Driving Rydberg-Rydberg transitions from a co-planar microwave waveguide
Hogan, S D; Merkt, F; Thiele, T; Filipp, S; Wallraff, A
2011-01-01
The coherent interaction between ensembles of helium Rydberg atoms and microwave fields in the vicinity of a solid-state co-planar waveguide is reported. Rydberg-Rydberg transitions, at frequencies between 25 GHz and 38 GHz, have been studied for states with principal quantum numbers in the range 30 - 35 by selective electric-field ionization. An experimental apparatus cooled to 100 K was used to reduce effects of blackbody radiation. Inhomogeneous, stray electric fields emanating from the surface of the waveguide have been characterized in frequency- and time-resolved measurements and coherence times of the Rydberg atoms on the order of 250 ns have been determined.
Absolute Generalized Oscillator Strength Profiles of Rydberg Transitions in C2F6
Institute of Scientific and Technical Information of China (English)
FAN Xiao-Wei(樊晓伟); LU Shan(卢杉); ZHANG Xian-Zhou(张现周); K.T.Leung
2004-01-01
Absolute generalized oscillator strengths (GOSs) for the two Rydberg excitations at 12.1 e V and 13.5 e V in C2 F6have been determined as functions of energy loss and momentum transfer (K) at impact energy of 2.5 keV. The GOS profiles for these two Rydberg transitions to 3 p Rydberg orbital have the characteristic dipole-dominated shapes with a strong maximum at K ＝ 0.
Doppler- and recoil-free laser excitation of Rydberg states via three-photon transitions
Ryabtsev, I I; Tretyakov, D B; Entin, V M; Yakshina, E A
2011-01-01
Three-photon laser excitation of Rydberg states by three different laser beams can be arranged in a star-like geometry that simultaneously eliminates the recoil effect and Doppler broadening. Our analytical and numerical calculations for a particular laser excitation scheme 5S_{1/2}->5P_{3/2}->6S_{1/2}->nP in Rb atoms have shown that compared to the one- and two-photon laser excitation this approach provides much narrower line width and longer coherence time for both cold atom samples and hot vapors, if the intermediate one-photon resonances of the three-photon transition are detuned by more than respective single-photon Doppler widths. This method can be used to improve fidelity of Rydberg quantum gates and precision of spectroscopic measurements in Rydberg atoms.
Non-equilibrium phase-transitions in multi-component Rydberg gases
Ding, D S; Shi, B S; Guo, G C
2016-01-01
Highly-excited Rydberg atoms have strong long-range interactions resulting in exotic optical prop erties such as large single photon non-linearities and intrinsic bistability. In this paper we study optical-driven non-equilibrium phase transitions in a thermal Rydberg gas with a sensitivity two order of magnitude higher than in previous work. In this regime we can elucidate the effect of inter actions on the bistable optical response, and exploit different branches in the potential in order to study multi-component Rydberg gases with a rich of phase diagram including overlapping bistable regions. In addition, we study the effect of polarization on the width of the hysteresis loop. Finally, we observe that the medium exhibits a dynamical instability resulting from the competing dynamics of excitation and decay.
Direct single-shot observation of millimeter wave superradiance in Rydberg-Rydberg transitions
Grimes, David D; Barnum, Timothy J; Zhou, Yan; Yelin, Susanne F; Field, Robert W
2016-01-01
We have directly detected millimeter wave (mm-wave) free space superradiant emission from Rydberg states ($n \\sim 30$) of barium atoms in a single shot. We trigger the cooperative effects with a weak initial pulse and detect with single-shot sensitivity and 20 ps time resolution, which allows measurement and shot-by-shot analysis of the distribution of decay rates, time delays, and time-dependent frequency shifts. Cooperative line shifts and decay rates are observed that exceed values that would correspond to the Doppler width of 250 kHz by a factor of 20 and the spontaneous emission rate of 50 Hz by a factor of $10^5$. The initial superradiant output pulse is followed by evolution of the radiation-coupled many-body system toward complex long-lasting emission modes. A comparison to a mean-field theory is presented which reproduces the quantitative time-domain results, but fails to account for either the frequency-domain observations or the long-lived features.
On the Rydberg transitions and elemental compositions in the laser produced Al (6063) plasma
Baig, M. A.; Fareed, M. A.; Rashid, B.; Ali, R.
2011-08-01
We present new studies on the optical emission spectra of the laser produced Al 6063 alloy plasma generated by the 1064 nm Nd: YAG laser. The spectrum reveals Rydberg transitions; nd 2D3/2,5/2 → 3p 2P1/2,3/2 (n = 3 - 8), ns 2S1/2 → 3p 2P1/2,3/2 (n = 4-6), and the dominant spectral lines of the other constituent elements. We have extracted the relative abundance of the impurities using the relative intensity ratio method. Besides, we have calculated the electron temperature (˜7580 K) from the Boltzmann plot method and the electron number densities (˜1.4 × 1017/cm3) from the Stark widths of the aluminum spectral lines. The plasma parameters determined in the present work are in agreement with that reported in the literature. The molecular vibrational transitions of the AlO free radical associated with the B 2∑→X 2∑ band system have also been identified.
On the Rydberg transitions and elemental compositions in the laser produced Al (6063) plasma
Energy Technology Data Exchange (ETDEWEB)
Baig, M. A.; Fareed, M. A.; Rashid, B.; Ali, R. [Atomic and Molecular Physics Laboratory, Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan)
2011-08-15
We present new studies on the optical emission spectra of the laser produced Al 6063 alloy plasma generated by the 1064 nm Nd: YAG laser. The spectrum reveals Rydberg transitions; nd {sup 2}D{sub 3/2,5/2}{yields} 3p {sup 2}P{sub 1/2,3/2} (n = 3 - 8), ns {sup 2}S{sub 1/2}{yields} 3p {sup 2}P{sub 1/2,3/2} (n 4-6), and the dominant spectral lines of the other constituent elements. We have extracted the relative abundance of the impurities using the relative intensity ratio method. Besides, we have calculated the electron temperature ({approx}7580 K) from the Boltzmann plot method and the electron number densities ({approx}1.4 x 10{sup 17}/cm{sup 3}) from the Stark widths of the aluminum spectral lines. The plasma parameters determined in the present work are in agreement with that reported in the literature. The molecular vibrational transitions of the AlO free radical associated with the B {sup 2}{Sigma}{yields}X {sup 2}{Sigma} band system have also been identified.
Entangled state fusion with Rydberg atoms
Ji, Y. Q.; Dai, C. M.; Shao, X. Q.; Yi, X. X.
2017-10-01
We propose a scheme for preparation of large-scale entangled GHZ states and W states with neutral Rydberg atoms. The scheme mainly depends on Rydberg antiblockade effect, i.e., as the Rydberg-Rydberg interaction strength and the detuning between the atom transition frequency and the classical laser frequency satisfies some certain conditions, the effective Rabi oscillation between the two ground states and the two excitation Rydberg states would be generated. The prominent advantage is that both two multiparticle GHZ states and two multiparticle W states can be fused in this model, especially the success probability for fusion of GHZ states can reach unit. In addition, the imperfections induced by the spontaneous emission is also discussed through numerical simulation.
Long-range Rydberg molecules, Rydberg macrodimers and Rydberg aggregates in an ultracold Cs gas
Saßmannshausen, Heiner; Merkt, Frédéric
2016-01-01
We present an overview of our recent investigations of long-range interactions in an ultracold Cs Rydberg gas. These interactions are studied by high-resolution photoassociation spectroscopy, using excitation close to one-photon transitions into $n$p$_{3/2}$ Rydberg states with pulsed and continuous-wave ultraviolet laser radiation, and lead to the formation of long-range Cs$_2$ molecules. We observe two types of molecular resonances. The first type originates from the correlated excitation of two atoms into Rydberg-atom-pair states interacting at long range via multipole-multipole interactions. The second type results from the interaction of one atom excited to a Rydberg state with one atom in the electronic ground state. Which type of resonances is observed in the experiments depends on the laser intensity and frequency and on the pulse sequences used to prepare the Rydberg states. We obtain insights into both types of molecular resonances by modelling the interaction potentials, using a multipole expansion...
Electromagnetically induced transparency of ultra-long-range Rydberg molecules
DEFF Research Database (Denmark)
Mirgorodskiy, Ivan; Christaller, Florian; Braun, Christoph
2017-01-01
We study the impact of Rydberg molecule formation on the storage and retrieval of Rydberg polaritons in an ultracold atomic medium. We observe coherent revivals appearing in the storage and retrieval efficiency of stored photons that originate from simultaneous excitation of Rydberg atoms...... and Rydberg molecules in the system with subsequent interference between the possible storage paths. We show that over a large range of principal quantum numbers the observed results can be described by a two-state model including only the atomic Rydberg state and the Rydberg dimer molecule state. At higher...... principal quantum numbers the influence of polyatomic molecules becomes relevant and the dynamics of the system undergoes a transition from coherent evolution of a few-state system to an effective dephasing into a continuum of molecular states....
Energy Technology Data Exchange (ETDEWEB)
Kalyar, M A; Rafiq, M; Baig, M A [Atomic and Molecular Physics Laboratory, Department of Physics, Quaid-i-Azam University, Islamabad 45320 (Pakistan)
2007-11-28
We report new measurements for the oscillator strengths of the 6s6p {sup 1}P{sub 1} {yields} 6snd {sup 1}D{sub 2} and 6s6p {sup 3}P{sub 1} {yields} 6snd {sup 3}D{sub 2} Rydberg transitions of barium using a thermionic diode ion detector in conjunction with a Nd:YAG pumped dye laser system. The f-values have been calibrated with the absolute photoionization cross-section measured at the first ionization threshold from the 6s6p {sup 1}P{sub 1} and 6s6p {sup 3}P{sub 1} excited states employing the saturation technique. An excellent agreement is found for the 6s6p {sup 1}P{sub 1} {yields} 6snd {sup 1}D{sub 2} Rydberg transitions with the earlier reported work. The data on the oscillator strength of the 6s6p {sup 3}P{sub 1} {yields} 6snd {sup 3}D{sub 2} Rydberg transitions are reported for the first time. The oscillator strength densities in the continuum corresponding to the 6s6p {sup 3}P{sub 1} excited state have also been determined and a smooth merging of the discrete f-values into the oscillator strength densities is observed across the ionization threshold.
Salah, Wa'el; Hassouneh, Ola
2017-04-01
We computed the energy levels, oscillator strengths f_{ij}, the radiative transition rates A_{ij}, the Landé g -factor, the magnetic dipole moment and the electric quadrupole hyperfine constants of the intermediate Rydberg series ns [k]J ( 4 ≤ n ≤ 6), nd [k]J (3 ≤ n ≤ 4), np [k]J (4 ≤ n ≤ 5) relative to the ground state 3p6 1S0 for neutral argon atom spectra. The values are obtained in the framework of the multiconfiguration Dirac-Hartree-Fock (MCDHF) approach. In this approach, Breit interaction, leading quantum electrodynamics (QED) effects and self-energy correction are taken into account. Moreover, these spectroscopic parameters have been calculated for many levels belonging to the configuration 3p54s, 3p55s, 3p56s, 3p53d, 3p54d, 3p54p, 3p55p as well as for transitions between levels 3p54s-3p54p, 3p54p-3p53d, 3p54p-3p55s, 3p55s-3p55p and 3p55p-3p56s. The large majority of the lines from the 4p-5s and 4p-3d, 5s-5p and 5p-6s transition arrays have been observed and the calculations are consistent with the J -file-sum rule. The obtained theoretical values are compared with previous experimental and theoretical data available in the literature. An overall satisfactory agreement is noticed allowing assessing the reliability of our data.
State-selective all-optical detection of Rydberg atoms
Karlewski, Florian; Grimmel, Jens; Sándor, Nóra; Fortágh, and József
2015-01-01
We present an all-optical protocol for detecting population in a selected Rydberg state of alkali atoms. The detection scheme is based on the interaction of an ensemble of ultracold atoms with two laser pulses: one weak probe pulse which is resonant with the transition between the ground state and the first excited state, and a pulse with high intensity which couples the first excited state to the selected Rydberg state. We show that by monitoring the absorption signal of the probe laser over time, one can deduce the initial population of the Rydberg state. Furthermore, it is shown that - for suitable experimental conditions - the dynamical absorption curve contains information on the initial coherence between the ground state and the selected Rydberg state. We present the results of a proof-of-principle measurement performed on a cold gas of $^{87}$Rb atoms. The method is expected to find application in quantum computing protocols based on Rydberg atoms.
Cpmmw Spectroscopy of Rydberg States of Nitric Oxide
Barnum, Timothy J.; Saladrigas, Catherine A.; Grimes, David; Coy, Stephen; Eyler, Edward E.; Field, Robert W.
2016-06-01
The spectroscopy of Rydberg states of NO has a long history [1], stimulating both experimental and theoretical advances in our understanding of Rydberg structure and dynamics. The closed-shell ion-core (1Σ+) and small NO+ dipole moment result in regular patterns of Rydberg series in the Hund's case (d) limit, which are well-described by long-range electrostatic models (e.g., [2]). We will present preliminary data on the core-nonpenetrating Rydberg states of NO (orbital angular momentum, ℓ ≥ 3) collected by chirped-pulse millimeter-wave (CPmmW) spectroscopy. Our technique directly detects electronic free induction decay (FID) between Rydberg states with Δn* ≈ 1 in the region of n* ˜ 40-50, providing a large quantity (12 GHz bandwidth in a single shot) of high quality (resolution ˜ 350 kHz) spectra. Transitions between high-ℓ, core-nonpenetrating Rydberg states act as reporters on the subtle details of the ion-core electric structure. * * [1] Huber KP. Die Rydberg-Serien im Absorptions-spektrum des NO-Molekuuls. Helv. Phys. Acta 3, 929 (1961). * * [2] Biernacki DT, Colson SD, Eyler EE. Rotationally resolved double resonance spectra of NO Rydberg states near the first ionization limit. J. Chem. Phys. 88, 2099 (1988).
Newly Identified Rydberg Emission Lines in Novae
Lynch, David K.; Rudy, R. J.; Bernstein, L. S.
2008-09-01
Newly Identified Rydberg Emission Lines in Novae David K. Lynch, Richard. J. Rudy (The Aerospace Corporation) & Lawrence S. Bernstein (Spectral Sciences, Inc.) Novae spectra in the near infrared frequently show a set of six emission lines that have not been positively identified (Williams, Longmore, & Geballe 1996, MNRAS, 279, 804; Lynch et al. 2001, AJ, 122, 2013; Rudy et al. 2002 ApJ, 573, 794; Lynch et al. 2004 Astron. J. 127, 1089-1097). These lines are at 0.8926, 1.1114, 1.1901, 1.5545, 2.0996 and 2.425 µm ± 0.005 µm. Krautter et al. (1984 A&A 137, 304) suggested that three of the lines were due to rydberg (hydrogenic) transitions in an unspecified atomic species that was in the 4th or 5th ionization stage (core charge = 4 & 5). We believe that Krautter et al.'s explanation is correct based on 4 additional lines that we have identified in the visible and near infrared spectrum of V723 Cassiopeiae. The observed Rydberg lines appear to originate from high angular momentum states with negligible quantum defects. The species cannot be determined with any certainty because in rydberg states, the outer electron sees a nucleus shielded by the inner electrons and together the inner atom appears to have a charge of +1, like hydrogen. As a result, the atom looks hydrogenic and species such as CV, NV, OV, MgV, SiV, etc. have their rydberg transitions at very similar wavelengths. All the lines represent permitted transitions, most likely formed by recombination. Atoms with core charges 4, 5 & 6 are rarely seen in the astrophysical environment because an extremely hot radiation field is necessary to ionize them. Thermonuclear runaways on the surface of a white dwarf can reach millions of degrees K, and thus there are enough X-ray photons available to achieve the necessary high ionization levels.
Saßmannshausen, Heiner; Deiglmayr, Johannes; Merkt, Frédéric
2016-12-01
We present an overview of our recent investigations of long-range interactions in an ultracold Cs Rydberg gas. These interactions are studied by high-resolution photoassociation spectroscopy, using excitation close to one-photon transitions into np3/2 Rydberg states with pulsed and continuous-wave ultraviolet laser radiation, and lead to the formation of long-range Cs2 molecules. We observe two types of molecular resonances. The first type originates from the correlated excitation of two atoms into Rydberg-atom-pair states interacting at long range via multipole-multipole interactions. The second type results from the interaction of one atom excited to a Rydberg state with one atom in the electronic ground state. Which type of resonances is observed in the experiments depends on the laser intensity and frequency and on the pulse sequences used to prepare the Rydberg states. We obtain insights into both types of molecular resonances by modelling the interaction potentials, using a multipole expansion of the long-range interaction for the first type of resonances and a Fermi-contact pseudo-potential for the second type of resonances. We analyse the relation of these long-range molecular resonances to molecular Rydberg states and ion-pair states, and discuss their decay channels into atomic and molecular ions. In experiments carried out with a two-colour two-photon excitation scheme, we observe a large enhancement of Rydberg-excitation probability, which we interpret as a saturable autocatalytic antiblockade phenomenon.
Rydberg matter: properties and decay
Manykin, Edward A.; Ojovan, Michael I.; Poluektov, Pavel P.
2006-03-01
Rydberg matter is a condensed excited state made of highly excited atoms. State of art of research in the field of Rydberg matter is briefly reviewed. Special attention is focused on the contribution of Russian and Swedish scientists' groups to the analysis of this problem. Most attention is concentrated on physical principles of pseudopotential method and density functional theory used to describe the Rydberg matter. The description of Rydberg matter as an excited state becomes viable after the formal replacement of excited atoms by ground state pseudoatoms. This procedure has been used to find parameters of Rydberg matter made of highly excited cesium atoms. Theoretical estimations conform to experimental data available.
Gnedin, Yu N; Ignjatovic, Lj M; Sakan, N M; Sreckovic, V A; Zakharov, M Yu; Bezuglov, N N; Klycharev, A N; 10.1016/j.newar.2009.07.003
2012-01-01
Elementary processes in astrophysical phenomena traditionally attract researchers attention. At first this can be attributed to a group of hemi-ionization processes in Rydberg atom collisions with ground state parent atoms. This processes might be studied as a prototype of the elementary process of the radiation energy transformation into electrical one. The studies of nonlinear mechanics have shown that so called regime of dynamic chaos should be considered as typical, rather than exceptional situation in Rydberg atoms collision. From comparison of theory with experimental results it follows that a such kind of stochastic dynamic processes, occurred during the single collision, may be observed.
Applicability of Rydberg atoms to quantum computers
Ryabtsev, Igor I.; Tretyakov, Denis B.; Beterov, Ilya I.
2005-01-01
The applicability of Rydberg atoms to quantum computers is examined from an experimental point of view. In many recent theoretical proposals, the excitation of atoms into highly excited Rydberg states was considered as a way to achieve quantum entanglement in cold atomic ensembles via dipole-dipole interactions that could be strong for Rydberg atoms. Appropriate conditions to realize a conditional quantum phase gate have been analysed. We also present the results of modelling experiments on microwave spectroscopy of single- and multi-atom excitations at the one-photon 37S1/2 → 37P1/2 and two-photon 37S1/2 → 38S1/2 transitions in an ensemble of a few sodium Rydberg atoms. The microwave spectra were investigated for various final states of the ensemble initially prepared in its ground state. The results may be applied to the studies on collective laser excitation of ground-state atoms aiming to realize quantum gates.
Dipolar exchange induced transparency with Rydberg atoms
Petrosyan, David
2017-03-01
A three-level atomic medium can be made transparent to a resonant probe field in the presence of a strong control field acting on an adjacent atomic transition to a long-lived state, which can be represented by a highly excited Rydberg state. The long-range interactions between the Rydberg state atoms then translate into strong, non-local, dispersive or absorptive interactions between the probe photons, which can be used to achieve deterministic quantum logic gates and single photon sources. Here we show that long-range dipole–dipole exchange interaction with one or more spins—two-level systems represented by atoms in suitable Rydberg states—can play the role of control field for the optically dense medium of atoms. This induces transparency of the medium for a number of probe photons n p not exceeding the number of spins n s , while all the excess photons are resonantly absorbed upon propagation. In the most practical case of a single spin atom prepared in the Rydberg state, the medium is thus transparent only to a single input probe photon. For larger number of spins n s , all n p ≤ n s photon components of the probe field would experience transparency but with an n p -dependent group velocity.
Energy Technology Data Exchange (ETDEWEB)
Nez, F
1993-10-15
The aim of this thesis is to make a pure measurement of the frequency of the 2S-8S/8D two-photon transition in atomic hydrogen. In that purpose we have built a frequency chain in which hydrogen frequencies are compared with the difference of two optical standards, the methane stabilized He-Ne laser (3.39 {mu}m) and the iodine stabilized He-Ne laser (633 nm). The radiation from a home made Ti-sapphire laser (TS2) at 778 nm is mixed, in a LiIO{sub 3} crystal, with the one of a auxiliary He-Ne laser at 3.39 {mu}m to produce a synthesized radiation at 633 nm. The frequency of the Ti-sapphire (TS1) laser used for the two photon excitation is 89 GHz away from the one of TS2. To compare these two lasers, we have used a Schottky diode. The two lasers and a microwave radiation at 89 GHz, produced by a Gunn diode, are focused on the Schottky diode. The Gunn diode is phase locked on an ultra-stable quartz oscillator. In this way, we have linked an optical frequency of atomic hydrogen to the cesium clock without interferometry. From our measurements, we have deduced a new value of the Rydberg constant: R{sub {infinity}} equals 109737.3156834 (24) cm{sup -1} with an uncertainty of 2.2 10{sup -11}. Our uncertainty is near the one of the Q.E.D calculations giving the theoretical values of the energy levels. This value, which is currently the most precise available, is in good agreement with the recent result obtained from the 1S-2S and 2S-4D transitions. (author)
Energy Technology Data Exchange (ETDEWEB)
Rudakov, Fedor M [ORNL; Zhang, Zhili [ORNL
2012-01-01
We present a technique for nonintrusive and standoff detection of large organic molecules using coherent microwave Rayleigh scattering from plasma produced by structure sensitive photoionization through Rydberg states. We test the method on 1,4-diazobicyclooctane. Transitions between the 3s Rydberg state and higher lying Rydberg states are probed using two-color photoionization with 266?nm photons and photons in the range of 460-2400 nm. Photoionization is detected using microwave radiation, which is scattered by the unbounded electrons. Highly resolved Rydberg spectra are acquired in vacuum and in air.
STIRAP on helium: Excitation to Rydberg states
Yuan, Deqian
Research in optically induced transitions between dierent atomic levels has a long history. For transitions between states driven by a coherent optical eld, the theoretical eciency could be ideally high as 100% but there could be many factors preventing this. In the three state helium atom excitation process, i.e. 23S→33P→nL , the stimulated emission from intermediate state makes it hard to achieve ecient population transfer to the nal state through an intuitive excitation order. One technique to achieve a higher eciency is Stimulated Raman Adiabatic Passage (STIRAP) which is being studied and under research in our lab. Unlike traditional three level excitation processes, STIRAP actually uses a counter intuitive pulsed laser beams timing arrangement. The excitation objects are metastable helium atoms traveling in a vacuum system with a longitudinal velocity of ~ 1070 m/s. We are using a 389 nm UV laser to connect the 23S and the 33P state and a frequency tunable ~790 nm IR laser to connect the 33P state and the dierent Rydberg states. A third 1083 nm wavelength laser beam drives the 23S → 23P transition to transversely separate the residual metastable atoms and the Rydberg atoms for eciency measurements. The data is taken by a stainless steel detector in the vacuum system. As the Rydberg atoms will get ionized by blackbody radiation under room temperature, we can utilize this for their detection. An ion detector sitting on the eld plate is capable to collect the ion signals of the Rydberg atoms for detection. So far the whole system has not been ready for data collection and measurement, so here we are using data and results from previous theses for discussions. The highest transition frequency that has ever been achieved in our lab is around 70% after corrections.
THz Detection and Imaging using Rydberg Atoms
Wade, Christopher; Sibalic, Nikola; Kondo, Jorge; de Melo, Natalia; Adams, Charles; Weatherill, Kevin
2016-05-01
Atoms make excellent electromagnetic field sensors because each atom of the same isotope is identical and has well-studied, permanent properties allowing calibration to SI units. Thus far, atoms have not generally been exploited for terahertz detection because transitions from the atomic ground state are constrained to a limited selection of microwave and optical frequencies. In contrast, highly excited `Rydberg' states allow us access to many strong, electric dipole transitions from the RF to THz regimes. Recent advances in the coherent optical detection of Rydberg atoms have been exploited by a number of groups for precision microwave electrometry Here we report the demonstration of a room-temperature, cesium Rydberg gas as a THz to optical interface. We present two configurations: First, THz-induced fluorescence offers non-destructive and direct imaging of the THz field, providing real-time, single shot images. Second, we convert narrowband terahertz photons to infrared photons with 6% quantum efficiency allowing us to use nano-Watts of THz power to control micro-Watts of laser power on microsecond timescales. Exploiting hysteresis and a room-temperature phase transition in the response of the medium, we demonstrate a latching optical memory for sub pico-Joule THz pulses.
Chitnis, Saurabh S; Vos, Kevin A; Burford, Neil; McDonald, Robert; Ferguson, Michael J
2016-01-14
Reactions of polydentate phosphines with sources of Pn(3+) (Pn = P, As, Sb, Bi) yield complexes of Pn(1+) (Pn = P, As) or Pn(3+) (Pn = Sb, Bi) acceptors. The distinction between coordination of a phosphine center to Pn and oxidation of a phosphine ligand is dependent on Pn. The first structurally verified triphosphine complexes of Sb(III) and Bi(III) acceptors are reported.
Topological spin models in Rydberg lattices
Kiffner, Martin; Jaksch, Dieter
2016-01-01
We show that resonant dipole-dipole interactions between Rydberg atoms in a triangular lattice can give rise to artificial magnetic fields for spin excitations. We consider the coherent dipole-dipole coupling between $np$ and $ns$ Rydberg states and derive an effective spin-1/2 Hamiltonian for the $np$ excitations. By breaking time-reversal symmetry via external fields we engineer complex hopping amplitudes for transitions between two rectangular sub-lattices. The phase of these hopping amplitudes depends on the direction of the hop. This gives rise to a staggered, artificial magnetic field which induces non-trivial topological effects. We calculate the single-particle band structure and investigate its Chern numbers as a function of the lattice parameters and the detuning between the two sub-lattices. We identify extended parameter regimes where the Chern number of the lowest band is $C=1$ or $C=2$.
Energy Technology Data Exchange (ETDEWEB)
Joe, Yong S. [Center for Computational Nanoscience, Department of Physics and Astronomy, Ball State University, Muncie, IN 47306 (United States)], E-mail: ysjoe@bsu.edu; Mkrtchian, Vanik E. [Institute for Physical Research, Armenian Academy of Sciences, Ashtarak-2, 378410, Republic of Armenia (Armenia); Lee, Sun H. [Center for Computational Nanoscience, Department of Physics and Astronomy, Ball State University, Muncie, IN 47306 (United States)
2009-03-02
We analyze bound states of an electron in the field of a positively charged nanoshell. We find that the binding and excitation energies of the system decrease when the radius of the nanoshell increases. We also show that the ground and the first excited states of this system have remarkably the same properties of the highly excited Rydberg states of a hydrogen-like atom, i.e., a high sensitivity to the external perturbations and long radiative lifetimes.
Bohmian picture of Rydberg atoms
Indian Academy of Sciences (India)
Partha Ghose; Manoj K Samal; Animesh Datta
2002-08-01
Unlike the previous theoretical results based on standard quantum mechanics that established the nearly elliptical shapes for the centre-of-mass motion in Rydberg atoms using numerical simulations, we show analytically that the Bohmian trajectories in Rydberg atoms are nearly elliptical.
Universal Nonequilibrium Properties of Dissipative Rydberg Gases
Marcuzzi, Matteo; Levi, Emanuele; Diehl, Sebastian; Garrahan, Juan P.; Lesanovsky, Igor
2014-11-01
We investigate the out-of-equilibrium behavior of a dissipative gas of Rydberg atoms that features a dynamical transition between two stationary states characterized by different excitation densities. We determine the structure and properties of the phase diagram and identify the universality class of the transition, both for the statics and the dynamics. We show that the proper dynamical order parameter is in fact not the excitation density and find evidence that the dynamical transition is in the "model A " universality class; i.e., it features a nontrivial Z2 symmetry and a dynamics with nonconserved order parameter. This sheds light on some relevant and observable aspects of dynamical transitions in Rydberg gases. In particular it permits a quantitative understanding of a recent experiment [C. Carr, Phys. Rev. Lett. 111, 113901 (2013)] which observed bistable behavior as well as power-law scaling of the relaxation time. The latter emerges not due to critical slowing down in the vicinity of a second order transition, but from the nonequilibrium dynamics near a so-called spinodal line.
Electromagnetically induced transparency with Rydberg atoms inside a high-finesse optical cavity
Sheng, Jiteng; Kumar, Santosh; Sedlacek, Jonathon; Chao, Yuanxi; Fan, Haoquan; Shaffer, James
2016-05-01
We present experimental work on the observation of Rydberg electromagnetically induced transparency (EIT) inside a high-finesse optical cavity. We show that a cold atomic cloud with controllable number of atoms can be transported into the cavity by using a focus-tunable lens. Rydberg atoms are excited via a two-photon transition in a ladder-type EIT configuration. A three-peak structure in the cavity transmission can be observed when Rydberg EIT atoms are generated inside the cavity. The two side peaks are caused by ``bright state polaritons'', while the central peak corresponds to a ``dark-state polariton'' The cavity Rydberg EIT system can be useful for single photon generation using the Rydberg blockade effect, studying many-body physics, and generating novel quantum states amongst many other applications. This work is supported by AFOSR.
Microwave-induced three-photon coherence of Rydberg atomic states
Kwak, Hyo Min; Jeong, Taek; Lee, Yoon-Seok; Moon, Han Seb
2016-12-01
We investigate the three-photon coherence (TPC) effects of the Rydberg state in a Doppler-broadened four-level ladder-type atomic system for the 5S1/2(F=3)-5P3/2(F‧=4)-50D5/2-51P3/2 transition of 85Rb atoms. Upon interaction of the Rydberg Rb atom of the ladder-type electromagnetically induced transparency (EIT) scheme with a resonant microwave (MW) field, we numerically analyze the spectral features of the Rydberg TPC from two viewpoints, Autler-Townes splitting (AT-splitting) of the Rydberg EIT and three-photon electromagnetically induced absorption (TPEIA). We determine the criterion to differentiate between AT-splitting of the Rydberg EIT and TPEIA in the Doppler-broadened ladder-type atomic system.
Coherent Transfer between Low-Angular-Momentum and Circular Rydberg States
Signoles, A.; Dietsche, E. K.; Facon, A.; Grosso, D.; Haroche, S.; Raimond, J. M.; Brune, M.; Gleyzes, S.
2017-06-01
We realize a coherent transfer between a laser-accessible low-angular-momentum Rydberg state and the circular Rydberg level with maximal angular momentum. It is induced by a radio frequency field with a high-purity σ+ polarization resonant on Stark transitions inside the hydrogenic Rydberg manifold. We observe over a few microseconds more than 20 coherent Rabi oscillations between the initial Rydberg state and the circular level. We characterize these many-Rydberg-level oscillations and find them in perfect agreement with a simple model. This coherent transfer opens the way to hybrid quantum gates bridging the gap between optical communication and quantum information manipulations with microwave cavity and circuit quantum electrodynamics.
Coherent excitation of a single atom to a Rydberg state
DEFF Research Database (Denmark)
Miroshnychenko, Yevhen; Gaëtan, Alpha; Evellin, Charles
2010-01-01
We present the coherent excitation of a single Rubidium atom to the Rydberg state 58d3/2 using a two-photon transition. The experimental setup is described in detail, as are experimental techniques and procedures. The coherence of the excitation is revealed by observing Rabi oscillations between ...
Coherent excitation of a single atom to a Rydberg state
DEFF Research Database (Denmark)
Miroshnychenko, Yevhen; Gaëtan, Alpha; Evellin, Charles
2010-01-01
We present the coherent excitation of a single Rubidium atom to the Rydberg state 58d3/2 using a two-photon transition. The experimental setup is described in detail, as are experimental techniques and procedures. The coherence of the excitation is revealed by observing Rabi oscillations between ...
Coherent excitation of a single atom to a Rydberg state
Miroshnychenko, Y; Evellin, C; Grangier, P; Comparat, D; Pillet, P; Wilk, T; Browaeys, A
2010-01-01
We present the coherent excitation of a single Rubidium atom to the Rydberg state (58d3/2) using a two-photon transition. The experimental setup is described in detail, as well as experimental techniques and procedures. The coherence of the excitation is revealed by observing Rabi oscillations between ground and Rydberg states of the atom. We analyze the observed oscillations in detail and compare them to numerical simulations which include imperfections of our experimental system. Strategies for future improvements on the coherent manipulation of a single atom in our settings are given.
Cavity quantum electrodynamics with a Rydberg-blocked atomic ensemble
DEFF Research Database (Denmark)
Guerlin, Christine; Brion, Etienne; Esslinger, Tilman
2010-01-01
The realization of a Jaynes-Cummings model in the optical domain is proposed for an atomic ensemble. The scheme exploits the collective coupling of the atoms to a quantized cavity mode and the nonlinearity introduced by coupling to high-lying Rydberg states. A two-photon transition resonantly......> and the collectively excited state |E> with a single Rydberg excitation distributed evenly on all atoms. The collectively enhanced coupling of all atoms to the cavity field with coherent coupling strengths which are much larger than the decay rates in the system leads to the strong coupling regime of the resulting...
Photoassociation of long-range $nD$ Rydberg molecules
Anderson, David A; Raithel, Georg
2014-01-01
We observe long-range homonuclear diatomic $nD$ Rydberg molecules photoassociated out of an ultracold gas of $^{87}$Rb atoms for 34$\\le n \\le$40. The measured ground-state binding energies of $^{87}$Rb$(nD-5S_{1/2})$ molecular states are larger than those of their $^{87}$Rb$(nS-5S_{1/2})$ counterparts, showing the dependence of the molecular bond on the angular momentum of the Rydberg atom. We exhibit the transition of $^{87}$Rb$(nD-5S_{1/2})$ molecules from a molecular-binding-dominant regime at low $n$ to a fine-structure-dominant regime at high $n$ [akin to Hund's cases (a) and (c), respectively]. In the analysis the fine structure of the $nD$ Rydberg atom and the hyperfine structure of the $5S_{1/2}$ atom are included.
Löw, Robert
2014-12-01
The old adage that you can't tango alone is certainly true for humans. But recent experiments show that it may also be applicable to Rydberg atoms, which keep a beat through the coherent exchange of energy.
Rydberg-induced optical nonlinearities from a cold atomic ensemble trapped inside a cavity
Boddeda, R.; Usmani, I.; Bimbard, E.; Grankin, A.; Ourjoumtsev, A.; Brion, E.; Grangier, P.
2016-04-01
We experimentally characterize the optical nonlinear response of a cold atomic medium placed inside an optical cavity, and excited to Rydberg states. The excitation to S and D Rydberg levels is carried out via a two-photon transition in an electromagnetically induced transparency configuration, with a weak (red) probe beam on the lower transition, and a strong (blue) coupling beam on the upper transition. The observed optical nonlinearities induced by S states for the probe beam can be explained using a semi-classical model with van der Waals’ interactions. For the D states, it appears necessary to take into account a dynamical decay of Rydberg excitations into a long-lived dark state. We show that the measured nonlinearities can be explained by using a Rydberg bubble model with a dynamical decay.
Rydberg-induced optical nonlinearities from a cold atomic ensemble trapped inside a cavity
Boddeda, Rajiv; Bimbard, Erwan; Grankin, Andrey; Ourjoumtsev, Alexei; Brion, Etienne; Grangier, Philippe
2015-01-01
We experimentally characterize the optical nonlinear response of a cold atomic medium placed inside an optical cavity, and excited to Rydberg states. The excitation to S and D Rydberg levels is carried out via a two-photon transition in an EIT (electromagnetically induced transparency) configuration, with a weak (red) probe beam on the lower transition, and a strong (blue) coupling beam on the upper transition. The observed optical nonlinearities induced by S states for the probe beam can be explained using a semi-classical model with van der Waals' interactions. For the D states, it appears necessary to take into account a dynamical decay of Rydberg excitations into a long-lived dark state. We show that the measured nonlinearities can be explained by using a Rydberg bubble model with a dynamical decay.
Rydberg States of Atoms and Molecules
Stebbings, R. F.; Dunning, F. B.
2011-03-01
List of contributors; Preface; 1. Rydberg atoms in astrophysics A. Dalgarno; 2. Theoretical studies of hydrogen Rydberg atoms in electric fields R. J. Damburg and V. V. Kolosov; 3. Rydberg atoms in strong fields D. Kleppner, Michael G. Littman and Myron L. Zimmerman; 4. Spectroscopy of one- and two-electron Rydberg atoms C. Fabre and S. Haroche; 5. Interaction of Rydberg atoms with blackbody radiation T. F. Gallagher; 6. Theoretical approaches to low-energy collisions of Rydberg atoms with atoms and ions A. P. Hickman, R. E. Olson and J. Pascale; 7. Experimental studies of the interaction of Rydberg atoms with atomic species at thermal energies F. Gounand and J. Berlande; 8. Theoretical studies of collisions of Rydberg atoms with molecules Michio Matsuzawa; 9. Experimental studies of thermal-energy collisions of Rydberg atoms with molecules F. B. Dunning and R. F. Stebbings; 10. High-Rydberg molecules Robert S. Freund; 11. Theory of Rydberg collisions with electrons, ions and neutrals M. R. Flannery; 12. Experimental studies of the interactions of Rydberg atoms with charged particles J. -F. Delpech; 13. Rydberg studies using fast beams Peter M. Koch; Index.
Microwave Hanle effect in Rydberg atoms
Ryabtsev, Igor I.; Tretyakov, Denis B.
2001-09-01
A microwave analog of the interference Hanle effect has been studied in sodium Rydberg atoms. Spontaneous emission of the microwave transition 37P3/2-->37S1/2 at 70.166 GHz was replaced by an induced transition from a pulsed microwave source. A dependence of population of the 37S1/2 state on the magnetic field was recorded in various conditions. Good agreement with the theoretical calculations has been found. The widths and shapes of observed resonances were defined by the spectral widths of the pulsed microwave radiation and parameters of laser excitation of the initial 37P3/2 state. The quantum beats of magnetic sublevels appeared in the signals when the polarization of exciting laser emission was orthogonal to the magnetic field, and the interference occurred in the scheme of transitions similar to the Mach-Zehnder optical interferometer.
Calculation of Rydberg interaction potentials
Weber, Sebastian; Tresp, Christoph; Menke, Henri; Urvoy, Alban; Firstenberg, Ofer; Büchler, Hans Peter; Hofferberth, Sebastian
2017-07-01
The strong interaction between individual Rydberg atoms provides a powerful tool exploited in an ever-growing range of applications in quantum information science, quantum simulation and ultracold chemistry. One hallmark of the Rydberg interaction is that both its strength and angular dependence can be fine-tuned with great flexibility by choosing appropriate Rydberg states and applying external electric and magnetic fields. More and more experiments are probing this interaction at short atomic distances or with such high precision that perturbative calculations as well as restrictions to the leading dipole-dipole interaction term are no longer sufficient. In this tutorial, we review all relevant aspects of the full calculation of Rydberg interaction potentials. We discuss the derivation of the interaction Hamiltonian from the electrostatic multipole expansion, numerical and analytical methods for calculating the required electric multipole moments and the inclusion of electromagnetic fields with arbitrary direction. We focus specifically on symmetry arguments and selection rules, which greatly reduce the size of the Hamiltonian matrix, enabling the direct diagonalization of the Hamiltonian up to higher multipole orders on a desktop computer. Finally, we present example calculations showing the relevance of the full interaction calculation to current experiments. Our software for calculating Rydberg potentials including all features discussed in this tutorial is available as open source.
