using a hyphenated high performance liquid chromatography ultraviolet cold vapor multipath atomic absorption spectrometry system

    International Nuclear Information System (INIS)

    Campos, Reinaldo C.; Goncalves, Rodrigo A.; Brandao, Geisamanda P.; Azevedo, Marlo S.; Oliveira, Fabiana; Wasserman, Julio

    2009-01-01

    The present work investigates the use of a multipath cell atomic absorption mercury detector for mercury speciation analysis in a hyphenated high performance liquid chromatography assembly. The multipath absorption cell multiplies the optical path while energy losses are compensated by a very intense primary source. Zeeman-effect background correction compensates for non-specific absorption. For the separation step, the mobile phase consisted in a 0.010% m/v mercaptoethanol solution in 5% methanol (pH = 5), a C 18 column was used as stationary phase, and post column treatment was performed by UV irradiation (60 deg. C, 13 W). The eluate was then merged with 3 mol L -1 HCl, reduction was performed by a NaBH 4 solution, and the Hg vapor formed was separated at the gas-liquid separator and carried through a desiccant membrane to the detector. The detector was easily attached to the system, since an external gas flow to the gas-liquid separator was provided. A multivariate approach was used to optimize the procedure and peak area was used for measurement. Instrumental limits of detection of 0.05 μg L -1 were obtained for ionic (Hg 2+ ) and HgCH 3 + , for an injection volume of 200 μL. The multipath atomic absorption spectrometer proved to be a competitive mercury detector in hyphenated systems in relation to the most commonly used atomic fluorescence and inductively coupled plasma mass spectrometric detectors. Preliminary application studies were performed for the determination of methyl mercury in sediments.

  16. Rapid food decomposition by H2O2-H2SO4 for determination of total mercury by flow injection cold vapor atomic absorption spectrometry.

    Science.gov (United States)

    Zenebon, Odair; Sakuma, Alice M; Dovidauskas, Sergio; Okada, Isaura A; de, MaioFrancaD; Lichtig, Jaim

    2002-01-01

    A mixture of 50% H2O2-H2SO4 (3 + 1, v/v) was used for decomposition of food in open vessels at 80 degrees C. The treatment allowed rapid total mercury determination by flow injection cold vapor atomic absorption spectrometry. Cabbage, potatoes, peanuts paste, hazelnuts paste, oats, tomatoes and their derivatives, oysters, shrimps, prawns, shellfish, marine algae, and many kinds of fish were analyzed by the proposed methodology with a limit of quantitation of 0.86 +/- 0.08 microg/L mercury in the final solution. Reference materials tested also gave excellent recovery.

  17. Localization of Cold Atoms in State-Dependent Optical Lattices via a Rabi Pulse

    International Nuclear Information System (INIS)

    Horstmann, Birger; Duerr, Stephan; Roscilde, Tommaso

    2010-01-01

    We propose a novel realization of Anderson localization in nonequilibrium states of ultracold atoms in an optical lattice. A Rabi pulse transfers part of the population to a different internal state with infinite effective mass. These frozen atoms create a quantum superposition of different disorder potentials, localizing the mobile atoms. For weakly interacting mobile atoms, Anderson localization is obtained. The localization length increases with increasing disorder and decreasing interaction strength, contrary to the expectation for equilibrium localization.

  18. The legacy of the cold war

    International Nuclear Information System (INIS)

    Martellini, M.

    1998-01-01

    More than fifty-two years have elapsed since the atomic bomb-was dropped on Hiroshima and Nagasaki. Over this period, the United States and the Soviet Union have engaged in a constant nuclear arms-race, in an effort to build a growing number of warheads and launching systems of increasingly higher destructive power, reflecting the logic of the balance of terror and the threat of mutually assured destruction. The years of the Cold War have, in fact, been dominated by the incredibly rapid growth of nuclear arsenals. The end of the Cold War, which was marked by the fall of the Berlin Wall in November 1989, coincided with the beginning of the process of nuclear disarmament and a diversion of funds from the industrial military complex. Nevertheless, 45 years of development and sophistication in nuclear armaments can't be immediately wiped off, for many reasons, the most evident of which being that the nuclear materials that forms the heart of atomic weapons, more precisely known as weapon-grade materials, can't be simply eliminated, as will be explained later in this text. Their dismantlement requires special technical means, which are not yet available to all nuclear powers. There are also other reasons why nuclear disarmament is such a complex and uneven process