Experimental demonstration of Rydberg dressing in a many-body system
Zeiher, Johannes; Schauss, Peter; Hild, Sebastian; Rubio-Abadal, Antonio; Choi, Jae-Yoon; van Bijnen, Rick; Pohl, Thomas; Bloch, Immanuel; Gross, Christian
2016-05-01
Rydberg atoms offer the possibility to study long range interacting systems of ultracold atoms due to their strong van der Waals interactions. Admixture of a Rydberg state to a ground state, known as Rydberg dressing, allows for increased experimental tunability of these interactions and promises to study novel phases of matter. Here we report on our results of the realization of Rydberg dressing in a many-body spin system. Starting from a two-dimensional spin-polarized Mott insulator of an ultracold gas of rubidium-87, we optically couple one spin component to a Rydberg p-state on a single photon ultra-violet transition at 297 nm. Using microwave Ramsey interferometry in the ground state manifold, we measure the spin-spin correlations emerging due to the admixture of long range interactions to the ground state. To show the predicted versatility of Rydberg dressing, we tune the range and anisotropy of the interaction. We furthermore discuss loss processes affecting our dressed ensembles and present initial indications of improved lifetimes in our system. Our results constitute an important step towards the realization of novel spin models with Rydberg dressed interactions.
Orthogonal flexible Rydberg aggregates
Leonhardt, K.; Wüster, S.; Rost, J. M.
2016-02-01
We study the link between atomic motion and exciton transport in flexible Rydberg aggregates, assemblies of highly excited light alkali-metal atoms, for which motion due to dipole-dipole interaction becomes relevant. In two one-dimensional atom chains crossing at a right angle adiabatic exciton transport is affected by a conical intersection of excitonic energy surfaces, which induces controllable nonadiabatic effects. A joint exciton-motion pulse that is initially governed by a single energy surface is coherently split into two modes after crossing the intersection. The modes induce strongly different atomic motion, leading to clear signatures of nonadiabatic effects in atomic density profiles. We have shown how this scenario can be exploited as an exciton switch, controlling direction and coherence properties of the joint pulse on the second of the chains [K. Leonhardt et al., Phys. Rev. Lett. 113, 223001 (2014), 10.1103/PhysRevLett.113.223001]. In this article we discuss the underlying complex dynamics in detail, characterize the switch, and derive our isotropic interaction model from a realistic anisotropic one with the addition of a magnetic bias field.
Orthogonal flexible Rydberg aggregates
Leonhardt, K; Rost, J M
2015-01-01
We study the link between atomic motion and exciton transport in flexible Rydberg aggregates, assemblies of highly excited light alkali atoms, for which motion due to dipole-dipole interaction becomes relevant. In two one-dimensional atom chains crossing at a right angle adiabatic exciton transport is affected by a conical intersection of excitonic energy surfaces, which induces controllable non-adiabatic effects. A joint exciton/motion pulse that is initially governed by a single energy surface is coherently split into two modes after crossing the intersection. The modes induce strongly different atomic motion, leading to clear signatures of non-adiabatic effects in atomic density profiles. We have shown how this scenario can be exploited as an exciton switch, controlling direction and coherence properties of the joint pulse on the second of the chains [K.~Leonhardt {\\it et al.}, Phys.~Rev.~Lett. {\\bf 113} 223001 (2014)]. In this article we discuss the underlying complex dynamics in detail, characterise the ...
Gravitational-wave phasing for low-eccentricity inspiralling compact binaries to 3PN order
Moore, Blake; Favata, Marc; Arun, K. G.; Mishra, Chandra Kant
2016-06-01
Although gravitational radiation causes inspiralling compact binaries to circularize, a variety of astrophysical scenarios suggest that binaries might have small but non-negligible orbital eccentricities when they enter the low-frequency bands of ground- and space-based gravitational-wave detectors. If not accounted for, even a small orbital eccentricity can cause a potentially significant systematic error in the mass parameters of an inspiralling binary [M. Favata, Phys. Rev. Lett. 112, 101101 (2014)]. Gravitational-wave search templates typically rely on the quasicircular approximation, which provides relatively simple expressions for the gravitational-wave phase to 3.5 post-Newtonian (PN) order. Damour, Gopakumar, Iyer, and others have developed an elegant but complex quasi-Keplerian formalism for describing the post-Newtonian corrections to the orbits and waveforms of inspiralling binaries with any eccentricity. Here, we specialize the quasi-Keplerian formalism to binaries with low eccentricity. In this limit, the nonperiodic contribution to the gravitational-wave phasing can be expressed explicitly as simple functions of frequency or time, with little additional complexity beyond the well-known formulas for circular binaries. These eccentric phase corrections are computed to 3PN order and to leading order in the eccentricity for the standard PN approximants. For a variety of systems, these eccentricity corrections cause significant corrections to the number of gravitational-wave cycles that sweep through a detector's frequency band. This is evaluated using several measures, including a modification of the useful cycles. By comparing to numerical solutions valid for any eccentricity, we find that our analytic solutions are valid up to e0≲0.1 for comparable-mass systems, where e0 is the eccentricity when the source enters the detector band. We also evaluate the role of periodic terms that enter the phasing and discuss how they can be incorporated into some of
Quantum information with Rydberg atoms
DEFF Research Database (Denmark)
Saffman, Mark; Walker, T.G.; Mølmer, Klaus
2010-01-01
qubits. The availability of a strong long-range interaction that can be coherently turned on and off is an enabling resource for a wide range of quantum information tasks stretching far beyond the original gate proposal. Rydberg enabled capabilities include long-range two-qubit gates, collective encoding...... of multiqubit registers, implementation of robust light-atom quantum interfaces, and the potential for simulating quantum many-body physics. The advances of the last decade are reviewed, covering both theoretical and experimental aspects of Rydberg-mediated quantum information processing.......Rydberg atoms with principal quantum number n»1 have exaggerated atomic properties including dipole-dipole interactions that scale as n4 and radiative lifetimes that scale as n3. It was proposed a decade ago to take advantage of these properties to implement quantum gates between neutral atom...
Energy Technology Data Exchange (ETDEWEB)
Nez, F
2005-06-15
This document reviews the theoretical and experimental achievements of the author since the beginning of his scientific career. This document is dedicated to the spectroscopy of hydrogen, deuterium and helium atoms. The first part is divided into 6 sub-sections: 1) the principles of hydrogen spectroscopy, 2) the measurement of the 2S-nS/nD transitions, 3) other optical frequency measurements, 4) our contribution to the determination of the Rydberg constant, 5) our current experiment on the 1S-3S transition, 6) the spectroscopy of the muonic hydrogen. Our experiments have improved the accuracy of the Rydberg Constant by a factor 25 in 15 years and we have achieved the first absolute optical frequency measurement of a transition in hydrogen. The second part is dedicated to the measurement of the fine structure constant and the last part deals with helium spectroscopy and the search for optical references in the near infrared range. (A.C.)
Radiative lifetime measurements of rubidium Rydberg states
Branden, Drew B; Mahlokozera, Tatenda; Vesa, Cristian; Wilson, Roy O; Zheng, Mao; Kortyna, Andrew; Tate, Duncan A
2009-01-01
We have measured the radiative lifetimes of ns, np and nd Rydberg states of rubidium in the range 28 < n < 45. To enable long-lived states to be measured, our experiment uses slow-moving Rb atoms in a magneto-optical trap (MOT). Two experimental techniques have been adopted to reduce random and systematic errors. First, a narrow-bandwidth pulsed laser is used to excite the target Rydberg state, resulting in minimal shot-to-shot variation in the initial state population. Second, we monitor the target state population as a function of time delay from the laser pulse using a short-duration, millimetre-wave pulse that is resonant with a one- or two-photon transition. We then selectively field ionize the monitor state, and detect the resulting electrons with a micro-channel plate. This signal is an accurate mirror of the target state population, and is uncontaminated by contributions from other states which are populated by black body radiation. Our results are generally consistent with other recent experime...
Microwave electric field sensing with Rydberg atoms
Stack, Daniel T.; Kunz, Paul D.; Meyer, David H.; Solmeyer, Neal
2016-05-01
Atoms form the basis of precise measurement for many quantities (time, acceleration, rotation, magnetic field, etc.). Measurements of microwave frequency electric fields by traditional methods (i.e. engineered antennas) have limited sensitivity and can be difficult to calibrate properly. Highly-excited (Rydberg) neutral atoms have very large electric-dipole moments and many dipole allowed transitions in the range of 1 - 500 GHz. It is possible to sensitively probe the electric field in this range using the combination of two quantum interference phenomena: electromagnetically induced transparency and the Autler-Townes effect. This technique allows for very sensitive field amplitude, polarization, and sub-wavelength imaging measurements. These quantities can be extracted by measuring properties of a probe laser beam as it passes through a warm rubidium vapor cell. Thus far, Rydberg microwave electrometry has relied upon the absorption of the probe laser. We report on our use of polarization rotation, which corresponds to the real part of the susceptibility, for measuring the properties of microwave frequency electric fields. Our simulations show that when a magnetic field is present and directed along the optical propagation direction a polarization rotation signal exists and can be used for microwave electrometry. One central advantage in using the polarization rotation signal rather than the absorption signal is that common mode laser noise is naturally eliminated leading to a potentially dramatic increase in signal-to-noise ratio.
Dispersive optical nonlinearities in an EIT-Rydberg medium
Stanojevic, Jovica; Bimbard, Erwan; Ourjoumtsev, Alexei; Grangier, Philippe
2013-01-01
We investigate dispersive optical nonlinearities that arise from Rydberg excitation blockade in cold Rydberg gases. We consider a two-photon transition scheme and study the non-linear response to a weak optical probe in presence of a strong control beam. For very low probe fields, the dominant nonlinearities are of the third order and they can be exactly evaluated in a steady state regime. In a more general case, the change in average atomic populations and coherences due to Rydberg interactions can be characterized by properly defined scaling parameters, which are generally complex numbers but in certain situations take the usual meaning of the number of atoms in a blockade sphere. They can be used in a simple "universal scaling" formula to determine the dispersive optical nonlinearity of the medium. We also develop a novel technique to account for the Rydberg interaction effects, by simplifying the treatment of nonlocal interaction terms, the so-called collisional integrals. We find algebraic relations that...
Laser frequency locking based on Rydberg electromagnetically induced transparency
Yuechun, Jiao; Jingkui, Li; Limei, Wang; Hao, Zhang; Linjie, Zhang; Jianming, Zhao; Suotang, Jia
2016-05-01
We present a laser frequency locking to Rydberg transition with electromagnetically induced transparency (EIT) spectra in a room-temperature cesium vapor cell. Cesium levels 6S1/2, 6P3/2, and the nD5/2 state, compose a cascade three-level system, where a coupling laser drives Rydberg transition, and probe laser detects the EIT signal. The error signal, obtained by demodulating the EIT signal, is used to lock the coupling laser frequency to Rydberg transition. The laser frequency fluctuation, ˜0.7 MHz, is obtained after locking on, with the minimum Allan variance to be 8.9 × 10-11. This kind of locking method can be used to stabilize the laser frequency to the excited transition. Project supported by the National Basic Research Program of China (Grant No. 2012CB921603), the National Natural Science Foundation of China (Grants Nos. 11274209, 61475090, 61378039, and 61378013), and the Research Project Supported by Shanxi Scholarship Council of China (Grant No. 2014-009).
Zelener, B. B.; Saakyan, S. A.; Sautenkov, V. A.; Manykin, E. A.; Zelener, B. V.; Fortov, V. E.
2016-04-01
Forbidden 2 P- nP and 2 P- nF transitions in the ranges of the principal quantum number n = 42-114 and n = 38-48 have been detected in the optical spectra of ultracold highly excited lithium-7 atoms. The presence of forbidden transitions is due to induced external electric fields. The quantum defects and ionization energy obtained in various experiments and predicted theoretically have been discussed.
Mayhew, C A
1984-01-01
The high resolution absorption spectra of the important group VI dihydrides and deuterides in the vacuum ultraviolet below, and up to, their first ionisation potentials are presented. These spectra were recorded using synchrotron radiation as the background light source in conjunction with a 3m normal incidence vacuum spectrograph, equipped with holographic gratings. Due to the nature of the originating orbital for the majority of optical transitions in the VUV well developed Rydberg series are observed. One particular series can be followed up to fairly high n, so that accurate values of the first ionisation potential are determined. The identifications of the Rydberg series are made from arguments relating to their oscillator strengths, quantum defects, symmetries and from comparisons with the spectra of the corresponding united atoms i.e. the inert gases. Examples of the symmetry assignments for Rydberg series from rotational band contour analyses of the lower Rydberg members for the H sub 2 S, H sub 2 Se ...
Collision-induced shifts of Rydberg levels of strontium
Energy Technology Data Exchange (ETDEWEB)
Marafi, M; Bhatia, K S; Makdisi, Y Y; Philips, G [Department of Physics, Kuwait University, PO Box 5969, Safat, 13060 (Kuwait)
2003-05-14
Measurements of spectral line shifts induced by collisions with rare gas perturbers are reported. High Rydberg states were prepared by multiphoton excitation using an excimer pumped tunable dye laser. A thermionic detector inside a heat pipe was used to collect the ionization products resulting from excited states. Analysis of the data for the shifts of the absorption transition to 5snd {sup 1}D{sub 2} states in strontium is presented.
Collision-induced shifts of Rydberg levels of strontium
Marafi, M.; Bhatia, K. S.; Makdisi, Y. Y.; Philips, G.
2003-05-01
Measurements of spectral line shifts induced by collisions with rare gas perturbers are reported. High Rydberg states were prepared by multiphoton excitation using an excimer pumped tunable dye laser. A thermionic detector inside a heat pipe was used to collect the ionization products resulting from excited states. Analysis of the data for the shifts of the absorption transition to 5snd 1D 2 states in strontium is presented.
Resonant quenching of Rydberg atomic states by highly polar molecules
Narits, A. A.; Mironchuk, E. S.; Lebedev, V. S.
2016-06-01
The results of theoretical studies of the resonant quenching and ion-pair formation processes induced by collisions of Rydberg atoms with highly polar molecules possessing small electron affinities are reported. We elaborate an approach for describing collisional dynamics of both processes and demonstrate the predominant role of resonant quenching channel of reaction for the destruction of Rydberg states by electron-attaching molecules. The approach is based on the solution of the coupled differential equations for the transition amplitudes between the ionic and Rydberg covalent terms of a quasimolecule formed during a collision of particles. It takes into account the possibility of the dipole-bound anion decay in the Coulomb field of the positive ionic core and generalizes previous models of charge-transfer processes involving Rydberg atoms to the cases, when the multistate Landau-Zener approaches become inapplicable. Our calculations for {{Rb}}({nl}) atom perturbed by {{{C}}}2{{{H}}}4{{SO}}3, {{CH}}2{CHCN}, {{CH}}3{{NO}}2, {{CH}}3{CN}, {{{C}}}3{{{H}}}2{{{O}}}3, and {{{C}}}3{{{H}}}4{{{O}}}3 molecules show that the curves representing the dependence of the resonant quenching cross sections on the principal quantum number n are bell-shaped with the positions of maxima being shifted towards lower values of n and the peak values, {σ }{max}({{q})}, several times higher than those for the ion-pair formation, {σ }{max}({{i})}. We obtain a simple power relation between the energy of electron affinity of a molecule and the position of maximum in n-dependence of the resonant quenching cross section. It can be used as an additional means for determining small binding energies of dipole-bound anions from the experimental data on resonant quenching of Rydberg states by highly polar molecules.
Effective Field Theory for Rydberg Polaritons
Gullans, M. J.; Thompson, J. D.; Wang, Y.; Liang, Q.-Y.; Vuletić, V.; Lukin, M. D.; Gorshkov, A. V.
2016-01-01
We develop an effective field theory (EFT) to describe the few- and many-body propagation of one dimensional Rydberg polaritons. We show that the photonic transmission through the Rydberg medium can be found by mapping the propagation problem to a non-equilibrium quench, where the role of time and space are reversed. We include effective range corrections in the EFT and show that they dominate the dynamics near scattering resonances in the presence of deep bound states. Finally, we show how the long-range nature of the Rydberg-Rydberg interactions induces strong effective N-body interactions between Rydberg polaritons. These results pave the way towards studying non-perturbative effects in quantum field theories using Rydberg polaritons. PMID:27661685
Scaling laws of Rydberg excitons
Heckötter, J.; Freitag, M.; Fröhlich, D.; Aßmann, M.; Bayer, M.; Semina, M. A.; Glazov, M. M.
2017-09-01
Rydberg atoms have attracted considerable interest due to their huge interaction among each other and with external fields. They demonstrate characteristic scaling laws in dependence on the principal quantum number n for features such as the magnetic field for level crossing or the electric field of dissociation. Recently, the observation of excitons in highly excited states has allowed studying Rydberg physics in cuprous oxide crystals. Fundamentally different insights may be expected for Rydberg excitons, as the crystal environment and associated symmetry reduction compared to vacuum give not only optical access to many more states within an exciton multiplet but also extend the Hamiltonian for describing the exciton beyond the hydrogen model. Here we study experimentally and theoretically the scaling of several parameters of Rydberg excitons with n , for some of which we indeed find laws different from those of atoms. For others we find identical scaling laws with n , even though their origin may be distinctly different from the atomic case. At zero field the energy splitting of a particular multiplet n scales as n-3 due to crystal-specific terms in the Hamiltonian, e.g., from the valence band structure. From absorption spectra in magnetic field we find for the first crossing of levels with adjacent principal quantum numbers a Br∝n-4 dependence of the resonance field strength, Br, due to the dominant paramagnetic term unlike for atoms for which the diamagnetic contribution is decisive, resulting in a Br∝n-6 dependence. By contrast, the resonance electric field strength shows a scaling as Er∝n-5 as for Rydberg atoms. Also similar to atoms with the exception of hydrogen we observe anticrossings between states belonging to multiplets with different principal quantum numbers at these resonances. The energy splittings at the avoided crossings scale roughly as n-4, again due to crystal specific features in the exciton Hamiltonian. The data also allow us to
Energy Technology Data Exchange (ETDEWEB)
Beauvoir, B. de
1996-12-15
The purpose of this work is to design a 778 nm standard laser for performing an absolute measurement of 2S-8S/D frequencies of hydrogen and deuterium atoms. This frequency calibration is based on a 5S-5D two-photon transition of the rubidium atom. Metrological performance of this laser is 10 times as good as that of He-Ne laser calibrated on iodine. It has been shown that the passage of a laser radiation through an optic fiber does not deteriorate its metrological properties. 2S-8S/8D transitions have been excited in an atomic jet by a titanium-sapphire laser. Spurious effects can shift and broaden lines. In order to prevent these effects, a theoretical line has been shaped and adjusted on experimental signals. The frequency comparison between the excitation laser and the standard laser has led to the measurement of the absolute frequency of the line concerned. The value of the Rydberg constant has been deduced: R{sub {infinity}} = 109737.3156859 (10) cm{sup -1}. The comparison of experimental data between deuterium and hydrogen has allowed us to determine the value of the Lamb shift of the 2S state of deuterium: L(2S-2P) = 1059,230 (9) MHz.
Spectral backbone of excitation transport in ultracold Rydberg gases
Scholak, Torsten; Wellens, Thomas; Buchleitner, Andreas
2014-12-01
The spectral structure underlying excitonic energy transfer in ultracold Rydberg gases is studied numerically, in the framework of random matrix theory, and via self-consistent diagrammatic techniques. Rydberg gases are made up of randomly distributed, highly polarizable atoms that interact via strong dipolar forces. Dynamics in such a system is fundamentally different from cases in which the interactions are of short range, and is ultimately determined by the spectral and eigenvector structure. In the energy levels' spacing statistics, we find evidence for a critical energy that separates delocalized eigenstates from states that are localized at pairs or clusters of atoms separated by less than the typical nearest-neighbor distance. We argue that the dipole blockade effect in Rydberg gases can be leveraged to manipulate this transition across a wide range: As the blockade radius increases, the relative weight of localized states is reduced. At the same time, the spectral statistics, in particular, the density of states and the nearest-neighbor level-spacing statistics, exhibits a transition from approximately a 1-stable Lévy to a Gaussian orthogonal ensemble. Deviations from random matrix statistics are shown to stem from correlations between interatomic interaction strengths that lead to an asymmetry of the spectral density and profoundly affect localization properties. We discuss approximations to the self-consistent Matsubara-Toyozawa locator expansion that incorporate these effects.
Quantum melting of two-component Rydberg crystals
Lan, Zhihao; Lesanovsky, Igor
2016-01-01
We investigate the quantum melting of one dimensional crystals that are realized in an atomic lattice in which ground state atoms are laser excited to two Rydberg states. We focus on a regime where both, intra- and inter-state density-density interactions as well as coherent exchange interactions contribute. We determine stable crystalline phases in the classical limit and explore their melting under quantum fluctuations introduced by the excitation laser as well as two-body exchange. We find that quantum fluctuations introduced by the laser give rise to a devil's staircase structure which one might associate with transitions in the classical limit. The melting through exchange interactions is shown to also proceed in a step-like fashion, in case of mesoscopic crystals, due to the proliferation of Rydberg spinwaves.
Energy Technology Data Exchange (ETDEWEB)
Boyé-Péronne, Séverine; Gauyacq, Dolores [Institut des Sciences Moléculaires d’Orsay, UMR 8214, CNRS and Université Paris-Sud, Bât. 210, F-91405 Orsay Cedex (France); Liévin, Jacques, E-mail: jlievin@ulb.ac.be [Service de Chimie Quantique et Photophysique, Université Libre de Bruxelles, Cpi 160/09, 50 Av. F.D. Roosevelt, B-1050 Bruxelles (Belgium)
2014-11-07
The first quantitative description of the Rydberg and valence singlet electronic states of vinylidene lying in the 0–10 eV region is performed by using large scale ab initio calculations. A deep analysis of Rydberg-valence interactions has been achieved thanks to the comprehensive information contained in the accurate Multi-Reference Configuration Interaction wavefunctions and an original population analysis highlighting the respective role played by orbital and state mixing in such interactions. The present theoretical approach is thus adequate for dealing with larger than diatomic Rydberg systems. The nine lowest singlet valence states have been optimized. Among them, some are involved in strong Rydberg-valence interactions in the region of the Rydberg state equilibrium geometry. The Rydberg states of vinylidene present a great similarity with the acetylene isomer, concerning their quantum defects and Rydberg molecular orbital character. As in acetylene, strong s-d mixing is revealed in the n = 3 s-d supercomplex. Nevertheless, unlike in acetylene, the close-energy of the two vinylidene ionic cores {sup 2}A{sub 1} and {sup 2}B{sub 1} results into two overlapped Rydberg series. These Rydberg series exhibit local perturbations when an accidental degeneracy occurs between them and results in avoided crossings. In addition, some Δl = 1 (s-p and p-d) mixings arise for some Rydberg states and are rationalized in term of electrostatic interaction from the electric dipole moment of the ionic core. The strongest dipole moment of the {sup 2}B{sub 1} cationic state also stabilizes the lowest members of the n = 3 Rydberg series converging to this excited state, as compared to the adjacent series converging toward the {sup 2}A{sub 1} ionic ground state. The overall energies of vinylidene Rydberg states lie above their acetylene counterpart. Finally, predictions for optical transitions in singlet vinylidene are suggested for further experimental spectroscopic
Morisawa, Yusuke; Yasunaga, Manaka; Sato, Harumi; Fukuda, Ryoichi; Ehara, Masahiro; Ozaki, Yukihiro
2014-10-09
Attenuated total reflection far-ultraviolet (ATR-FUV) spectra in the 145-260 nm region were measured for surfaces (thickness 50-200 nm) of various kinds of nylons in cast films to explore their electronic transitions in the FUV region. ATR-FUV spectra show two major bands near 150 and 200 nm in the surface condensed phase of nylons. Transmittance (Tr) spectra were also observed in particular for the analysis of valence excitations. Time-dependent density functional theory (TD-DFT/CAM-B3LYP) calculations were carried out using the model systems to provide the definitive assignments of their absorption spectra and to elucidate their peak shifts in several nylons, in particular, focusing on their crystal alignment structures and intermolecular hydrogen bondings. Two major bands of nylon films near 150 and 200 nm are characterized as σ-Rydberg 3p and π-π* transitions of nylons, respectively. These assignments are also coherent with those of liquid n-alkanes (n = 5-14) and liquid amides observed previously. The Rydberg transitions are delocalized over the hydrocarbon chains, while the π-π* transitions are relatively localized at the amide group. Differences in the peak positions and intensity were found in both ATR- and Tr-FUV spectra for different nylons. A red-shift of the π-π* amide band in the FUV spectra of nylon-6 and nylon-6/6 models in α-form is attributed to the crystal structure pattern and the intermolecular hydrogen bondings, which result in the different delocalization character of the π-π* transitions and transition dipole coupling.
Observation of Rydberg Series in Sodium Vapour by Two-Photon Resonant Nondegenerate Four-Wave Mixing
Institute of Scientific and Technical Information of China (English)
王延帮; 姜谦; 李隆; 米辛; 俞祖和; 傅盘铭
2001-01-01
We apply two-photon resonant nondegenerate four-wave mixing with a resonant intermediate state for the obser- vation of Rydberg states in sodium vapour. The broadening and shift of the sodium 3S- 11D transition perturbed by argon are investigated. This technique can achieve Doppler-free resolution of narrow spectral structures of Rydberg levels if lasers with narrow bandwidths are employed.
Efficient Grover search with Rydberg blockade
DEFF Research Database (Denmark)
Mølmer, Klaus; Isenhower, Larry; Saffman, Mark
2011-01-01
We present efficient methods to implement the quantum computing Grover search algorithm using the Rydberg blockade interaction. We show that simple π-pulse excitation sequences between ground and Rydberg excited states readily produce the key conditional phase shift and inversion...
Rydberg polaritons in a thermal vapor
Ripka, Fabian; Löw, Robert; Pfau, Tilman
2016-01-01
We present a pulsed four-wave mixing (FWM) scheme via a Rydberg state to create, store and retrieve collective Rydberg polaritons. The storage medium consists of a gas of thermal Rb atoms confined in a 220 {\\mu}m thick cell, which are heated above room temperature. The experimental sequence consists of a pulsed excitation of Rydberg polaritons via the D1 line, a variable delay or storage time, and a final retrieval pulse via the D2 line. The lifetime of the Rydberg polaritons is around 1.2 ns, almost entirely limited by the excitation bandwidth and the corresponding motional dephasing of the atoms. The presented scheme combined with a tightly confined atomic ensemble is a good candidate for a deterministic single-photon source, as soon as strong interactions in terms of a Rydberg blockade are added.
Millimetre wave spectroscopy of high Rydberg states
Merkt, F.; Osterwalder, A.
We have recently developed high-resolution vacuum ultraviolet laser sources and combined these with millimetre waves in double-resonance experiments to achieve a spectral resolution of up to 60 kHz in the spectra of high Rydberg states. The article describes the main features of our experimental procedure and presents studies in which we have used millimetre wave spectroscopy (a) to obtain information on the energy level structure, including the spin-orbit and hyperfine structure, of atomic Rydberg states at high principal quantum numbers n , (b) to record spectrally resolved spectra of the high Rydberg states ( n ≥100) detected in pulsed-field-ionization zero-kinetic-energy photoelectron spectra, (c) to measure stray electric fields and ion concentrations in the gas phase, (d) to test and improve the selectivity of the electric field ionization of high Rydberg states and (e) to observe for the first time the hyperfine structure in high- n , low- l molecular Rydberg states.
Rydberg EIT in High Magnetic Field
Ma, Lu; Anderson, David; Miller, Stephanie; Raithel, Georg
2016-05-01
We present progress towards an all-optical approach for measurements of strong magnetic fields using electromagnetically induced transparency (EIT) with Rydberg atoms in an atomic vapor. Rydberg EIT spectroscopy is a promising technique for the development of atom-based, calibration- and drift-free technology for high magnetic field sensing. In this effort, Rydberg EIT is employed to spectroscopically investigate the response of Rydberg atoms exposed to strong magnetic fields, in which Rydberg atoms are in the strong-field regime. In our setup, two neodymium block magnets are used to generate fields of about 0.8 Tesla, which strongly perturb the atoms. Information on the field strength and direction is obtained by a comparison of experimental spectra with calculated spectral maps. Investigations of magnetic-field inhomogeneities and other decoherence sources will be discussed.
Velasco, A. M.; Lavín, C.; Díaz-Tinoco, Manuel; Ortiz, J. V.
2017-01-01
In this work, electron-propagator methods are applied to the calculation of the ionization potential and vertical excitation energies for several Rydberg series of the CaH molecule. The present calculations cover more highly excited states than those previously reported. In particular, excitation energies for ns (n>5), np (n>5), nd (n>4) and nf Rydberg states are given. Oscillator strengths for electronic transitions involving Rydberg states of CaH, as well as photoionization cross sections for Rydberg channels, also have been determined by using the Molecular Quantum Defect Orbital approach. Good agreement has been found with the scarce comparative data that are available for oscillator strengths. To our knowledge, predictions of photoionization cross sections from the outermost orbital of CaH are made here for the first time. A Cooper minimum and mixed atomic orbital character in some of the Dyson orbitals are among the novel features of these present calculations.
Multichannel long-range Rydberg molecules
Eiles, Matthew T
2015-01-01
A generalized class of ultra-long-range Rydberg molecules is proposed which consist of a multichannel Rydberg atom whose outermost electron creates a chemical bond with a distant ground state atom. Such multichannel Rydberg molecules exhibit favorable properties for laser excitation, because states exist where the quantum defect varies strongly with the principal quantum number. The resulting occurrence of near degeneracies with states of high orbital angular momentum promotes the admixture of low $l$ into the high $l$ deeply bound `trilobite' molecule states, thereby circumventing the usual difficulty posed by electric dipole selection rules. Such states also can exhibit multi-scale binding possibilities that could present novel options for quantum manipulation.
Effects of molecular resonances on Rydberg blockade
Derevianko, Andrei; Topcu, Turker; Kroeze, Ronen M; Lukin, Mikhail D
2015-01-01
We study the effect of resonances associated with complex molecular interaction of Rydberg atoms on Rydberg blockade. We show that densely-spaced molecular potentials between doubly-excited atomic pairs become unavoidably resonant with the optical excitation at short interatomic separations. Such molecular resonances limit the coherent control of individual excitations in Rydberg blockade. As an illustration, we compute the molecular interaction potentials of Rb atoms near the $100s$ states asymptote to characterize such detrimental molecular resonances, determine the resonant loss rate to molecules and inhomogeneous light shifts. Techniques to avoid the undesired effect of molecular resonances are discussed.
Multi channel quantum defect theory calculations of the Rydberg spectra of HCO
Douguet, Nicolas; Orel, Ann
2014-05-01
We present a first-principles theoretical study of the photoionization spectra of vibrationally autoionizing Rydberg states converging to excited states of HCO+. The clamped-nuclei scattering matrix, quantum defects parameters and transition dipole moments are explicitly calculated using the complex variational Kohn technique. The multi-channel quantum defect theory and vibrational frame transformation are then used to calculate the absorption spectrum. The results are compared with experimental data on double-resonance spectroscopy of the high Rydberg states of formyl radical. This work is supported by the DOE Office of Basic Energy Science and the National Science Foundation, Grant No's PHY-10-68785 and PHY-11-60611.
Dipolar Rydberg-atom gas prepared by adiabatic passage through an avoided crossing
Wang, Limei; Zhang, Linjie; Li, Changyong; Yang, Yonggang; Zhao, Jianming; Raithel, Georg; Jia, Suotang
2015-01-01
The passage of cold cesium 49S$_{1/2}$ Rydberg atoms through an electric-field-induced multi-level avoided crossing with nearby hydrogen-like Rydberg levels is employed to prepare a cold, dipolar Rydberg atom gas. When the electric field is ramped through the avoided crossing on time scales on the order of 100~ns or slower, the 49S$_{1/2}$ population adiabatically transitions into high-\\emph{l} Rydberg Stark states. The adiabatic state transformation results in a cold gas of Rydberg atoms with large electric dipole moments. After a waiting time of about $1~\\mu$s and at sufficient atom density, the adiabatically transformed highly dipolar atoms become undetectable, enabling us to discern adiabatic from diabatic passage behavior through the avoided crossing. We attribute the state-selectivity to $m$-mixing collisions between the dipolar atoms. The data interpretation is supported by numerical simulations of the passage dynamics and of binary $m$-mixing collisions.
Sheng, Jiteng; Chao, Yuanxi; Kumar, Santosh; Fan, Haoquan; Sedlacek, Jonathon; Shaffer, James P.
2017-09-01
We present an experimental study of cavity-assisted Rydberg-atom electromagnetically induced transparency (EIT) using a high-finesse optical cavity (F ˜28 000 ). Rydberg atoms are excited via a two-photon transition in a ladder-type EIT configuration. A three-peak structure of the cavity transmission spectrum is observed when Rydberg EIT is generated inside the cavity. The two symmetrically spaced side peaks are caused by bright-state polaritons, while the central peak corresponds to a dark-state polariton. Anticrossing phenomena and the effects of mirror adsorbate electric fields are studied under different experimental conditions. We determine a lower bound on the coherence time for the system of 7.26 ±0.06 μ s , most likely limited by laser dephasing. The cavity-Rydberg EIT system can be useful for single-photon generation using the Rydberg blockade effect, studying many-body physics, and generating novel quantum states among many other applications.
Nguyen, Thanh Long; Celistrino Teixeira, Raul; Hermann Avigliano, Carla; Cantat Moltrecht, Tigrane; Raimond, Jean Michel; Haroche, Serge; Gleyzes, Sebastiens; Brune, Michel
2016-05-01
Dipole-dipole interactions between Rydberg atoms are a flourishing tool for quantum information processing and for quantum simulation of complex many-body problems. Microwave spectroscopy of a dense Rydberg gas trapped close to a superconducting atom chip in the strong dipole blockade regime reveals directly the many-body atomic interaction spectrum. We present here a direct measurement of the interaction energy distribution in the strong dipole blockade regime, based on microwave spectroscopy. We first apply this method to the observation of the excitation dynamics of the Rydberg gas, conditioned by dipole-dipole interactions, in either the strong blockade regime or the so-called facilitation regime. We also observe with this method the atomic cloud expansion driven by the repulsive Van der Waals interaction after excitation. This measurement, in good agreement with Monte Carlo simulations of the excitation process and of the cloud dynamics, reveals the limits of the frozen gas approximation. This method can help investigate self-organization and dynamical phase transitions in Rydberg-atom based quantum simulators. This study thus opens a promising route for quantum simulation of many-body systems and quantum information transport in chains of strongly interacting Rydberg atom.
Role of Rydberg states in the photostability of heterocyclic dimers: the case of pyrazole dimer.
Zilberg, Shmuel; Haas, Yehuda
2012-11-26
A new route for the nonradiative decay of photoexcited, H-bonded, nitrogen-containing, heterocyclic dimers is offered and exemplified by a study of the pyrazole dimer. In some of these systems the N(3s) Rydberg state is the lowest excited singlet state. This state is formed by direct light absorption or by nonradiative transition from the allowed ππ* state. An isomer of this Rydberg state is formed by H atom transfer to the other component of the dimer. The newly formed H-bonded radical pair is composed of two radicals (a H-adduct of pyrazole, a heterocyclic analogue of the NH(4) radical) and the pyrazolium π-radical. It is calculated to have a shallow local minimum and is the lowest point on the PES of the H-pyrazole/pyrazolium radical pair. This species can cross back to the ground state of the original dimer through a relatively small energy gap and compete with the H-atom loss channel, known for the monomer. In both Rydberg dimers, an electron occupies a Rydberg orbital centered mostly on one of the two components of the dimer. This Rydberg Center Shift (RCS) mechanism, proposed earlier (Zilberg, S.; Kahan, A.; Haas, Y. Phys. Chem. Chem. Phys. 2012, 14, 8836), leads to deactivation of the electronically excited dimer while keeping it intact. It, thus, may explain the high photostability of the pyrazole dimer as well as other heterocyclic dimers.
Strong coupling of Rydberg atoms and surface phonon polaritons on piezoelectric superlattices
Sheng, Jiteng; Shaffer, James P
2016-01-01
We propose a hybrid quantum system where the strong coupling regime can be achieved between a Rydberg atomic ensemble and propagating surface phonon polaritons on a piezoelectric superlattice. By exploiting the large electric dipole moment and long lifetime of Rydberg atoms as well as tightly confined surface phonon polariton modes, it is possible to achieve a coupling constant far exceeding the relevant decay rates. The frequency of the surface mode can be selected so it is resonant with a Rydberg transition by engineering the piezoelectric superlattice. We describe a way to observe the Rabi splitting associated with the strong coupling regime under realistic experimental conditions. The system can be viewed as a new type of optomechanical system.
Detrimental adsorbate fields in experiments with cold Rydberg gases near surfaces
Hattermann, H; Karlewski, F; Jessen, F; Cano, D; Fortágh, J
2012-01-01
We observe the shift of Rydberg levels of rubidium close to a copper surface when atomic clouds are repeatedly deposited on it. We measure transition frequencies of rubidium to S and D Rydberg states with principal quantum numbers n between 31 and 48 using the technique of electromagnetically induced transparency. The spectroscopic measurement shows a strong increase of electric fields towards the surface that evolves with the deposition of atoms. Starting with a clean surface, we measure the evolution of electrostatic fields in the range between 30 and 300 \\mum from the surface. We find that after the deposition of a few hundred atomic clouds, each containing ~10^6 atoms, the field of adsorbates reaches 1 V/cm for a distance of 30 \\mum from the surface. This evolution of the electrostatic field sets serious limitations on cavity QED experiments proposed for Rydberg atoms on atom chips.
Detrimental adsorbate fields in experiments with cold Rydberg gases near surfaces
Hattermann, H.; Mack, M.; Karlewski, F.; Jessen, F.; Cano, D.; Fortágh, J.
2012-08-01
We observe the shift of Rydberg levels of rubidium close to a copper surface when atomic clouds are repeatedly deposited on it. We measure transition frequencies of rubidium to S and D Rydberg states with principal quantum numbers n between 31 and 48 using the technique of electromagnetically induced transparency. The spectroscopic measurement shows a strong increase of electric fields towards the surface that evolves with the deposition of atoms. Starting with a clean surface, we measure the evolution of electrostatic fields in the range between 30 and 300 μm from the surface. We find that after the deposition of a few hundred atomic clouds, each containing ˜106 atoms, the field of adsorbates reaches 1 V/cm for a distance of 30 μm from the surface. This evolution of the electrostatic field sets serious limitations on cavity QED experiments proposed for Rydberg atoms on atom chips.
The Spectral Backbone of Excitation Transport in Ultra-Cold Rydberg Gases
Scholak, Torsten; Buchleitner, Andreas
2014-01-01
The spectral structure underlying excitonic energy transfer in ultra-cold Rydberg gases is studied numerically, in the framework of random matrix theory, and via self-consistent diagrammatic techniques. Rydberg gases are made up of randomly distributed, highly polarizable atoms that interact via strong dipolar forces. Dynamics in such a system is fundamentally different from cases in which the interactions are of short range, and is ultimately determined by the spectral and eigenvector structure. In the energy levels' spacing statistics, we find evidence for a critical energy that separates delocalized eigenstates from states that are localized at pairs or clusters of atoms separated by less than the typical nearest-neighbor distance. We argue that the dipole blockade effect in Rydberg gases can be leveraged to manipulate this transition across a wide range: As the blockade radius increases, the relative weight of localized states is reduced. At the same time, the spectral statistics -- in particular, the den...
Tailoring interactions with light and Rydberg states
Pohl, Thomas
2016-05-01
By virtue of their large polarizability, ultracold Rydberg atoms hold promise for exploring long-range interacting quantum systems. In this talk, I will describe different ideas to generate tunable interactions between ultracold atoms via virtual excitation of Rydberg states. This includes finite-range interactions in quantum gases and various kinds of spin interactions in synthetic quantum magnets formed by atomic lattices. Recent experimental results on both approaches will also be discussed.
Quantum Manybody Physics with Rydberg Polaritons
2016-06-22
AFRL-AFOSR-VA-TR-2017-0033 Quantum Manybody Physics with Rydberg Polaritons Jonathan Simon UNIVERSITY OF CHICAGO THE 5801 S ELLIS AVE CHICAGO, IL...abstract is to be limited. DISTRIBUTION A: Distribution approved for public release. Title: Quantum Manybody Physics with Rydberg Polaritons AFOSR AWARD...developed. In conjunction with synthetic magnetic fields generated through non-planar cavities, we are now poised to explore fractional quantum hall physics
Efficient Multiparticle Entanglement via Asymmetric Rydberg Blockade
DEFF Research Database (Denmark)
Saffman, Mark; Mølmer, Klaus
2009-01-01
We present an efficient method for producing N particle entangled states using Rydberg blockade interactions. Optical excitation of Rydberg states that interact weakly, yet have a strong coupling to a second control state is used to achieve state dependent qubit rotations in small ensembles....... On the basis of quantitative calculations, we predict that an entangled quantum superposition state of eight atoms can be produced with a fidelity of 84% in cold Rb atoms....