  19. Rovibrational coupling in molecular nitrogen at high temperature: An atomic-level study

    Energy Technology Data Exchange (ETDEWEB)

    Valentini, Paolo, E-mail: vale0142@umn.edu; Norman, Paul, E-mail: norma198@umn.edu; Zhang, Chonglin, E-mail: zhang993@umn.edu; Schwartzentruber, Thomas E., E-mail: schwart@aem.umn.edu [Department of Aerospace Engineering and Mechanics, College of Science and Engineering, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

    2014-05-15

    This article contains an atomic-level numerical investigation of rovibrational relaxation in molecular nitrogen at high temperature (>4000 K), neglecting dissociation. We conduct our study with the use of pure Molecular Dynamics (MD) and Classical Trajectory Calculations (CTC) Direct Simulation Monte Carlo (DSMC), verified to produce statistically identical results at the conditions of interest here. MD and CTC DSMC solely rely on the specification of a potential energy surface: in this work, the site-site Ling-Rigby potential. Additionally, dissociation is prevented by modeling the N–N bond either as a harmonic or an anharmonic spring. The selected molecular model was shown to (i) recover the shear viscosity (obtained from equilibrium pure MD Green-Kubo calculations) of molecular nitrogen over a wide range of temperatures, up to dissociation; (ii) predict well the near-equilibrium rotational relaxation behavior of N{sub 2}; (iii) reproduce vibrational relaxation times in excellent accordance with the Millikan-White correlation and previous semi-classical trajectory calculations in the low temperature range, i.e., between 4000 K and 10 000 K. By simulating isothermal relaxations in a periodic box, we found that the traditional two-temperature model assumptions become invalid at high temperatures (>10 000 K), due to a significant coupling between rotational and vibrational modes for bound states. This led us to add a modification to both the Jeans and the Landau-Teller equations to include a coupling term, essentially described by an additional relaxation time for internal energy equilibration. The degree of anharmonicity of the N{sub 2} bond determines the strength of the rovibrational coupling. Although neglecting N{sub 2} dissociation only provides a partial description of a nitrogen system at very high temperatures, high-energy trends for bound-bound transitions are essential to understand nonequilibrium gas flows, with possible implications on rovibration

  20. Rovibrational coupling in molecular nitrogen at high temperature: An atomic-level study

    International Nuclear Information System (INIS)

    Valentini, Paolo; Norman, Paul; Zhang, Chonglin; Schwartzentruber, Thomas E.

    2014-01-01

    This article contains an atomic-level numerical investigation of rovibrational relaxation in molecular nitrogen at high temperature (>4000 K), neglecting dissociation. We conduct our study with the use of pure Molecular Dynamics (MD) and Classical Trajectory Calculations (CTC) Direct Simulation Monte Carlo (DSMC), verified to produce statistically identical results at the conditions of interest here. MD and CTC DSMC solely rely on the specification of a potential energy surface: in this work, the site-site Ling-Rigby potential. Additionally, dissociation is prevented by modeling the N–N bond either as a harmonic or an anharmonic spring. The selected molecular model was shown to (i) recover the shear viscosity (obtained from equilibrium pure MD Green-Kubo calculations) of molecular nitrogen over a wide range of temperatures, up to dissociation; (ii) predict well the near-equilibrium rotational relaxation behavior of N 2 ; (iii) reproduce vibrational relaxation times in excellent accordance with the Millikan-White correlation and previous semi-classical trajectory calculations in the low temperature range, i.e., between 4000 K and 10 000 K. By simulating isothermal relaxations in a periodic box, we found that the traditional two-temperature model assumptions become invalid at high temperatures (>10 000 K), due to a significant coupling between rotational and vibrational modes for bound states. This led us to add a modification to both the Jeans and the Landau-Teller equations to include a coupling term, essentially described by an additional relaxation time for internal energy equilibration. The degree of anharmonicity of the N 2 bond determines the strength of the rovibrational coupling. Although neglecting N 2 dissociation only provides a partial description of a nitrogen system at very high temperatures, high-energy trends for bound-bound transitions are essential to understand nonequilibrium gas flows, with possible implications on rovibration

  1. Speciation of mercury in fish samples by flow injection catalytic cold vapour atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Zhang Yanlin; Adeloju, Samuel B.