Storage enhanced nonlinearities in a cold atomic Rydberg ensemble
Distante, Emanuele; Cristiani, Matteo; Paredes-Barato, David; de Riedmatten, Hugues
2016-01-01
The combination of electromagnetically induced transparency (EIT) with the nonlinear interaction between Rydberg atoms provides an effective interaction between photons. In this paper, we investigate the storage of optical pulses as collective Rydberg atomic excitations in a cold atomic ensemble. By measuring the dynamics of the stored Rydberg polaritons, we experimentally demonstrate that storing a probe pulse as Rydberg polaritons strongly enhances the Rydberg mediated interaction compared to the slow propagation case. We show that the process is characterized by two time scales. At short storage times, we observe a strong enhancement of the interaction due to the reduction of the Rydberg polariton group velocity down to zero. For longer storage times, we observe a further, weaker enhancement dominated by Rydberg induced dephasing of the multiparticle components of the state. In this regime, we observe a non-linear dependence of the Rydberg polariton coherence time with the input photon number. Our results ...
Production of high-n strontium Rydberg atoms
Ye, S.; Zhang, X.; Killian, T. C.; Dunning, F. B.; Hiller, M.; Yoshida, S.; Burgdörfer, J.
2014-04-01
The photoexcitation of strontium Rydberg atoms with n ~ 300 is being examined using a crossed laser-atom beam approach to enable study of quasi-stable two-electron excited states and of strongly-coupled Rydberg systems.
Excitation and ionization of hydrogen Rydberg states in a plasma
Energy Technology Data Exchange (ETDEWEB)
Glab, W.; Nayfeh, M.H.
1982-08-01
Hydrogen Rydberg states in a hydrogen plasma are optically excited from the plasma-excited n = 2 state. Photoionization and optogalvanic, which are due to electron-impact ionization and other collisional processes, are used to monitor the Rydberg states. This process may be used to study collisional ionization of the Rydberg states.
Excitation and ionization of hydrogen Rydberg states in a plasma.
Glab, W; Nayfeh, M H
1982-08-01
Hydrogen Rydberg states in a hydrogen plasma are optically excited from the plasma-excited n = 2 state. Photoionization and optogalvanic ionization, which is due to electron-impact ionization and other collisional processes, are used to monitor the Rydberg states. This process may be used to study collisional ionization of the Rydberg states.
Correlated Photon Dynamics in Dissipative Rydberg Media
Zeuthen, Emil; Gullans, Michael J.; Maghrebi, Mohammad F.; Gorshkov, Alexey V.
2017-07-01
Rydberg blockade physics in optically dense atomic media under the conditions of electromagnetically induced transparency (EIT) leads to strong dissipative interactions between single photons. We introduce a new approach to analyzing this challenging many-body problem in the limit of a large optical depth per blockade radius. In our approach, we separate the single-polariton EIT physics from Rydberg-Rydberg interactions in a serialized manner while using a hard-sphere model for the latter, thus capturing the dualistic particle-wave nature of light as it manifests itself in dissipative Rydberg-EIT media. Using this approach, we analyze the saturation behavior of the transmission through one-dimensional Rydberg-EIT media in the regime of nonperturbative dissipative interactions relevant to current experiments. Our model is able to capture the many-body dynamics of bright, coherent pulses through these strongly interacting media. We compare our model with available experimental data in this regime and find good agreement. We also analyze a scheme for generating regular trains of single photons from continuous-wave input and derive its scaling behavior in the presence of imperfect single-photon EIT.
Effective dynamics of strongly dissipative Rydberg gases
Marcuzzi, M; Olmos, B; Lesanovsky, I
2014-01-01
We investigate the evolution of interacting Rydberg gases in the limit of strong noise and dissipation. Starting from a description in terms of a Markovian quantum master equation we derive effective equations of motion that govern the dynamics on a "coarse-grained" timescale where fast dissipative degrees of freedom have been adiabatically eliminated. Specifically, we consider two scenarios which are of relevance for current theoretical and experimental studies --- Rydberg atoms in a two-level (spin) approximation subject to strong dephasing noise as well as Rydberg atoms under so-called electromagnetically induced transparency (EIT) conditions and fast radiative decay. In the former case we find that the effective dynamics is described by classical rate equations up to second order in an appropriate perturbative expansion. This drastically reduces the computational complexity of numerical simulations in comparison to the full quantum master equation. When accounting for the fourth order correction in this e...
Observation of pendular butterfly Rydberg molecules
Niederprüm, Thomas; Eichert, Tanita; Lippe, Carsten; Pérez-Ríos, Jesús; Greene, Chris H; Ott, Herwig
2016-01-01
Obtaining full control over the internal and external quantum states of molecules is the central goal of ultracold chemistry and allows for the study of coherent molecular dynamics, collisions and tests of fundamental laws of physics. When the molecules additionally have a permanent electric dipole moment, the study of dipolar quantum gases and spin-systems with long-range interactions as well as applications in quantum information processing are possible. Rydberg molecules constitute a class of exotic molecules, which are bound by the interaction between the Rydberg electron and the ground state atom. They exhibit extreme bond lengths of hundreds of Bohr radii and giant permanent dipole moments in the kilo-Debye range. A special type with exceptional properties are the so-called butterfly molecules, whose electron density resembles the shape of a butterfly. Here, we report on the photoassociation of butterfly Rydberg molecules and their orientation in a weak electric field. Starting from a Bose-Einstein cond...
Rydberg optical Feshbach resonances in cold gases
Sándor, Nóra; Julienne, Paul S; Pupillo, Guido
2016-01-01
We propose a novel scheme to efficiently tune the scattering length of two colliding ground-state atoms by off-resonantly coupling the scattering-state to an excited Rydberg-molecular state using laser light. For the s-wave scattering of two colliding ${^{87}}\\mathrm{Rb}$ atoms, we demonstrate that the effective optical length and pole strength of this Rydberg optical Feshbach resonance can be tuned over several orders of magnitude, while incoherent processes and losses are minimised. Given the ubiquity of Rydberg molecular states, this technique should be generally applicable to homo-nuclear atomic pairs as well as to atomic mixtures with s-wave (or even p-wave) scattering.
Long-range interactions between Rydberg atoms
Deiglmayr, Johannes
2016-10-01
We present an overview over theoretical models to describe adiabatic potential-energy curves, experimental excitation spectra, and electronic and nuclear dynamics in interacting Rydberg-atom pairs at large internuclear separations. The potential-energy curves and molecular wavefunctions are determined from the multipole expansion of the static Coulomb interaction which is evaluated numerically in a product basis of atomic orbitals. The convergence of this approach both in the truncation of the multipole expansion as well as in the size of the product basis is discussed, and the comparison of simulated excitation spectra is established as a useful criterium to test the convergence of the calculation. We finally discuss the dynamics of electronic and nuclear motions of pairs of Rydberg atoms, focusing on the stability of ultralong range Rydberg molecules with respect to autoionization.
Interaction of Helium Rydberg State Molecules with Dense Helium.
Bonifaci, Nelly; Li, Zhiling; Eloranta, Jussi; Fiedler, Steven L
2016-11-17
The interaction potentials of the He2(*) excimer, in the a(3)Σu, b(3)Πg, c(3)Σg, and d(3)Σu electronic states with a ground state helium atom are presented. The symmetry of the interaction potentials closely follows the excimer Rydberg electron density with pronounced short-range minima appearing along the nodal planes of the Rydberg orbital. In such cases, a combination of the electrostatic short-range attraction combined with Pauli repulsion leads to the appearance of unusual long-range maxima in the potentials. Bosonic density functional calculations show that the (3)d state excimer resides in a localized solvation bubble in dense helium at 4.5 K, with radii varying from 12.7 Å at 0.1 MPa to 10.8 Å at 2.4 MPa. The calculated (3)d → (3)b pressure-induced fluorescence band shifts are in good agreement with experimental results determined by application of corona discharge. The magnitude of the spectral shifts indicate that the observed He2(*) molecules emit from dense helium whereas the corresponding fluorescence signal from the discharge zone appears quenched. This implies that fluorescence spectroscopy involving this electronic transition can only be used to probe the state of the surrounding medium rather than the discharge zone itself.
Spontaneous avalanche ionization of a strongly blockaded Rydberg gas
Robert-de-Saint-Vincent, M; Schempp, H; Günter, G; Whitlock, S; Weidemüller, M
2012-01-01
We report the sudden and spontaneous evolution of an initially correlated gas of repulsively interacting Rydberg atoms to an ultracold plasma. Under continuous laser coupling we create a Rydberg ensemble in the strong blockade regime, which at longer times undergoes an ionization avalanche. By combining optical imaging and ion detection, we access the full information on the dynamical evolution of the system, including the rapid increase in the number of ions and a sudden depletion of the Rydberg and ground state densities. Rydberg-Rydberg interactions are observed to strongly affect the dynamics of plasma formation. Using a coupled rate-equation model to describe our data, we extract the average energy of electrons trapped in the plasma, and an effective cross-section for ionizing collisions between Rydberg atoms and atoms in low-lying states. Our results suggest that the initial correlations of the Rydberg ensemble should persist through the avalanche. This would provide the means to overcome disorder-induc...
Locke, Clayton R.; Kobayashi, Tohru; Midorikawa, Katsumi
2017-01-01
Odd-mass-selective ionization of palladium for purposes of resource recycling and management of long-lived fission products can be achieved by exploiting transition selection rules in a well-established three-step excitation process. In this conventional scheme, circularly polarized lasers of the same handedness excite isotopes via two intermediate 2D5/2 core states, and a third laser is then used for ionization via autoionizing Rydberg states. We propose an alternative excitation scheme via intermediate 2D3/2 core states before the autoionizing Rydberg state, improving ionization efficiency by over 130 times. We confirm high selectivity and measure odd-mass isotopes of >99.7(3)% of the total ionized product. We have identified and measured the relative ionization efficiency of the series of Rydberg states that converge to upper ionization limit of the 4 d 9(2D3/2) level, and identify the most efficient excitation is via the Rydberg state at 67668.18(10) cm-1.
Linear Atom Guides: Guiding Rydberg Atoms and Progress Toward an Atom Laser
Traxler, Mallory A.
In this thesis, I explore a variety of experiments within linear, two-wire, magnetic atom guides. Experiments include guiding of Rydberg atoms; transferring between states while keeping the atoms contained within the guide; and designing, constructing, and testing a new experimental apparatus. The ultimate goal of the atom guiding experiments is to develop a continuous atom laser. The guiding of 87Rb 59D5/2 Rydberg atoms is demonstrated. The evolution of the atoms is driven by the combined effects of dipole forces acting on the center-of-mass degree of freedom as well as internal-state transitions. Time delayed microwave and state-selective field ionization, along with ion detection, are used to investigate the evolution of the internal-state distribution as well as the Rydberg atom motion while traversing the guide. The observed decay time of the guided-atom signal is about five times that of the initial state. A population transfer between Rydberg states contributes to this lengthened lifetime, and also broadens the observed field ionization spectrum. The population transfer is attributed to thermal transitions and, to a lesser extent, initial state-mixing due to Rydberg-Rydberg collisions. Characteristic signatures in ion time-of-flight signals and spatially resolved images of ion distributions, which result from the coupled internal-state and center-of-mass dynamics, are discussed. Some groups have used a scheme to make BECs where atoms are optically pumped from one reservoir trap to a final state trap, irreversibly transferring those atoms from one trap to the other. In this context, transfer from one guided ground state to another is studied. In our setup, before the atoms enter the guide, they are pumped into the | F = 1, mF = --1> state. Using two repumpers, one tuned to the F = 1 → F' = 0 transition (R10) and the other tuned to the F = 1 → F' = 2 transition (R12), the atoms are pumped between these guided states. Magnetic reflections within the guide
Kondo, Jorge M; Guttridge, Alex; Wade, Christopher G; De Melo, Natalia R; Adams, Charles S; Weatherill, Kevin J
2015-01-01
We report on the observation of Electromagnetically Induced Transparency (EIT) and Absorption (EIA) of highly-excited Rydberg states in thermal Cs vapor using a 4-step excitation scheme. The advantage of this 4-step scheme is that the final transition to the Rydberg state has a large dipole moment and one can achieve similar Rabi frequencies to 2 or 3 step excitation schemes using two orders of magnitude less laser power. Consequently each step is driven by a relatively low power infra-red diode laser opening up the prospect for new applications. The observed lineshapes are in good agreement with simulations based on multilevel optical Bloch equations.
Collisions of Rydberg Atoms with Charged Particles
MacAdam, Keith B.
2000-10-01
The long range of Coulomb interactions, together with the large size, long radiative lifetimes and high state densities of highly excited Rydberg atoms, results in inelastic collision cross sections of prodigious size -- often large enough to outweigh small number densities in astrophysica and cool laboratory plasmas -- and in other unusual features. This talk will provide: (a) a brief survey of the significant features of collisions between electron or positive ions and state-selected Rydberg atoms and of recent experiments( O. Makarov and K.B. MacAdam, Phys. Rev. A 60), 2131-8 (1999); and K.B. MacAdam, J.C. Day and D.M. Homan, Comm. At. Mol. Phys./Comm. Mod. Phys. 1(2), Part D, 57-73 (1999). to investigate them; (b) an introduction to some of the special techniques that have been developed(J.L. Horn, D.M. Homan, C.S. Hwang, W.L. Fuqua III and K.B. MacAdam, Rev. Sci. Instrum. 69), 4086-93 (1998). for preparation, manipulation and detection of Rydberg atoms; and (c) a glimpse at new directions in Rydberg atom collision research.
Anisotropic Interactions between Cold Rydberg Atoms
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
Storage Enhanced Nonlinearities in a Cold Atomic Rydberg Ensemble.
Distante, E; Padrón-Brito, A; Cristiani, M; Paredes-Barato, D; de Riedmatten, H
2016-09-09
The combination of electromagnetically induced transparency with the nonlinear interaction between Rydberg atoms provides an effective interaction between photons. In this Letter, we investigate the storage of optical pulses as collective Rydberg atomic excitations in a cold atomic ensemble. By measuring the dynamics of the stored Rydberg polaritons, we experimentally demonstrate that storing a probe pulse as Rydberg polaritons strongly enhances the Rydberg mediated interaction compared to the slow propagation case. We show that the process is characterized by two time scales. At short storage times, we observe a strong enhancement of the interaction due to the reduction of the Rydberg polariton group velocity down to 0. For longer storage times, we observe a further, weaker enhancement dominated by Rydberg induced dephasing of the multiparticle components of the state. In this regime, we observe a nonlinear dependence of the Rydberg polariton coherence time with the input photon number. Our results have direct consequences in Rydberg quantum optics and may enable the test of new theories of strongly interacting Rydberg systems.
Storage Enhanced Nonlinearities in a Cold Atomic Rydberg Ensemble
Distante, E.; Padrón-Brito, A.; Cristiani, M.; Paredes-Barato, D.; de Riedmatten, H.
2016-09-01
The combination of electromagnetically induced transparency with the nonlinear interaction between Rydberg atoms provides an effective interaction between photons. In this Letter, we investigate the storage of optical pulses as collective Rydberg atomic excitations in a cold atomic ensemble. By measuring the dynamics of the stored Rydberg polaritons, we experimentally demonstrate that storing a probe pulse as Rydberg polaritons strongly enhances the Rydberg mediated interaction compared to the slow propagation case. We show that the process is characterized by two time scales. At short storage times, we observe a strong enhancement of the interaction due to the reduction of the Rydberg polariton group velocity down to 0. For longer storage times, we observe a further, weaker enhancement dominated by Rydberg induced dephasing of the multiparticle components of the state. In this regime, we observe a nonlinear dependence of the Rydberg polariton coherence time with the input photon number. Our results have direct consequences in Rydberg quantum optics and may enable the test of new theories of strongly interacting Rydberg systems.
Stark spectrum of barium in highly excited Rydberg states
Institute of Scientific and Technical Information of China (English)
Yang Hai-Feng; Gao Wei; Cheng Hong; Liu Xiao-Jun; Liu Hong-Ping
2013-01-01
We present observations of Stark spectra of barium in highly excited Rydberg states in the energy region around n =35.The one-photon excitation concerns the π transition.The observed Stark spectra at electric fields ranging from 0 to 60 V·cm-1 are well explained by the diagonalization of the Hamiltonian incorporating the core effects.From the Stark maps,the anti-crossings between energy levels are identified experimentally and theoretically.The time of flight spectra at the specified Stark states are recorded,where the deceleration and acceleration of barium atoms are observed.This is very consistent with the prediction derived from the Stark maps from the point of view of energy conservation.
Charged oscillator quantum state generation with Rydberg atoms
Stevenson, Robin; Hofferberth, Sebastian; Lesanovsky, Igor
2016-01-01
We explore the possibility of engineering quantum states of a charged mechanical oscillator by coupling it to a stream of atoms in superpositions of high-lying Rydberg states. Our scheme relies on the driving of a two-phonon resonance within the oscillator by coupling it to an atomic two-photon transition. This approach effectuates a controllable open system dynamics on the oscillator that permits the creation of squeezed and other non-classical states. We show that these features are robust to thermal noise arising from a coupling of the oscillator with the environment. The possibility to create non-trivial quantum states of mechanical systems, provided by the proposed setup, is central to applications such as sensing and metrology and moreover allows the exploration of fundamental questions concerning the boundary between classical and quantum mechanical descriptions of macroscopic objects.
Cavity polaritons with Rydberg blockade and long-range interactions
Litinskaya, Marina; Pupillo, Guido
2016-01-01
We study interactions between polaritons, arising when photons strongly couple to collective excitations in an array of two-level atoms trapped in an optical lattice inside a cavity. We consider two types of interactions between atoms: Dipolar forces and atomic saturability, which ranges from hard-core repulsion to Rydberg blockade. We show that, in spite of the underlying repulsion in the subsystem of atomic excitations, saturability induces a broadband bunching of photons for two-polariton scattering states. We interpret this bunching as a result of interference, and trace it back to the mismatch of the quantization volumes for atomic excitations and photons. We examine also bound bipolaritonic states: These include states created by dipolar forces, as well as a gap bipolariton, which forms solely due to saturability effects in the atomic transition. Both types of bound states exhibit strong bunching in the photonic component. We discuss the dependence of bunching on experimentally relevant parameters.
Experimental Research of Spontaneous Evolution from Ultracold Rydberg Atoms to Plasma
Institute of Scientific and Technical Information of China (English)
ZHANG Lin-Jie; FENG Zhi-Gang; LI An-Ling; ZHAO Jian-Ming; LI Chang-Yong; JIA Suo-Tang
2008-01-01
@@ The spontaneous evolution from ultracold Rydberg atoms to plasma is investigated in a caesium MOT by using the method of field ionization. The plasma transferred from atoms in different Rydberg states (n = 22-32) are obtained experimentally. Dependence of the threshold time of evolving to plasma and the threshold number of initial Rydberg atoms on the principal quantum number of initial Rydberg states is studied. The experimental results are in agreement with hot-cold Rydberg-Rydberg atom collision ionization theory.
Radiation trapping in a dense cold Rydberg gas
Sadler, D P; Boddy, D; Bounds, A D; Keegan, N C; Lochead, G; Jones, M P A; Olmos, B
2016-01-01
Cold atomic gases resonantly excited to Rydberg states can exhibit strong optical nonlinearity at the single photon level. We observe that in such samples radiation trapping leads to an additional mechanism for Rydberg excitation. Conversely we demonstrate that Rydberg excitation provides a novel in situ probe of the spectral, statistical, temporal and spatial properties of the trapped re-scattered light. We also show that absorption can lead to an excitation saturation that mimics the Rydberg blockade effect. Collective effects due to multiple scattering may co-exist with co-operative effects due to long-range interactions between the Rydberg atoms, adding a new dimension to quantum optics experiments with cold Rydberg gases.
A Laser Stabilization System for Rydberg Atom Physics
2015-09-06
A Laser Stabilization System for Rydberg Atom Physics We purchased 2 dual wavelength ultrastable ultralow expansion glass cavities along with optics...term locking could be achieved for 2 photon Rydberg atom excitation. Both systems were offset locked using a high bandwidth resonant electro-optic...Rydberg Atom Physics Report Title We purchased 2 dual wavelength ultrastable ultralow expansion glass cavities along with optics and electronics to
Intrication de deux atomes en utilisant le blocage de Rydberg
Gaëtan, A.
2010-12-01
Considérons un système quantique constitué de deux sous-systèmes : on dit qu'il est dans un état intriqué s'il existe des corrélations quantiques entre les états de ces derniers. La compréhension et la mise en œuvre d'états intriqués ont de nombreuses applications (métrologie quantique, étude des systèmes fortement corrélés, traitement quantique de l'information, etc.) et constituent le contexte général de ce travail de thèse. Plus en détail, nous démontrons la réalisation d'un état intriqué de deux atomes neutres piégés indépendamment. Pour cela, nous exploitons le phénomène de blocage de Rydberg : lorsqu'on essaie d'exciter simultanément deux atomes séparés de quelques micromètres vers un état de Rydberg donné, la forte interaction entre atomes de Rydberg peut empêcher cette excitation simultanée. Dans ce cas, seul un des deux atomes est excité et l'on génère ainsi des corrélations quantiques entre les états des deux atomes, c'est-à-dire de l'intrication. Dans notre expérience, deux atomes de 87Rb dans l'état fondamental 5S1/2 sont piégés chacun dans une pince optique microscopique, à une distance relative de 4 micromètres. En réalisant des transitions entre l'état 5S1/2 et l'état de Rydberg 58D3/2 par des transitions à deux photons, nous obtenons un état intriqué des deux atomes dans les sous-niveaux |5S1/2, f = 1, mf = 1> et |5S1/2, f = 2, mf = 2>. Afin de quantifier l'intrication, nous mesurons la fidélité par rapport à l'état-cible en réalisant des transitions Raman entre ces deux sous-niveaux. La fidélité des paires d'atomes présentes à la fin de l'expérience est supérieure à la valeur seuil de 0,5, ce qui prouve la création d'un état intriqué.
Ultralong-range triatomic Rydberg molecules in an electric field
Fernández, Javier Aguilera; González-Férez, Rosario
2016-01-01
We investigate the electronic structure of a triatomic Rydberg molecule formed by a Rydberg atom and two neutral ground-state atoms. Taking into account the $s$-wave and $p$-wave interactions we perform electronic structure calculations and analyze the adiabatic electronic potentials evolving from the Rb$(n=35, l\\ge 3)$ Rydberg degenerate manifold. We hereby focus on three different classes of geometries of the Rydberg molecules, including symmetric, asymmetric and planar configurations. The metamorphosis of these potential energy surfaces in the presence of an external electric field is explored.
Condensate losses and oscillations induced by Rydberg atoms
Karpiuk, Tomasz; Rzążewski, Kazimierz; Gaj, Anita; Krupp, Alexander T; Löw, Robert; Hofferberth, Sebastian; Pfau, Tilman
2016-01-01
We numerically analyze the impact of a single Rydberg electron onto a Bose-Einstein condensate. Both $S-$ and $D-$ Rydberg states are studied. The radial size of $S-$ and $D-$states are comparable, hence the only difference is due to the angular dependence of the wavefunctions. We find the atom losses in the condensate after the excitation of a sequence of Rydberg atoms. Additionally, we investigate the mechanical effect in which the Rydberg atoms force the condensate to oscillate. Our numerical analysis is based on the classical fields approximation. Finally, we compare numerical results to experimental data.
Condensate losses and oscillations induced by Rydberg atoms
Karpiuk, Tomasz; Brewczyk, Mirosław; Rzążewski, Kazimierz; Gaj, Anita; Krupp, Alexander T.; Löw, Robert; Hofferberth, Sebastian; Pfau, Tilman
2017-03-01
We numerically analyze the impact of a single Rydberg electron onto a Bose–Einstein condensate. Both S- and D-Rydberg states are studied. The radial size of S- and D-states are comparable, hence the only difference is due to the angular dependence of the wavefunctions. We find the atom losses in the condensate after the excitation of a sequence of Rydberg atoms. Additionally, we investigate the mechanical effect in which the Rydberg atoms force the condensate to oscillate. Our numerical analysis is based on the classical fields approximation. Finally, we compare numerical results to experimental data.
Ultracold Long-Range Rydberg Molecules with Complex Multichannel Spectra
Eiles, Matthew; Greene, Chris
2016-05-01
A generalized class of exotic long-range Rydberg molecules consisting of a multichannel Rydberg atom bound to a distant ground state atom by the Rydberg electron is predicted. These molecules are characterized by the rich physics provided by the strongly perturbed multichannel Rydberg spectra of divalent atoms, in contrast to the regular Rydberg series of the alkali atoms used to form Rydberg molecules to date. These multichannel Rydberg molecules exhibit favorable properties for laser excitation, because states exist where the quantum defect varies strongly with the principal quantum number n. In particular, the nd Rydberg state of calcium becomes nearly degenerate with states of high orbital angular momentum over the range 17 molecular states are predicted to occur in the low- J states of silicon, which are strongly perturbed due to channel interactions between Rydberg series leading to the spin-orbit split ionization thresholds. These interactions manifest themselves in potential curves exhibiting two distinct length scales, providing novel opportunities for quantum manipulation. Supported in part by the National Science Foundation under Grant No. PHY-1306905.
A single strontium Rydberg ion confined in a Paul trap
Higgins, Gerard; Pokorny, Fabian; Zhang, Chi; Kress, Florian; Maier, Christine; Haag, Johannes; Bodart, Quentin; Lesanovsky, Igor; Hennrich, Markus
2016-01-01
Trapped Rydberg ions are a promising new system for quantum information processing. They have the potential to join the precise quantum operations of trapped ions and the strong, long-range interactions between Rydberg atoms. Technically, the ion trap will need to stay active while exciting the ions into the Rydberg state, else the strong Coulomb repulsion will quickly push the ions apart. Thus, a thorough understanding of the trap effects on Rydberg ions is essential for future applications. Here we report the observation of two fundamental trap effects. First, we investigate the interaction of the Rydberg electron with the quadrupolar electric trapping field. This effect leads to Floquet sidebands in the spectroscopy of Rydberg D-states whereas Rydberg S-states are unaffected due to their symmetry. Second, we report on the modified trapping potential in the Rydberg state compared to the ground state which results from the strong polarizability of the Rydberg ion. We observe the resultant energy shifts as a ...
Cooper, Keith
2016-04-01
Quantum computers of the future could operate via the energy transitions of excited atoms, or even from pure light, if a rapidly growing area of atomic physics continues to meet with success, writes Keith Cooper.
Electromagnetically induced grating with Rydberg atoms
Asghar, Sobia; Ziauddin, Qamar, Shahid; Qamar, Sajid
2016-09-01
We present a scheme to realize electromagnetically induced grating in an ensemble of strongly interacting Rydberg atoms, which act as superatoms due to the dipole blockade mechanism. The ensemble of three-level cold Rydberg-dressed (87Rb) atoms follows a cascade configuration where a strong standing-wave control field and a weak probe pulse are employed. The diffraction intensity is influenced by the strength of the probe intensity, the control field strength, and the van der Waals (vdW) interaction. It is noticed that relatively large first-order diffraction can be obtained for low-input intensity with a small vdW shift and a strong control field. The scheme can be considered as an amicable solution to realize the atomic grating at the microscopic level, which can provide background- and dark-current-free diffraction.
Effective Field Theory for Rydberg Polaritons
Gullans, M J; Thompson, J D; Liang, Q -Y; Vuletic, V; Lukin, M D; Gorshkov, A V
2016-01-01
We study non-perturbative effects in N-body scattering of Rydberg polaritons using effective field theory (EFT). We develop an EFT in one dimension and show how a suitably long medium can be used to prepare shallow N-body bound states. We then derive the effective N-body interaction potential for Rydberg polaritons and the associated N-body contact force that arises in the EFT. We use the contact force to find the leading order corrections to the binding energy of the N-body bound states and determine the photon number at which the EFT description breaks down. We find good agreement throughout between the predictions of EFT and numerical simulations of the exact two and three photon wavefunction transmission.
Observation of pendular butterfly Rydberg molecules.
Niederprüm, Thomas; Thomas, Oliver; Eichert, Tanita; Lippe, Carsten; Pérez-Ríos, Jesús; Greene, Chris H; Ott, Herwig
2016-10-05
Engineering molecules with a tunable bond length and defined quantum states lies at the heart of quantum chemistry. The unconventional binding mechanism of Rydberg molecules makes them a promising candidate to implement such tunable molecules. A very peculiar type of Rydberg molecules are the so-called butterfly molecules, which are bound by a shape resonance in the electron-perturber scattering. Here we report the observation of these exotic molecules and employ their exceptional properties to engineer their bond length, vibrational state, angular momentum and orientation in a small electric field. Combining the variable bond length with their giant dipole moment of several hundred Debye, we observe counter-intuitive molecules which locate the average electron position beyond the internuclear distance.
Rydberg blockade in a hot atomic beam
Yoshida, S.; Burgdörfer, J.; Zhang, X.; Dunning, F. B.
2017-04-01
The dipole blockade of very-high-n , n ˜300 , strontium 5 s n f 1F3 Rydberg atoms in a hot atomic beam is studied. For such high n , the blockade radius can exceed the linear dimensions of the excitation volume. Rydberg atoms formed inside the excitation volume can, upon leaving the region, continue to suppress excitation until they have moved farther away than the blockade radius. Moreover, the high density of states originating from the many magnetic sublevels associated with the F states results in a small but finite probability of excitation of L =3 n 1F3 atom pairs at small internuclear separations below the blockade radius. We demonstrate that these effects can be distinguished from one another by the distinct features they imprint on the Mandel Q parameter as a function of the duration of the exciting laser.
Thermal ionization of Cs Rydberg states
Glukhov, I. L.; Ovsiannikov, V. D.
2009-01-01
Rates Pnl of photoionization from Rydberg ns-, np-, nd-states of a valence electron in Cs, induced by black-body radiation, were calculated on the basis of the modified Fues model potential method. The numerical data were approximated with a three-term expression which reproduces in a simple analytical form the dependence of Pnl on the ambient temperature T and on the principal quantum number n. The comparison between approximate and exactly calculated values of the thermal ionization rate demonstrates the applicability of the proposed approximation for highly excited states with n from 20 to 100 in a wide temperature range of T from 100 to 10,000 K. We present coefficients of this approximation for the s-, p- and d-series of Rydberg states.
Coherent dynamics of Rydberg atoms in cosmic-microwave-background radiation
Tscherbul, Timur V.; Brumer, Paul
2014-01-01
Rydberg atoms excited by cold blackbody radiation are shown to display long-lived quantum coherences on time scales of tens of picoseconds. By solving non-Markovian equations of motion with no free parameters we obtain the time evolution of the density matrix and demonstrate that the blackbody-induced temporal coherences manifest as slowly decaying (100 ps) quantum beats in time-resolved fluorescence. An analytic model shows the dependence of the coherent dynamics on the energy splitting between atomic eigenstates, transition dipole moments, and coherence time of the radiation. Experimental detection of the fluorescence signal from a trapped ensemble of 108 Rydberg atoms is discussed, but shown to be technically challenging at present, requiring cosmic-microwave-background amplification somewhat beyond current practice.
Reservoir engineering with ultracold Rydberg atoms
Schönleber, David W.; Bentley, Christopher D. B.; Eisfeld, Alexander
2016-01-01
We apply reservoir engineering to construct a thermal environment with controllable temperature in an ultracold atomic Rydberg system. A Boltzmann distribution of the system's eigenstates is produced by optically driving a small environment of ultracold atoms, which is coupled to a photonic continuum through spontaneous emission. This technique provides a useful tool for quantum simulation of dynamics coupled to a thermal environment. Additionally, we demonstrate that pure eigenstates, such a...
Microscopic Characterization of Scalable Coherent Rydberg Superatoms
Directory of Open Access Journals (Sweden)
Johannes Zeiher
2015-08-01
Full Text Available Strong interactions can amplify quantum effects such that they become important on macroscopic scales. Controlling these coherently on a single-particle level is essential for the tailored preparation of strongly correlated quantum systems and opens up new prospects for quantum technologies. Rydberg atoms offer such strong interactions, which lead to extreme nonlinearities in laser-coupled atomic ensembles. As a result, multiple excitation of a micrometer-sized cloud can be blocked while the light-matter coupling becomes collectively enhanced. The resulting two-level system, often called a “superatom,” is a valuable resource for quantum information, providing a collective qubit. Here, we report on the preparation of 2 orders of magnitude scalable superatoms utilizing the large interaction strength provided by Rydberg atoms combined with precise control of an ensemble of ultracold atoms in an optical lattice. The latter is achieved with sub-shot-noise precision by local manipulation of a two-dimensional Mott insulator. We microscopically confirm the superatom picture by in situ detection of the Rydberg excitations and observe the characteristic square-root scaling of the optical coupling with the number of atoms. Enabled by the full control over the atomic sample, including the motional degrees of freedom, we infer the overlap of the produced many-body state with a W state from the observed Rabi oscillations and deduce the presence of entanglement. Finally, we investigate the breakdown of the superatom picture when two Rydberg excitations are present in the system, which leads to dephasing and a loss of coherence.
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.
Efimov, D. K.; Miculis, K.; Bezuglov, N. N.; Ekers, A.
2016-06-01
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 {n}d={n}i={n}0 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 {n}i\\gt {n}0\\gt {n}d 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.
Correlation effects in double rydberg atoms
Energy Technology Data Exchange (ETDEWEB)
Camus, P. (Lab. Aime Cotton, Centre National de la Recherche Scientifique 2, 91 Orsay (France))
1994-01-01
The present review is devoted to the recent advances performed in alkaline-earth atoms by the selective laser preparation of autoionizing asymmetrical double Rydberg states which have, so far, not been observed in natural environments. Because the great amount of flexibility achieved by the sequential laser electron excitations, a wide choice of two-electron situations have been investigated and analyzed which exhibit spectral features due to long-range effects of the Coulomb electron-electron repulsion. To overcome the autoionization broadening of the lines, double Rydberg states with a non-core penetrating high-l outer electron were produced by combining temporal laser excitation technique with the electric-field switching method. The study of the spectral correlation signatures in N snl double Rydberg states versus l allow to understand their evolution from simple spectra (l [>=] 10) due to long-range dipole interaction to more complex data (l [<=] 7) induced by short-range multipole effects when two electrons start to influence more each other. (orig.).
A coherent quantum annealer with Rydberg atoms
Glaetzle, A. W.; van Bijnen, R. M. W.; Zoller, P.; Lechner, W.
2017-06-01
There is a significant ongoing effort in realizing quantum annealing with different physical platforms. The challenge is to achieve a fully programmable quantum device featuring coherent adiabatic quantum dynamics. Here we show that combining the well-developed quantum simulation toolbox for Rydberg atoms with the recently proposed Lechner-Hauke-Zoller (LHZ) architecture allows one to build a prototype for a coherent adiabatic quantum computer with all-to-all Ising interactions and, therefore, a platform for quantum annealing. In LHZ an infinite-range spin-glass is mapped onto the low energy subspace of a spin-1/2 lattice gauge model with quasi-local four-body parity constraints. This spin model can be emulated in a natural way with Rubidium and Caesium atoms in a bipartite optical lattice involving laser-dressed Rydberg-Rydberg interactions, which are several orders of magnitude larger than the relevant decoherence rates. This makes the exploration of coherent quantum enhanced optimization protocols accessible with state-of-the-art atomic physics experiments.
A coherent quantum annealer with Rydberg atoms.
Glaetzle, A W; van Bijnen, R M W; Zoller, P; Lechner, W
2017-06-22
There is a significant ongoing effort in realizing quantum annealing with different physical platforms. The challenge is to achieve a fully programmable quantum device featuring coherent adiabatic quantum dynamics. Here we show that combining the well-developed quantum simulation toolbox for Rydberg atoms with the recently proposed Lechner-Hauke-Zoller (LHZ) architecture allows one to build a prototype for a coherent adiabatic quantum computer with all-to-all Ising interactions and, therefore, a platform for quantum annealing. In LHZ an infinite-range spin-glass is mapped onto the low energy subspace of a spin-1/2 lattice gauge model with quasi-local four-body parity constraints. This spin model can be emulated in a natural way with Rubidium and Caesium atoms in a bipartite optical lattice involving laser-dressed Rydberg-Rydberg interactions, which are several orders of magnitude larger than the relevant decoherence rates. This makes the exploration of coherent quantum enhanced optimization protocols accessible with state-of-the-art atomic physics experiments.
Excitation dynamics of interacting Rydberg atoms in small lattices
Energy Technology Data Exchange (ETDEWEB)
Wu, G., E-mail: gwu@physnet.uni-hamburg.de [Zentrum für Optische Quantentechnologien, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); Physikalisches Institut, Universität Heidelberg, Im Neuenheimer Feld 226, 69120 Heidelberg (Germany); Kurz, M.; Liebchen, B. [Zentrum für Optische Quantentechnologien, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); Schmelcher, P. [Zentrum für Optische Quantentechnologien, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany)
2015-01-23
We study the Rydberg excitation dynamics of laser-driven atoms confined in a one-dimensional three-site lattice with open boundary conditions. Different regular excitation patterns are obtained within various parameter regimes. In the case of a weak Rydberg–Rydberg interaction, the excitation probability possesses a nodal structure which is characterized by an envelope with a period inversely proportional to the interaction. For strong Rydberg interaction we observe dipole blockade and antiblockade effects and an appropriate detuning leads to an overall oscillatory behavior of the Rydberg probability density which is modulated only by small oscillations. Besides an exact diagonalization procedure we study the system by performing first and second order perturbation theory as well as a spectral analysis. - Highlights: • We study Rydberg excitation in small 1-d lattices. • For weak Rydberg interaction, the excitation probability possesses an envelope structure. • For strong Rydberg interaction, we observe dipole blockade and antiblockade effects. • A specific detuning leads to degeneracy and regular oscillatory behavior of the Rydberg density.
Rydberg atom interactions from 300 K to 300 K
Pillet, P.; Gallagher, T. F.
2016-09-01
Cold Rydberg atoms provide novel approaches to many-body problems and quantum simulation. To introduce the recent work presented in this special issue, we present here a quick history of a half-century research activity in the Rydberg-atom field, focusing our attention on the giant interactions between Rydberg atoms and other atoms. These interactions are the origin of many effects observed with Rydberg atoms: pressure shifts, dipole-dipole energy transfer, and avalanche-ionization. These effects have led to evidence of new bound chemical states, such as trilobites states, many-body effects in frozen Rydberg gases, and the spontaneous formation of ultra-cold plasmas. They open exciting new prospects at the intersection of atomic physics, condensed matter physics, and plasma physics.
Rydberg atoms in hollow-core photonic crystal fibres
Epple, G; Euser, T G; Joly, N Y; Pfau, T; Russell, P St J; Löw, R
2014-01-01
The exceptionally large polarisability of highly excited Rydberg atoms (six orders of magnitude higher than ground-state atoms) makes them of great interest in fields such as quantum optics, quantum computing, quantum simulation and metrology. If however they are to be used routinely in applications, a major requirement is their integration into technically feasible, miniaturised devices. Here we show that a Rydberg medium based on room temperature caesium vapour can be confined in broadband-guiding kagome-style hollow-core photonic crystal fibres. Three-photon spectroscopy performed on a caesium-filled fibre detects Rydberg states up to a principal quantum number of n = 40. Besides small energy level shifts we observe narrow lines confirming the coherence of the Rydberg excitation. Using different Rydberg states and core diameters we study the influence of confinement within the fibre core after different exposure times. Understanding these effects is essential for the successful future development of novel ...
Blockade involving high- n, n ~ 300 , strontium Rydberg atoms
Yoshida, Shuhei; Burgdörfer, Joachim; Zhang, Xinyue; Dunning, F. Barry
2016-05-01
The blockade of high- n strontium n1F3 Rydberg states contained in a hot atomic beam is investigated both theoretically and experimentally. One difficulty in such experiments is that, once created, Rydberg atoms move out of the excitation volume reducing blockade effects. While the effects of such motion are apparent, the data provide strong evidence of blockade, consistent with theoretical predictions. Because of their relatively high angular momentum (L = 3) , a pair of n1F3 Rydberg atoms have many degenerate states whose degeneracy is removed by Rydberg-Rydberg interactions yielding a high density of states near the target energy. To evaluate the effect of blockade not only the energy shifts but also the modification of the oscillator strengths for excitation have to be taken into account. The n-scaling of the interactions and the importance of high-order multipoles will also be discussed. Research supported by the NSF and Robert A. Welch Foundation.
Coherent Excitation of Lithium to Rydberg States and Application to Rydberg Atom Optics
Stevens, G.; Widmer, M.; Tudorica, F.; Iu, C.-H.; Metcalf, H.
1996-05-01
We present a theoretical analysis of several schemes for coherently exciting lithium atoms in a thermal beam to Rydberg states in a four level/three laser system, previously discussed by Oreg et al.(J. Oreg et al.), Phys. Rev. A 45, 4888 (1992). The time evolution of the dressed states and their populations are calculated numerically, solving the optical Bloch equations by a fourth order Runge-Kutta integration. Our code closely models actual experimental conditions, including spontaneous decay, beam profiles, intensities and detunings. Large Rydberg populations (50%) around n=15 may be obtained by non-adiabatic excitation, with each laser power on the order of 1 mW. We discuss the effects of an externally controlled time dependent detuning in the Rydberg state, for example as produced by atoms traversing an inhomogeneous electric field. An understanding of this excitation mechanism is important for large angle reflection of coherently excited atoms using field gradients. Some primitive ideas of Stark-Rydberg atom optics are presented.
Pulsed Rydberg four-wave mixing with motion-induced dephasing in a thermal vapor
Chen, Yi-Hsin; Löw, Robert; Pfau, Tilman
2015-01-01
We report on time-resolved pulsed four-wave mixing (FWM) signals in a thermal Rubidium vapor involving a Rydberg state. We observe FWM signals with dephasing times up to 7 ns, strongly dependent on the excitation bandwidth to the Rydberg state. The excitation to the Rydberg state is driven by a pulsed two-photon transition on ns time scales. Combined with a third cw de-excitation laser, a strongly directional and collective emission is generated according to a combination of the phase matching effect and averaging over Doppler classes. In contrast to a previous report [1] using off-resonant FWM, at a resonant FWM scheme we observe additional revivals of the signal shortly after the incident pulse has ended. We infer that this is a revival of motion-induced constructive interference between the coherent emissions of the thermal atoms. The resonant FWM scheme reveals a richer temporal structure of the signals, compared to similar, but off-resonant excitation schemes. A simple explanation lies in the selectivity...
Pulsed Rydberg four-wave mixing with motion-induced dephasing in a thermal vapor.
Chen, Yi-Hsin; Ripka, Fabian; Löw, Robert; Pfau, Tilman
We report on time-resolved pulsed four-wave mixing (FWM) signals in a thermal Rubidium vapor involving a Rydberg state. We observe FWM signals with dephasing times up to 7 ns, strongly dependent on the excitation bandwidth to the Rydberg state. The excitation to the Rydberg state is driven by a pulsed two-photon transition on ns timescales. Combined with a cw de-excitation laser, a strongly directional and collective emission is generated according to a combination of the phase matching effect and averaging over Doppler classes. In contrast to a previous report (Huber et al. in Phys Rev A 90: 053806, 2014) using off-resonant FWM, at a resonant FWM scheme we observe additional revivals of the signal shortly after the incident pulse has ended. We infer that this is a revival of motion-induced constructive interference between the coherent emissions of the thermal atoms. The resonant FWM scheme reveals a richer temporal structure of the signals, compared to similar, but off-resonant excitation schemes. A simple explanation lies in the selectivity of Doppler classes. Our numerical simulations based on a four-level model including a whole Doppler ensemble can qualitatively describe the data.
Two-dimensional (2+n) REMPI of CH(3)Br: photodissociation channels via Rydberg states.
Kvaran, Agúst; Wang, Huasheng; Matthíasson, Kristján; Bodi, Andras
2010-09-23
(2+n) resonance enhanced multiphoton ionization (REMPI) spectra of CH(3)Br for the masses H(+), CH(m)(+), (i)Br(+), H(i)Br(+), and CH(m)(i)Br(+) (m = 0-3; i = 79, 81) have been recorded in the 66 000-81 000 cm(-1) resonance energy range. Signals due to resonance transitions from the zero vibrational energy level of the ground state CH(3)Br to a number of Rydberg states [Ω(c)]nl;ω (Ω(c) = 3/2, 1/2; ω = 0, 2; l = 1(p), 2(d)) and various vibrational states were identified. C((3)P) and C*((1)D) atom and HBr intermediate production, detected by (2+1) REMPI, most probably is due to photodissociation of CH(3)Br via two-photon excitations to Rydberg states followed by an unusual breaking of four bonds and formation of two bonds to give the fragments H(2) + C/C* + HBr prior to ionization. This observation is supported by REMPI observations as well as potential energy surface (PES) ab initio calculations. Bromine atom production by photodissociation channels via two-photon excitation to Rydberg states is identified by detecting bromine atom (2+1) REMPI.
Wang, Shiliang; Shi, Yujun; Dénommée, Stéphane; Simard, Benoit; Lee, Yuan-Pern
2003-10-01
Rydberg states of CH2CO and CD2CO in the 54 000-72 000 cm-1 spectral range have been reinvestigated using two-photon resonance-enhanced multiphoton-ionization spectroscopy. Improved resolution and sensitivity has allowed for identifications of more Rydberg states than in previous work. Based on an analysis of rotational structures and quantum defects and a comparison with the results of theoretical calculations, transitions to the 3pz, 4py, 4pz, and 5py, three components of 4d, and two components of 4f Rydberg states with a ground-state ionic core (X˜ 2B1) are identified. Several transitions have been reassigned. Vibrational wave numbers indicate that the geometry of the [X˜ 2B1]3py(1A2) state is almost identical to that of the corresponding cation in its ground electronic state, with C2v symmetry, whereas that of the [X˜ 2B1]3px(1A1) state differs significantly from those of the neutral molecule and the cation in their ground states, consistent with previous quantum chemical calculations that indicated that the [X˜ 2B1]3px(1A1) state has Cs symmetry. The energy ordering of the three components of the 3p Rydberg states is found to be 3pxout-of-plane bending, CH2 or CD2 wagging) and b2 symmetries (e.g., C=C=O in-plane bending) are observed in several Rydberg states of CH2CO and CD2CO.
He, Hua; Tyson, Chauntae; Saito, Maia; Bobev, Svilen
2013-01-01
The new Zintl compounds Ba(3)Al(3)P(5), Ba(3)Al(3)As(5,) and Ba(3)Ga(3)P(5) have been synthesized using molten metal fluxes. They are isoelectronic and isotypic, crystallizing with a novel rhombohedral structure type in the space group R3c with unit cell constants a = 14.5886(9) Å, c = 28.990(3) Å for Ba(3)Al(3)P(5), a = 14.613(3) Å, c = 28.884(8) Å for Ba(3)Ga(3)P(5), and a = 14.9727(13) Å, c = 29.689(4) Å for Ba(3)Al(3)As(5), respectively. The structures are based on TrPn(4) (Tr = Al, Ga; Pn = P, As) tetrahedra that share both edges and corners, leading to intricate arrangements embodied in the [Tr(4)Pn(9)](15-) and [Tr(3)Pn(6)](9-) strands, interconnected by dimeric [Tr(2)Pn(6)](12-) units. The Ba(2+) cations reside within cylindrical channels within the polyanionic framework and provide the valence electrons needed for Tr-Pn covalent bonding. In spite of the large and complex structure, there are no homoatomic Tr-Tr or Pn-Pn interactions, hence, the structures can be readily rationalized in the context of the Zintl-Klemm formalism as follows [Ba(2+)](3)[Tr(3+)](3)[Pn(3-)](5); calculations on their electronic band-structures confirm this reasoning and reveal about 1.4-1.9 eV energy band gaps, that is, semiconducting behavior. Structural parallels with other known Zintl compounds are also presented.
Atomic Fock State Preparation Using Rydberg Blockade
Ebert, Matthew; Gibbons, Michael; Zhang, Xianli; Saffman, Mark; Walker, Thad G
2013-01-01
We use coherent excitation of 3-16 atom ensembles to demonstrate collective Rabi flopping mediated by Rydberg blockade. Using calibrated atom number measurements, we quantitatively confirm the expected $\\sqrt{N}$ Rabi frequency enhancement to within 4%. The resulting atom number distributions are consistent with essentially perfect blockade. We then use collective Rabi $\\pi$ pulses to produce ${\\cal N}=1,2$ atom number Fock states with fidelities of 62% and 48% respectively. The ${\\cal N}=2$ Fock state shows the collective Rabi frequency enhancement without corruption from atom number fluctuations.
Floating Rydberg crystals formed by resonant excitation
Gärttner, M; Gasenzer, T; Evers, J
2013-01-01
The dynamics of a cloud of ultra-cold Rydberg atoms is studied at off-resonant laser driving. We find that excitation crystals are formed dynamically as a consequence of interaction-induced resonant excitations. These crystals have lattice constants independent of the trap length, are spatially not localized with respect to the trap, and sensitively depend on the shape of the interaction potential. Compared to previously proposed crystals, this leads to qualitatively different results for the spatial excitation density, the Mandel $Q$ parameter, and the total number of excitations.
Alignment of D-state Rydberg molecules
Krupp, Alexander T; Balewski, Jonathan B; Ilzhöfer, Philipp; Hofferberth, Sebastian; Löw, Robert; Pfau, Tilman; Kurz, Markus; Schmelcher, Peter
2014-01-01
We report on the formation of ultralong-range Rydberg D-state molecules via photoassociation in an ultracold cloud of rubidium atoms. By applying a magnetic offset field on the order of 10 G and high resolution spectroscopy, we are able to resolve individual rovibrational molecular states. A full theory, using the Born-Oppenheimer approximation including s- and p-wave scattering, reproduces the measured binding energies. The calculated molecular wavefunctions show that in the experiment we can selectively excite stationary molecular states with an extraordinary degree of alignment or anti-alignment with respect to the magnetic field axis.
Optimal control of Rydberg lattice gases
Cui, Jian; van Bijnen, Rick; Pohl, Thomas; Montangero, Simone; Calarco, Tommaso
2017-09-01
We present optimal control protocols to prepare different many-body quantum states of Rydberg atoms in optical lattices. Specifically, we show how to prepare highly ordered many-body ground states, GHZ states as well as some superposition of symmetric excitation number Fock states, that inherit the translational symmetry from the Hamiltonian, within sufficiently short excitation times minimising detrimental decoherence effects. For the GHZ states, we propose a two-step detection protocol to experimentally verify the optimised preparation of the target state based only on standard measurement techniques. Realistic experimental constraints and imperfections are taken into account by our optimisation procedure making it applicable to ongoing experiments.
Yang, Lei; Gao, Hong; Zhou, Jingang; Ng, C. Y.
2015-09-01
We have measured the high-resolution vacuum ultraviolet (VUV) photoion (VUV-PI) and VUV pulsed-field ionization-photoion (VUV-PFI-PI) spectra of chlorine atoms (Cl) in the VUV energy range 103,580-105,600 cm-1 (12.842-13.093 eV) using a tunable VUV laser as the photoexcitation and photoionization source. Here, Cl atoms are prepared in the Cl(2P3/2) and Cl(2P1/2) fine-structure states by 193.3 nm laser photodissociation of chlorobenzene. The employment of VUV-PFI-PI detection has allowed the identification of Rydberg transitions that are not observed in VUV-PI measurements. More than 180 new Rydberg transition lines with principal quantum number up to n = 61 have been identified and assigned to members of nine Rydberg series originating from the neutral Cl(2P3/2) and Cl(2P1/2) fine-structure states. Two of these Rydberg series are found to converge to the Cl+(3P2), four to the Cl+(3P1), and three to the Cl+(3P0) ionization limits. Based on the convergence limits determined by least-squares fits of the observed Rydberg transitions to the modified Ritz formula, we have obtained a more precise ionization energy (IE) for the formation of the ionic Cl+(3P2) from the ground Cl(2P3/2) state to be 104,591.01 ± 0.13 cm-1. This is consistent with previous IE measurements, but has a smaller uncertainty. The analysis of the quantum defects obtained for the Rydberg transitions reveals that many high-n Rydberg transitions are perturbed.
RF-dressed Rydberg atoms in hollow-core fibres
2016-01-01
The giant electro-optical response of Rydberg atoms manifests itself in the emergence of sidebands in the Rydberg excitation spectrum if the atom is exposed to a radio-frequency (RF) electric field. Here we report on the study of RF-dressed Rydberg atoms inside hollow-core photonic crystal fibres (HC-PCF), a system that enables the use of low modulation voltages and offers the prospect of miniaturised vapour-based electro-optical devices. Narrow spectroscopic features caused by the RF field a...
RF-dressed Rydberg atoms in hollow-core fibres
2016-01-01
This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by the Institute of Physics. The giant electro-optical response of Rydberg atoms manifests itself in the emergence of sidebands in the Rydberg excitation spectrum if the atom is exposed to a radio-frequency (RF) electric field. Here we report on the study of RF-dressed Rydberg atoms inside hollow-core photonic crystal fibres (HC-PCF), a system that enables the use of low modulation volta...
RF-dressed Rydberg atoms in hollow-core fibres
Veit, Christian; Kübler, Harald; Euser, Tijmen G; Russell, Philip St J; Löw, Robert
2016-01-01
The giant electro-optical response of Rydberg atoms manifests itself in the emergence of sidebands in the Rydberg excitation spectrum if the atom is exposed to a radio-frequency (RF) electric field. Here we report on the study of RF-dressed Rydberg atoms inside hollow-core photonic crystal fibres (HC-PCF), a system that enables the use of low modulation voltages and offers the prospect of miniaturised vapour-based electro-optical devices. Narrow spectroscopic features caused by the RF field are observed for modulation frequencies up to 500 MHz.
Anomalous excitation facilitation in inhomogeneously broadened Rydberg gases
Letscher, Fabian; Niederprüm, Thomas; Ott, Herwig; Fleischhauer, Michael
2016-01-01
When atomic gases are laser driven to Rydberg states in an off resonant way, a single Rydberg atom may enhance the excitation rate of surrounding atoms. This leads to a facilitated excitation referred to as Rydberg anti-blockade. In the usual facilitation scenario, the detuning of the laser from resonance compensates the interaction shift. Here, we discuss a different excitation mechanism, which we call anomalous facilitation. This occurs on the "wrong side" of the resonance and originates from inhomogeneous broadening. The anomalous facilitation may be seen in experiments of attractively interacting atoms on the blue detuned side, where facilitation is not expected to appear.
Spectroscopy of strontium Rydberg states using electromagnetically induced transparency
Mauger, Sarah; Millen, James; Jones, M. P. A.
2007-01-01
We report on the all-optical detection of Rydberg states in a effusive atomic beam of strontium atoms using electromagnetically induced transparency (EIT). Using narrow-linewidth CW lasers we obtain an EIT linewidth of 5 MHz. To illustrate the high spectroscopic resolution offered by this method, we have measured isotope shifts of the 5s18d ^1D_2 and 5s19s ^1S_0 Rydberg states. This technique could be applied to high-resolution, non-destructive measurements of ultra-cold Rydberg gases and pla...
Quasi-Magic optical traps for Rydberg atoms
Zhang, S; Saffman, M
2011-01-01
We propose blue-detuned optical traps that are suitable for trapping of both ground state and Rydberg excited atoms. Addition of a background compensation field or suitable choice of the trap geometry provides a magic trapping condition for ground and Rydberg atoms at the trap center. Deviations from the magic condition at finite temperature are calculated. Designs that achieve less than 200 kHz differential trap shift between Cs ground and 125s Rydberg states for 10 {\\mu}K Cs atoms are presented. Consideration of the trapping potential and photoionization rates
Deterministic entanglement of Rydberg ensembles by engineered dissipation
DEFF Research Database (Denmark)
Dasari, Durga; Mølmer, Klaus
2014-01-01
We propose a scheme that employs dissipation to deterministically generate entanglement in an ensemble of strongly interacting Rydberg atoms. With a combination of microwave driving between different Rydberg levels and a resonant laser coupling to a short lived atomic state, the ensemble can...... be driven towards a dark steady state that entangles all atoms. The long-range resonant dipole-dipole interaction between different Rydberg states extends the entanglement beyond the van der Walls interaction range with perspectives for entangling large and distant ensembles....
Tada, M; Ogawa, I; Funahashi, H; Yamamoto, K; Matsuki, S
2000-01-01
Coherent time evolution of highly excited Rydberg states in Rb (98 < n < 150) under pulsed electric field in high slew-rate regime was investigated with the field ionization detection. The electric field necessary to ionize the Rydberg states was found to take discrete values successively depending on the slew rate. Specifically the slew-rate dependence of the ionization field varies with the quantum defect value of the states, i.e. with the energy position of the states relative to the adjacent manifold. This discrete transitional behavior of the ionization field observed for the first time is considered to be a manifestation of the strong coherence effect in the time evolution of the Rydberg states in pulsed electric field and opens a new effective way to stringently select a low-l state from the nearby states by field ionization.
Polarization spectra of Zeeman sublevels in Rydberg electromagnetically induced transparency
Bao, Shanxia; Zhang, Hao; Zhou, Jian; Zhang, Linjie; Zhao, Jianming; Xiao, Liantuan; Jia, Suotang
2016-10-01
The polarization spectra of electromagnetically induced transparency (EIT) for Zeeman sublevels in a cascade system with Rydberg state are demonstrated. The magnitude dependence of Rydberg-EIT on the polarizations of probe and coupling laser fields is studied, and shown mainly due to the strengths of relative dipole matrix elements between degenerate Zeeman sublevels. We further investigate the polarization spectra of Rydberg-EIT in the optimal polarization combinations of left-handed and right-handed circularly polarized fields when an external magnetic field is applied. The existence of nondegenerate Zeeman sublevels in an external magnetic field results in the splitting of Rydberg-EIT. The theoretical calculations are very consistent with the experimental spectra.
Dipole blockade in a cold Rydberg atomic sample
Comparat, Daniel; 10.1364/JOSAB.27.00A208
2010-01-01
We review here the studies performed about interactions in an assembly of cold Rydberg atoms. We focus more specially the review on the dipole-dipole interactions and on the effect of the dipole blockade in the laser Rydberg excitation, which offers attractive possibilities for quantum engineering. We present first the various interactions between Rydberg atoms. The laser Rydberg excitation of such an assembly is then described with the introduction of the dipole blockade phenomenon. We report recent experiments performed in this subject by starting with the case of a pair of atoms allowing the entanglement of the wave-functions of the atoms and opening a fascinating way for the realization of quantum bits and quantum gates. We consider then several works on the blockade effect in a large assembly of atoms for three different configurations: blockade through electric-field induced dipole, through F\\"orster resonance and in van der Waals interaction. The properties of coherence and cooperativity are analyzed. ...
Controllable interactions between Rydberg atoms and ultracold plasmas
Energy Technology Data Exchange (ETDEWEB)
Pillet, P; Vogt, T; Viteau, M; Chotia, A; Zhao, J; Comparat, D; Gallagher, T F; Tate, D [Laboratoire Aime Cotton, CNRS, Univ Paris-Sud, Bat.505, Campus d' Orsay, 91405 Orsay cedex (France); Gaetan, A; Miroshnychenko, Y; Wilk, T; Browaeys, A; Grangier, P, E-mail: pierre.pillet@lac.u-psud.f [Laboratoire Charles Fabry de l' Institut d' Optique CNRS, Univ Paris-Sud, Campus Polytechnique, RD 128, 91127 Palaiseau cedex (France)
2009-11-15
We discuss the control of dipole-dipole interactions in a frozen assembly of Rydberg atoms. We report the evidence of dipole blockade of the Rydberg excitation for two configurations: dipole blockade induced by electric field and dipole blockade in Foerster resonance. We demonstrate that two individual atoms separated by {approx} 4 {mu}m can act as a collective dipole if their interaction is strong enough to be in the dipole blockade regime. This observation is crucial for the quantum entanglement of two or more atoms using dipole-dipole interaction. The dipole-dipole interactions between Rydberg atoms are also responsible for Penning ionization leading to the formation of an ultracold plasma. We have demonstrated that Penning ionization of np Rydberg cesium atoms can be prevented by considering repulsive dipole-dipole interactions.
Role of Rydberg States In High-order Harmonic Generation
Beaulieu, Samuel; Comby, Antoine; Wanie, Vincent; Petit, Stéphane; Légaré, François; Catoire, Fabrice; Mairesse, Yann
2016-01-01
The role of Rydberg states in strong field physics has known a renewed interest in the past few years with the study of resonant high-order harmonic generation. In addition to its fundamental in- terest, this process could create bright sources of coherent vacuum and extreme ultraviolet radiation with controlled polarization state. We investigate the spectral, spatial and temporal characteristics of the radiation produced near the ionization threshold of argon by few-cycle laser pulses. The intensity-dependence of the emission shows that two different pathways interfere to populate the Rydberg states. Furthermore, we show that the population of Rydberg states can lead to different emission mecanisms: either direct emission through XUV Free Induction Decay, or sequentially with absorption of additional photons, in processes similar to resonance-enhanced multiphoton above- threshold ionization. Last, using the attosecond lighthouse technique we show that the resonant emission from Rydberg states is not temporal...
Borromean three-body FRET in frozen Rydberg gases
Faoro, R.; Pelle, B.; Zuliani, A.; Cheinet, P.; Arimondo, E.; Pillet, P.
2015-09-01
Controlling the interactions between ultracold atoms is crucial for quantum simulation and computation purposes. Highly excited Rydberg atoms are considered in this prospect for their strong and controllable interactions known in the dipole-dipole case to induce non-radiative energy transfers between atom pairs, similarly to fluorescence resonance energy transfer (FRET) in biological systems. Here we predict few-body FRET processes in Rydberg atoms and observe the first three-body resonance energy transfer in cold Rydberg atoms using cold caesium atoms. In these resonances, additional relay atoms carry away an energy excess preventing the two-body resonance, leading thus to a Borromean type of energy transfer. These few-body processes present strong similarities with multistep FRET between chromophores sometimes called donor-bridge-acceptor or superexchange. Most importantly, they generalize to any Rydberg atom and could lead to new implementations of few-body quantum gates or entanglement.
Rydberg-interaction-based quantum gates free from blockade error
Shi, Xiao-Feng
2016-01-01
Accurate quantum gates are basic elements for building quantum computers. There has been great interest in designing quantum gates by using blockade effect of Rydberg atoms recently. The fidelity and operation speed of these gates, however, are fundamentally limited by the blockade error. Here we propose another type of quantum gates, which are based on Rydberg blockade effect, yet free from any blockade error. In contrast to the `blocking' method in previous schemes, we use Rydberg energy shift to realise a rational generalised Rabi frequency so that a novel $\\pi$ phase for one input state of the gate emerges. This leads to an accurate Rydberg-blockade based two-qubit quantum gate that can operate in a $0.1\\mu s$ timescale or faster thanks to that it operates by a Rabi frequency which is comparable to the blockade shift.
Van der Waals explosion of cold Rydberg clusters
Faoro, R; Archimi, M; Masella, G; Valado, M M; Arimondo, E; Mannella, R; Ciampini, D; Morsch, O
2015-01-01
We report on the direct measurement in real space of the effect of the van der Waals forces between individual Rydberg atoms on their external degrees of freedom. Clusters of Rydberg atoms with inter-particle distances of around 5 {\\mu}m are created by first generating a small number of seed excitations in a magneto-optical trap, followed by off-resonant excitation that leads to a chain of facilitated excitation events. After a variable expansion time the Rydberg atoms are field ionized, and from the arrival time distributions the size of the Rydberg cluster after expansion is calculated. Our experimental results agree well with a numerical simulation of the van der Waals explosion.
Electron Rydberg wave packets in one-dimensional atoms
Indian Academy of Sciences (India)
Supriya Chatterjee; Amitava Choudhuri; Aparna Saha; B Talukdar
2010-09-01
An expression for the transition probability or form factor in one-dimensional Rydberg atom irradiated by short half-cycle pulse was constructed. In applicative contexts, our expression was found to be more useful than the corresponding result given by Landau and Lifshitz. Using the new expression for the form factor, the motion of a localized quantum wave packet was studied with particular emphasis on its revival and super-revival properties. Closed form analytical expressions were derived for expectation values of the position and momentum operators that characterized the widths of the position and momentum distributions. Transient phase-space localization of the wave packet produced by the application of a single impulsive kick was explicitly demonstrated. The undulation of the uncertainty product as a function of time was studied in order to visualize how the motion of the wave packet in its classical trajectory spreads throughout the orbit and the system becomes nonclassical. The process, however, repeats itself such that the atom undergoes a free evolution from a classical, to a nonclassical, and back to a classical state.
Generating non-Gaussian states using collisions between Rydberg polaritons
Stanojevic, Jovica; Bimbard, Erwan; Ourjoumtsev, Alexei; Pillet, Pierre; Grangier, Philippe
2012-01-01
We investigate theoretically the deterministic generation of quantum states with negative Wigner functions, by using giant non-linearities due to collisional interactions between Rydberg polaritons. The state resulting from the polariton interactions may be transferred with high fidelity into a photonic state, which can be analyzed using homodyne detection followed by quantum tomography. Besides generating highly non-classical states of the light, this method can also provide a very sensitive probe for the physics of the collisions involving Rydberg states.
Newton's cradle and entanglement transport in a flexible Rydberg chain
Wüster, S; Eisfeld, A; Rost, J -M
2010-01-01
In a regular, flexible chain of Rydberg atoms, a single electronic excitation localizes on two atoms that are in closer mutual proximity than all others. We show how the interplay between excitonic and atomic motion causes electronic excitation and diatomic proximity to propagate through the Rydberg chain as a combined pulse. In this manner entanglement is transferred adiabatically along the chain, reminiscent of momentum transfer in Newton's cradle.
Ultrafast structural dynamics and isomerization in Rydberg-exited Quadricyclane
Energy Technology Data Exchange (ETDEWEB)
Rudakov, Fedor M [ORNL
2012-01-01
The quadricyclane - norbornadiene system is an important model for the isomerization dynamics between highly strained molecules. In a breakthrough observation for a polyatomic molecular system of that complexity, we follow the photoionization from Rydberg states in the time-domain to derive a measure for the time-dependent structural dynamics and the time-evolving structural dispersion even while the molecule is crossing electronic surfaces. The photoexcitation to the 3s and 3p Rydberg states deposits significant amounts of energy into vibrational motions. We observe the formation and evolution of the vibrational wavepacket on the Rydberg surface and the internal conversion from the 3p Rydberg states to the 3s state. In that state, quadricyclane isomerizes to norbornadiene with a time constant of {tau}{sub 2} = 136(45) fs. The lifetime of the 3p Rydberg state in quadricyclane is {tau}{sub 1} = 320(31) and the lifetime of the 3s Rydberg state in norbornadiene is {tau}{sub 3} = 394(32).
Rydberg atoms in hollow-core photonic crystal fibres
Epple, G.; Kleinbach, K. S.; Euser, T. G.; Joly, N. Y.; Pfau, T.; Russell, P. St. J.; Löw, R.
2014-06-01
The exceptionally large polarizability of highly excited Rydberg atoms—six orders of magnitude higher than ground-state atoms—makes them of great interest in fields such as quantum optics, quantum computing, quantum simulation and metrology. However, if they are to be used routinely in applications, a major requirement is their integration into technically feasible, miniaturized devices. Here we show that a Rydberg medium based on room temperature caesium vapour can be confined in broadband-guiding kagome-style hollow-core photonic crystal fibres. Three-photon spectroscopy performed on a caesium-filled fibre detects Rydberg states up to a principal quantum number of n=40. Besides small energy-level shifts we observe narrow lines confirming the coherence of the Rydberg excitation. Using different Rydberg states and core diameters we study the influence of confinement within the fibre core after different exposure times. Understanding these effects is essential for the successful future development of novel applications based on integrated room temperature Rydberg systems.
Direct excitation of butterfly states in Rydberg molecules
Lippe, Carsten; Niederpruem, Thomas; Thomas, Oliver; Eichert, Tanita; Ott, Herwig
2016-05-01
Since their first theoretical prediction Rydberg molecules have become an increasing field of research. These exotic states originate from the binding of a ground state atom in the electronic wave function of a highly-excited Rydberg atom mediated by a Fermi contact type interaction. A special class of long-range molecular states, the butterfly states, were first proposed by Greene et al.. These states arise from a shape resonance in the p-wave scattering channel of a ground state atom and a Rydberg electron and are characterized by an electron wavefunction whose density distribution resembles the shape of a butterfly. We report on the direct observation of deeply bound butterfly states of Rydberg molecules of 87 Rb. The butterfly states are studied by high resolution spectroscopy of UV-excited Rydberg molecules. We find states bound up to - 50 GHz from the 25 P1/2 , F = 1 state, corresponding to binding lengths of 50a0 to 500a0 and with permanent electric dipole moments of up to 500 Debye. This distinguishes the observed butterfly states from the previously observed long range Rydberg molecules in rubidium.
Production of very-high-n strontium Rydberg atoms
Ye, S.; Zhang, X.; Killian, T. C.; Dunning, F. B.; Hiller, M.; Yoshida, S.; Nagele, S.; Burgdörfer, J.
2013-10-01
The production of very-high-n (n˜300-500) strontium Rydberg atoms is explored using a crossed-laser-atom-beam geometry. n1S0 and n1D2 states are created by two-photon excitation via the 5s5p 1P1 intermediate state using radiation with wavelengths of ˜461 and ˜413 nm. Rydberg atom densities as high as ˜3×105 cm-3 have been achieved, sufficient that Rydberg-Rydberg interactions can become important. The isotope shifts in the Rydberg series limits are determined by tuning the 461-nm light to preferentially excite the different strontium isotopes. Photoexcitation in the presence of an applied electric field is examined. The initially quadratic Stark shift of the n1P1 and n1D2 states becomes near-linear at higher fields and the possible use of n1D2 states to create strongly polarized, quasi-one-dimensional electronic states in strontium is discussed. The data are analyzed with the aid of a two-active-electron (TAE) approximation. The two-electron Hamiltonian, within which the Sr2+ core is represented by a semi-empirical potential, is numerically diagonalized allowing the calculation of the energies of high-n Rydberg states and their photoexcitation probabilities.
D-state Rydberg electrons interacting with ultracold atoms
Energy Technology Data Exchange (ETDEWEB)
Krupp, Alexander Thorsten
2014-10-02
This thesis was established in the field of ultracold atoms where the interaction of highly excited D-state electrons with rubidium atoms was examined. This work is divided into two main parts: In the first part we study D-state Rydberg molecules resulting from the binding of a D-state Rydberg electron to a ground state rubidium atom. We show that we can address specific rovibrational molecular states by changing our laser detuning and thus create perfectly aligned axial or antialigned toroidal molecules, in good agreement with our theoretical calculations. Furthermore the influence of the electric field on the Rydberg molecules was investigated, creating novel states which show a different angular dependence and alignment. In the second part of this thesis we excite single D-state Rydberg electrons in a Bose-Einstein condensate. We study the lifetime of these Rydberg electrons, the change of the shape of our condensate and the atom losses in the condensate due to this process. Moreover, we observe quadrupolar shape oscillations of the whole condensate created by the consecutive excitation of Rydberg atoms and compare all results to previous S-state measurements. In the outlook we propose a wide range of further experiments including the proposal of imaging a single electron wavefunction by the imprint of its orbit into the Bose-Einstein condensate.
nf Rydberg complexes of NO in a magnetic field, probed by double resonance multiphoton ionization
Guizard, S.; Shafizadeh, N.; Horani, M.; Gauyacq, D.
1991-06-01
nf (v=1) Rydberg states of NO have been probed by double resonance multiphoton ionization in a 1 T external magnetic field. Due to the nonpenetrating character of the f orbitals, these Rydberg states are very sensitive probes of any external perturbation. As n increases, a decoupling of the angular momentum l of the Rydberg electron from the molecular frame occurs gradually, as the magnetic interaction becomes more and more important with respect to intramolecular forces. Up to n≂15, only the linear Zeeman perturbation has been taken into account. The rotational-electronic structure of the 7f and 15f states has been interpreted theoretically by considering the linear Zeeman perturbation in addition to the Coulombic interaction and the long range interaction due to the quadrupole moment and the polarizability of the ion core. The intensities and line positions of the transitions from the intermediate A 2Σ+,v=1 level to the 7f and 15f levels have been calculated. The alignment of the N, MS, MN Zeeman sublevels of the A state by the two-photon pump excitation from the ground state as well as the polarization of both lasers have been taken into account in the calculations. A good agreement between the observed and the calculated transitions has been obtained. For the 7f levels, the electronic-rotational structure is well described in a coupled case (d) representation. For the 15f levels, the strong coupling of l to the field axis led to the first observation of the Paschen-Back effect in a molecule, within each rotational N+ series, with an accompanying drastic simplification of the spectra. This level is better described in a decoupled case (d) representation corresponding to a moderately strong field regime.
Lifetimes of Rydberg states of Eu atoms
Jing, Hua; Ye, Shi-Wei; Dai, Chang-Jian
2015-01-01
The radiative lifetimes of the Eu 4f76snp (8PJ or 10PJ) Rydberg states with J = 5/2 and 11/2 are investigated with a combination of multi-step laser excitation and pulsed electric field ionization, from which their dependence on the effective principal quantum number is observed. The lifetimes of 21 states are reported along with an evaluation of their experimental uncertainty. The influence of blackbody radiation, due to the oven temperature, on the lifetime of the higher-n states is detected. The non-hydrogen behavior of the investigated states is also observed. Project supported by the National Natural Science Foundation of China (Grant No. 11174218).
Attosecond pulse characterization with coherent Rydberg wavepackets
Pabst, Stefan
2016-01-01
We propose a new technique to fully characterize the temporal structure of extreme ultraviolet pulses by ionizing a bound coherent electronic wavepacket. The populated energy levels make it possible to interfere different spectral components leading to quantum beats in the photoelectron spectrum as a function of the delay between ionization and initiation of the wavepacket. The influence of the dipole phase, which is the main obstacle for state-of-the-art pulse characterization schemes, can be eliminated by angle integration of the photoelectron spectrum. We show that particularly atomic Rydberg wavepackets are ideal and that wavepackets involving multiple electronic states provide redundant information which can be used to cross-check the consistency of the phase reconstruction.
Visualization and interpretation of Rydberg states
Kocbach, Ladislav
2012-01-01
For many purposes it is desirable to have an easily understandable and accurate picture of the atomic states. This is especially true for the highly excited states which exhibit features not present in the well known states hydrogen-like orbitals with usual values of the quantum numbers. It could be expected that such visualizations are readily available. Unfortunately, that is not the case. We illustrate the problems by showing several less fortunate earlier presentations in some scientifically most valuable works, and show more suitable visualizations for those cases. The selected cases are not chosen to criticize the authors' approach. Rather, we have taken these very important papers to underline the need for serious work with graphical representations which this work attempts to be a part of. In this text we discuss the problems encountered when visualizing Rydberg states, review some existing presentations and propose guidelines for applications. The focus of this work are so called Stark states and coh...
Atomic Rydberg Reservoirs for Polar Molecules
Zhao, Bo; Pupillo, Guido; Zoller, Peter
2011-01-01
We discuss laser dressed dipolar and Van der Waals interactions between atoms and polar molecules, so that a cold atomic gas with laser admixed Rydberg levels acts as a designed reservoir for both elastic and inelastic collisional processes. The elastic scattering channel is characterized by large elastic scattering cross sections and repulsive shields to protect from close encounter collisions. In addition, we discuss a dissipative (inelastic) collision where a spontaneously emitted photon carries away (kinetic) energy of the collision partners, thus providing a significant energy loss in a single collision. This leads to the scenario of rapid thermalization and cooling of a molecule in the mK down to the \\mu K regime by cold atoms.
Atomic Rydberg Reservoirs for Polar Molecules
Zhao, B.; Glaetzle, A. W.; Pupillo, G.; Zoller, P.
2012-05-01
We discuss laser-dressed dipolar and van der Waals interactions between atoms and polar molecules, so that a cold atomic gas with laser admixed Rydberg levels acts as a designed reservoir for both elastic and inelastic collisional processes. The elastic scattering channel is characterized by large elastic scattering cross sections and repulsive shields to protect from close encounter collisions. In addition, we discuss a dissipative (inelastic) collision where a spontaneously emitted photon carries away (kinetic) energy of the collision partners, thus providing a significant energy loss in a single collision. This leads to the scenario of rapid thermalization and cooling of a molecule in the mK down to the μK regime by cold atoms.
A Rydberg impurity in a dense background gas (Conference Presentation)
Liebisch, Tara; Schlagmüller, Michael; Engel, Felix; Westphal, Karl; Kleinbach, Kathrin; Böttcher, Fabian; Loew, Robert; Hofferberth, Sebastian; Pfau, Tilman; Perez-Rios, Jesus; Greene, Chris
2016-04-01
A single Rydberg atom impurity excited in a BEC is a system that can be utilized to measure the quantum mechanical properties of electron - neutral scattering andthe electron probability density of a Rydberg atom. The Rydberg electron - neutral atom scattering process, is a fundamental scattering process, which can be described via Fermi's pseudopotential as V{ěc{r},ěc{R} )=2pi {a}[k(R)]&delta^{(3)}(ěc{r}-ěc{R}). The scattering length is dependent on the momentum of the Rydberg electron, and therefore is dependent on the separation of the Rydberg electron from the ion core. At the classical outermost turning point of the electron, it has the slowest momentum leading to s-wave dominated scattering potentials 10's of MHz in depth for nPRL 85 2458 (2000), Bendkowsky et al. PRL 105 163201 (2010)). In alkali atoms there is a shape resonance for p-wave scattering, which becomes relevant at ion-neutral separations of 75nm (I.I. Fabrikant J.Phys B 19, 1527 (1985)). This shape resonance potential is several GHz deep, spanning the energy level spacing between n and n-1 principal quantum numbers. At high BEC densities of 5x10^14cm-3 the nearest neighbor spacing is less than 70nm. A Rydberg atom excited within a BEC, is an excitation of the Rydberg atom and all N neutral atoms located within the Rydberg orbit, described as nS+N x 5S. The nS+N x 5S state is density shifted from the Rydberg resonance. Not only does the distribution of atoms within the Rydberg orbit lead to a density shift, but, at these high densities, atoms excited in the nS+N x 5S state near the shape resonance potential cause large perturbations to the density shift, leading to a line broadening. Therefore the spectroscopic line shape of a Rydberg atom in a BEC allows us to probe the theoretically calculated p-wave shape resonance potential. Furthermore, we can observe and measure the dynamics of neutrals excited in the nS+N x 5S state. In the ultracold regime of a BEC, the background neutral atoms within
Limão-Vieira, P.; Duflot, D.; Ferreira da Silva, F.; Lange, E.; Jones, N. C.; Hoffmann, S. V.; Śmiałek, M. A.; Jones, D. B.; Brunger, M. J.
2016-07-01
We present the experimental high-resolution vacuum ultraviolet (VUV) photoabsorption spectra of phenol covering for the first time the full 4.3-10.8 eV energy-range, with absolute cross sections determined. Theoretical calculations on the vertical excitation energies and oscillator strengths were performed using time-dependent density functional theory and the equation-of-motion coupled cluster method restricted to single and double excitations level. These have been used in the assignment of valence and Rydberg transitions of the phenol molecule. The VUV spectrum reveals several new features not previously reported in the literature, with particular reference to the 6.401 eV transition, which is here assigned to the 3sσ/σ∗(OH)←3π(3a″) transition. The measured absolute photoabsorption cross sections have been used to calculate the photolysis lifetime of phenol in the earth's atmosphere (0-50 km).
Non-equilibrium physics of Rydberg lattices in the presence of noise and dissipative processes
Abdussalam, Wildan; Gil, Laura I. R.