    2012-01-01

    Highlights: ► Successful speciation of inorganic and organic Hg with Fe 3+ , Cu 2+ and thiourea as catalysts. ► Best sensitivity enhancement and similar sensitivity for MeHg and Hg 2+ with Fe 3+ . ► Successful use of Hg 2+ as the primary standard for quantification of inorganic and total-Hg. ► Quantitative extraction of Hg and MeHg with 2 M HCl which contained thiourea. ► Integration with FIA for rapid analysis with a sample throughput of 180 h −1 . - Abstract: A rapid flow injection catalytic cold vapour atomic absorption spectrometric (FI-CCV-AAS) method is described for speciation and determination of mercury in biological samples. Varying concentrations of NaBH 4 were employed for mercury vapour generation from inorganic and mixture of inorganic and organic (total) Hg. The presence of Fe 3+ , Cu 2+ and thiourea had catalytic effect on mercury vapour generation from methylmercury (MeHg) and, when together, Cu 2+ and thiourea had synergistic catalytic effect on the vapour generation. Of the two metal ions, Fe 3+ gave the best sensitivity enhancement, achieving the same sensitivity for MeHg and inorganic Hg 2+ . Due to similarity of resulting sensitivity, Hg 2+ was used successfully as a primary standard for quantification of inorganic and total Hg. The catalysis was homogeneous in nature, and it was assumed that the breaking of the C-Hg bond was facilitated by the delocalization of the 5d electron pairs in Hg atom. The extraction of MeHg and inorganic mercury (In-Hg) in fish samples were achieved quantitatively with hydrochloric acid in the presence of thiourea and determined by FI-CCV-AAS. The application of the method to the quantification of mercury species in a fish liver reference material DOLT-4 gave 91.5% and 102.3% recoveries for total and methyl mercury, respectively. The use of flow injection enabled rapid analysis with a sample throughput of 180 h −1 .

  2. Ionization due to the interaction between two Rydberg atoms

    International Nuclear Information System (INIS)

    Robicheaux, F

    2005-01-01

    Using a classical trajectory Monte Carlo method, we have computed the ionization resulting from the interaction between two cold Rydberg atoms. We focus on the products resulting from close interaction between two highly excited atoms. We give information on the distribution of ejected electron energies, the distribution of internal atom energies and the velocity distribution of the atoms and ions after the ionization. If the potential for the atom is not purely Coulombic, the average interaction between two atoms can change from attractive to repulsive giving a Van de Graaff-like mechanism for accelerating atoms. In a small fraction of ionization cases, we find that the ionization leads to a positive molecular ion where all of the distances are larger than 1000 Bohr radii

  3. Atomic scattering in the diffraction limit: electron transfer in keV Li+-Na(3s, 3p) collisions

    DEFF Research Database (Denmark)

    Poel, Mike van der; Nielsen, C.V.; Rybaltover, M.

    2002-01-01

    We measure angle differential cross sections (DCS) in Li+ + Na --> Li + Na+ electron transfer collisions in the 2.7-24 keV energy range. We do this with a newly constructed apparatus which combines the experimental technique of cold target recoil ion momentum spectroscopy with a laser-cooled target...... of the de Broglie wavelength lambda(dB) = 150 fm at a velocity v = 0.20 au and the effective atomic diameter for electron capture 2R = 20 au. Parallel AO and MO semiclassical coupled-channel calculations of the Na(3s, 3p) --> Li(2s, 2p) state-to-state collision amplitudes have been performed, and quantum...

  4. Inner-shell correlations and Sturm expansions in coupled perturbation calculations of atomic systems

    International Nuclear Information System (INIS)

    Sherstyuk, A.I.; Solov'eva, G.S.