2016-12-01
We study the non-equilibrium dynamics of driven spin lattices in the presence of decoherence caused by either laser phase noise or strong decay. In the first case, we discriminate between correlated and uncorrelated noise and explore their effect on the mean density of Rydberg states and the full counting statistics (FCS). We find that while the mean density is almost identical in both cases, the FCS differ considerably. The main method employed is the Langevin equation (LE) but for the sake of efficiency in certain regimes, we use a Markovian master equation and Monte Carlo rate equations, respectively. In the second case, we consider dissipative systems with more general power-law interactions. We determine the phase diagram in the steady state and analyse its generation dynamics using Monte Carlo rate equations. In contrast to nearest-neighbour models, there is no transition to long-range-ordered phases for realistic interactions and resonant driving. Yet, for finite laser detunings, we show that Rydberg lattices can undergo a dissipative phase transition to a long-range-ordered antiferromagnetic (AF) phase. We identify the advantages of Monte Carlo rate equations over mean field (MF) predictions.
Rydberg atoms in low-frequency fields : fundamental aspects and applications
Gürtler, Andreas Stefan
2003-01-01
In this thesis we investigate highly excited atoms, so-called Rydberg atoms, in oscillating fields with frequencies from the megahertz to the terahertz domain. The strong interaction of Rydberg atoms with external fields is used to establish a connection between the ionization of Rydberg atoms by ra
Rydberg atoms in low-frequency fields : fundamental aspects and applications
Gürtler, Andreas Stefan
2003-01-01
In this thesis we investigate highly excited atoms, so-called Rydberg atoms, in oscillating fields with frequencies from the megahertz to the terahertz domain. The strong interaction of Rydberg atoms with external fields is used to establish a connection between the ionization of Rydberg atoms by
Lifetimes of ultra-long-range strontium Rydberg molecules
Camargo, F; Ding, R; Sadeghpour, H R; Yoshida, S; Burgdörfer, J; Dunning, F B; Killian, T C
2015-01-01
The lifetimes of the lower-lying vibrational states of ultralong-range strontium Rydberg molecules comprising one ground-state 5s2 1S0 atom and one Rydberg atom in the 5s38s 3S1 state are reported. The molecules are created in an ultracold gas held in an optical dipole trap and their numbers determined using ?eld ionization, the product electrons being detected by a microchannel plate. The measurements show that, in marked contrast to earlier measurements involving rubidium Rydberg molecules, the lifetimes of the low-lying molecular vibrational states are very similar to those of the parent Rydberg atoms. This results because the strong p-wave resonance in low-energy electronrubidium scattering, which plays an important role in determining the molecular lifetimes, is not present for strontium. The absence of this resonance o?ers advantages for experiments involving strontium Rydberg atoms as impurities in quantum gases and for testing theories of molecular formation and decay.
Production of very-high-$n$ strontium Rydberg atoms
Ye, Shuzhen; Killian, Thomas C; Dunning, F Barry; Hiller, Moritz; Yoshida, Shuhei; Nagele, Stefan; Burgdörfer, Joachim
2013-01-01
The production of very-high-$n$, $n\\sim300$-500, strontium Rydberg atoms is explored using a crossed laser-atom beam geometry. $n$$^{1}$S$_{0}$ and $n$$^{1}$D$_{2}$ states are created by two-photon excitation via the 5s5p $^{1}$P$_{1}$ intermediate state using radiation with wavelengths of $\\sim$~461 and $\\sim$ 413 nm. Rydberg atom densities as high as $\\sim 3 \\times 10^{5}$ cm$^{-3}$ have been achieved, sufficient that Rydberg-Rydberg interactions can become important. The isotope shifts in the Rydberg series limits are determined by tuning the 461 nm light to preferentially excite the different strontium isotopes. Photoexcitation in the presence of an applied electric field is examined. The initially quadratic Stark shift of the $n$$^{1}$P$_{1}$ and $n$$^{1}$D$_{2}$ states becomes near-linear at higher fields and the possible use of $n{}^{1}$D$_{2}$ states to create strongly-polarized, quasi-one-dimensional electronic states in strontium is discussed. The data are analyzed with the aid of a two-active-elect...
Ionization photophysics and Rydberg spectroscopy of diacetylene
Schwell, Martin
2012-11-01
Photoionization of diacetylene was studied using synchrotron radiation over the range 8-24 eV, with photoelectron-photoion coincidence (PEPICO) and threshold photoelectron-photoion coincidence (TPEPICO) techniques. Mass spectra, ion yields, total and partial ionization cross-sections were measured. The adiabatic ionization energy of diacetylene was determined as IE ad=(10.17±0.01) eV, and the appearance energy of the principal fragment ion C4H+ as AE=(16.15±0.03) eV. Calculated appearance energies of other fragment ions were used to infer aspects of dissociation pathways forming the weaker fragment ions C+ 4, C3H+, C+3 and C 4H+. Structured autoionization features observed in the PEPICO spectrum of diacetylene in the 11-13 eV region were assigned to vibrational components of three new Rydberg series, R1(nsσg, n=4-11), R2(ndσg, n=4-7) and R3(ndδg, n=4-6) converging to the A2Πu state of the cation, and to a new series R01(nsσg, n=3) converging to the B\\' 2Σ+u state of the cation. The autoionization mechanisms and their consistence with specific selection rules are discussed. © 2012 Taylor and Francis.
Enhanced electron attachment to Rydberg states in molecular hydrogen volume discharges
Pinnaduwage, L. A.; Ding, W. X.; McCorkle, D. L.; Lin, S. H.; Mebel, A. M.; Garscadden, A.
1999-05-01
We review recent studies on negative ion formation and studies in other areas that are relevant to the role of high-Rydberg states of H2 and H3 in hydrogen negative ion sources. Possible mechanisms for the formation of these excited states are discussed, including the formation of long-lived superexcited (core-excited) Rydberg states. Experimental evidence for negative ion formation via electron attachment to core-excited Rydberg states in a glow discharge apparatus is presented. An expression for the dissociative electron attachment rate constant for Rydberg molecules is derived based on electron capture by a Rydberg molecule due to polarization interaction.
Interaction-Enhanced Imaging of Rydberg P states
Gavryusev, Vladislav; Kekić, Armin; Zürn, Gerhard; Signoles, Adrien
2016-01-01
The Interaction Enhanced Imaging technique allows to detect the spatial distribution of strongly interacting impurities embedded within a gas of background atoms used as a contrast medium. Here we present a detailed study of this technique, applied to detect Rydberg $P$ states. We experimentally realize fast and efficient three-photon excitation of $P$ states, optimized according to the results of a theoretical effective two-level model. Few Rydberg $P$-state atoms, prepared in a small cloud with dimensions comparable to the blockade radius, are detected with a good sensitivity by averaging over 50 shots. The main aspects of the technique are described with a hard-sphere model, finding good agreement with experimental data. This work paves the way to a non-destructive optical detection of single Rydberg atoms with high spatial and temporal resolution.
Inelastic Photon Scattering via the Intracavity Rydberg Blockade
Grankin, A.; Brion, E.; Boddeda, R.; Ćuk, S.; Usmani, I.; Ourjoumtsev, A.; Grangier, P.
2016-12-01
Electromagnetically induced transparency (EIT) in a ladder system involving a Rydberg level is known to yield giant optical nonlinearities for the probe field, even in the few-photon regime. This enhancement is due to the strong dipole-dipole interactions between Rydberg atoms and the resulting excitation blockade phenomenon. In order to study such highly correlated media, ad hoc models or low-excitation assumptions are generally used to tackle their dynamical response to optical fields. Here, we study the behavior of a cavity Rydberg-EIT setup in the nonequilibrium quantum field formalism, and we obtain analytic expressions for elastic and inelastic components of the cavity transmission spectrum, valid up to higher excitation numbers than previously achieved. This allows us to identify and interpret a polaritonic resonance structure, to our knowledge unreported so far.
Inelastic Photon Scattering via the Intracavity Rydberg Blockade.
Grankin, A; Brion, E; Boddeda, R; Ćuk, S; Usmani, I; Ourjoumtsev, A; Grangier, P
2016-12-16
Electromagnetically induced transparency (EIT) in a ladder system involving a Rydberg level is known to yield giant optical nonlinearities for the probe field, even in the few-photon regime. This enhancement is due to the strong dipole-dipole interactions between Rydberg atoms and the resulting excitation blockade phenomenon. In order to study such highly correlated media, ad hoc models or low-excitation assumptions are generally used to tackle their dynamical response to optical fields. Here, we study the behavior of a cavity Rydberg-EIT setup in the nonequilibrium quantum field formalism, and we obtain analytic expressions for elastic and inelastic components of the cavity transmission spectrum, valid up to higher excitation numbers than previously achieved. This allows us to identify and interpret a polaritonic resonance structure, to our knowledge unreported so far.
Contactless nonlinear optics mediated by long-range Rydberg interactions
Busche, Hannes; Huillery, Paul; Ball, Simon W.; Ilieva, Teodora; Jones, Matthew P. A.; Adams, Charles S.
2017-07-01
In conventional nonlinear optics, linear quantum optics, and cavity quantum electrodynamics to create effective photon-photon interactions photons must have, at one time, interacted with matter inside a common medium. In contrast, in Rydberg quantum optics, optical photons are coherently and reversibly mapped onto collective atomic Rydberg excitations, giving rise to dipole-mediated effective photon-photon interactions that are long range. Consequently, a spatial overlap between the light modes is no longer required. We demonstrate such a contactless coupling between photons stored as collective Rydberg excitations in spatially separate optical media. The potential induced by each photon modifies the retrieval mode of its neighbour, leading to correlations between them. We measure these correlations as a function of interaction strength, distance and storage time, demonstrating an effective interaction between photons separated by 15 times their wavelength. Contactless effective photon-photon interactions are relevant for scalable multichannel photonic devices and the study of strongly correlated many-body dynamics using light.
Entangling quantum gate in trapped ions via Rydberg blockade
Li, Weibin
2013-01-01
We present a theoretical analysis of the implementation of an entangling quantum gate between two trapped Ca$^+$ ions which is based on the dipolar interaction among ionic Rydberg states. In trapped ions the Rydberg excitation dynamics is usually strongly affected by mechanical forces due to the strong couplings between electronic and vibrational degrees of freedom in inhomogeneous electric fields. We demonstrate that this harmful effect can be overcome by using dressed states that emerge from the microwave coupling of nearby Rydberg states. At the same time these dressed states exhibit long range dipolar interactions which we use to implement a controlled adiabatic phase gate. Our study highlights a route towards a trapped ion quantum processor in which quantum gates are realized independently of the vibrational modes.
Imaging the evolution of an ultracold strontium Rydberg gas
McQuillen, P; Strickler, T; Dunning, F B; Killian, T C
2012-01-01
Clouds of ultracold strontium 5s48s 1S0 or 5s47d 1D2 Rydberg atoms are created by two photon excitation of laser cooled 5s2 1S0 atoms. The spontaneous evolution of the cloud of low orbital angular momentum (low-l) Rydberg states towards an ultracold neutral plasma is observed by imaging resonant light scattered from core ions, a technique that provides both spatial and temporal resolution. Evolution is observed to be faster for the S-states, which display isotropic attractive interactions, than for the D-states, which exhibit anisotropic, principally repulsive interactions. Immersion of the atoms in a dilute ultracold neutral plasma speeds up the evolution and allows the number of Rydberg atoms initially created to be determined.
Rydberg atoms inside hollow-core photonic crystal fibres
Löw, Robert; Epple, Georg; Kleinbach, Kathrin; Euser, Tijmen; Joly, Nicolas; Pfau, Tilman; Russell, Philip
2014-05-01
Rydberg atoms have peculiar properties as enhanced sensitivities to AC/DC electric fields or exaggerated strong interactions between them, leading to optical non-linearities on the single photon level. These properties are mostly studied with spectroscopic methods often limited by the free space diffraction limit. This can be avoided by confining Rydberg atoms inside hollow core fibres offering a perfect match of guided light modes with the atomic gas in terms of atom-light coupling. Additionally we choose Kagome type fibres due to their extremely thin structures, promising a reduced atom wall coupling. With coherent three photon spectroscopy we can show that Rydberg atoms can be excited within these fibres up to states of n = 46 without severe perturbations by the fibre environment.
Radio-frequency-modulated Rydberg states in a vapor cell
Miller, Stephanie A; Raithel, Georg
2016-01-01
We measure strong radio-frequency (RF) electric fields using rubidium Rydberg atoms prepared in a room-temperature vapor cell as field sensors. Electromagnetically induced transparency is employed as an optical readout. We RF-modulate the 60$S_{1/2}$ and 58$D_{5/2}$ Rydberg states with 50~MHz and 100~MHz fields, respectively. For weak to moderate RF fields, the Rydberg levels become Stark-shifted, and sidebands appear at even multiples of the driving frequency. In high fields, the adjacent hydrogenic manifold begins to intersect the shifted levels, providing rich spectroscopic structure suitable for precision field measurements. A quantitative description of strong-field level modulation and mixing of $S$ and $D$ states with hydrogenic states is provided by Floquet theory. Additionally, we estimate the shielding of DC electric fields in the interior of the glass vapor cell.
Rydberg blockade effects at n ˜300 in strontium
Zhang, X.; Dunning, F. B.; Yoshida, S.; Burgdörfer, J.
2015-11-01
Rydberg blockade at n ˜300 , is examined using strontium n F13 Rydberg atoms excited in an atomic beam in a small volume defined by two tightly focused crossed laser beams. The observation of blockade for such states is challenging due to their extreme sensitivity to stray fields and the many magnetic sublevels associated with F states which results in a high local density of states. Nonetheless, with a careful choice of laser polarization to selectively excite only a limited number of these sublevels, sizable blockade effects are observed on an ˜0.1 mm length scale extending blockade measurements into the near-macroscopic regime and enabling study of the dynamics of strongly coupled many-body high-n Rydberg systems under carefully controlled conditions.
Electrically Dressed Ultralong-Range Polar Rydberg Molecules
Kurz, Markus
2013-01-01
We investigate the impact of an electric field on the structure of ultralong-range polar diatomic Rydberg molecules. Both the s-wave and p-wave interactions of the Rydberg electron and the neutral ground state atom are taken into account. In the presence of the electric field the angular degree of freedom between the electric field and the internuclear axis acquires vibrational character and we encounter two-dimensional oscillatory adiabatic potential energy surfaces with an antiparallel equilibrium configuration. The electric field allows to shift the corresponding potential wells in such a manner that the importance of the p-wave interaction can be controlled and the individual wells are energetically lowered at different rates. As a consequence the equilibrium configuration and corresponding energetically lowest well move to larger internuclear distances for increasing field strength. For strong fields the admixture of non-polar molecular Rydberg states leads to the possibility of exciting the large angula...
Charge-induced optical bistability in thermal Rydberg vapor
Weller, Daniel; Rico, Andy; Löw, Robert; Kübler, Harald
2016-01-01
We investigate the phenomenon of optical bistability in a driven ensemble of Rydberg atoms. By performing two experiments with thermal vapors of rubidium and cesium, we are able to shed light onto the underlying interaction mechanisms causing such a non-linear behavior. Due to the different properties of these two atomic species, we conclude that the large polarizability of Rydberg states in combination with electric fields of spontaneously ionized Rydberg atoms is the relevant interaction mechanism. In the case of rubidium, we directly measure the electric field in a bistable situation via two-species spectroscopy. In cesium, we make use of the different sign of the polarizability for different l-states and the possibility of applying electric fields. Both these experiments allow us to rule out dipole-dipole interactions, and support our hypothesis of a charge-induced bistability.
Towards Rydberg quantum optics in a hollow core fiber
Noaman, Mohammad; Langbecker, Maria; Windpassinger, Patrick
2016-05-01
Cold atoms inside hollow-core fibers present a promising candidate to study strongly coupled light-matter systems. Adding coherent quantum state control and the intriguing features of Rydberg atoms, i.e. long range dipolar interactions leading to a dipole blockade, to the system should allow for the generation of exotic polaritonic and photonic states. This talk will review the current status of our experimental setup where laser cooled Rubidium atoms are transported into a hollow-core fiber. We present the first measurements of Rydberg EIT in the dipole trap in front of the fiber and discuss the progress towards Rydberg physics in a quasi-one-dimensional geometry. This work is supported by FP7, Marie Curie ITN 317485, QTea.
Many-body Physics with Alkaline-Earth Rydberg lattices
Mukherjee, R; Nath, R; Jones, M P A; Pohl, T
2011-01-01
We explore the prospects for confining alkaline-earth Rydberg atoms in an optical lattice via optical dressing of the secondary core valence electron. Focussing on the particular case of strontium, we identify experimentally accessible magic wavelengths for simultaneous trapping of ground and Rydberg states. A detailed analysis of relevant loss mechanisms shows that the overall lifetime of such a system is limited only by the spontaneous decay of the Rydberg state, and is not significantly affected by photoionization or autoionization. The van der Waals C_6 coefficients for the 5sns series are calculated, and we find that the interactions are attractive. Finally we show that the combination of magic-wavelength lattices and attractive interactions could be exploited to generate many-body Greenberger-Horne-Zeilinger (GHZ) states.
Energy Technology Data Exchange (ETDEWEB)
Mironchuk, E. S.; Narits, A. A.; Lebedev, V. S., E-mail: vlebedev@sci.lebedev.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)
2015-11-15
The resonant mechanism of interaction of alkaline-earth atoms having a low electron affinity to Rydberg atoms in circular (l = vertical bar m vertical bar = n–1) and near-circular states has been studied. To describe the dynamics of resonant processes accompanied by nonadiabatic transitions between ionic and Rydberg covalent terms of a quasimolecule, an approach based on the integration of coupled equations for the probability amplitudes has been developed taking into account the possibility of the decay of an anion in the Coulomb field of the positive ionic core of a highly excited atom. The approach involves the specific features of the problem associated with the structure of the wavefunction of a Rydberg electron in states with high orbital angular momenta l ∼ n–1. This approach provides a much more accurate description of the dynamics of electronic transitions at collisions between atoms than that within the modified semiclassical Landau–Zener model. In addition, this approach makes it possible to effectively take into account many channels of the problem. The cross sections for resonant quenching of Rydberg states of the Li(nlm) atom with given principal n, orbital l = n–1, and magnetic m quantum numbers at thermal collisions with the Ca(4s{sup 2}) and Sr(5s{sup 2}) atoms have been calculated. The dependences of the results on n, m, and angle α between the relative velocity of the atoms and the normal to the plane of the orbit of the Rydberg electron have been obtained. The influence of orientational effects on the efficiency of the collisional destruction of circular and near-circular states has been studied. The results indicate a higher stability of such states to their perturbations by neutral particles as compared to usually studied nl states with low values of l (l ≪ n)
Mironchuk, E. S.; Narits, A. A.; Lebedev, V. S.
2015-11-01
The resonant mechanism of interaction of alkaline-earth atoms having a low electron affinity to Rydberg atoms in circular ( l = | m| = n-1) and near-circular states has been studied. To describe the dynamics of resonant processes accompanied by nonadiabatic transitions between ionic and Rydberg covalent terms of a quasimolecule, an approach based on the integration of coupled equations for the probability amplitudes has been developed taking into account the possibility of the decay of an anion in the Coulomb field of the positive ionic core of a highly excited atom. The approach involves the specific features of the problem associated with the structure of the wavefunction of a Rydberg electron in states with high orbital angular momenta l ~ n-1. This approach provides a much more accurate description of the dynamics of electronic transitions at collisions between atoms than that within the modified semiclassical Landau-Zener model. In addition, this approach makes it possible to effectively take into account many channels of the problem. The cross sections for resonant quenching of Rydberg states of the Li( nlm) atom with given principal n, orbital l = n-1, and magnetic m quantum numbers at thermal collisions with the Ca(4 s 2) and Sr(5 s 2) atoms have been calculated. The dependences of the results on n, m, and angle α between the relative velocity of the atoms and the normal to the plane of the orbit of the Rydberg electron have been obtained. The influence of orientational effects on the efficiency of the collisional destruction of circular and near-circular states has been studied. The results indicate a higher stability of such states to their perturbations by neutral particles as compared to usually studied nl states with low values of l ( l ≪ n).
Preparation of circular Rydberg states in helium using the crossed-fields method
Zhelyazkova, V.; Hogan, S. D.
2016-08-01
Helium atoms have been prepared in the circular |n =55 ,ℓ =54 , mℓ=+54 > Rydberg state using the crossed electric and magnetic fields method. The atoms, initially traveling in pulsed supersonic beams, were photoexcited from the metastable 1 s 2 s S31 level to the outermost, mℓ=0 Rydberg-Stark state with n =55 in the presence of a strong electric field and weak perpendicular magnetic field. Following excitation, the electric field was adiabatically switched off causing the atoms to evolve into the circular state with mℓ=+54 defined with respect to the magnetic-field quantization axis. The circular states were detected by ramped electric-field ionization along the magnetic-field axis. The dependence of the circular state production efficiency on the strength of the excitation electric field, and the electric-field switch-off time was studied, and microwave spectroscopy of the circular-to-circular |55 ,54 ,+54 >→|56 ,55 ,+55 > transition at ˜38.5 GHz was performed.
Non-equilibrium physics of Rydberg lattices in the presence of noise and dissipative processes
Abdussalam, Wildan
2016-01-01
We study the non-equilibrium dynamics of driven spin lattices in the presence of decoherence caused by either laser phase noise or strong decay. In the first case, we discriminate between correlated and uncorrelated noise and explore their effect on the mean density of Rydberg states and the full counting statistics (FCS). We find that while the mean density is almost identical in both cases, the FCS differ considerably. The main method employed is the Langevin equation (LE) but for the sake of efficiency in certain regimes, we use a Markovian master equation and Monte Carlo rate equations, respectively. In the second case, we consider dissipative systems with more general power-law interactions. We determine the phase diagram in the steady state and analyse its generation dynamics using Monte Carlo rate equations. In contrast to nearest-neighbour models, there is no transition to long-range-ordered phases for realistic interactions and resonant driving. Yet, for finite laser detunings, we show that Rydberg l...
Implementation of Chiral Quantum Optics with Rydberg and Trapped-ion Setups
Vermersch, Benoît; Hauke, Philipp; Zoller, Peter
2016-01-01
We propose two setups for realizing a chiral quantum network, where two-level systems representing the nodes interact via directional emission into discrete waveguides, as introduced in Ref.~[T.\\ Ramos \\emph{et al.}, arXiv:1602.00926]. The first implementation realizes a spin waveguide via Rydberg states in a chain of atoms, whereas the second one realizes a phonon waveguide via the localized vibrations of a string of trapped ions. For both architectures, we show that strong chirality can be obtained by a proper design of synthetic gauge fields in the couplings from the nodes to the waveguide. In the Rydberg case, this is achieved via intrinsic spin-orbit coupling in the dipole-dipole interactions, while for the trapped ions it is obtained by engineered sideband transitions. We take long-range couplings into account that appear naturally in these implementations, discuss useful experimental parameters, and analyze potential error sources. Finally, we describe effects that can be observed in these implementati...
Implementation of chiral quantum optics with Rydberg and trapped-ion setups
Vermersch, Benoît; Ramos, Tomás; Hauke, Philipp; Zoller, Peter
2016-06-01
We propose two setups for realizing a chiral quantum network, where two-level systems representing the nodes interact via directional emission into discrete waveguides, as introduced in T. Ramos et al. [Phys. Rev. A 93, 062104 (2016), 10.1103/PhysRevA.93.062104]. The first implementation realizes a spin waveguide via Rydberg states in a chain of atoms, whereas the second one realizes a phonon waveguide via the localized vibrations of a string of trapped ions. For both architectures, we show that strong chirality can be obtained by a proper design of synthetic gauge fields in the couplings from the nodes to the waveguide. In the Rydberg case, this is achieved via intrinsic spin-orbit coupling in the dipole-dipole interactions, while for the trapped ions it is obtained by engineered sideband transitions. We take long-range couplings into account that appear naturally in these implementations, discuss useful experimental parameters, and analyze potential error sources. Finally, we describe effects that can be observed in these implementations within state-of-the-art technology, such as the driven-dissipative formation of entangled dimer states.
Preparation of circular Rydberg states in helium using the crossed fields method
Zhelyazkova, V
2016-01-01
Helium atoms have been prepared in the circular $|n=55,\\ell=54,m_{\\ell}=+54\\rangle$ Rydberg state using the crossed electric and magnetic fields method. The atoms, initially travelling in pulsed supersonic beams, were photoexcited from the metastable $1s2s\\,^3S_1$ level to the outermost, $m_{\\ell}=0$ Rydberg-Stark state with $n=55$ in the presence of a strong electric field and weak perpendicular magnetic field. Following excitation, the electric field was adiabatically switched off causing the atoms to evolve into the circular state with $m_{\\ell}=+54$ defined with respect to the magnetic field quantization axis. The circular states were detected by ramped electric field ionization along the magnetic field axis. The dependence of the circular state production efficiency on the strength of the excitation electric field, and the electric-field switch-off time was studied, and microwave spectroscopy of the circular-to-circular $|55,54,+54\\rangle\\rightarrow|56,55,+55\\rangle$ transition at $\\sim38.5$~GHz was perf...
Energy Technology Data Exchange (ETDEWEB)
Reshak, A.H., E-mail: maalidph@yahoo.co.uk [New Technologies – Research Centre, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic); Center of Excellence Geopolymer and Green Technology, School of Material Engineering, University Malaysia Perlis, 01007 Kangar, Perlis (Malaysia)
2015-11-05
We explored the influence of changing the pnicogens by substituting As by Sb on the optical properties of Ba{sub 2}Cd{sub 2}Pn{sub 3} (Pn = As and Sb). Calculation show that there exists subtle difference in the electronic structures when we substitute As by Sb, which lead to significant influence on the optical properties, taking into account the size and the electro-negativity differences between As and Sb atoms. The full potential method within the recently modified Becke-Johnson potential explore that the Ba{sub 2}Cd{sub 2}Pn{sub 3} (Pn = As and Sb) compounds are narrow band gap semiconductors of about 0.49 and 0.32 eV. The optical properties explore that these material have negative uniaxial anisotropy, negative birefringence and considerable anisotropy between the optical components in the polarization directions [100], [010] and [001] with respect to the crystal axis. Furthermore, the optical properties confirm that Ba{sub 2}Cd{sub 2}Sb{sub 3} possess a band gap which is smaller than that of Ba{sub 2}Cd{sub 2}As{sub 3}. The optical properties helps to get deep insight into the electronic structure. - Highlights: • The optical properties of Ba{sub 2}Cd{sub 2}Pn{sub 3} (Pn = As and Sb) were investigated. • The subtle difference in electronic structures influence the optical properties. • Ba{sub 2}Cd{sub 2}Pn{sub 3} (Pn = As and Sb) are narrow band gap semiconductors. • The investigated compounds exhibit negative uniaxial anisotropy and birefringence.
Correlated Photon Emission from Multiatom Rydberg Dark States
DEFF Research Database (Denmark)
Pritchard, J.D.; Adams, C.S.; Mølmer, Klaus
2012-01-01
We consider three-level atoms driven by two resonant light fields in a ladder scheme where the upper level is a highly excited Rydberg state. We show that the dipole-dipole interactions between Rydberg excited atoms prevents the formation of single particle dark states and leads to strongly corre...... correlated photon pairs from atoms separated by distances large compared to the emission wavelength. For a pair of atoms, this enables realization of an efficient photon-pair source with on average one pair every 30 μs....
Periodic Orbit Theory for Rydberg Atoms in External Fields
Dando, P. A.; Monteiro, T. S.; Owen, S. M.
1998-03-01
Although hydrogen in external fields is a paradigm for the application of periodic orbits and the Gutzwiller trace formula to a real system, the trace formula has never been applied successfully to other Rydberg atoms. We show that spectral fluctuations of general Rydberg atoms are given with remarkable precision by the addition of diffractive terms. Previously unknown features in atomic spectra are exposed: there are new modulations that are neither periodic orbits nor combinations of periodic orbits; ``core shadowing'' generally decreases primitive periodic orbit amplitudes but can also lead to increases.
Periodic Orbit Theory for Rydberg Atoms in External Fields
Dando, P A; Owen, S M
1998-01-01
Although hydrogen in external fields is a paradigm for the application of periodic orbits and the Gutzwiller trace formula to a real system, the trace formula has never been applied successfully to other Rydberg atoms. We show that spectral fluctuations of general Rydberg atoms are given with remarkable precision by the addition of diffractive terms. Previously unknown features in atomic spectra are exposed: there are new modulations that are neither periodic orbits nor combinations of periodic orbits; `core-shadowing' generally decreases primitive periodic orbit amplitudes but can also lead to increases.
Entanglement of two individual neutral atoms using Rydberg blockade
Wilk, T; Evellin, C; Wolters, J; Miroshnychenko, Y; Grangier, P; Browaeys, A
2009-01-01
We report the generation of entanglement between two individual 87Rb atoms in hyperfine ground states |F=1,M=1> and |F=2,M=2> which are held in two optical tweezers separated by 4 $\\mu$m. Our scheme relies on the Rydberg blockade effect which prevents the simultaneous excitation of the two atoms to a Rydberg state. The entangled state is generated in about 200 ns using pulsed two-photon excitation. We quantify the entanglement by applying global Raman rotations on both atoms. Correcting for losses we measure a fidelity of 0.75 with respect to the target state.
Relativistic Multichannel Treatment of Ionic Rydberg States of Lanthanum
Institute of Scientific and Technical Information of China (English)
ZHANG Xin-Feng; JIA Feng-Dong; ZHONG Zhi-Ping; XUE Ping; XU Xiang-Yuan; YAN Jun
2007-01-01
Ionic Rydberg energy levels of lanthanum are calculated from first principles by relativistic multichannel theory within the framework of multichannel quantum defect theory. The present calculated results are in better agreement with the experimental measurements than the previous calculations [J. Phys. B 34 (2001)369] due to the consideration of dynamical polarizations. Moreover, in the experimental spectra achieved by a five-laser resonance excitation via the intermediate state 5d6d3 F2, a series of weak ionic Rydberg states and some of perturbing states are found and assigned in this work.
Multibit CkNOT quantum gates via Rydberg blockade
DEFF Research Database (Denmark)
Isenhower, L.; Saffman, Mark; Mølmer, Klaus
2011-01-01
Long range Rydberg blockade interactions have the potential for efficient implementation of quantum gates between multiple atoms. Here we present and analyze a protocol for implementation of a k-atom controlled NOT (CkNOT) neutral atom gate. This gate can be implemented using sequential or simult......Long range Rydberg blockade interactions have the potential for efficient implementation of quantum gates between multiple atoms. Here we present and analyze a protocol for implementation of a k-atom controlled NOT (CkNOT) neutral atom gate. This gate can be implemented using sequential...
Anisotropic blockade using pendular long-range Rydberg molecules
Eiles, Matthew T.; Lee, Hyunwoo; Pérez-Ríos, Jesús; Greene, Chris H.
2017-05-01
We propose an experiment to demonstrate a blockade mechanism caused by long-range anisotropic interactions in an ultracold dipolar gas composed of the recently observed "butterfly" Rydberg molecules. At the blockade radius, the strong intermolecular interaction between two adjacent molecules shifts their molecular states out of resonance with the photoassociation laser, preventing their simultaneous excitation. When the molecules are prepared in a quasi-one-dimensional (Q1D) trap, the interaction's strength can be tuned via a weak external field. The molecular density thus depends strongly on the angle between the trap axis and the field. The available Rydberg and internal molecular states provide a wide range of tunability.
Polarization-selective optical nonlinearities in cold Rydberg atoms
Wu, Jin-Hui; Artoni, M.; La Rocca, G. C.
2015-12-01
We study the interaction between a probe and a trigger weak fields in a sample of cold rubidium atoms in the presence of a coupling and a dressing strong fields. Dipole Rydberg blockade may occur and can be set to depend on the probe and trigger polarizations giving rise to diverse regimes of electromagnetically induced transparency (EIT) with a concomitant small probe and trigger absorption and dispersion. This is shown to be relevant to the implementation of polarization conditional probe and trigger cross nonlinearities in cold Rydberg atoms.
A note on the assignments of Rydberg states of COS
Wu, C. Y. R.
1982-01-01
Assignments of the Rydberg states which converge to the respective X-tilde and B-tilde ion states of the COS(+) ion are reported. The assignments were made based on previously established orderings for the quantum defects of isoelectronic molecules. The Rydberg series I and II, which converge to the X-tilde 2 Pi state of COS(+), and the series III, IV, V, VI and VII, which converge to the B-tilde 2 Sigma + state, are assigned to molecular orbitals characterized by predominant sulfur orbitals, in contrast to those converging to the C-tilde states, which are characterized by oxygen atomic orbitals.
Electric dipole moments of lithium atoms in Rydberg states
Dong, Hui-Jie; Huang, Ke-Shu; Li, Chang-Yong; Zhao, Jian-Ming; Zhang, Lin-Jie; Jia, Suo-Tang
2014-09-01
Recently, the diverse properties of Rydberg atoms, which probably arise from its large electric dipole moment (EDM), have been explored. In this paper, we report electric dipole moments along with Stark energies and charge densities of lithium Rydberg states in the presence of electric fields, calculated by matrix diagonalization. Huge electric dipole moments are discovered. In order to check the validity of the EDMs, we also use these electric dipole moments to calculate the Stark energies by numerical integration. The results agree with those calculated by matrix diagonalization.
Gavryusev, Vladislav; Ferreira-Cao, Miguel; Kekić, Armin; Zürn, Gerhard; Signoles, Adrien
2016-12-01
The Interaction Enhanced Imaging technique allows to detect the spatial distribution of strongly interacting impurities embedded within a gas of background atoms used as a contrast medium [1]. Here we present a detailed study of this technique, applied to detect Rydberg P states. We experimentally realize fast and efficient three-photon excitation of P states, optimized according to the results of a theoretical effective two-level model. Few Rydberg P-state atoms, prepared in a small cloud with dimensions comparable to the blockade radius, are detected with a good sensitivity by averaging over 50 shots. The main aspects of the technique are described with a hard-sphere model, finding good agreement with experimental data. This work paves the way to a non-destructive optical detection of single Rydberg atoms with high spatial and temporal resolution.
Three-photon excitation of hydrogen Rydberg states.
Glab, W L; Nayfeh, M H
1983-01-01
A three-photon process using radiation at 2430 and 3660 A and with a 1s-2s two-photon resonance is used to excite atomic hydrogen from the ground state to Rydberg states of high principal quantum number. Collision-induced ionization is used to monitor the excitation.
Three-photon excitation of hydrogen Rydberg states
Energy Technology Data Exchange (ETDEWEB)
Glab, W.L.; Nayfeh, M.H.
1983-01-01
A three-photon process using radiation at 2430 and 3660 A and with a 1s-2s two-photon resonance is used to excite atomic hydrogen from the ground state to Rydberg states of high principal quantum number. Collision-induced ionization is used to monitor the excitation.
Entanglement of two ground state neutral atoms using Rydberg blockade
DEFF Research Database (Denmark)
Miroshnychenko, Yevhen; Browaeys, Antoine; Evellin, Charles
2011-01-01
We report on our recent progress in trapping and manipulation of internal states of single neutral rubidium atoms in optical tweezers. We demonstrate the creation of an entangled state between two ground state atoms trapped in separate tweezers using the effect of Rydberg blockade. The quality of...
Bistability vs. Metastability in Driven Dissipative Rydberg Gases
Letscher, Fabian; Niederprüm, Thomas; Fleischhauer, Michael; Ott, Herwig
2016-01-01
We investigate the possibility of a bistable phase in an open many-body system. To this end we discuss the microscopic dynamics of a continuously off-resonantly driven Rydberg lattice gas in the regime of strong decoherence. Our experimental results reveal a prolongation of the temporal correlations with respect to the lifetime of a single Rydberg excitation and show strong evidence for the formation of finite-sized Rydberg excitation clusters in the steady state. We simulate our data using a simplified and a full many-body rate-equation model. The results are compatible with the formation of metastable states associated with a bimodal counting distribution as well as dynamic hysteresis. A scaling analysis reveals however, that the correlation times remain finite for all relevant system parameters. This suggest that the Rydberg aggregate is composed of many small clusters and all correlation lengths remain finite. This is a strong indication for the absence of a global bistable phase, previously suggested to ...
Control of spatial correlations between Rydberg excitations using rotary echo
Thaicharoen, N; Raithel, G
2016-01-01
We manipulate correlations between Rydberg excitations in cold atom samples using a rotary-echo technique. The correlations are due to interactions between the Rydberg atoms. In the rotary-echo excitation sequence, the phase of the excitation pulse is flipped at a selected time during the pulse. We measure the resultant change in the spatial pair correlation function of the excitations via direct position-sensitive atom imaging. For zero detuning of the lasers from the interaction-free Rydberg-excitation resonance, the pair-correlation value at the most likely nearest-neighbor Rydberg-atom distance is substantially enhanced when the phase is flipped at the middle of the excitation pulse. In this case, the rotary echo eliminates most uncorrelated (un-paired) atoms, leaving an abundance of correlated atom pairs at the end of the sequence. In off-resonant cases, a complementary behavior is observed. We further characterize the effect of the rotary-echo excitation sequence on the excitation-number statistics of t...
Lifetime Measurement for 6snp Rydberg States of Barium
Institute of Scientific and Technical Information of China (English)
SHEN Li; WANG Lei; YANG Hai-Feng; LIU Xiao-Jun; LIU Hong-Ping
2011-01-01
@@ We present a simple and efficient method for measuring the atomic lifetimes in order of tens of microseconds and demonstrate it in the lifetime determination of barium Rydberg states.This method extracts the lifetime information from the time-of-flight spectrum directly, which is much more efficient than other methods such as the time-delayed field ionization and the traditional laser induced fluorescence.The lifetimes determined with our method for barium Rydberg 6snp(n=37-59)series are well coincident with the values deduced from the absolute oscillator strengths of barium which were given in the literature [J.Phys.B 14(1981)4489, 29(1996)655]on experiments.%We present a simple and efficient method for measuring the atomic lifetimes in order of tens of microseconds and demonstrate it in the lifetime determination of barium Rydberg states. This method extracts the lifetime information from the time-of-flight spectrum directly, which is much more efficient than other methods such as the time-delayed field ionization and the traditional laser induced fluorescence. The lifetimes determined with our method for barium Rydberg 6snp (n=37-59) series are well coincident with the values deduced from the absolute oscillator strengths of barium which were given in the literature [J. Phys. B 14 (1981) 4489, 29 (1996) 655] onexperiments.
Controlling Rydberg atom excitations in dense background gases
Liebisch, Tara Cubel; Engel, Felix; Nguyen, Huan; Balewski, Jonathan; Lochead, Graham; Böttcher, Fabian; Westphal, Karl M; Kleinbach, Kathrin S; Schmid, Thomas; Gaj, Anita; Löw, Robert; Hofferberth, Sebastian; Pfau, Tilman; Pérez-Ríos, Jesús; Greene, Chris H
2016-01-01
We discuss the density shift and broadening of Rydberg spectra measured in cold, dense atom clouds in the context of Rydberg atom spectroscopy done at room temperature, dating back to the experiments of Amaldi and Segr\\`e in 1934. We discuss the theory first developed in 1934 by Fermi to model the mean-field density shift and subsequent developments of the theoretical understanding since then. In particular, we present a model whereby the density shift is calculated using a microscopic model in which the configurations of the perturber atoms within the Rydberg orbit are considered. We present spectroscopic measurements of a Rydberg atom, taken in a Bose-Einstein condensate (BEC) and thermal clouds with densities varying from $5\\times10^{14}\\textrm{cm}^{-3}$ to $9\\times10^{12}\\textrm{cm}^{-3}$. The density shift measured via the spectrum's center of gravity is compared with the mean-field energy shift expected for the effective atom cloud density determined via a time of flight image. Lastly, we present calcul...
Topological matter with collective encoding and Rydberg blockade
DEFF Research Database (Denmark)
Nielsen, Anne E. B.; Mølmer, Klaus
2010-01-01
We propose to use a permutation symmetric sample of multilevel atoms to simulate the properties of topologically ordered states. The Rydberg blockade interaction is used to prepare states of the sample which are equivalent to resonating valence bond states, Laughlin states, and string-net condens......-net condensates and to create and study the properties of their quasi-particle-like fundamental excitations....