    1995-01-01

    It is shown that virtual Hartree-Fock orbitals in Sturm-type expansions can be used to calculate the response of atomic systems to an external field within the framework of the coupled perturbation theory with allowance for correlation effects. The corrected electron-electron interaction in a system with field-distorted orbitals is considered by adding a nonlocal potential to a one-electron Hartree-Fock operator within each group of equivalent elections. The remaining correlation effects are calculated by solving a system of equations for corrections to the radial functions. The system is solved iteratively, with each subsequent iteration corresponding to a correction of an increasingly higher order in the electron--electron interaction. The explicit expression derived for the polarizability contains one-and two-particle radial integrals of the Sturm functions

  5. Generating a picokelvin ultracold atomic ensemble in microgravity

    International Nuclear Information System (INIS)

    Wang, Lu; Ma, Zhao-Yuan; Zhang, Peng; Chen, Xu-Zong

    2013-01-01

    Applying the direct Monte Carlo simulation (DSMC) method developed for a cold atom system, we study the evaporative cooling process in tilted optical dipole traps with a magnetic field gradient-induced over-levitation or merely a gravitational force. We propose a two-stage decomposed evaporative cooling process in a microgravity environment, and suggest that quantum degeneracy can be obtained at a few picokelvins with several thousand atoms. (paper)

  6. Synthesis of antihydrogen atoms in a CUSP trap

    Energy Technology Data Exchange (ETDEWEB)

    Kuroda, Naofumi, E-mail: kuroda@phys.c.u-tokyo.ac.jp [University of Tokyo, Graduate School of Arts and Sciences (Japan); Enomoto, Yoshinori [RIKEN Advanced Science Institute (Japan); Michishio, Koji [Tokyo University of Science, Department of Physics (Japan); Kim, Chanhyoun [University of Tokyo, Graduate School of Arts and Sciences (Japan); Higaki, Hiroyuki [Hiroshima University, Graduate School of Advanced Science of Matter (Japan); Nagata, Yugo; Kanai, Yasuyuki [RIKEN Advanced Science Institute (Japan); Torii, Hiroyuki A. [University of Tokyo, Graduate School of Arts and Sciences (Japan); Corradini, Maurizzio; Leali, Marco; Lodi-Rizzini, Evandro; Mascagna, Valerio; Venturelli, Luca; Zurlo, Nicola [Universita di Brescia and Instituto Nazionale di Fisica Nucleare, Dipartimento di Chimica e Fisica per l' Ingegneria e per i Materiali (Italy); Fujii, Koki; Ohtsuka, Miki; Tanaka, Kazuo [University of Tokyo, Graduate School of Arts and Sciences (Japan); Imao, Hiroshi [RIKEN Nishina Center for Accelerator-Based Science (Japan); Nagashima, Yasuyuki [Tokyo University of Science, Department of Physics (Japan); Matsuda, Yasuyuki [University of Tokyo, Graduate School of Arts and Sciences (Japan); and others

    2012-05-15

    ASACUSA collaboration has been making a path to realize high precision microwave spectroscopy of ground-state hyperfine transitions of antihydrogen atom in flight for stringent test of the CPT symmetry. Recently, we have succeeded in synthesizing our first cold antihydrogen atoms employing a CUSP trap. It is expected that synthesized antihydrogen atoms in the low-field-seeking states are preferentially focused along the cusp magnetic field axis whereas those in the high-field-seeking states are not focused, resulting in the formation of a spin-polarized antihydrogen beam. We report the recent results of antihydrogen atom synthesis and beam production developed with the CUSP trap.

  7. Synthesis of antihydrogen atoms in a CUSP trap

    International Nuclear Information System (INIS)

    Kuroda, Naofumi; Enomoto, Yoshinori; Michishio, Koji; Kim, Chanhyoun; Higaki, Hiroyuki; Nagata, Yugo; Kanai, Yasuyuki; Torii, Hiroyuki A.; Corradini, Maurizzio; Leali, Marco; Lodi-Rizzini, Evandro; Mascagna, Valerio; Venturelli, Luca; Zurlo, Nicola; Fujii, Koki; Ohtsuka, Miki; Tanaka, Kazuo; Imao, Hiroshi; Nagashima, Yasuyuki; Matsuda, Yasuyuki

    2012-01-01

    ASACUSA collaboration has been making a path to realize high precision microwave spectroscopy of ground-state hyperfine transitions of antihydrogen atom in flight for stringent test of the CPT symmetry. Recently, we have succeeded in synthesizing our first cold antihydrogen atoms employing a CUSP trap. It is expected that synthesized antihydrogen atoms in the low-field-seeking states are preferentially focused along the cusp magnetic field axis whereas those in the high-field-seeking states are not focused, resulting in the formation of a spin-polarized antihydrogen beam. We report the recent results of antihydrogen atom synthesis and beam production developed with the CUSP trap.

  8. Local heteroepitaxy as an adhesion mechanism in aluminium coatings cold gas sprayed on AlN substrates

    International Nuclear Information System (INIS)

    Wüstefeld, Christina; Rafaja, David; Motylenko, Mykhaylo; Ullrich, Christiane; Drehmann, Rico; Grund, Thomas; Lampke, Thomas; Wielage, Bernhard

    2017-01-01

    Cold gas sprayed Al coatings deposited onto wurtzitic AlN substrates show excellent adhesion. As a possible adhesion mechanism, the local heteroepitaxy between Al and AlN was considered and verified experimentally in Al coatings, which were deposited using magnetron sputtering or cold gas spraying on single-crystalline and polycrystalline AlN substrates. Analysis of the local orientation relationships at the Al/AlN interfaces revealed that preferentially such lattice planes of Al align parallel with the upright lattice planes of AlN, which possess similar interplanar distances. The matching lattice planes in the Al coatings grew as continuations of the lattice planes in the AlN substrates. In all samples under study, the parallel alignment of the lattice planes {220}_A_l and {110}_A_l_N was found. Additional orientation relationships between Al and AlN arose if parallel lattice planes with similar interplanar spacing could be found in both counterparts via rotation of the lattice planes {220}_A_l around their normal direction. Still, the oriented growth of Al on AlN is only possible if Al atoms in the deposited coatings are mobile enough to rearrange along the AlN surface. Whereas the mobility of Al atoms in a magnetron sputtering process is expected to be sufficiently high, the intrinsic mobility of Al atoms in the cold gas sprayed particles is anticipated to be low. However, the auxiliary microstructure analyses have shown that local recrystallization and partial melting are two phenomena, which can facilitate the rearrangement of Al atoms within the cold gas sprayed coating.

  9. Spectrum of spin waves in cold polarized gases

    Energy Technology Data Exchange (ETDEWEB)

    Andreeva, T. L., E-mail: phdocandreeva@yandex.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

    2017-02-15

    The spin dynamics of cold polarized gases are investigated using the Boltzmann equation. The dispersion relation for spin waves (transverse component of the magnetic moment) and the spin diffusion coefficient of the longitudinal component of the magnetic moment are calculated without using fitting parameters. The spin wave frequency and the diffusion coefficient for rubidium atoms are estimated numerically.

  10. Spatial distribution of cold antihydrogen formation

    International Nuclear Information System (INIS)

    Madsen, N.; Hangst, J.S.; Amoretti, M.; Carraro, C.; Macri, M.; Testera, G.; Variola, A.; Amsler, C.; Pruys, H.; Regenfus, C.; Bonomi, G.; Doser, M.; Kellerbauer, A.; Landua, R.; Bowe, P.D.; Charlton, M.; Joergensen, L.V.; Mitchard, D.; Werf, D.P. van der; Cesar, C.L.

    2005-01-01

    Antihydrogen is formed when antiprotons are mixed with cold positrons in a nested Penning trap. We present experimental evidence, obtained using our antihydrogen annihilation detector, that the spatial distribution of the emerging antihydrogen atoms is independent of the positron temperature and axially enhanced. This indicates that antihydrogen is formed before the antiprotons are in thermal equilibrium with the positron plasma. This result has important implications for the trapping and spectroscopy of antihydrogen

  11. Atom-atom interactions around the band edge of a photonic crystal waveguide.

    Science.gov (United States)

    Hood, Jonathan D; Goban, Akihisa; Asenjo-Garcia, Ana; Lu, Mingwu; Yu, Su-Peng; Chang, Darrick E; Kimble, H J

    2016-09-20

    Tailoring the interactions between quantum emitters and single photons constitutes one of the cornerstones of quantum optics. Coupling a quantum emitter to the band edge of a photonic crystal waveguide (PCW) provides a unique platform for tuning these interactions. In particular, the cross-over from propagating fields [Formula: see text] outside the bandgap to localized fields [Formula: see text] within the bandgap should be accompanied by a transition from largely dissipative atom-atom interactions to a regime where dispersive atom-atom interactions are dominant. Here, we experimentally observe this transition by shifting the band edge frequency of the PCW relative to the [Formula: see text] line of atomic cesium for [Formula: see text] atoms trapped along the PCW. Our results are the initial demonstration of this paradigm for coherent atom-atom interactions with low dissipation into the guided mode.