Optical Control of the Resonant Dipole-Dipole Interaction between Rydberg Atoms
de Léséleuc, Sylvain; Barredo, Daniel; Lienhard, Vincent; Browaeys, Antoine; Lahaye, Thierry
2017-08-01
We report on the local control of the transition frequency of a spin 1 /2 encoded in two Rydberg levels of an individual atom by applying a state-selective light shift using an addressing beam. With this tool, we first study the spectrum of an elementary system of two spins, tuning it from a nonresonant to a resonant regime, where "bright" (super-radiant) and "dark" (subradiant) states emerge. We observe the collective enhancement of the microwave coupling to the bright state. We then show that after preparing an initial single spin excitation and letting it hop due to the spin-exchange interaction, we can freeze the dynamics at will with the addressing laser, while preserving the coherence of the system. In the context of quantum simulation, this scheme opens exciting prospects for engineering inhomogeneous X Y spin Hamiltonians or preparing spin-imbalanced initial states.
Prospects of charged-oscillator quantum-state generation with Rydberg atoms
Stevenson, Robin; Minář, Jiří; Hofferberth, Sebastian; Lesanovsky, Igor
2016-10-01
We explore the possibility of engineering quantum states of a charged mechanical oscillator by coupling it to a stream of atoms in superpositions of high-lying Rydberg states. Our scheme relies on the driving of a two-phonon resonance within the oscillator by coupling it to an atomic two-photon transition. This approach effectuates a controllable open system dynamics on the oscillator that in principle permits versatile dissipative creation of squeezed and other nonclassical states which are central to sensing applications or for studies of fundamental questions concerning the boundary between classical and quantum-mechanical descriptions of macroscopic objects. We show that these features survive thermal coupling of the oscillator with the environment. We perform a detailed feasibility study finding that current state-of-the-art parameters result in atom-oscillator couplings which are too weak to efficiently implement the proposed oscillator state preparation protocol. Finally, we comment on ways to circumvent the present limitations.
Frequency-modulated excitation of Rydberg potassium atoms by using B-spline
Institute of Scientific and Technical Information of China (English)
Li Xiao-Yong; Wang Guo-Li; Zhou Xiao-Xin
2012-01-01
By using the B-spline expansion technique and a model potential of the alkali atoms,the properties of frequencymodulated excitation of Rydberg potassium atoms in a static electric field and a microwave field are investigated by using the time-dependent two-level approach.We successfully reproduce the square wave oscillations in the low frequency,the stair step population oscillations in the intermediate frequency,and the multiphoton transitions in the high frequency with respect to the unmodulated Rabi frequency,which have been observed experimentally by Noel et al.[Phys.Rev.A 58 2265 (1998)].Furthermore,we also numerically obtain the discretized Rabi oscillations predicted in the Landau-Zener accumulation model.
Stark spectra of Rydberg states in atomic cesium in the vicinity of n=18
Institute of Scientific and Technical Information of China (English)
Dong Hui-Jie; Wang Ting; Li Chang-Yong; Zhao Jian-Ming; Zhang Lin-Jie
2013-01-01
The Stark structures in a cesium atom around n =18 are numerically calculated.The results show that the components of 20D states with a small azimuthal quantum number |m| shift upward a lot,and those with a large |m| shift downward a little within 1100 V/cm.All components of P states shift downward.Experimental work has been performed in ultracold atomic cesium.Atoms initially in 6P3/2 state are excited to high-n Rydberg states by a polarization light perpendicular to the field,and Stark spectra with 丨m丨=1/2,3/2,5/2 are simultaneously observed with a large linewidth for the first time.The observed spectra are analyzed in detail.The relative transition probability is calculated.The experimental results are in good agreement with our numerical computation.
Divalent Rydberg atoms in optical lattices: intensity landscape and magic trapping
Topcu, Turker
2013-01-01
We develop a theoretical understanding of trapping divalent Rydberg atoms in optical lattices. Because the size of the Rydberg electron cloud can be comparable to the scale of spatial variations of laser intensity, we pay special attention to averaging optical fields over the atomic wavefunctions. Optical potential is proportional to the ac Stark polarizability. We find that in the independent particle approximation for the valence electrons, this polarizability breaks into two contributions: the singly ionized core polarizability and the contribution from the Rydberg electron. Unlike the usually employed free electron polarizability, the Rydberg contribution depends both on laser intensity profile and the rotational symmetry of the total electronic wavefunction. We focus on the $J=0$ Rydberg states of Sr and evaluate the dynamic polarizabilities of the 5s$n$s($^1S_0$) and 5s$n$p($^3P_0$) Rydberg states. We specifically choose Sr atom for its optical lattice clock applications. We find that there are several ...
Ionization of Rydberg H atoms at band-gap metal surfaces via surface and image states
So, E; Softley, T P
2015-01-01
Wavepacket propagation calculations are reported for the interaction of a Rydberg hydrogen atom ($n=2-8)$ with Cu(111) and Cu(100) surfaces (represented by a Chulkov potential), in comparison with a Jellium surface. Both copper surfaces have a projected band gap at the surface in the energy range degenerate with some or all of the Rydberg energies. The charge transfer of the Rydberg electron to the surface is found to be enhanced for $n$ values at which there is a near-degeneracy between the Rydberg energy level and an image state or a surface state of the surface. The enhancement is facilitated by the strong overlap of the surface image-state orbital lying outside the surface and the orbital of the incoming Rydberg atom. These calculations point to the possibility of using Rydberg-surface collisions as a probe of surface electronic structure.
Coincidence spectroscopy of high-lying Rydberg states produced in strong laser fields
Larimian, Seyedreza; Erattupuzha, Sonia; Lemell, Christoph; Yoshida, Shuhei; Nagele, Stefan; Maurer, Raffael; Baltuška, Andrius; Burgdörfer, Joachim; Kitzler, Markus; Xie, Xinhua
2016-09-01
We demonstrate the detection of high-lying Rydberg states produced in strong laser fields with coincidence spectroscopy. Electron emission after the interaction of strong laser pulses with atoms and molecules is measured together with the parent ions in coincidence measurements. These electrons originate from high-lying Rydberg states with quantum numbers from n ˜20 up to n ≲120 formed by frustrated field ionization. Ionization rates are retrieved from the measured ionization signal of these Rydberg states. Simulations show that both tunneling ionization by a weak dc field and photoionization by blackbody radiation contribute to delayed electron emission on the nano- to microsecond scale. Furthermore, the dependence of the Rydberg-state production on the ellipticity of the driving laser field indicates that such high-lying Rydberg states are populated through electron recapture. The present experiment provides detailed quantitative information on Rydberg production in strong-field interaction.
Rydberg dressing of a one-dimensional Bose-Einstein condensate
Płodzień, Marcin; van Druten, N J; Kokkelmans, Servaas
2016-01-01
We study the influence of Rydberg dressed interactions in a one-dimensional (1D) Bose-Einstein Condensate (BEC). We show that 1D is advantageous over 3D for observing BEC Rydberg dressing. The effects of dressing are studied by investigating collective BEC dynamics after a rapid switch-off of the Rydberg dressing interaction. The results can be interpreted as an effective modification of the $s$-wave scattering length. We include this modification in an analytical model for the 1D BEC, and compare it to numerical calculations of Rydberg dressing under realistic experimental conditions.
Full counting statistics of laser excited Rydberg aggregates in a one-dimensional geometry
Schempp, H; Robert-de-Saint-Vincent, M; Hofmann, C S; Breyel, D; Komnik, A; Schönleber, D W; Gärttner, M; Evers, J; Whitlock, S; Weidemüller, M
2014-01-01
We experimentally study the full counting statistics of few-body Rydberg aggregates excited from a quasi-one-dimensional Rydberg gas. We measure asymmetric excitation spectra and increased second and third order statistical moments of the Rydberg number distribution, from which we determine the average aggregate size. Direct comparisons with numerical simulations reveal the presence of liquid-like spatial correlations, and indicate sequential growth of the aggregates around an initial grain. These findings demonstrate the importance of dissipative effects in strongly correlated Rydberg gases and introduce a way to study spatio-temporal correlations in strongly-interacting many-body quantum systems without imaging.
Quantum signature for laser-driven correlated excitation of Rydberg atoms
Wu, Huaizhi; Li, Yong; Yang, Zhen-Biao; Zheng, Shi-Biao
2017-01-01
The excitation dynamics of a laser-driven Rydberg-atom system exhibits a cooperative effect due to the interatomic Rydberg-Rydberg interaction, but the large many-body system with inhomogeneous Rydberg coupling is hard to exactly solve or numerically study by density-matrix equations. In this paper, we find that the laser-driven Rydberg-atom system with most of the atoms being in the ground state can be described by a simplified interaction model resembling the optical Kerr effect if the distance-dependent Rydberg-Rydberg interaction is replaced by an infinite-range coupling. We can then quantitatively study the effect of the quantum fluctuations on the Rydberg excitation with the interatomic correlation involved and analytically calculate the statistical characteristics of the excitation dynamics in the steady state, revealing the quantum signature of the driven-dissipative Rydberg-atom system. The results obtained here will be of great interest for other spin-1/2 systems with spin-spin coupling.
Rydberg series for quartet states of Li-like sulfur ion
Sun, Yan; Sang, CuiCui; Hu, Feng; Qian, XinYu; Liu, DongDong; Mei, MaoFei; Gou, BingCong
2017-01-01
The energy levels and transition parameters of Li-like quartet states 1s2snl and 1s2pnl‧ (l=s, p, d; l‧=s, p, d, f; n=2-7) pertaining to 4Po and 4Le (L=S, P, D) Rydberg series in S13+ ion are calculated using a multi-configuration Rayleigh-Ritz variation method. Relativistic effects and mass polarization contributions are taken into account by using the first-order perturbation theory. The quantum electrodynamics (QED) effects and higher-order relativistic corrections are considered to obtain accurate energy levels by the screened hydrogenic formula. The transition oscillator strengths, transition rates, and wavelengths of electric-dipole transitions for 1s2sns4Se-1s2lnl‧ 4Po and 1s2snp+1s2pns+1s2pnd4Po-1s2lnl‧ 4Le (L=S, P, D) in S13+ ion are systematically calculated and compared with available reference data. Our calculated results will provide valuable data for related experiments in the future.
Topcu, Turker
2015-01-01
We investigate the effect of series perturbation on the second order dipole-dipole interactions between strontium atoms in $5sns({^1}S_0)$ and $5snp({^1}P_1)$ Rydberg states as a means of engineering long-range interactions between atoms in a way that gives an exceptional level of control over the strength and the sign of the interaction by changing $n$. We utilize experimentally available data to estimate the importance of perturber states at low $n$, and find that van der Waals interaction between two strontium atoms in the $5snp({^1}P_1)$ states shows strong peaks outside the usual hydrogenic $n^{11}$ scaling. We identify this to be the result of the perturbation of $5snd({^1}D_2)$ intermediate states by the $4d^2({^1}D_2)$ and $4dn's({^1}D_2)$ states in the $n<20$ range. This demonstrates that divalent atoms in general present a unique advantage for creating substantially stronger or weaker interaction strengths than those can be achieved using alkali metal atoms due to their highly perturbed spectra t...
Transmission-line decelerators for atoms in high Rydberg states
Lancuba, P
2014-01-01
Beams of helium atoms in Rydberg states with principal quantum number $n=52$, and traveling with an initial speed of 1950 m/s, have been accelerated, decelerated and guided while confined in moving electric traps generated above a curved, surface-based electrical transmission line with a segmented center conductor. Experiments have been performed with atoms guided at constant speed, and with accelerations exceeding $10^7$ m/s$^2$. In each case the manipulated atoms were detected by spatially resolved, pulsed electric field ionization. The effects of tangential and centripetal accelerations on the effective trapping potentials experienced by the atoms in the decelerator have been studied, with the resulting observations highlighting contributions from the density of excited Rydberg atoms to the acceleration, deceleration and guiding efficiencies in the experiments.
Transmission-line decelerators for atoms in high Rydberg states
Lancuba, P.; Hogan, S. D.
2014-11-01
Beams of helium atoms in Rydberg states with principal quantum number n =52 , and traveling with an initial speed of 1950 m/s, have been accelerated, decelerated, and guided while confined in moving electric traps generated above a curved, surface-based electrical transmission line with a segmented center conductor. Experiments have been performed with atoms guided at constant speed, and with accelerations exceeding 107 m /s 2. In each case, the manipulated atoms were detected by spatially resolved, pulsed electric field ionization. The effects of tangential and centripetal accelerations on the effective trapping potentials experienced by the atoms in the decelerator have been studied, with the resulting observations highlighting contributions from the density of excited Rydberg atoms to the acceleration, deceleration, and guiding efficiencies in the experiments.
Few-body quantum physics with strongly interacting Rydberg polaritons
Bienias, Przemyslaw
2016-12-01
We present an extension of our recent paper [Bienias et al., Phys. Rev. A 90, 053804 (2014)] in which we demonstrated the scattering properties and bound-state structure of two Rydberg polaritons, as well as the derivation of the effective low-energy many-body Hamiltonian. Here, we derive a microscopic Hamiltonian describing the propagation of Rydberg slow light polaritons in one dimension. We describe possible decoherence processes within a Master equation approach, and derive equations of motion in a Schroedinger picture by using an effective non-Hermitian Hamiltonian. We illustrate diagrammatic methods on two examples: First, we show the solution for a single polariton in an external potential by exact summation of Feynman diagrams. Secondly, we solve the two body problem in a weakly interacting regime exactly.
Entanglement of two individual neutral atoms using Rydberg blockade.
Wilk, T; Gaëtan, A; Evellin, C; Wolters, J; Miroshnychenko, Y; Grangier, P; Browaeys, A
2010-01-08
We report the generation of entanglement between two individual 87Rb atoms in hyperfine ground states |F=1,M=1> and |F=2,M=2> which are held in two optical tweezers separated by 4 microm. Our scheme relies on the Rydberg blockade effect which prevents the simultaneous excitation of the two atoms to a Rydberg state. The entangled state is generated in about 200 ns using pulsed two-photon excitation. We quantify the entanglement by applying global Raman rotations on both atoms. We measure that 61% of the initial pairs of atoms are still present at the end of the entangling sequence. These pairs are in the target entangled state with a fidelity of 0.75.
Rydberg-Stark deceleration of atoms and molecules
Hogan, Stephen D
2016-01-01
The large electric dipole moments associated with highly excited Rydberg states of atoms and molecules make gas-phase samples in these states very well suited to deceleration and trapping using inhomogeneous electric fields. The methods of Rydberg-Stark deceleration with which this can be achieved are reviewed here. Using these techniques, the longitudinal motion of beams of atoms and molecules moving at speeds as high as 2500~m/s have been manipulated, with changes in kinetic energy of up to $|\\Delta E_{\\mathrm{kin}}|=1.3\\times10^{-20}$~J ($|\\Delta E_{\\mathrm{kin}}|/e=80$~meV or $|\\Delta E_{\\mathrm{kin}}|/hc=650$~cm$^{-1}$) achieved, while decelerated and trapped samples with number densities of $10^6$--$10^7$~cm$^{-3}$ and translational temperatures of $\\sim150$~mK have been prepared. Applications of these samples in areas of research at the interface between physics and physical chemistry are discussed.
Relativistic and Radiative Energy Shifts for Rydberg States
Jentschura, U D; Evers, J; Mohr, P J; Keitel, C H
2004-01-01
We investigate relativistic and quantum electrodynamic effects for highly-excited bound states in hydrogenlike systems (Rydberg states). In particular, hydrogenic one-loop Bethe logarithms are calculated for all circular states (l = n-1) in the range 20 20 to an accuracy of five to seven decimal digits, within the specified manifolds of atomic states. Within the numerical accuracy, the results constitute unified, general formulas for quantum electrodynamic corrections whose validity is not restricted to a single atomic state. The results are relevant for accurate predictions of radiative shifts of Rydberg states and for the description of the recently investigated laser-dressed Lamb shift, which is observable in a strong coherent-wave light field.
L\\'evy statistics of interacting Rydberg gases
Vogt, Thibault; Thiery, Alexandre; Li, Wenhui
2016-01-01
A statistical analysis of the laser excitation of cold and randomly distributed atoms to Rydberg states is developed. We first demonstrate with a hard ball model that the distribution of energy level shifts in an interacting gas obeys L\\'evy statistics, in any dimension $d$ and for any interaction $-C_p/R^p$ under the condition $d/p<1$. This result is confirmed with a Monte Carlo rate equations simulation of the actual laser excitation in the particular case $p=6$ and $d=3$. With this finding, we develop a statistical approach for the modeling of probe light transmission through a cold atom gas driven under conditions of electromagnetically induced transparency involving a Rydberg state. The simulated results are in good agreement with experiment.
The chaotic property in the autoionization of Rydberg lithium atom
Institute of Scientific and Technical Information of China (English)
Zhou Hui; Li Hong-Yun; Gao Song; Zhang Yan-Hui; Jia Zheng-Mao; Lin Sheng-Lu
2008-01-01
This paper presents theoretical computations of the ionization rate of Rydberg lithium atom above the classical ionization threshold using semiclassical approximation. The yielded random pulse trains of the escape electrons are recorded as a function of emission time such that they can be related to the terms of the recurrence periods of the photoabsorption. This fact illustrates that it is ionic core scattering processes which give rise to chaos in autoionization dynamics and this is verified by comparison of our results with the hydrogen atom situation. In order to reveal the chaotic properties in detail, the sensitive dependence of the ionization rate upon the scaled energy is discussed for different scaled energies. This approach provides a simple explanation for the chaotic character in autoionization decay of Rydberg alkali-metal atoms.
Single-photon absorber based on strongly interacting Rydberg atoms
Tresp, Christoph; Mirgorodskiy, Ivan; Gorniaczyk, Hannes; Paris-Mandoki, Asaf; Hofferberth, Sebastian
2016-01-01
Removing exactly one photon from an arbitrary input pulse is an elementary operation in quantum optics and enables applications in quantum information processing and quantum simulation. Here we demonstrate a deterministic single-photon absorber based on the saturation of an optically thick free-space medium by a single photon due to Rydberg blockade. Single-photon subtraction adds a new component to the Rydberg quantum optics toolbox, which already contains photonic logic building-blocks such as single-photon sources, switches, transistors, and conditional $\\pi$-phase shifts. Our approach is scalable to multiple cascaded absorbers, essential for preparation of non-classical light states for quantum information and metrology applications, and, in combination with the single-photon transistor, high-fidelity number-resolved photon detection.
Intrinsic Optical Bistability in a Strongly-Driven Rydberg Ensemble
de Melo, Natalia R; Sibalic, Nikola; Kondo, Jorge M; Adams, Charles S; Weatherill, Kevin J
2016-01-01
We observe and characterize intrinsic optical bistability in a dilute Rydberg vapor. The bistability is characterized by sharp jumps between states of low and high Rydberg occupancy with jump up and down positions displaying hysteresis depending on the direction in which the control parameter is changed. We find that the shift in frequency of the jump point scales with the fourth power of the principal quantum number. Also, the width of the hysteresis window increases with increasing principal quantum number, before reaching a peak and then closing again. The experimental results are consistent with predictions from a simple theoretical model based on semiclassical Maxwell-Bloch equations including the effect of broadening and frequency shifts. These results provide insight to the dynamics of driven dissipative systems.
Few-body quantum physics with strongly interacting Rydberg polaritons
Bienias, Przemyslaw
2016-01-01
We present an extension of our recent paper [Bienias et al., Phys. Rev. A 90, 053804 (2014)] in which we demonstrated the scattering properties and bound-state structure of two Rydberg polaritons, as well as the derivation of the effective low-energy many-body Hamiltonian. Here, we derive a microscopic Hamiltonian describing the propagation of Rydberg slow light polaritons in one dimension. We describe possible decoherence processes within a Master equation approach, and derive equations of motion in a Schroedinger picture by using an effective non-Hermitian Hamiltonian. We illustrate diagrammatic methods on two examples: First, we show the solution for a single polariton in an external potential by exact summation of Feynman diagrams. Secondly, we solve the two body problem in a weakly interacting regime exactly.
Robust quantum logic in neutral atoms via adiabatic Rydberg dressing
Keating, Tyler; Cook, Robert L.; Hankin, Aaron M.; Jau, Yuan-Yu; Biedermann, Grant W.; Deutsch, Ivan H.
2015-01-01
We study a scheme for implementing a controlled-Z (cz) gate between two neutral-atom qubits based on the Rydberg blockade mechanism in a manner that is robust to errors caused by atomic motion. By employing adiabatic dressing of the ground electronic state, we can protect the gate from decoherence due to random phase errors that typically arise because of atomic thermal motion. In addition, the adiabatic protocol allows for a Doppler-free configuration that involves counterpropagating lasers in a σ+/σ- orthogonal polarization geometry that further reduces motional errors due to Doppler shifts. The residual motional error is dominated by dipole-dipole forces acting on doubly excited Rydberg atoms when the blockade is imperfect. For reasonable parameters, with qubits encoded into the clock states of 133Cs, we predict that our protocol could produce a cz gate in <10 μ s with error probability on the order of 10-3.
Entanglement of two individual atoms using the Rydberg blockade
Browaeys, A; Wilk, T; Evellin, C; Wolters, J; Miroshnychenko, Y; Grangier, P; Pillet, P; Comparat, D; Chotia, A; Viteau, M
2009-01-01
We report on our recent progress on the manipulation of single rubidium atoms trapped in optical tweezers and the generation of entanglement between two atoms, each individually trapped in neighboring tweezers. To create an entangled state of two atoms in their ground states, we make use of the Rydberg blockade mechanism. The degree of entanglement is measured using global rotations of the internal states of both atoms. Such internal state rotations on a single atom are demonstrated with a high fidelity.
Half Cycle Pulse Train Induced State Redistribution of Rydberg Atoms
Mandal, P K
2009-01-01
Population transfer between low lying Rydberg states independent of the initial state is realized using a train of half-cycle pulses with pulse durations much less than the classical orbit period. We demonstrate experimentally the transfer of population from initial states around n=50 down to n<40 as well as up to the continuum. The measured population transfer matches well to a model of the process for 1D atoms.
Time-domain Ramsey interferometry with interacting Rydberg atoms
Sommer, Christian; Pupillo, Guido; Takei, Nobuyuki; Takeda, Shuntaro; Tanaka, Akira; Ohmori, Kenji; Genes, Claudiu
2016-11-01
We theoretically investigate the dynamics of a gas of strongly interacting Rydberg atoms subject to a time-domain Ramsey interferometry protocol. The many-body dynamics is governed by an Ising-type Hamiltonian with long-range interactions of tunable strength. We analyze and model the contrast degradation and phase accumulation of the Ramsey signal and identify scaling laws for varying interrogation times, ensemble densities, and ensemble dimensionalities.
Nondestructive Detection of Polar Molecules via Rydberg Atoms
Zeppenfeld, Martin
2016-01-01
A highly sensitive, general, and preferably nondestructive technique to detect polar molecules would greatly advance a number of fields, in particular quantum science with cold and ultracold molecules. Here, we propose using resonant energy transfer between molecules and Rydberg atoms to detect molecules. Based on an energy transfer cross section of $>10^{-6}\\,$cm$^2$ for sufficiently low collision energies, a near unit efficiency non-destructive detection of basically any polar molecule spec...
Exploring dipole blockade using high- n strontium Rydberg atoms
Zhang, Xinyue; Ye, Shuzhen; Dunning, F. Barry; Hiller, Moritz; Yoshida, Shuhei; Burgdörfer, Joachim
2014-05-01
Studies of the production of strongly-polarized quasi-1D high- n, n ~ 300 , strontium `` nF'' Rydberg states in an atomic beam by three-photon excitation in a weak dc field suggest that (in the absence of blockade effects) densities of ~106 cm-3 might be achieved. At such densities the interparticle separation, ~ 100 μm , becomes comparable to that at which dipole blockade effects are expected to become important. Apparatus modifications are underway to allow the exploration of blockade at very high- n and the effects of the high energy level density. Blockade is also being examined through calculations of the energy spectrum for two interaction atoms. Access to the blockade regime promises creation of Rydberg atoms at well-defined separations whose interactions can be coherently controlled using electric field pulses thereby enabling study of the dynamics of strongly-coupled Rydberg systems. Research supported by the NSF, the Robert A. Welch Foundation, and the FWF (Austria).
Huo, Mingxia
2016-01-01
We propose an approach to detect individual Rydberg molecules with each molecule consisting of two atoms in different Rydberg states. The scheme exploits the movement of atoms in the presence of an external force that exerts only on atoms in one Rydberg state. Since the movement of atoms in the other Rydberg state depends on whether they are bound with atoms directly driven by the applied force, bound atoms can be distinguished from unbound atoms. By utilizing electromagnetically induced tran...
Rydberg Wave Packets and Half-Cycle Electromagnetic Pulses
Raman, Chandra S.
1998-05-01
This dissertation summarizes an examination of the dynamics of atomic Rydberg wave packets with coherent pulses of THz electromagnetic radiation consisting of less than a single cycle of the electric field. The bulk of the energy is contained in just a half-cycle. Previous work ( R. Jones, D. You, and P. Bucksbaum, ``Ionization of Rydberg atoms by subpicosecond half-cycle electromagnetic pulses,'' Phys. Rev. Lett.), vol. 70, 1993. had shown how these half-cycle pulses can be used to ionize the highly excited states of an atom, and that a classical view of electronic motion in the atom explains the ionization mechanism. To further probe the boundary between classical trajectories and quantum mechanics, in this work I investigate dynamical combinations of Rydberg states, or Rydberg wave packets, and how they ionize under the influence of a half-cycle electromagnetic pulse. With time-domain techniques I am able to extract the dynamics of the wave packet from the ionization rate, and to observe wave packet motion in both the electronic radial ( C. Raman, C. Conover, C. Sukenik, and P. Bucksbaum, ``Ionization of Rydberg wavepackets by sub-picosecond half-cycle electromagnetic pulses,'' Phys. Rev. Lett.), vol. 76, 1996.and angular ( C. Raman, T. Weinacht, and P. Bucksbaum, ``Stark wavepackets viewed with half cycle pulses.'' Phys. Rev. A), vol. 55, No. 6, 1997. coordinates. This is the first time a wavepacket technique has been used to view electron motion everywhere on its trajectory, and not just at the nucleus. This is the principal feature of half-cycle pulse ionization. Semiclassical ideas of ionization in conjunction with quantum descriptions of the wave packet, are capable of reproducing the main trends in the data, and in the absence of a rigorous model I rely on these. Experiments of this nature provide examples of the ongoing effort to use the coherent properties of radiation to control electronic motion in an atom, as well as to probe the boundaries between
Generation of tunable coherent far-infrared radiation using atomic Rydberg states
Energy Technology Data Exchange (ETDEWEB)
Bookless, W.
1980-12-01
A source of tunable far-infrared radiation has been constructed. The system has been operated at 91.6 cm/sup -1/ with a demonstrated tunability of .63 cm/sup -1/. The system is based on a Rydberg state transition in optically pumped potassium vapor. The transition energy is tuned by the application of an electric field to the excited vapor. The transition wavelength and the shifted wavelength were detected and measured by the use of a Michelson interferometer and a liquid helium cooled Ga:Ge bolometer and the data was reduced using Fast Fourier transform techniques. Extensive spectroscopy was done on the potassium vapor to elucidate the depopulation paths and rates of the excited levels. Both theoretical and experimental results are presented to support the conclusions of the research effort. Additionally, possible alternative approaches to the population of the excited state are explored and recommendations are made for the future development of this source as well as the potential uses of it in molecular spectroscopy.
Optical techniques for Rydberg physics in lattice geometries : A technical guide
Naber, J.B.; Vos, J.; Rengelink, R.J.; Nusselder, R.J.; Davtyan, D.
2016-01-01
We address the technical challenges when performing quantum information experiments with ultracold Rydberg atoms in lattice geometries. We discuss the following key aspects: (i) the coherent manipulation of atomic ground states, (ii) the coherent excitation of Rydberg states, and (iii) spatial addre
Bünermann, Oliver; Kornilov, Oleg; Haxton, Daniel J; Leone, Stephen R; Neumark, Daniel M; Gessner, Oliver
2012-12-07
The ejection dynamics of Rydberg atoms and molecular fragments from electronically excited helium nanodroplets are studied with time-resolved extreme ultraviolet ion imaging spectroscopy. At excitation energies of 23.6 ± 0.2 eV, Rydberg atoms in n = 3 and n = 4 states are ejected on different time scales and with significantly different kinetic energy distributions. Specifically, n = 3 Rydberg atoms are ejected with kinetic energies as high as 0.85 eV, but their appearance is delayed by approximately 200 fs. In contrast, n = 4 Rydberg atoms appear within the time resolution of the experiment with considerably lower kinetic energies. Major features in the Rydberg atom kinetic energy distributions for both principal quantum numbers can be described within a simple elastic scattering model of localized perturbed atomic Rydberg atoms that are expelled from the droplet due to their repulsive interaction with the surrounding helium bath. Time-dependent kinetic energy distributions of He(2) (+) and He(3) (+) ions are presented that support the formation of molecular ions in an indirect droplet ionization process and the ejection of neutral Rydberg dimers on a similar time scale as the n = 3 Rydberg atoms.
Stretching and bending dynamics in triatomic ultralong-range Rydberg molecules
Fey, Christian; Schmelcher, Peter
2016-01-01
We investigate polyatomic ultralong-range Rydberg molecules consisting of three ground state atoms bound to a Rydberg atom via $s$- and $p$-wave interactions. By employing the finite basis set representation of the unperturbed Rydberg electron Green's function we reduce the computational effort to solve the electronic problem substantially. This method is subsequently applied to determine the potential energy surfaces of triatomic systems in electronic $s$- and $p$-Rydberg states. Their molecular geometry and resulting vibrational structure are analyzed within an adiabatic approach that separates the vibrational bending and stretching dynamics. This procedure yields information on the radial and angular arrangement of the nuclei and indicates in particular that kinetic couplings between bending and stretching modes induce a linear structure in triatomic $l=0$ ultralong-range Rydberg molecules.
Two-atom Rydberg blockade using direct 6S to nP excitation
Hankin, A. M.; Jau, Y.-Y.; Parazzoli, L. P.; Chou, C. W.; Armstrong, D. J.; Landahl, A. J.; Biedermann, G. W.
2014-03-01
We explore a single-photon approach to Rydberg state excitation and Rydberg blockade. Using detailed theoretical models, we show the feasibility of direct excitation, predict the effect of background electric fields, and calculate the required interatomic distance to observe Rydberg blockade. We then measure and control the electric field environment to enable coherent control of Rydberg states. With this coherent control, we demonstrate Rydberg blockade of two atoms separated by 6.6(3) μm. When compared with the more common two-photon excitation method, this single-photon approach is advantageous because it eliminates channels for decoherence through photon scattering and ac Stark shifts from the intermediate state while moderately increasing Doppler sensitivity.
Stretching and bending dynamics in triatomic ultralong-range Rydberg molecules
Fey, Christian; Kurz, Markus; Schmelcher, Peter
2016-07-01
We investigate polyatomic ultralong-range Rydberg molecules consisting of three ground-state atoms bound to a Rydberg atom via s - and p -wave interactions. By employing the finite basis set representation of the unperturbed Rydberg electron Green's function we reduce the computational effort to solve the electronic problem substantially. This method is subsequently applied to determine the potential energy surfaces of triatomic systems in electronic s - and p -Rydberg states. Their molecular geometry and resulting vibrational structure are analyzed within an adiabatic approach that separates the vibrational bending and stretching dynamics. This procedure yields information on the radial and angular arrangement of the nuclei and indicates in particular that kinetic couplings between bending and stretching modes induce a linear structure in triatomic l =0 ultralong-range Rydberg molecules.
Semiclassical calculation of ionisation rate for Rydberg helium atoms in an electric field
Institute of Scientific and Technical Information of China (English)
Wang De-Hua
2011-01-01
The ionisation of Rydberg helium atoms in an electric field above the classical ionisation threshold has been examined using the semiclassical method, with particular emphasis on discussing the influence of the core scattering on the escape dynamics of electrons. The results show that the Rydberg helium atoms ionise by emitting a train of electron pulses. Unlike the case of the ionisation of Rydberg hydrogen atom in parallel electric and magnetic fields,where the pulses of the electron are caused by the external magnetic field, the pulse trains for Rydberg helium atoms are created through core scattering. Each peak in the ionisation rate corresponds to the contribution of one core-scattered combination trajectory. This fact further illustrates that the ionic core scattering leads to the chaotic property of the Rydberg helium atom in external fields. Our studies provide a simple explanation for the escape dynamics in the ionisation of nonhydrogenic atoms in external fields.
Rydberg-Blockade Effects in Autler-Townes Spectra of Ultracold Strontium
DeSalvo, B J; Gaul, C; Pohl, T; Yoshida, S; Burgdörfer, J; Hazzard, K R A; Dunning, F B; Killian, T C
2015-01-01
We present a combined experimental and theoretical study of the effects of Rydberg interactions on Autler-Townes spectra of ultracold gases of atomic strontium. Realizing two-photon Rydberg excitation via a long-lived triplet state allows us to probe the thus far unexplored regime where Rydberg state decay presents the dominant decoherence mechanism. The effects of Rydberg interactions are observed in shifts, asymmetries, and broadening of the measured atom-loss spectra. The experiment is analyzed within a one-body density matrix approach, accounting for interaction-induced level shifts and dephasing through nonlinear terms that approximately incorporate correlations due to the Rydberg blockade. This description yields good agreement with our experimental observations for short excitation times. For longer excitation times, the loss spectrum is altered qualitatively, suggesting additional dephasing mechanisms beyond the standard blockade mechanism based on pure van der Waals interactions.
Kono, Mitsuhiko; He, Yabai; Baldwin, Kenneth G. H.; Orr, Brian J.
2016-03-01
Mass-selective sub-Doppler two-photon excitation (TPE) spectroscopy is employed to resolve isotopic contributions for transitions to high-energy Rydberg levels of xenon in an atomic beam, using narrowband pulses of coherent ultraviolet light at 205-213 nm generated by nonlinear-optical conversion processes. Previous research (Kono et al 2013 J. Phys. B: At. Mol. Opt. Phys. 46 35401), has determined isotope energy shifts and hyperfine structure for 33 high-energy Rydberg levels of gas-phase xenon and accessed Rydberg levels at TPE energies in the range of 94 100-97 300 cm-1 with unprecedented spectroscopic resolution. The new isotopic-mass-resolved results were obtained by adding a pulsed free-jet atomic-beam source and a mass-selective time-of-flight detector to the apparatus in order to discern individual xenon isotopes and extract previously unresolved spectroscopic information. Resulting isotope energy shifts and hyperfine-coupling parameters are examined with regard to trends in principal quantum number n and in atomic angular-momentum quantum numbers, together with empirical and theoretical precedents for such trends.
Gas-liquid phase transition in modified pseudopotential and “shelf Coulomb” ultracold plasma models
Butlitsky, M. A.; Zelener, B. B.; Zelener, B. V.
2016-11-01
Phase diagrams for the “shelf Coulomb” and the modified pseudopotential plasma models developed in our previous works are compared. Qualitative agreement is observed between gas-liquid phase transition region of “shelf Coulomb” model and liquid-gas structure region of modified pseudopotential one. The possibility of experimental finding of the phase transition in nonequilibrium ultracold Rydberg plasma is considered. Parameters (density, temperature, levels of Rydberg atoms) for such a transition are estimated. Conclusion is made that “shelf Coulomb” model phase transition is practically impossible to observe in equilibrium strongly coupled plasmas due to high neutral atoms density at low temperatures: T crit ≈ 0.076.
Gong, Pu; Yu, Hongyi; Wang, Yong; Yao, Wang
2017-03-01
We investigate the optical transition selection rules for excitonic Rydberg series formed in massive Dirac cones. The entanglement of the exciton envelop function with the pseudospin texture leads to anomalous selection rules for one-photon generation of excitons, where d orbitals can be excited with the opposite helicity selection rule from the s orbitals in a given valley. The trigonal warping effects in realistic hexagonal lattices further renders more excited states bright, where p orbitals can also be accessed by one-photon excitation with the opposite valley selection rules to the s orbitals. The one-photon generation of exciton in the various states and the intraexcitonic transition between these states are both dictated by the discrete in-plane rotational symmetry of the lattices, and our results show that in hexagonal 2D materials the symmetry allowed transitions are enabled when trigonal warping effects are included in the massive Dirac fermion model. In monolayer transition metal dichalcogenides where excitons can be generated by visible light and intraexcitonic transitions can be induced by infrared light, we give the strength of these optical transitions, estimated using modified hydrogenlike envelope functions combined with the optical transition matrix elements between the Bloch states calculated at various k points.
Yang, Xueming
In this review, a few examples of state-to-state dynamics studies of both unimolecular and bimolecular reactions using the H-atom Rydberg tagging TOF technique were presented. From the H2O photodissociation at 157 nm, a direction dissociation example is provided, while photodissociation of H2O at 121.6 has provided an excellent dynamical case of complicated, yet direct dissociation process through conical intersections. The studies of the O(1D) + H2 → OH + H reaction has also been reviewed here. A prototype example of state-to-state dynamics of pure insertion chemical reaction is provided. Effect of the reagent rotational excitation and the isotope effect on the dynamics of this reaction have also been investigated. The detailed mechanism for abstraction channel in this reaction has also been closely studied. The experimental investigations of the simplest chemical reaction, the H3 system, have also been described here. Through extensive collaborations between theory and experiment, the mechanism for forward scattering product at high collision energies for the H + HD reaction was clarified, which is attributed to a slow down mechanism on the top of a quantized barrier transition state. Oscillations in the product quantum state resolved different cross sections have also been observed in the H + D2 reaction, and were attributed to the interference of adiabatic transition state pathways from detailed theoretical analysis. The results reviewed here clearly show the significant advances we have made in the studies of the state-to-state molecular reaction dynamics.
Storage and control of optical photons using Rydberg polaritons.
Maxwell, D; Szwer, D J; Paredes-Barato, D; Busche, H; Pritchard, J D; Gauguet, A; Weatherill, K J; Jones, M P A; Adams, C S
2013-03-08
We use a microwave field to control the quantum state of optical photons stored in a cold atomic cloud. The photons are stored in highly excited collective states (Rydberg polaritons) enabling both fast qubit rotations and control of photon-photon interactions. Through the collective read-out of these pseudospin rotations it is shown that the microwave field modifies the long-range interactions between polaritons. This technique provides a powerful interface between the microwave and optical domains, with applications in quantum simulations of spin liquids, quantum metrology and quantum networks.
Asymptotics of Rydberg states for the hydrogen atom
Energy Technology Data Exchange (ETDEWEB)
Thomas, L.E. [Virginia Univ., Charlottesville, VA (United States). Dept. of Mathematics; Villegas-Blas, C. [Universidad Nacional Autonoma de Mexico, Instituto de Matematicas, Unidad Cuernavaca, A. P. 273-3 Admon. 3, Cuernavaca Morelos 62251 (Mexico)
1997-08-01
The asymptotics of Rydberg states, i.e., highly excited bound states of the hydrogen atom Hamiltonian, and various expectations involving these states are investigated. We show that suitable linear combinations of these states, appropriately rescaled and regarded as functions either in momentum space or configuration space, are highly concentrated on classical momentum space or configuration space Kepler orbits respectively, for large quantum numbers. Expectations of momentum space or configuration space functions with respect to these states are related to time-averages of these functions over Kepler orbits. (orig.)
Self-excitation of Rydberg atoms at a metal surface
Bordo, V. G.
2017-08-01
The novel effect of self-excitation of an atomic beam propagating above a metal surface is predicted and a theory is developed. Its underlying mechanism is positive feedback provided by the reflective surface for the atomic polarization. Under certain conditions the atomic beam flying in the near field of the metal surface acts as an active device that supports sustained atomic dipole oscillations, which generate, in their turn, an electromagnetic field. This phenomenon does not exploit stimulated emission and therefore does not require population inversion in atoms. An experiment with Rydberg atoms in which this effect should be most pronounced is proposed and the necessary estimates are given.
Self-excitation of Rydberg atoms at a metal surface
DEFF Research Database (Denmark)
Bordo, Vladimir
2017-01-01
The novel effect of self-excitation of an atomic beam propagating above a metal surface is predicted and a theory is developed. Its underlying mechanism is positive feedback provided by the reflective surface for the atomic polarization. Under certain conditions the atomic beam flying in the near...... field of the metal surface acts as an active device that supports sustained atomic dipole oscillations, which generate, in their turn, an electromagnetic field. This phenomenon does not exploit stimulated emission and therefore does not require population inversion in atoms. An experiment with Rydberg...... atoms in which this effect should be most pronounced is proposed and the necessary estimates are given....