  12. Heat Treatment of Gas-Atomized Powders for Cold Spray Deposition

    Science.gov (United States)

    Story, William A.; Brewer, Luke N.

    2018-02-01

    This communication demonstrates the efficacy of heat treatment on the improved deposition characteristics of aluminum alloy powders. A novel furnace was constructed for solutionizing of feedstock powders in an inert atmosphere while avoiding sintering. This furnace design achieved sufficiently high cooling rates to limit re-precipitation during powder cooling. Microscopy showed homogenization of the powder particle microstructures after heat treatment. Cold spray deposition efficiency with heat-treated powders substantially increased for the alloys AA2024, AA6061, and AA7075.

  13. Explanation of the Hund's rule for atomic spectra

    International Nuclear Information System (INIS)

    Muftakhova, F.I.; Zilberman, L.A.

    1982-01-01

    An original formula for electrostatic interaction in many-electron atoms, based on a new mathematical method, related by recoupling a matrix of n vector coupling momenta and its permutation properties, is given in general form. Hund's rule for atomic spectra-like maximum probability of couple momentum of l 2 configuration in the LS term of lsup(n) configuration is explained. Also, non-competence of exchange interaction notion for d and f atoms is based on mentioned formula. (Auth.)

  14. Switching of light with light using cold atoms inside a hollow optical fiber

    DEFF Research Database (Denmark)

    Bajcsy, Michal; Hofferberth, S.; Peyronel, Thibault

    2010-01-01

    We demonstrate a fiber-optical switch that operates with a few hundred photons per switching pulse. The light-light interaction is mediated by laser-cooled atoms. The required strong interaction between atoms and light is achieved by simultaneously confining photons and atoms inside the microscopic...... hollow core of a single-mode photonic-crystal fiber....

  15. Outer crust of nonaccreting cold neutron stars

    International Nuclear Information System (INIS)

    Ruester, Stefan B.; Hempel, Matthias; Schaffner-Bielich, Juergen

    2006-01-01

    The properties of the outer crust of nonaccreting cold neutron stars are studied by using modern nuclear data and theoretical mass tables, updating in particular the classic work of Baym, Pethick, and Sutherland. Experimental data from the atomic mass table from Audi, Wapstra, and Thibault of 2003 are used and a thorough comparison of many modern theoretical nuclear models, both relativistic and nonrelativistic, is performed for the first time. In addition, the influences of pairing and deformation are investigated. State-of-the-art theoretical nuclear mass tables are compared to check their differences concerning the neutron drip line, magic neutron numbers, the equation of state, and the sequence of neutron-rich nuclei up to the drip line in the outer crust of nonaccreting cold neutron stars

  16. Universal Borromean Binding in Spin-Orbit-Coupled Ultracold Fermi Gases

    Directory of Open Access Journals (Sweden)

    Xiaoling Cui

    2014-08-01

    Full Text Available Borromean rings and Borromean binding, a class of intriguing phenomena as three objects are linked (bound together while any two of them are unlinked (unbound, widely exist in nature and have been found in systems of biology, chemistry, and physics. Previous studies have suggested that the occurrence of such a binding in physical systems typically relies on the microscopic details of pairwise interaction potentials at short range and is, therefore, nonuniversal. Here, we report a new type of Borromean binding in ultracold Fermi gases with Rashba spin-orbit coupling, which is universal against short-range interaction details, with its binding energy only dependent on the s-wave scattering length and the spin-orbit-coupling strength. We show that the occurrence of this universal Borromean binding is facilitated by the symmetry of the single-particle dispersion under spin-orbit coupling and is, therefore, symmetry selective rather than interaction selective. The state is robust over a wide range of mass ratios between composing fermions, which are accessible by Li-Li, K-K, and K-Li mixtures in cold-atom experiments. Our results reveal the importance of single- particle spectral symmetry in few-body physics and shed light on the emergence of new quantum phases in a many-body system with exotic few-body correlations.

  17. Impurity coupled to an artificial magnetic field in a Fermi gas in a ring trap

    Science.gov (United States)

    Ünal, F. Nur; Hetényi, B.; Oktel, M. Ã.-.

    2015-05-01

    The dynamics of a single impurity interacting with a many-particle background is one of the central problems of condensed-matter physics. Recent progress in ultracold-atom experiments makes it possible to control this dynamics by coupling an artificial gauge field specifically to the impurity. In this paper, we consider a narrow toroidal trap in which a Fermi gas is interacting with a single atom. We show that an external magnetic field coupled to the impurity is a versatile tool to probe the impurity dynamics. Using a Bethe ansatz, we calculate the eigenstates and corresponding energies exactly as a function of the flux through the trap. Adiabatic change of flux connects the ground state to excited states due to flux quantization. For repulsive interactions, the impurity disturbs the Fermi sea by dragging the fermions whose momentum matches the flux. This drag transfers momentum from the impurity to the background and increases the effective mass. The effective mass saturates to the total mass of the system for infinitely repulsive interactions. For attractive interactions, the drag again increases the effective mass which quickly saturates to twice the mass of a single particle as a dimer of the impurity and one fermion is formed. For excited states with momentum comparable to number of particles, effective mass shows a resonant behavior. We argue that standard tools in cold-atom experiments can be used to test these predictions.

  18. Atomic collisions under extreme conditions in space

    International Nuclear Information System (INIS)

    Itikawa, Yukikazu

    1987-01-01

    In space, atoms and molecules are often placed under the extreme conditions which are very difficult to be realized on Earth. For instance, extremely hot and dense plasmas are found in and around various stellar objects (e.g., neutron stars) on one hand and extremely cold and diffuse gases prevail in interstellar space on the other. There is so strong a magnetic field that electron clouds in atoms and molecules are distorted. The study of atomic collisions under the extreme conditions is not only helpful in understanding the astrophysical environment but also reveals new aspects of the physics of atoms and molecules. This paper is an invitation to the study. (References are not exhaustive but only provide a clue with which more details can be found.) (author)

  19. Coherent population transfer and superposition of atomic states via stimulated Raman adiabatic passage using an excited-doublet four-level atom

    International Nuclear Information System (INIS)

    Jin Shiqi; Gong Shangqing; Li Ruxin; Xu Zhizhan

    2004-01-01

    Coherent population transfer and superposition of atomic states via a technique of stimulated Raman adiabatic passage in an excited-doublet four-level atomic system have been analyzed. It is shown that the behavior of adiabatic passage in this system depends crucially on the detunings between the laser frequencies and the corresponding atomic transition frequencies. Particularly, if both the fields are tuned to the center of the two upper levels, the four-level system has two degenerate dark states, although one of them contains the contribution from the excited atomic states. The nonadiabatic coupling of the two degenerate dark states is intrinsic, it originates from the energy difference of the two upper levels. An arbitrary superposition of atomic states can be prepared due to such nonadiabatic coupling effect

  20. Preliminary optimization experiments of coupled liquid hydrogen moderator for KENS-II

    International Nuclear Information System (INIS)

    Watanabe, N.; Kiyanagi, Y.; Inoue, K.; Furusaka, M.; Ikeda, S.; Arai, M.; Iwasa, H.

    1989-01-01

    As a preliminary optimization experiment on the cold-neutron source for KENS-II, energy and time distributions of cold neutrons emanating from coupled liquid-hydrogen moderators with and without a premoderator in a graphite reflector were measured and compared with those from a decoupled liquid-hydrogen moderator. The results showed that the energy spectra from the coupled liquid-hydrogen moderators are almost the same as those from a decoupled one. Relative gain of the former to the latter is fairly high, more than 5, and further increases with increasing wavelength. The broadening of the neutron pulse width in coupled moderators at the cold-neutron region is not so significant and only 1.5 times compared to the solid methane moderator presently operated at KENS-II. 2 refs., 12 figs., 1 tab