Nondestructive detection of polar molecules via Rydberg atoms
Zeppenfeld, M.
2017-04-01
A highly sensitive, general, and preferably nondestructive technique to detect polar molecules would greatly advance a number of fields, in particular quantum science with cold and ultracold molecules. Here, we propose using resonant energy transfer between molecules and Rydberg atoms to detect molecules. Based on an energy transfer cross-section of > 10-6 cm2 for sufficiently low collision energies, a near unit efficiency non-destructive detection of basically any polar molecule species in a well-defined internal state should be possible.
Seeded excitation avalanches in off-resonantly driven Rydberg gases
Simonelli, Cristiano; Masella, Guido; Asteria, Luca; Arimondo, Ennio; Ciampini, Donatella; Morsch, Oliver
2016-01-01
We report an experimental investigation of the facilitated excitation dynamics in off-resonantly driven Rydberg gases by separating the initial off-resonant excitation phase from the facilitation phase, in which successive facilitation events lead to excitation avalanches. We achieve this by creating a controlled number of initial seed excitations. Greater insight into the avalanche mechanism is obtained from an analysis of the full counting distributions. We also present simple mathematical models and numerical simulations of the excitation avalanches that agree well with our experimental results.
Nondestructive Detection of Polar Molecules via Rydberg Atoms
Zeppenfeld, Martin
2016-01-01
A highly sensitive, general, and preferably nondestructive technique to detect polar molecules would greatly advance a number of fields, in particular quantum science with cold and ultracold molecules. Here, we propose using resonant energy transfer between molecules and Rydberg atoms to detect molecules. Based on an energy transfer cross section of $>10^{-6}\\,$cm$^2$ for sufficiently low collision energies, a near unit efficiency non-destructive detection of basically any polar molecule species in a well defined internal state should be possible.
Fast Rydberg antiblockade regime and its applications in quantum logic gates
Su, Shi-Lei; Gao, Ya; Liang, Erjun; Zhang, Shou
2017-02-01
Unlike the Rydberg blockade regime, the Rydberg antiblockade regime (RABR) allows more than one Rydberg atom to be excited, which can bring other interesting phenomena and applications. We propose an alternative scheme to quickly achieve the RABR. The proposed RABR can be implemented by adjusting the detuning of the classical driving field, which is, in turn, based on the former numbers of the excited Rydberg atoms. In contrast to the former schemes, the current one enables more than two atoms to be excited to Rydberg states in a short period of time and thus is useful for large-scale quantum information processing. The proposed RABR can be used to construct two- and multiqubit quantum logic gates. In addition, a Rydberg excitation superatom, which can decrease the blockade error and enlarge the blockade radius for Rydberg blockade-based schemes, is constructed based on the suggested RABR and used to realize a more robust quantum logic gate. The mechanical effect and the ionization are discussed, and the performance is investigated using the master-equation method. Finally, other possible applications of the present RABR are also given.
Rydberg-Stark states in oscillating electric fields
Zhelyazkova, V
2015-01-01
Experimental and theoretical studies of the effects of weak radio-frequency electric fields on Rydberg-Stark states with electric dipole moments as large as 10000 D are reported. High-resolution laser spectroscopic studies of Rydberg states with principal quantum number $n=52$ and $53$ were performed in pulsed supersonic beams of metastable helium with the excited atoms detected by pulsed electric field ionisation. Experiments were carried out in the presence of sinusoidally oscillating electric fields with frequencies of 20~MHz, amplitudes of up to 120~mV/cm, and dc offsets of up to 4.4~V/cm. In weak fields the experimentally recorded spectra are in excellent agreement with the results of calculations carried out using Floquet methods to account for electric dipole couplings in the oscillating fields. This highlights the validity of these techniques for the accurate calculation of the Stark energy level structure in such fields, and the limitations of the calculations in stronger fields where $n-$mixing and ...
Rydberg-Stark states in oscillating electric fields
Zhelyazkova, V.; Hogan, S. D.
2015-12-01
Experimental and theoretical studies of the effects of weak radio-frequency electric fields on Rydberg-Stark states with electric dipole moments as large as 10,000 D are reported. High-resolution laser spectroscopic studies of Rydberg states with principal quantum number n = 52 and 53 were performed in pulsed supersonic beams of metastable helium with the excited atoms detected by pulsed electric field ionisation. Experiments were carried out in the presence of sinusoidally oscillating electric fields with frequencies of 20 MHz, amplitudes of up to 120 mV/cm, and dc offsets of up to 4.4 V/cm. In weak fields, the experimentally recorded spectra are in excellent agreement with the results of calculations carried out using Floquet methods to account for electric dipole couplings in the oscillating fields. This highlights the validity of these techniques for the accurate calculation of the Stark energy level structure in such fields, and the limitations of the calculations in stronger fields where n-mixing and higher order contributions become important.
Chaotic Energy Hopping in Bidirectionally Kicked Rydberg Atoms
Burke, Korana; Mitchell, Kevin; Ye, Shuzhen; Dunning, F. Barry
2012-06-01
A highly excited (n 306) quasi one-dimensional Rydberg atom exposed to periodic alternating external electric field pulses exhibits chaotic behavior. Time evolution of this system is governed by a geometric structure of phase space called a homoclinic tangle and its turnstile. The turnstile is responsible for organizing chaotic ionization. We present and explain the results from an experiment designed to probe the structure of the phase space turnstile. We create time-independent Rydberg wave packets, subject them to alternating electric field kicks, and measure the ionization fraction. We present the behavior of the ionization fraction as a function of the applied kick strength and show that this behavior is directly connected to the size and shape of the underlying turnstile. For short kicking periods the ionization fraction as a function of the applied kick strength exhibits step-function-like behavior that changes into s-shape behavior for large kicking periods. Next we use the geometric structure of phase space to design a short pulse sequence that quickly and efficiently transfers electronic wave packet from a high energy state to a much lower energy state. Finally, we show how the phase space geometry influences the efficiency of the transport between energy states.
Rydberg-Stark deceleration of atoms and molecules
Energy Technology Data Exchange (ETDEWEB)
Hogan, Stephen D. [University College London, Department of Physics and Astronomy, London (United Kingdom)
2016-12-15
The large electric dipole moments associated with highly excited Rydberg states of atoms and molecules make gas-phase samples in these states very well suited to deceleration and trapping using inhomogeneous electric fields. The methods of Rydberg-Stark deceleration with which this can be achieved are reviewed here. Using these techniques, the longitudinal motion of beams of atoms and molecules moving at speeds as high as 2500 m/s have been manipulated, with changes in kinetic energy of up to vertical stroke ΔE{sub kin} vertical stroke = 1.3 x 10{sup -20} J (vertical stroke ΔE{sub kin} vertical stroke /e = 80 meV or vertical stroke ΔE{sub kin} vertical stroke /hc = 650 cm{sup -1}) achieved, while decelerated and trapped samples with number densities of 10{sup 6}-10{sup 7} cm{sup -3} and translational temperatures of ∝150 mK have been prepared. Applications of these samples in areas of research at the interface between physics and physical chemistry are discussed. (orig.)
Controlled long-range interactions between Rydberg atoms and ions
Secker, T.; Gerritsma, R.; Glaetzle, A. W.; Negretti, A.
2016-07-01
We theoretically investigate trapped ions interacting with atoms that are coupled to Rydberg states. The strong polarizabilities of the Rydberg levels increase the interaction strength between atoms and ions by many orders of magnitude, as compared to the case of ground-state atoms, and may be mediated over micrometers. We calculate that such interactions can be used to generate entanglement between an atom and the motion or internal state of an ion. Furthermore, the ion could be used as a bus for mediating spin-spin interactions between atomic spins in analogy to much employed techniques in ion-trap quantum simulation. The proposed scheme comes with attractive features as it maps the benefits of the trapped-ion quantum system onto the atomic one without obviously impeding its intrinsic scalability. No ground-state cooling of the ion or atom is required and the setup allows for full dynamical control. Moreover, the scheme is to a large extent immune to the micromotion of the ion. Our findings are of interest for developing hybrid quantum information platforms and for implementing quantum simulations of solid-state physics.
Measurement and numerical calculation of Rubidium Rydberg Stark spectra
Grimmel, Jens; Karlewski, Florian; Jessen, Florian; Reinschmidt, Malte; Sándor, Nóra; Fortágh, József
2015-01-01
We report on the measurement of Stark shifted energy levels of $^{87}$Rb Rydberg atoms in static electric fields by means of electromagnetically induced transparency (EIT). Electric field strengths of up to 500V/cm, ranging beyond the classical ionisation threshold, were applied using electrodes inside a glass cell with rubidium vapour. Stark maps for principal quantum numbers $n=35$ and $n=70$ have been obtained with high signal-to-noise ratio for comparison with results from ab initio calculations following the method described in [M. L. Zimmerman et al., Phys. Rev. A 20, 2251 (1979)], which was originally only verified for states around $n=15$. We also calculate the dipole matrix elements between low-lying states and Stark shifted Rydberg states to give a theoretical estimate of the relative strength of the EIT signal. The present work significantly extends the experimental verification of this numerical method in the range of both high principal quantum numbers and high electric fields with an accuracy of...
Controlled long-range interactions between Rydberg atoms and ions
Secker, Thomas; Glaetzle, Alexander W; Negretti, Antonio
2016-01-01
We theoretically investigate trapped ions interacting with atoms that are coupled to Rydberg states. The strong polarizabilities of the Rydberg levels increases the interaction strength between atoms and ions by many orders of magnitude, as compared to the case of ground state atoms, and may be mediated over micrometers. We calculate that such interactions can be used to generate entanglement between an atom and the motion or internal state of an ion. Furthermore, the ion could be used as a bus for mediating spin-spin interactions between atomic spins in analogy to much employed techniques in ion trap quantum simulation. The proposed scheme comes with attractive features as it maps the benefits of the trapped ion quantum system onto the atomic one without obviously impeding its intrinsic scalability. No ground state cooling of the ion or atom is required and the setup allows for full dynamical control. Moreover, the scheme is to a large extent immune to the micromotion of the ion. Our findings are of interest...
Auto transfer to Rydberg states during ion-atom collisions
Energy Technology Data Exchange (ETDEWEB)
Bachau, H.; Harel, C. (Laboratoire des Collisions Atomiques, Unite Propre de Recherche 260 du CNRS, Universite Bordeaux I, 351 Cours de la Liberation, 33405 Talence (France)); Barat, M.; Roncin, P. (Laboratoire des Collisions Atomiques et Moleculaires, Unite associee 281 du CNRS, Universite de Paris Sud, Batiment 351, 91405 Orsay (France)); Bordenave-Montesquieu, A.; Moretto-Capelle, P.; Benoit-Cattin, P.; Gleizes, A.; Benhenni, M. (IRSAMC, Unite associee 770 du CNRS, Universite Paul Sabatier, 118 route de Narbonne, 31062 Toulouse (France))
1993-06-05
Electron capture by slow multiply charged ions colliding on rare-gas targets is known to populate highly excited states of the projectile. On the basis of experimental measurement of energy and angle differential cross-sections we have shown that capture to a resonant doubly excited state may lead to Autoionizing Double Capture (ADC) as well as to True Double Capture (TDC). In this model TDC appears as a two step post-collisional process, the state populated by the collision decays to (or delutes into) a dense adjacent Rydberg series, followed by radiative deexcitation of the inner electron of the (3,n) Rydberg states. We report here new experimental observations in electron spectra measured in [ital N][sup 7+]+[ital He]. Auto transfer to Rydber states has also important consequences on the determination of the lifetime of the autoionizing states, some discrepancies between theoretical width values for low [ital N][sup 5+](4,4) resonant states will be discussed and partially resolved.
Autoionizing Distribution of the Triply Excited Double Rydberg States in La Atom
Institute of Scientific and Technical Information of China (English)
SUN Wei; XIE Xiu-Ping; HUANG Wen; ZHONG Zhi-Ping; XU Cheng-Bin; XUE Ping; XU Xiang-Yuan
2000-01-01
The autoionization distribution of the triply excited double Rydberg states (TEDRS) 5d5/2NLnl (N _< 22; n _<50; L, l < 4) of La has been investigated by using five-laser resonance excitation in combination with a method of sequential ionization by a pulsed electric field and a constant electric field. The experimental results exhibit that the La atoms in TEDRS predominantly single-autoionize to the ionic Rydberg states located in a few Rydberg manifolds. Furthermore, a difference of autoionization mechanisms between TEDRS above and those below the double ionization threshold is found.
Towards an experimentally feasible controlled-phase gate on two blockaded Rydberg atoms
Murphy, Michael; Calarco, Tommaso; Grangier, Philippe; Browaeys, Antoine
2011-01-01
We investigate the implementation of a controlled-Z gate on a pair of Rydberg atoms in spatially separated dipole traps where the joint excitation of both atoms into the Rydberg level is strongly suppressed (the Rydberg blockade). We follow the adiabatic gate scheme of Jaksch et al. [1], where the pair of atoms are coherently excited using lasers, and apply it to the experimental setup outlined in Ga\\"etan et al. [2]. We apply optimisation to the experimental parameters to improve gate fidelity, and consider the impact of several experimental constraints on the gate success.
Exploiting Rydberg Atom Surface Phonon Polariton Coupling for Single Photon Subtraction
Kübler, H; Sedlacek, J; Zabawa, P; Shaffer, J P
2013-01-01
We investigate a hybrid quantum system that consists of a superatom coupled to a surface phonon-polariton. We apply this hybrid quantum system to subtract individual photons from a beam of light. Rydberg atom blockade is used to attain absorption of a single photon by an atomic microtrap. Surface phonon-polariton coupling to the superatom then triggers the transfer of the excitation to a storage state, a single Rydberg atom. The approach utilizes the interaction between a superatom and a Markovian bath that acts as a controlled decoherence mechanism to irreversibly project the superatom state into a single Rydberg atom state that can be read out.
Electrical read out for coherent phenomena involving Rydberg atoms in thermal vapor cells
Barredo, D; Daschner, R; Löw, R; Pfau, T
2012-01-01
We present a very sensitive and scalable method to measure the population of highly excited Rydberg states in a thermal vapor cell of rubidium atoms. We detect the Rydberg ionization current in a 5 mm electrically contacted cell. The measured current is found to be in excellent agreement with a theory for the Rydberg population based on a master equation for the three level problem including an ionization channel and the full Doppler distributions at the corresponding temperatures. The signal-to-noise ratio of the current detection is substantially better than purely optical techniques.
Rydberg atom detection of the temporal coherence of cosmic microwave background radiation
Tscherbul, Timur V
2013-01-01
Rydberg atoms immersed in cold blackbody radiation are shown to display long-lived quantum coherence effects on timescales of tens of picoseconds. By solving non-Markovian equations of motion with no free parameters we obtain the time evolution of the density matrix, and demonstrate that the blackbody-induced temporal coherences manifest as quantum beats in time-resolved fluorescence intensities of the Rydberg atoms. A measurable fluorescence signal can be obtained with a cold trapped ensemble of 1e8 Rydberg atoms subject to 2.7 K cosmic microwave background radiation (CMB), allowing for novel insights into previously unexamined quantum coherence properties of CMB.
Microwave probes Dipole Blockade and van der Waals Forces in a Cold Rydberg Gas
Teixeira, R Celistrino; Nguyen, Thanh Long; Cantat-Moltrecht, T; Raimond, Jean-Michel; Haroche, S; Gleyzes, S; Brune, M
2015-01-01
We show that microwave spectroscopy of a dense Rydberg gas trapped on a superconducting atom chip in the dipole blockade regime reveals directly the dipole-dipole many-body interaction energy spectrum. We use this method to investigate the expansion of the Rydberg cloud under the effect of repulsive van der Waals forces and the breakdown of the frozen gas approximation. This study opens a promising route for quantum simulation of many-body systems and quantum information transport in chains of strongly interacting Rydberg atoms.
Electrical readout for coherent phenomena involving Rydberg atoms in thermal vapor cells.
Barredo, D; Kübler, H; Daschner, R; Löw, R; Pfau, T
2013-03-22
We present a very sensitive and scalable method to measure the population of highly excited Rydberg states in a thermal vapor cell of rubidium atoms. We detect the Rydberg ionization current in a 5 mm electrically contacted cell. The measured current is found to be in qualitatively good agreement with a theory for the Rydberg population based on a master equation for the three-level problem, including an ionization channel and the full Doppler distributions at the corresponding temperatures. The signal-to-noise ratio of the current detection is substantially better than that of purely optical techniques.
Energy Technology Data Exchange (ETDEWEB)
Albrecht, Sebastian
2014-08-15
Rydberg transitions of Rubidium have been achieved. Recorded spectra of the transitions to the principal quantum numbers n=20, 58, 79, 97 and 150 are shown. This proofs the applicability of the built laser sys- tem to the full range of two-photon Rydberg excitation of Rubidium. When the ground, intermediate and exited state are varied, the resulting spectrum of resonances is explained and analysed representatively on the transition to the Rydberg D-states of {sup 85}Rb with n = 97. The energy shift of the atomic levels by both electric and magnetic fields are examined. By measuring the two photon transition frequency of 5 {sup 2}S{sub 1/2} → 150 {sup 2}D{sub 5/2}, the ionization energy of 85 Rb is redetermined.
Ugray, Lisa Madeleine
2013-01-01
This thesis is divided into two parts, each of which supports constructing and using a lithium magneto-optical trap for cold collision studies: Part I: One outgoing channel of interest from cold collisions is the production of ion pairs. We describe an effective method for calculating bound-to-continuum cross-sections for charged binary systems by examining transitions to states above the binding energy that become bound when the system is placed within an infinite spherical well. This approach is verified for ionization of a hydrogen atom, and is then applied to the heavy Rydberg system Li+...I-. Part II: A wavemeter previously built in the lab is redesigned for increased reliability and ease of use by replacing the optical hardware with a rocker system, which can be aligned in mere minutes rather than half a day as was previously the case. The new wavemeter has been tested through saturated absorption spectroscopy of lithium.
Holmlid, Leif
2011-01-01
The interpretation of the more than 300 diffuse interstellar bands (DIBs) is one of the most long-standing problems in interstellar spectra since the two first bands were reported in 1921. We now predict the frequencies of 260 diffuse interstellar bands (DIBs) using the Rydberg Matter model we have developed previously. These transitions involve mainly He atoms, but other two-electron atoms like Ca and other metals can take part in the absorption processes. Approximately 70% of the total intensity of the DIBs is due to absorption in doubly excited states and 30% in singly excited He atoms. The doubly excited states are in inverted states while the He atoms are thermal. The possibilities to observe DIBs in the UV and NIR ranges are discussed and band positions are predicted.
Spin mixing in Cs ultralong-range Rydberg molecules: a case study
Markson, Samuel; Schmidt, Richard; Shaffer, James P; Sadeghpour, H R
2016-01-01
We calculate vibrational spectra of ultralong-range Cs(32p) Rydberg molecules which form in an ultracold gas of Cs atoms. We account for the partial-wave scattering of the Rydberg electrons from the ground Cs perturber atoms by including the full set of spin-resolved ${}^{1,3}S_J$ and ${}^{1,3}P_J$ scattering phase shifts, and allow for the mixing of singlet (S=0) and triplet (S=1) spin states through Rydberg electron spin-orbit and ground electron hyperfine interactions. Excellent agreement with observed data in Sa{\\ss}mannshausen et al. [Phys. Rev. Lett. 113, 133201(2015)] in line positions and profiles is obtained. We also determine the spin-dependent permanent electric dipole moments for these molecules. This is the first such calculation of ultralong-range Rydberg molecules in which all of the relativistic contributions are accounted for.
Field ionization process of Eu 4f76snp Rydberg states
Institute of Scientific and Technical Information of China (English)
张婧; 沈礼; 戴长建
2015-01-01
The field ionization process of the Eu 4f76snp Rydberg states, converging to the first ionization limit, 4f76s 9S4, is systematically investigated. The spectra of the Eu 4f76snp Rydberg states are populated with three-step laser excitation, and detected by electric field ionization (EFI) method. Two different kinds of the EFI pulses are applied after laser excitation to observe the possible impacts on the EFI process. The exact EFI ionization thresholds for the 4f76snp Rydberg states can be determined by observing the corresponding EFI spectra. In particular, some structures above the EFI threshold are found in the EFI spectra, which may be interpreted as the effect from black body radiation (BBR). Finally, the scaling law of the EFI threshold for the Eu 4f76snp Rydberg states with the effective quantum number is built.
Towards a deterministic single-photon source by Rydberg FWM effect in a thermal microcell
Chen, Yi-Hsin; Ripka, Fabian; Löw, Robert; Pfau, Tilman
2015-05-01
The generation and manipulation of single photons are the key ingredients for the photonic-based quantum security communication and information processing. One promising candidate to realize the on-demand single-photon source is based on the combination of four-wave-mixing (FWM) and Rydberg blockade effects in a micrometer scale thermal microcell. Similar to our past studies of coherent Rydberg dynamics and van-der Waals interaction in a three-level system, we implement a pulsed FWM scheme to observe both coherent dynamics and effects of dephasing due to Rydberg-Rydberg interaction. Furthermore, we investigate the effects of the excitation volume by use of low- and high- NA optics and spatial confinement. We discuss prospects for the generation of non-classical light. AvH; ERC; BMBF.
Quantum repeater with Rydberg-blocked atomic ensembles in fiber-coupled cavities
DEFF Research Database (Denmark)
Brion, Etienne; Carlier, F.; Akulin, M.;
2012-01-01
We propose and analyze a quantum repeater architecture in which Rydberg-blocked atomic ensembles inside optical cavities are linked by optical fibers. Entanglement generation, swapping, and purification are achieved through collective laser manipulations of the ensembles and photon transmission...
Aguilera-Fernández, Javier; Sadeghpour, H. R.; Schmelcher, Peter; González-Férez, Rosario
2015-09-01
We investigate the structure and features of an ultralong-range triatomic Rydberg molecule formed by a Rb Rydberg atom and a KRb diatomic molecule. In our numerical description, we perform a realistic treatment of the internal rotational motion of the diatomic molecule, and take into account the Rb(n, l ≥ 3) Rydberg degenerate manifold and the energetically closest neighboring levels with principal quantum numbers n' > n and orbital quantum number l ≤ 2. We focus here on the adiabatic electronic potentials evolving from the Rb(n,l ≥ 3) and Rb(n = 26, l = 2) manifolds. The directional properties of the KRb diatomic molecule within the Rb-KRb triatomic Rydberg molecule are also analyzed in detail.
Radio-frequency Electrometry Using Rydberg Atoms in Vapor Cells: Towards the Shot Noise Limit
Kumar, Santosh; Fan, Haoquan; Jahangiri, Akbar; Kuebler, Harald; Shaffer, James P.; 5. Physikalisches Institut, Universitat Stuttgart, Germany Collaboration
2016-05-01
Rydberg atoms are a promising candidate for radio frequency (RF) electric field sensing. Our method uses electromagnetically induced transparency with Rydberg atoms in vapor cells to read out the effect that the RF electric field has on the Rydberg atoms. The method has the potential for high sensitivity (pV cm-1 Hz- 1 / 2) and can be self-calibrated. Some of the main factors limiting the sensitivity of RF electric field sensing from reaching the shot noise limit are the residual Doppler effect and the sensitivity of the optical read-out using the probe laser. We present progress on overcoming the residual Doppler effect by using a new multi-photon scheme and reaching the shot noise detection limit using frequency modulated spectroscopy. Our experiments also show promise for studying quantum optical effects such as superradiance in vapor cells using Rydberg atoms. This work is supported by DARPA, ARO, and NRO.
Spectroscopy of cold rubidium Rydberg atoms for applications in quantum information
Ryabtsev, I I; Tretyakov, D B; Entin, V M; Yakshina, E A
2016-01-01
Atoms in highly excited (Rydberg) states have a number of unique properties which make them attractive for applications in quantum information. These are large dipole moments, lifetimes and polarizabilities, as well as strong long-range interactions between Rydberg atoms. Experimental methods of laser cooling and precision spectroscopy enable the trapping and manipulation of single Rydberg atoms and applying them for practical implementation of quantum gates over qubits of a quantum computer based on single neutral atoms in optical traps. In this paper, we give a review of the experimental and theoretical work performed by the authors at the Rzhanov Institute of Semiconductor Physics SB RAS and Novosibirsk State University on laser and microwave spectroscopy of cold Rb Rydberg atoms in a magneto-optical trap and on their possible applications in quantum information. We also give a brief review of studies done by other groups in this area.
Accessing Rydberg-dressed interactions using many-body Ramsey dynamics
Mukherjee, Rick; Hazzard, Kaden R A
2015-01-01
We demonstrate that Ramsey spectroscopy can be used to observe Rydberg-dressed interactions. In contrast to many prior proposals, our scheme operates comfortably within experimentally measured lifetimes, and accesses a regime where quantum superpositions are crucial. The key idea is to build a spin-1/2 from one level that is Rydberg-dressed and another that is not. These levels may be hyperfine or long-lived electronic states. An Ising spin model governs the Ramsey dynamics, for which we derive an exact solution. Due to the structure of Rydberg interactions, the dynamics differs significantly from that in other spin systems. As one example, spin echo can increase the rate at which coherence decays. The results also apply to bare (undressed) Rydberg states as a special case, for which we quantitatively reproduce recent ultrafast experiments without fitting.
Accessing Rydberg-dressed interactions using many-body Ramsey dynamics
Mukherjee, Rick; Killian, Thomas C.; Hazzard, Kaden R. A.
2016-11-01
We demonstrate that Ramsey spectroscopy can be used to observe Rydberg-dressed interactions in a many-body system well within experimentally measured lifetimes, in contrast to previous research, which either focused on interactions near Förster resonances or on few-atom systems. We build a spin-1/2 from one level that is Rydberg-dressed and another that is not. These levels may be hyperfine or long-lived electronic states. An Ising spin model governs the Ramsey dynamics, which we demonstrate can be used to characterize the Rydberg-dressed interactions. Furthermore, the dynamics can differ significantly from that observed in other spin systems. As one example, spin echo can increase the rate at which coherence decays. The results also apply to bare (undressed) Rydberg states as a special case, for which we quantitatively reproduce recent ultrafast experiments without fitting.
Aguilera-Fernández, Javier; Schmelcher, Peter; González-Férez, Rosario
2015-01-01
We investigate the structure and features of an ultralong-range triatomic Rydberg molecule formed by a Rb Rydberg atom and a KRb diatomic molecule. In our numerical description, we perform a realistic treatment of the internal rotational motion of the diatomic molecule, and take into account the Rb($n, l\\ge 3$) Rydberg degenerate manifold and the energetically closest neighboring levels with principal quantum numbers $n'>n$ and orbital quantum number $l\\le2$. We focus here on the adiabatic electronic potentials evolving from the Rb($n, l\\ge 3$) and Rb($n=26, l=2$) manifolds. The directional properties of the KRb diatomic molecule within the Rb-KRb triatomic Rydberg molecule are also analyzed in detail.
Imai, M; Kitazawa, S; Komaki, K; Kawatsura, K; Shibata, H; Tawara, H; Azuma, T; Kanai, Y; Yamazaki, Y
2002-01-01
Spectra for Coster-Kronig (C-K) transition 1s sup 2 2p( sup 2 P sub 3 sub / sub 2)9l->1s sup 2 2s( sup 2 S sub 1 sub / sub 2)epsilon l sup ' of Be-like S sup 1 sup 2 sup + ions produced following penetration of 2.5 MeV/u S sup q sup + ions (q=7, 10, 12, 13) through C-foil targets of various thickness (1-6.9 mu g/cm sup 2) have been probed using zero-degree electron spectroscopy. It has been found that in collisions for S sup q sup + (q=7, 10) ion incidence, in which the C-K electrons originate from the projectile bound electrons, a fraction of the angular momentum l=1 of the Rydberg state decreases, and fractions of higher (l>=2) angular momenta increase, while the total intensity of the C-K electrons grows, as target foil thickness increases. The electron spectra for S sup q sup + (q=13) incident ions, in which the autoionizing Be-like state is preferably formed by electron capture from the target continuum upon or near the exiting surface, do not change in l-distribution or intensity. The shift to higher l ...
Adsorbate dynamics on a silica-coated gold surface measured by Rydberg Stark spectroscopy
Naber, J.; Machluf, S.; Torralbo-Campo, L.; Soudijn, M. L.; van Druten, N. J.; van Linden van den Heuvell, H. B.; Spreeuw, R. J. C.
2016-05-01
Trapping a Rydberg atom close to a surface is an important step towards the realisation of many proposals for quantum information processing or hybrid quantum systems. One of the challenges in these experiments is posed by the electric field emanating from contaminations on the surface. Here we report on measurements of an electric field created by 87Rb atoms adsorbed on a 25 nm thick layer of SiO2, covering a 90 nm layer of Au. The electric field is measured using a two-photon transition to the 23{D}5/2 and 25{S}1/2 states. The electric field value that we measure is higher than typical values measured above metal surfaces, but is consistent with a recent measurement above a SiO2 surface. In addition, we measure the temporal behaviour of the field and observe that we can reduce it in a single experimental cycle, using ultraviolet light or by mildly locally heating the surface with one of the excitation lasers, whereas the buildup of the field takes thousands of cycles. We explain these results by a change in the adatom distribution on the surface. These results indicate that, while the stray electric field can be reduced, achieving field-free conditions above a silica-coated gold chip remains challenging.
Adsorbate dynamics on a silica-coated gold surface measured by Rydberg Stark spectroscopy
Naber, J; Torralbo-Campo, L; Soudijn, M L; van Druten, N J; Heuvell, H B van Linden van den; Spreeuw, R J C
2015-01-01
Trapping a Rydberg atom close to a surface is an important step towards the realisation of many proposals of quantum information or hybrid quantum systems. One of the challenges in these experiments is to overcome the electric field emanating from contaminations on the surface. Here we report on measurements of an electric field created by $^{87}$Rb atoms absorbed on a 25$\\,$nm thick layer of SiO$_2$, covering a 90$\\,$nm layer of Au. The electric field is measured using a two-photon transition to the 23$D_{5/2}$ and 25$S_{1/2}$ state. The electric field value that we measure is higher than typical values measured above metal surfaces, but is consistent with other measurements above SiO$_2$ surfaces. In addition, we measure the temporal behaviour of the field and observe that we can reduce it in a single experimental cycle, using UV light or by mildly heating the surface, whereas the buildup of the field takes thousands of cycles. We explain these results by a change in the ad-atoms distribution on the surface...
Superconducting Resonator-Rydberg Atom Hybrid in the Strong Coupling Regime
Yu, Deshui; Valado, Maria Martinez; Hufnagel, Christoph; Kwek, Leong Chuan; Amico, Luigi; Dumke, Rainer
2016-01-01
We propose a promising hybrid quantum system, where a highly-excited atom strongly interacts with a superconducting LC oscillator via the electric field of capacitor. An external electrostatic field is applied to tune the energy spectrum of atom. The atomic qubit is implemented by two eigenstates near an avoided-level crossing in the DC Stark map of Rydberg atom. Varying the electrostatic field brings the atomic-qubit transition on- or off-resonance to the microwave resonator, leading to a strong atom-resonator coupling with an extremely large cooperativity. Like the nonlinearity induced by Josephson junctions in superconducting circuits, the large atom-resonator interface disturbs the harmonic potential of resonator, resulting in an artificial two-level particle. Different universal two-qubit logic gates can also be performed on our hybrid system within the space where an atomic qubit couples to a single photon with an interaction strength much larger than any relaxation rates, opening the door to the cavity...
Superconducting resonator and Rydberg atom hybrid system in the strong coupling regime
Yu, Deshui; Landra, Alessandro; Valado, María Martínez; Hufnagel, Christoph; Kwek, Leong Chuan; Amico, Luigi; Dumke, Rainer
2016-12-01
We propose a promising hybrid quantum system, where a highly excited atom strongly interacts with a superconducting L C oscillator via the electric field of capacitor. An external electrostatic field is applied to tune the energy spectrum of the atom. The atomic qubit is implemented by two eigenstates near an avoided-level crossing in the dc Stark map of a Rydberg atom. Varying the electrostatic field brings the atomic-qubit transition on or off resonance with respect to the microwave resonator, leading to a strong atom-resonator coupling with an extremely large cooperativity. Like the nonlinearity induced by Josephson junctions in superconducting circuits, the large atom-resonator interface disturbs the harmonic potential of the resonator, resulting in an artificial two-level particle. Different universal two-qubit logic gates can also be performed on our hybrid system within the space where an atomic qubit couples to a single photon with an interaction strength much larger than any relaxation rates, opening the door to the cavity-mediated state transmission.
The regularities of the Rydberg energy levels of many-valence electron atom Al
Institute of Scientific and Technical Information of China (English)
郑能武; 孙育杰
2000-01-01
Within the scheme of the weakest bound electron potential model theory, the concept of spectral-level-like series is presented by reasonably classifying the Rydberg energy level of atom Al. Based on this concept, the regularities of the Rydberg energy levels are systematically studied. The deviations of the calculated values from the experimental values are generally about several percent of 1 cm, which is of high accuracy.
Takei, Nobuyuki; Genes, Claudiu; Pupillo, Guido; Goto, Haruka; Koyasu, Kuniaki; Chiba, Hisashi; Weidemüller, Matthias; Ohmori, Kenji
2015-01-01
Many-body interactions govern a variety of important quantum phenomena ranging from superconductivity and magnetism in condensed matter to solvent effects in chemistry. Understanding those interactions beyond mean field is a holy grail of modern sciences. AMO physics with advanced laser technologies has recently emerged as a new platform to study quantum many-body systems. One of its latest developments is the study of long-range interactions among ultracold particles to reveal the effects of many-body correlations. Rydberg atoms distinguish themselves by their large dipole moments and tunability of dipolar interactions. Most of ultracold Rydberg experiments have been performed with narrow-band lasers in the Rydberg blockade regime. Here we demonstrate an ultracold Rydberg gas in a complementary regime, where electronic coherence is created using a broadband picosecond laser pulse, thus circumventing the Rydberg blockade to induce strong many-body correlations. The effects of long-range Rydberg interactions h...
Simulating Quantum Spin Models using Rydberg-Excited Atomic Ensembles in Magnetic Microtrap Arrays
Whitlock, Shannon; Hannaford, Peter
2016-01-01
We propose a scheme to simulate lattice spin models based on strong and long-range interacting Rydberg atoms stored in a large-spacing array of magnetic microtraps. Each spin is encoded in a collective spin state involving a single $nP$ Rydberg atom excited from an ensemble of ground-state alkali atoms prepared via Rydberg blockade. After the excitation laser is switched off the Rydberg spin states on neighbouring lattice sites interact via general isotropic or anisotropic spin-spin interactions. To read out the collective spin states we propose a single Rydberg atom triggered avalanche scheme in which the presence of a single Rydberg atom conditionally transfers a large number of ground-state atoms in the trap to an untrapped state which can be readily detected by site-resolved absorption imaging. Such a quantum simulator should allow the study of quantum spin systems in almost arbitrary two-dimensional configurations. This paves the way towards engineering exotic spin models, such as spin models based on tr...
Probing a scattering resonance with Rydberg molecules inside a Bose-Einstein condensate
Perez-Rios, J.; Schlagmüller, M.; Liebisch, T. C.; Nguyen, H.; Lochead, G.; Engel, F.; Böottcher, F.; Westphal, K. M.; Kleinbach, K. S.; Löw, R.; Hofferberth, S.; Pfau, T.; Greene, C. H.
2016-05-01
The spectroscopy of a single Rydberg atom within a Bose-Einstein condensate is studied, and as a result a line shape dependence on the principal Rydberg quantum number n is observed, apart from the expected density shift due to the large number of neutrals inside the Rydberg orbit. The observed line broadening depends on the Rydberg electron-neutral interaction, in particular, it manifests the influence of the e-Rb(5S) p-wave scattering shape resonance, which dramatically affects the potential energy landscape for the neutrals embedded within the Rydberg orbit. The observed spectroscopic line shapes are reproduced with an overall good agreement by means of a microscopic model, in which the atoms overlapped with the Rydberg orbit are treated as zero-velocity point-like particles, with binding energies associated with the ion-neutral distance. We acknowledge support from Deutsche Forschungsge5 meinschaft (DFG) within the SFB/TRR21 and the project PF 381/13-1. This work has been supported by NSF under Grand Number PHY-130690.
Hüter, O.; Temps, F.
2016-12-01
The radiationless electronic relaxation and α -CC bond fission dynamics of jet-cooled acetone in the S1 (n π* ) state and in high-lying 3p and 3d Rydberg states have been investigated by femtosecond time-resolved mass spectrometry and photoelectron imaging. The S1 state was accessed by absorption of a UV pump photon at selected wavelengths between λ = 320 and 250 nm. The observed acetone mass signals and the S1 photoelectron band decayed on sub-picosecond time scales, consistent with a recently proposed ultrafast structural relaxation of the molecules in the S1 state away from the Franck-Condon probe window. No direct signatures could be observed by the experiments for CC dissociation on the S1 potential energy hypersurface in up to 1 ns. The observed acetyl mass signals at all pump wavelengths turned out to be associated with absorption by the molecules of one or more additional pump and/or probe photons. In particular, absorption of a second UV pump photon by the S1 (n π* ) state was found to populate a series of high-lying states belonging to the n = 3 Rydberg manifold. The respective transitions are favored by much larger cross sections compared to the S1 ← S0 transition. The characteristic energies revealed by the photoelectron images allowed for assignments to the 3p and 3dyz states. At two-photon excitation energies higher than 8.1 eV, an ultrafast reaction pathway for breaking the α -CC bond in 50-90 fs via the 3dyz Rydberg state and the elusive π π* state was observed, explaining the formation of acetyl radicals after femtosecond laser excitation of acetone at these wavelengths.
Driven-dissipative dynamics of a strongly interacting Rydberg gas
Glaetzle, A W; Zhao, B; Pupillo, G; Zoller, P
2012-01-01
We study the non-equilibrium many-body dynamics of a cold gas of ground state alkali atoms weakly admixed by Rydberg states with laser light. On a timescale shorter than the lifetime of the dressed states, effective dipole-dipole or van der Waals interactions between atoms can lead to the formation of strongly correlated phases, such as atomic crystals. Using a semiclassical approach, we study the long-time dynamics where decoherence and dissipative processes due to spontaneous emission and blackbody radiation dominate, leading to heating and melting of atomic crystals as well as particle losses. These effects can be substantially mitigated by performing active laser cooling in the presence of atomic dressing.
Lensing effect of electromagnetically induced transparency involving a Rydberg state
Han, Jingshan; Manjappa, Manukumara; Guo, Ruixiang; Kiffner, Martin; Li, Wenhui
2015-01-01
We study the lensing effect experienced by a weak probe field under conditions of electromagnetically induced transparency (EIT) involving a Rydberg state. A Gaussian coupling beam tightly focused on a laser-cooled atomic cloud produces an inhomogeneity in the coupling Rabi frequency along the transverse direction and makes the EIT area acting like a gradient-index medium. We image the probe beam at the position where it exits the atomic cloud, and observe that a red-detuned probe light is strongly focused with a greatly enhanced intensity whereas a blue-detuned one is de-focused with a reduced intensity. Our experimental results agree very well with the numerical solutions of Maxwell-Bloch equations.
Ultracold molecular Rydberg physics in a high density environment
Eiles, Matthew T; Robicheaux, F; Greene, Chris H
2016-01-01
Sufficiently high densities in Bose-Einstein condensates provide favorable conditions for the production of ultralong-range polyatomic molecules consisting of one Rydberg atom and a number of neutral ground state atoms. The chemical binding properties and electronic wave functions of these exotic molecules are investigated analytically via hybridized diatomic states. The effects of the molecular geometry on the system's properties are studied through comparisons of the adiabatic potential curves and electronic structures for both symmetric and randomly configured molecular geometries. General properties of these molecules with increasing numbers of constituent atoms and in different geometries are presented. These polyatomic states have spectral signatures that lead to non-Lorentzian line-profiles.
Characterizing high- n quasi-one-dimensional strontium Rydberg atoms
Hiller, Moritz; Yoshida, Shuhei; Burgdörfer, Joachim; Ye, Shuzhen; Zhang, Xinyue; Dunning, F. Barry
2014-05-01
The production of high- n, n ~ 300 , quasi-one-dimensional strontium Rydberg atoms by two-photon excitation of selected extreme Stark states in the presence of a weak dc field is examined using a crossed laser-atom beam geometry. The polarization of the product states is probed using three independent techniques which are analyzed with the aid of classical-trajectory Monte Carlo simulations that employ initial ensembles based on quantum calculations using a two-active-electron model. Comparisons between theory and experiment demonstrate that the product states have large dipole moments, ~ 1 . 0 - 1 . 2n2 a . u . and that they can be engineered using pulsed electric fields to create a wide variety of target states. Research supported by the NSF, the Robert A Welch Foundation, and the FWF (Austria).
Coherent conversion between optical and microwave photons in Rydberg gases
Kiffner, Martin; Kaczmarek, Krzysztof T; Jaksch, Dieter; Nunn, Joshua
2016-01-01
Quantum information encoded in optical photons can be transmitted over long distances with very high information density, and suffers from negligible thermal noise at room temperature. On the other hand, microwave photons at cryogenic temperatures can be confined in high quality resonators and strongly coupled to solid-state qubits, providing a quantum bus to connect qubits and a route to deterministic photonic non-linearities. The coherent interconversion of microwave and optical photons has therefore recently emerged as a highly desirable capability that would enable freely-scalable networks of optically-linked qubits, or large-scale photonic information processing with multi-photon interactions mediated by microwaves. Here, we propose a route to efficient and coherent microwave-optical conversion based on frequency mixing in Rydberg atoms. The interaction requires no microfabricated components or cavities, and is tunable, broadband, and both spatially and spectrally multimode.
Makdisi, Y.; Philip, G.; Bhatia, K. S.; Connerade, J.-P.
2001-02-01
An experimental study of the two-photon spectra of high members of the Sr I 5snd 1,3D2 Rydberg series is described. We use transverse excitation of an atomic beam with a narrow-bandwidth tuneable dye laser within a heat pipe equipped for field ionization detection. The presence of weak collisions has revealed several anomalies. Strong spin-orbit interaction and the breakdown of parity and selection rules combined with `l' mixing are observed. The breakdown is due to the Stark field present in the interaction region. Single-photon transitions originating from the 5snp 1P1 and 5snp3PJ states populated by electron impact excitations are also observed. They create highly compact doubly excited 4d23PJ, 5p21D2 and 4d5p 3PJ states, which act as dominant intruders in the observed spectrum. Such states with highly localized orbitals survive collision and field effects, whereas Rydberg states are highly sensitive to external perturbations. Also, we have observed l-changing collisional processes like Ar + Sr (5s}nd 1,3D2) → Sr (5snl,l≥ 3). Several members of a new series which begin to appear at large n are observed and are tentatively designated as the 5snf 1F3 Rydberg series. Furthermore, we have observed and identified several members of the Sr I 5snp 1P1 and 5snp 3P2 Rydberg series by two-photon absorption from the ground state. They are excited via the breakdown of parity and other selection rules, owing to the presence of external fields. New values of energy levels of the Sr I 5snd 1,3D2 Rydberg series are presented: n=25-73 for singlet and n=25-47 for triplet members, obtained from two-photon spectra. Comparison of these values with those given by other authors who used different excitation schemes shows good agreement. The spectrum of fluorescence emission from a low-pressure discharge around the field ionization probe was obtained using a monochromator-photomultiplier detection system. The emission lines confirm the collisional excitations observed in the
Energy Technology Data Exchange (ETDEWEB)
Makdisi, Y.; Philip, G.; Bhatia, K.S. [Department of Physics, Kuwait University, Safat (Kuwait); Connerade, J.P. [Physics Department, Imperial College, London (United Kingdom)]. E-mail: j.connerade@ic.ac.uk
2001-02-28
An experimental study of the two-photon spectra of high members of the Sr I 5snd {sup 1,3}D{sub 2} Rydberg series is described. We use transverse excitation of an atomic beam with a narrow-bandwidth tuneable dye laser within a heat pipe equipped for field ionization detection. The presence of weak collisions has revealed several anomalies. Strong spin-orbit interaction and the breakdown of parity and selection rules combined with 'l' mixing are observed. The breakdown is due to the Stark field present in the interaction region. Single-photon transitions originating from the 5snp {sup 1}P{sub 1} and 5snp{sup 3}P{sub J} states populated by electron impact excitations are also observed. They create highly compact doubly excited 4d{sup 23}P{sub J}, 5p{sup 21}D{sub 2} and 4d5p {sup 3}P{sub J} states, which act as dominant intruders in the observed spectrum. Such states with highly localized orbitals survive collision and field effects, whereas Rydberg states are highly sensitive to external perturbations. Also, we have observed l-changing collisional processes like Ar + Sr (5s{r_brace}nd {sup 1,3}D{sub 2}){yields}Sr (5snl,l{>=}3). Several members of a new series which begin to appear at large n are observed and are tentatively designated as the 5snf {sup 1}F{sub 3} Rydberg series. Furthermore, we have observed and identified several members of the Sr I 5snp {sup 1}P{sub 1} and 5snp {sup 3}P{sub 2} Rydberg series by two-photon absorption from the ground state. They are excited via the breakdown of parity and other selection rules, owing to the presence of external fields. New values of energy levels of the Sr I 5snd {sup 1,3}D{sub 2} Rydberg series are presented: n=25-73 for singlet and n=25-47 for triplet members, obtained from two-photon spectra. Comparison of these values with those given by other authors who used different excitation schemes shows good agreement. The spectrum of fluorescence emission from a low-pressure discharge around the field ionization
Magic wavelengths for the $5s-18s$ transition in rubidium
Goldschmidt, E A; Koller, S B; Wyllie, R; Brown, R C; Porto, J V; Safronova, U I; Safronova, M S
2015-01-01
Magic wavelengths, for which there is no differential ac Stark shift for the ground and excited state of the atom, allow trapping of excited Rydberg atoms without broadening the optical transition. This is an important tool for implementing quantum gates and other quantum information protocols with Rydberg atoms, and reliable theoretical methods to find such magic wavelengths are thus extremely useful. We use a high-precision all-order method to calculate magic wavelengths for the $5s-18s$ transition of rubidium, and compare the calculation to experiment by measuring the light shift for atoms held in an optical dipole trap at a range of wavelengths near a calculated magic value.
Yakshina, E. A.
2016-10-21
The observation of the Stark-tuned Förster resonances between Rydberg atoms excited by narrowband cw laser radiation requires usage of a Stark-switching technique in order to excite the atoms first in a fixed electric field and then to induce the interactions in a varied electric field, which is scanned across the Förster resonance. In our experiments with a few cold Rb Rydberg atoms, we have found that the transients at the edges of the electric pulses strongly affect the line shapes of the Förster resonances, since the population transfer at the resonances occurs on a time scale of ∼100 ns, which is comparable with the duration of the transients. For example, a short-term ringing at a certain frequency causes additional radio-frequency-assisted Förster resonances, while nonsharp edges lead to asymmetry. The intentional application of the radio-frequency field induces transitions between collective states, whose line shape depends on the interaction strengths and time. Spatial averaging over the atom positions in a single interaction volume yields a cusped line shape of the Förster resonance. We present a detailed experimental and theoretical analysis of the line shape and time dynamics of the Stark-tuned Förster resonances Rb(nP3/2)+Rb(nP3/2)→Rb(nS1/2)+Rb([n+1]S1/2) for two Rb Rydberg atoms interacting in a time-varying electric field.
Angular-momentum couplings in long-range Rb$_2$ Rydberg molecules
Anderson, David A; Raithel, Georg
2014-01-01
We study angular-momentum couplings in $^{87}$Rb$_2$ Rydberg molecules formed between Rydberg and 5S$_{1/2}$ ground-state atoms. We use a Fermi model that includes S-wave and P-wave singlet and triplet scattering of the Rydberg electron with the 5S$_{1/2}$ atom, along with the fine structure coupling of the Rydberg atom and hyperfine structure coupling of the 5S$_{1/2}$ atom. We discuss the effects of these couplings on the adiabatic molecular potentials. We obtain bound-state energies, lifetimes, and electric and magnetic dipole moments for the vibrational ground states of the $^{87}$Rb$(n$D$+5$S$_{1/2})$ molecules in all adiabatic potentials, with fine and hyperfine structure included. We also study the effect of the hyperfine structure on the deep $^3$S-wave- and $^3$P-wave-dominated adiabatic molecular potentials, which support high-$\\ell$ $^{87}$Rb$_2$ Rydberg molecules.
Probing a scattering resonance in Rydberg molecules with a Bose-Einstein condensate
Schlagmüller, Michael; Nguyen, Huan; Lochead, Graham; Engel, Felix; Böttcher, Fabian; Westphal, Karl M; Kleinbach, Kathrin S; Löw, Robert; Hofferberth, Sebastian; Pfau, Tilman; Pérez-Ríos, Jesús; Greene, Chris H
2015-01-01
We present spectroscopy of a single Rydberg atom excited within a Bose-Einstein condensate. We not only observe the density shift as discovered by Amaldi and Segre in 1934, but a line shape which changes with the principal quantum number n. The line broadening depends precisely on the interaction potential energy curves of the Rydberg electron with the neutral atom perturbers. In particular, we show the relevance of the triplet p-wave shape resonance in the Rydberg electron-Rb(5S) scattering, which significantly modifies the interaction potential. With a peak density of 5.5x10^14 cm^-3, and therefore an inter-particle spacing of 1300 a0 within a Bose-Einstein condensate, the potential energy curves can be probed at these Rydberg ion - neutral atom separations. We present a simple microscopic model for the spectroscopic line shape by treating the atoms overlapped with the Rydberg orbit as zero-velocity, uncorrelated, point-like particles, with binding energies associated with their ion-neutral separation, and ...
Spectroscopy of cesium Rydberg atoms in strong radio-frequency fields
Jiao, Yuechun; Li, Jingkui; Raithel, Georg; Zhao, Jianming; Jia, Suotang
2016-01-01
We study Rydberg atoms modulated by strong radio-frequency (RF) fields with a frequency of 70 MHz. The Rydberg atoms are prepared in a room temperature cesium cell, and their level structure is probed using electromagnetically induced transparency (EIT). As the RF field increases from the weak- into the strong-field regime, the range of observed RF-induced phenomena progresses from AC level shifts through increasingly pronounced and numerous RF-modulation sidebands to complex state-mixing and level-crossings with high-l hydrogen-like states. Weak anharmonic admixtures in the RF field generate clearly visible modifications in the Rydberg-EIT spectra. A Floquet analysis is employed to model the Rydberg spectra, and good agreement with the experimental observations is found. Our results show that all-optical spectroscopy of Rydberg atoms in vapor cells can serve as an antenna-free, atom-based and calibration-free technique to measure and map RF electric fields and to analyze their higher-harmonic contents.
The Role of Rydberg-Valence Coupling in the Ultrafast Relaxation Dynamics of Acetone.
Koch, Markus; Thaler, Bernhard; Heim, Pascal; Ernst, Wolfgang E
2017-08-31
The electronic structure of excited states of acetone is represented by a Rydberg manifold that is coupled to valence states which provide very fast and efficient relaxation pathways. We observe and characterize the transfer of population from photoexcited Rydberg states (6p, 6d, 7s) to a whole series of lower Rydberg states (3p to 4d) and a simultaneous decay of population from these states. We obtain these results with time-resolved photoelectron-photoion coincidence (PEPICO) detection in combination with the application of Bayesian statistics for data analysis. Despite the expectedly complex relaxation behavior, we find that a simple sequential decay model is able to describe the observed PEPICO transients satisfactorily. We obtain a slower decay (∼320 fs) from photoexcited states compared to a faster decay (∼100 fs) of states that are populated by internal conversion, demonstrating that different relaxation dynamics are active. Within the series of Rydberg states populated by internal conversion, the decay dynamics seem to be similar, and a trend of slower decay from lower states indicates an increasingly higher energy barrier along the decay pathway for lower states. The presented results agree all in all with previous relaxation studies within the Rydberg manifold. The state-resolved observation of transient population ranging from 3p to 4d can serve as reference for time-dependent simulations.
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 ...
Parigi, Valentina; Bimbard, Erwan; Stanojevic, Jovica; Hilliard, Andrew J; Nogrette, Florence; Tualle-Brouri, Rosa; Ourjoumtsev, Alexei; Grangier, Philippe
2012-12-07
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 the medium. The measurements allow a direct estimation of the "blockaded fraction" of atoms within the atomic ensemble.
Bhowmick, Arup; Mohapatra, Ashok K
2016-01-01
We demonstrate the phenomenon of blockade in two-photon excitations to the Rydberg state in thermal vapor. A technique based on optical heterodyne is used to measure the dispersion of a probe beam far off resonant to the D2 line of rubidium in the presence of a strong laser beam that couples to the Rydberg state via two-photon resonance. Density dependent suppression of the dispersion peak is observed while coupling to the Rydberg state with principal quantum number, n = 60. The experimental observation is explained using the phenomenon of Rydberg blockade. The blockade radius is measured to be about 2.2 {\\mu}m which is consistent with the scaling due to the Doppler width of 2-photon resonance in thermal vapor. Our result promises the realization of single photon source and strong single photon non-linearity based on Rydberg blockade in thermal vapor.
Localization phenomena in interacting Rydberg lattice gases with position disorder
Marcuzzi, Matteo; Barredo, Daniel; de Léséleuc, Sylvain; Labuhn, Henning; Lahaye, Thierry; Browaeys, Antoine; Levi, Emanuele; Lesanovsky, Igor
2016-01-01
Disordered systems provide paradigmatic instances of ergodicity breaking and localization phenomena. Here we explore the dynamics of excitations in a system of Rydberg atoms held in optical tweezers. The finite temperature produces an intrinsic uncertainty in the atomic positions, which translates into quenched correlated disorder in the interatomic interaction strengths. In a simple approach, the dynamics in the many-body Hilbert space can be understood in terms of a one-dimensional Anderson-like model with disorder on every other site, featuring both localized and delocalized states. We conduct an experiment on an eight-atom chain and observe a clear suppression of excitation transfer. Our experiment accesses a regime which is described by a two-dimensional Anderson model on a "trimmed" square lattice. Our results thus provide a concrete example in which the absence of excitation propagation in a many-body system is directly related to Anderson-like localization in the Hilbert space, which is believed to be...
Non-Hydrogenic Rydberg Atroms in Magnetic Fields
Dando, P. A.; Monteiro, T. S.; Jans, W.; Schweizer, W.
The classical and quantal dynamics of non-hydrogenic Rydberg atoms in magnetic fields are investigated. Previous attempts to infer classical behaviour from quantum properties produced conflicting results: at low scaled energies (ɛ = -0.5) the nearest-neighbour statistics (NNS) were found to be at the chaotic (Wigner) limit while quantum phase-space distributions suggested a high degree of regularity. Here the classical limit is investigated directly by solving the equations of motion of the Diamagnetic Kepler problem (DKP) with an additional non-Coulombic model potential. It is found that typically trajectories are, over a long time-scale, ergodic. However over a shorter time-scale--in between collisions with the core--classical trajectories remain confined on the tori of the DKP. The origin of a well-known resonance in the NNS of hydrogen at ɛ = -0.316 is clarified by the comparison with the non-hydrogenic behaviour. However, the classical model only partially explains the quantum behaviour. The difficulties of quantizing such a system are discussed.
Pulse-induced focusing of Rydberg wave packets
Arbó, D. G.; Reinhold, C. O.; Burgdörfer, J.; Pattanayak, A. K.; Stokely, C. L.; Zhao, W.; Lancaster, J. C.; Dunning, F. B.
2003-06-01
We demonstrate that strong transient phase-space localization can be achieved by the application of a single impulsive “kick” in the form of a short (600 ps) unidirectional electric-field pulse to a strongly polarized, quasi-one-dimensional Rydberg atom. The underlying classical dynamics is analyzed and it is shown that phase-space localization results from a focusing effect analogous to rainbow scattering. Moreover, it is shown that the essential features of the classical analysis remain valid in a quantum-mechanical treatment of the system in terms of its phase-space Husimi distribution. The degree of phase-space localization is characterized by the coarse-grained Renyi entropy. Transient phase-space localization is demonstrated experimentally using extreme redshifted m=0 potassium Stark states in the n=351 manifold and a short probe pulse. The experimental data are in good agreement with theoretical predictions. The localized state provides an excellent starting point for further control and manipulation of the electron wave packet.
Scattering matrix theory for Cs Rydberg atoms in magnetic field
Institute of Scientific and Technical Information of China (English)
2008-01-01
Based on the closed orbit theory framework together with the quantum defect the-ory and time-independent scattering matrices theory,we calculate the recurrence spectra of diamagnetic Cs atoms at several different scaled energies near the second ionization threshold.It is revealed that the new extra peaks in spectra are attributed to the combination recurrences of semiclassical closed orbits arising from core-scattered events.This method considers the dynamic states of the Rydberg electron in the core region and long-range region and can be analytically resumed to include all orders of core-scattering automatically.With this approach a convergent recurrence spectrum can be reasonably achieved.It is found that the spectral complexity depends highly sensitively on the scaled energy.With the in-crease of the scaled energy,the spectral structure changes from simple to com-plicate and the dynamic feature from regular to chaotic.The comparison of the re-currence spectra with Dando’s result under the same conditions demonstrates that there exist some similarities and differences between them,and furthermore,the feasibility of the scattering matrix method is explained.
The role of high Rydberg states in enhanced O- formation in a pulsed O2 discharge
Ding, W. X.; Pinnaduwage, L. A.; Tav, C.; McCorkle, D. L.
1999-08-01
Formation of O- ions in a pulsed discharge of O2 was investigated in a Langmuir-probe-assisted photodetachment experiment. A large enhancement of negative ion formation was observed in the afterglow. Experimental results are consistent with O- formation via electron attachment to high Rydberg states of O2 that survive into the afterglow. Such excited states can be produced by high-energy electron impact during the discharge. The lifetime of high-Rydberg molecules is estimated to be longer than 10 microseconds. The efficient production of O- ion by electron attachment to high-Rydberg O2 molecules was further confirmed in a laser excitation experiment. The O- ions and O atoms produced via enhanced dissociative electron attachment to excited states of O2 may be important for the chemical processes that occur in pulsed plasma remediation of contaminated air.
Mean-field energy-level shifts and dielectric properties of strongly polarized Rydberg gases
Zhelyazkova, V.; Jirschik, R.; Hogan, S. D.
2016-11-01
Mean-field energy-level shifts arising as a result of strong electrostatic dipole interactions within dilute gases of polarized helium Rydberg atoms have been probed by microwave spectroscopy. The Rydberg states studied had principal quantum numbers n =70 and 72, and electric dipole moments of up to 14 050 D, and were prepared in pulsed supersonic beams at particle number densities on the order of 108 cm-3. Comparisons of the experimental data with the results of Monte Carlo calculations highlight effects of the distribution of nearest-neighbor spacings in the pulsed supersonic beams, and the dielectric properties of the strongly polarized Rydberg gases, on the microwave spectra. These observations reflect the emergence of macroscopic electrical properties of the atomic samples when strongly polarized.
Resonant Rydberg Dressing of Alkaline-Earth Atoms via Electromagnetically Induced Transparency
Gaul, C.; DeSalvo, B. J.; Aman, J. A.; Dunning, F. B.; Killian, T. C.; Pohl, T.
2016-06-01
We develop an approach to generate finite-range atomic interactions via optical Rydberg-state excitation and study the underlying excitation dynamics in theory and experiment. In contrast to previous work, the proposed scheme is based on resonant optical driving and the establishment of a dark state under conditions of electromagnetically induced transparency (EIT). Analyzing the driven dissipative dynamics of the atomic gas, we show that the interplay between coherent light coupling, radiative decay, and strong Rydberg-Rydberg atom interactions leads to the emergence of sizable effective interactions while providing remarkably long coherence times. The latter are studied experimentally in a cold gas of strontium atoms for which the proposed scheme is most efficient. Our measured atom loss is in agreement with the theoretical prediction based on binary effective interactions between the driven atoms.
Resonant Rydberg-dressing of Alkaline-Earth Atoms via Electromagnetically Induced Transparency
Gaul, C; Aman, J A; Dunning, F B; Killian, T C; Pohl, T
2015-01-01
We develop an approach to generate finite-range atomic interactions via optical Rydberg-state excitation and study the underlying excitation dynamics in theory and experiment. In contrast to previous work, the proposed scheme is based on resonant optical driving and the establishment of a dark state under conditions of electromagnetically induced transparency. Analyzing the driven dissipative dynamics of the atomic gas, we show that the interplay between coherent light coupling, radiative decay and strong Rydberg-Rydberg atom interactions leads to the emergence of sizeable effective interactions while providing remarkably long coherence times. The latter are studied experimentally in a cold gas of Strontium atoms for which the proposed scheme is most efficient. Our measured atom loss is in excellent agreement with the theoretical prediction based on binary effective interactions between the driven atoms.
Han, Jingshan; Vogt, Thibault; Li, Wenhui
2016-10-01
We perform spectroscopic measurements of electromagnetically induced transparency (EIT) in a strongly interacting Rydberg gas. We observe a significant spectral shift and attenuation of the transparency resonance due to the presence of interactions between Rydberg atoms. We characterize the attenuation as the result of an effective dephasing and show that the shift and the dephasing rate increase versus atomic density, probe Rabi frequency, and principal quantum number of Rydberg states. Moreover, we find that the spectral shift is reduced if the size of a Gaussian atomic cloud is increased and that the dephasing rate increases with the EIT pulse duration at large-parameter regimes. We simulate our experiment with a semianalytical model, which yields results in good agreement with our experimental data.
Mean-field energy-level shifts and dielectric properties of strongly polarized Rydberg gases
Zhelyazkova, V; Hogan, S D
2016-01-01
Mean-field energy-level shifts arising as a result of strong electrostatic dipole interactions within dilute gases of polarized helium Rydberg atoms have been probed by microwave spectroscopy. The Rydberg states studied had principal quantum numbers $n=70$ and 72, and electric dipole moments of up to 14050 D, and were prepared in pulsed supersonic beams at particle number densities on the order of $10^{8}$ cm$^{-3}$. Comparisons of the experimental data with the results of Monte Carlo calculations highlight effects of the distribution of nearest-neighbor spacings in the pulsed supersonic beams, and the dielectric properties of the strongly polarized Rydberg gases, on the microwave spectra. These observations reflect the emergence of macroscopic electrical properties of the atomic samples when strongly polarized.
Implementation of an experimentally feasible controlled-phase gate on two blockaded Rydberg atoms
Müller, Matthias M.; Murphy, Michael; Montangero, Simone; Calarco, Tommaso; Grangier, Philippe; Browaeys, Antoine
2014-03-01
We investigate the implementation of a controlled-Z gate on a pair of Rydberg atoms in spatially separated dipole traps where the joint excitation of both atoms into the Rydberg level is strongly suppressed (the Rydberg blockade). We follow the adiabatic gate scheme of Jaksch et al. [D. Jaksch, J. I. Cirac, P. Zoller, S. L. Rolston, R. Côté, and M. D. Lukin, Phys. Rev. Lett. 85, 2208 (2000), 10.1103/PhysRevLett.85.2208], where the pair of atoms is coherently excited using lasers, and apply it to the experimental setup outlined by Gaëtan et al. [A. Gaëtan, Y. Miroshnychenko, T. Wilk, A. Chotia, M. Viteau, D. Comparat, P. Pillet, A. Browaeys, and P. Grangier, Nat. Phys. 5, 115 (2009), 10.1038/nphys1183]. We apply optimization to the experimental parameters to improve gate fidelity and consider the impact of several experimental constraints on the gate success.
Observation of Rydberg-atom macrodimers: micrometer-sized diatomic molecules
Saßmannshausen, Heiner
2016-01-01
Long-range metastable molecules consisting of two cesium atoms in high Rydberg states have been observed in an ultracold gas. A sequential three-photon two-color photoassociation scheme was employed to form these molecules in states which correlate to $np(n+1)s$ dissociation asymptotes. Spectral signatures of bound molecular states are clearly resolved at the positions of avoided crossings between long-range van der Waals potential curves. The experimental results are in agreement with simulations based on a detailed model of the long-range multipole-multipole interactions of Rydberg-atom pair states. We show that a full model is required to accurately predict the occurrence of bound Rydberg macrodimers. The macrodimers are distinguished from repulsive molecular states by their behavior with respect to spontaneous ionization and possible decay channels are discussed.
Semiclassical Calculation of Recurrence Spectra of Rydberg Hydrogen Atom Near a Metal Surface
Institute of Scientific and Technical Information of China (English)
WANG De-Hua
2009-01-01
Using closed orbit theory, we give a clear physical picture description of the Rydberg hydrogen atom near a metal surface and calculate the Fourier transformed recurrence spectra of this system at different scaled energies below ionization threshold.The results show that with the increase of the scaled energy, the number of the closed orbit increases greatly.Some of the orbits are created by the bifurcation of the perpendicular orbit.This case is quite similar to the Rydberg atom in an electric field.When the scaled energy increases furthermore, chaotic orbits appear.This study provides a different perspective on the dynamical behavior of the Rydberg atom near a metal surface.
A high fidelity Rydberg blockade entangling gate using shaped, analytic pulses
Theis, L S; Wilhelm, F K; Saffmann, M
2016-01-01
We show that the use of shaped pulses improves the fidelity of a Rydberg blockade two-qubit entangling gate by several orders of magnitude compared to previous protocols based on square pulses or optimal control pulses. Using analytical Derivative Removal by Adiabatic Gate (DRAG) pulses that reduce excitation of primary leakage states and an analytical method of finding the optimal Rydberg blockade we generate Bell states with a fidelity of $F>0.9999$ in a 300 K environment for a gate time of only $50\\;{\\rm ns}$, which is an order of magnitude faster than previous protocols. These results establish the potential of neutral atom qubits with Rydberg blockade gates for scalable quantum computation.
Universal time-evolution of a Rydberg lattice gas with perfect blockade
Olmos, B; Lesanovsky, I; Velázquez, L
2012-01-01
We investigate the dynamics of a strongly interacting spin system that is motivated by current experimental realizations of strongly interacting Rydberg gases in lattices. In particular we are interested in the temporal evolution of quantities such as the density of Rydberg atoms and density-density correlations when the system is initialized in a fully polarized state without Rydberg excitations. We show that in the thermodynamic limit the expectation values of these observables converge at least logarithmically to universal functions and outline a method to obtain these functions. We prove that a finite one-dimensional system follows this universal behavior up to a given time. The length of this universal time period depends on the actual system size. This shows that already the study of small systems allows to make precise predictions about the thermodynamic limit provided that the observation time is sufficiently short. We discuss this for various observables and for systems with different dimensions, int...
Accessing Rydberg-dressed interactions using many-body Ramsey dynamics
Mukherjee, Rick; Killian, Thomas; Hazzard, Kaden
2016-05-01
We demonstrate that Ramsey spectroscopy can be used to observe Rydberg-dressed interactions in a many-body system. Our scheme operates comfortably within experimentally measured lifetimes, and accesses a regime where quantum superpositions are crucial. We build a spin-1/2 from one level that is Rydberg-dressed and another that is not. These levels may be hyperfine or long-lived electronic states. An Ising spin model governs the Ramsey dynamics, for which we derive an exact solution. Due to the structure of Rydberg interactions, the dynamics differs significantly from that in other spin systems. As one example, spin echo can increase the rate at which coherence decays. The results are relevant for the current ongoing experiments, including those at Rice University.
Van der Waals Interactions among Alkali Rydberg Atoms with Excitonic States
Zoubi, Hashem
2015-01-01
We investigate the influence of the appearance of excitonic states on van der Waals interactions among two Rydberg atoms. The atoms are assumed to be in different Rydberg states, e.g., in the $|ns\\rangle$ and $|np\\rangle$ states. The resonant dipole-dipole interactions yield symmetric and antisymmetric excitons, with energy splitting that give rise to new resonances as the atoms approach each other. Only far from these resonances the van der Waals coefficients, $C_6^{sp}$, can be defined. We calculate the $C_6$ coefficients for alkali atoms and present the results for lithium by applying perturbation theory. At short interatomic distances of several $\\mu m$, we show that the widely used simple model of two-level systems for excitons in Rydberg atoms breaks down, and the correct representation implies multi-level atoms. Even though, at larger distances one can keep the two-level systems but in including van der Waals interactions among the atoms.
Few-body Cs Rydberg Atom Interactions in a 1064 nm Dipole Trap
Booth, Donald; Tallant, Jonathan; Marangoni, Bruno; Marcassa, Luis; Shaffer, James
2011-05-01
In studying few-body physics, the number density of atoms is an important parameter in achieving a good signal to noise ratio. We have recently improved our apparatus by implementing a crossed 1064 nm far off-resonance trap (FORT), which enables us to trap atoms at three orders of magnitude greater density than our MOT. Future directions for the apparatus, which include the study of anisotropic interactions among Rydberg atoms in the dipole trap, three-body recombination, ``trilobite-like'' molecules, and the detection of ultra-long range Rydberg macrodimers in Cs, will be described. Our presentation will focus on data on three-body recombination and long-range Rydberg ``trilobite-like'' molecules. We acknowledge funding from ARO (W911NF-08-1-0257), NSF (PHY-0855324) and NSF (OISE-0756321).
Electro-Optomechanical Transduction & Quantum Hard-Sphere Model for Dissipative Rydberg-EIT Media
DEFF Research Database (Denmark)
Zeuthen, Emil
transduction functionality into the well-established framework of electrical engineering, thereby facilitating its implementation in potential applications such as nuclear magnetic resonance imaging and radio astronomy. We consider such optomechanical sensing of weak electrical signals and discuss how...... the equivalent circuit formalism can be used to optimize the electrical circuit design. We also discuss the parameter requirements for transducing microwave photons in the quantum regime. Part II: Effective photon-photon interactions can be engineered by combining long-range Rydberg interactions between atoms....... We introduce a new approach to analyzing this challenging many-body problem in the limit of large optical depth per blockade radius. The idea is to separate the single-polariton EIT physics from the Rydberg-Rydberg interactions in a serialized manner while using a hard-sphere model for the latter...
Neutralization distances of Ar^Z+ Rydberg ions interacting with solid surfaces
Majkic, M. D.; Nedeljkovic, N. N.; Galijas, S. M. D.
2008-07-01
We apply the recently developed time-symmetrized, two-state vector model to investigate the intermediate stages of the electron capture into the Rydberg states of multiply charged Ar^Z+ ions (core charge Z >> 1, principal quantum number n_A >> 1) escaping Al-solid surface at low velocity. The simple analytical formulae derived for the corresponding neutralization rates enable us to analyze the neutralization distances for the low-l Rydberg states (n_A,l_A,m_A), for different charge states Z of the ion. It is found that the inclusion of core polarization significantly reduces the neutralization distances. The neutralization distances for the highest Rydberg levels that can be populated in the vicinity of solid surface are in agreement with the data deduced from experiments in which the kinetic energy gain due to the image acceleration of the ions is measured.
A Rydberg blockade CNOT gate and entanglement in a 2D array of neutral atom qubits
Maller, K M; Xia, T; Sun, Y; Piotrowicz, M J; Carr, A W; Isenhower, L; Saffman, M
2015-01-01
We present experimental results on two-qubit Rydberg blockade quantum gates and entanglement in a two-dimensional qubit array. Without post selection against atom loss we achieve a Bell state fidelity of $0.73\\pm 0.05$, the highest value reported to date. The experiments are performed in an array of single Cs atom qubits with a site to site spacing of $3.8 ~ \\mu\\rm m$. Using the standard protocol for a Rydberg blockade C$_Z$ gate together with single qubit operations we create Bell states and measure their fidelity using parity oscillations. We analyze the role of AC Stark shifts that occur when using two-photon Rydberg excitation and show how to tune experimental conditions for optimal gate fidelity.
Energy Technology Data Exchange (ETDEWEB)
Buchleitner, A
1993-12-15
We develop a theoretical formalism which provides a powerful tool for the detailed numerical analysis of the interaction of three-dimensional hydrogen atoms with an intense radiation field. The application of this approach to the microwave ionization of Rydberg states of hydrogen provides the most realistic numerical experiments ever made in this area. A thorough analysis of ionization signals and thresholds, of level dynamics and of the phase space projections of associated wave functions is provided for a one-dimensional model of the atom. The comparison to the ionization of three-dimensional atoms confirms the validity of the one-dimensional model for extended initial states and, hence, dynamical localization theory, as far as the ionization threshold is concerned. Three classes of three-dimensional initial states with distinct symmetries are identified and they appear to be more or less adapted to the symmetries of the eigenstates of the microwave problem. 'Scarred' wavefunctions of the three-dimensional hydrogen atom exposed to microwave field are shown. Finally, the dynamics of a circular state in a microwave and in an intense laser field are compared. (author)
Yakshina, E A; Beterov, I I; Entin, V M; Andreeva, C; Cinins, A; Markovski, A; Iftikhar, Z; Ekers, A; Ryabtsev, I I
2016-01-01
The observation of the Stark-tuned F\\"orster resonances between Rydberg atoms excited by narrowband cw laser radiation requires usage of a Stark-switching technique in order to excite the atoms first in a fixed electric field and then to induce the interactions in a varied electric field, which is scanned across the F\\"orster resonance. In our experiments with a few cold Rb Rydberg atoms we have found that the transients at the edges of the electric pulses strongly affect the line shapes of the F\\"orster resonances, since the resonances occur mainly on a time scale of ~100 ns, which is comparable with the duration of the transients. For example, a short-term ringing at a certain frequency causes additional radio-frequency-assisted F\\"orster resonances, while non-sharp edges lead to asymmetry. The intentional application of the radio-frequency field induces transitions between collective states, whose line shape depends on the interaction strengths and time. Spatial averaging over the atom positions in a singl...
Han, Jingshan; Li, Wenhui
2016-01-01
We perform spectroscopic measurements of electromagnetically induced transparency (EIT) in a strongly interacting Rydberg gas, and observe a significant spectral shift of the transparency from the single-atom EIT resonance as well as a spectral dephasing of the same order. We characterize the shift and dephasing as a function of atomic density, probe Rabi frequency, and principal quantum number of Rydberg states, and demonstrate that the observed spectral shift and dephasing are reduced if the size of a Gaussian atomic cloud is increased. We simulate our experiment with a semi-analytical model, which gives results in good agreement with our experimental data.
Stabilization of circular Rydberg atoms by circularly polarized infrared laser fields
Energy Technology Data Exchange (ETDEWEB)
Askeland, S.; Soerngaard, S. A.; Nepstad, R.; Foerre, M. [Department of Physics and Technology, University of Bergen, N-5007 Bergen (Norway); Pilskog, I. [Department of Physics and Technology, University of Bergen, N-5007 Bergen (Norway); Laboratoire de Chimie Physique - Matiere et Rayonnement, Universite Pierre et Marie Curie - CNRS (UMR 7614), F-75231 Paris Cedex 05 (France)
2011-09-15
The ionization dynamics of circular Rydberg states in strong circularly polarized infrared (800 nm) laser fields is studied by means of numerical simulations with the time-dependent Schroedinger equation. We find that at certain intensities, related to the radius of the Rydberg states, atomic stabilization sets in, and the ionization probability decreases as the intensity is further increased. Moreover, there is a strong dependence of the ionization probability on the rotational direction of the applied laser field, which can be understood from a simple classical analogy.
Feng, Qiang; Xu, Yun-Feng; Sun, Jin-Da; Tian, Shan-Xi; Shan, Xiao-Bin; Liu, Fu-Yi; Sheng, Liu-Si
2009-10-01
Photodissociation efficiency spectrum of anionic oxygen atom produced via ion-pair dissociations of carbon dioxide is recorded by means of the synchrotron radiation excitation (XUV photon energy 17.40-20.00 eV). The present spectrum is assigned as the Rydberg-like excited ion-pair states, i.e., Tanaka-Ogawa and Henning series, tilde C2Σg+ (CO+2) vibrational ground-state and excitation series. Three Rydberg series, npσu, npπu, and nfu, converging to tilde C2Σg+ (0, 0, 0), show the higher cross sections.
Preparation of circular Rydberg states in helium using the crossed fields method
Zhelyazkova, V.; Hogan, S. D.
2016-01-01
Helium atoms have been prepared in the circular $|n=55,\\ell=54,m_{\\ell}=+54\\rangle$ Rydberg state using the crossed electric and magnetic fields method. The atoms, initially travelling in pulsed supersonic beams, were photoexcited from the metastable $1s2s\\,^3S_1$ level to the outermost, $m_{\\ell}=0$ Rydberg-Stark state with $n=55$ in the presence of a strong electric field and weak perpendicular magnetic field. Following excitation, the electric field was adiabatically switched off causing t...
Preparation of circular Rydberg states in helium using the crossed-fields method
Zhelyazkova, V.; Hogan, S. D.
2016-01-01
Helium atoms have been prepared in the circular |n=55,ℓ=54,mℓ=+54⟩ Rydberg state using the crossed electric and magnetic fields method. The atoms, initially traveling in pulsed supersonic beams, were photoexcited from the metastable 1s2sS13 level to the outermost, mℓ=0 Rydberg-Stark state with n=55 in the presence of a strong electric field and weak perpendicular magnetic field. Following excitation, the electric field was adiabatically switched off causing the atoms to evolve into the circul...
An optically resolvable Schr\\"odinger's cat from Rydberg dressed cold atom clouds
Möbius, S; Eisfeld, A; Wüster, S; Rost, J -M
2012-01-01
In Rydberg dressed ultra-cold gases, ground state atoms inherit properties of a weakly admixed Rydberg state, such as sensitivity to long-range interactions. We show that through hyperfine-state dependent interactions, a pair of atom clouds can evolve into a spin and subsequently into a spatial Schr\\"odinger's cat state: The pair, containing 20 atoms in total, is in a coherent superposition of two configurations, with cloud locations separated by micrometers. The mesoscopic nature of the superposition state can be proven with absorption imaging, while the coherence can be revealed though recombination and interference of the split wave packets.
Calculation of the fine structure of the level in Rydberg state of lithium
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
The level shift and level formula of lithium atom in Rydberg states are achieved by means of the calculation of polarization of the atomic core (including the contribution of dipole moment, quadrupole moment and octupole moment);meanwhile, the effect of relativity theory, the orbital angular momentum L and the spin angular momentum S coupling (LS coupling), and high order correction of the effective potential are considered. The some fine structures (N=5～12,L=4～9,J=L±1/2) and the corresponding level intervals in Rydberg states can be calculated by the above-mentioned level formula and compared with correlated experimental data.
Optical-optical double-resonant multiphoton ionization spectra of Rydberg states of nitrogen dioxide
Institute of Scientific and Technical Information of China (English)
Zhang Gui-Yin; Zhang Lian-Shui; Sun Bo; Han Xiao-Feng; Yu Wei
2005-01-01
The optical-optical double-resonant multiphoton ionization(OODR-MPI) technique has been applied to the study of the Rydberg states of nitrogen dioxide. The results show that ,althougy the OODR-MPI spectra of NO2 are composed of regular progression bands at different pump laser intensities, their ionization pathways are different.The NO2 mollecule is ionized through the (3+1+1)double-resonant process as the pump laser intensity is in a high value, or else it is through the (1+2+1)rpocess.The final resonant states in the two ionizing processes have been attributed to different Rydberg states.
Fine structure in a strong magnetic field: Paschen-Back effect reconsidered in Rydberg atoms
Liu, Wenyu; Gu, Sihong; Li, Baiwen
1996-05-01
Using a kind of potential model wave function for alkali metal atoms, we nonperturbatively study the effect of fine structure on the Rydberg spectra of Cs atom in a strong magnetic field. Our numerical results reveal spectral structure dramatically different from the well-established Paschen-Back effect, and we argue that the fine structure of the Rydberg Cs atom cannot be neglected even in a magnetic field as strong as several teslas. We also give an error estimate of our results and a word on possible experimental verification.
Beterov, I I
2015-01-01
We calculate interspecies Rydberg-Rydberg interaction strengths for the heavy alkalis Rb and Cs. The presence of strong F\\"orster resonances makes interspecies coupling a promising approach for long range entanglement generation. We also provide an overview of the strongest F\\"orster resonances for Rb-Rb and Cs-Cs using different principal quantum numbers for the two atoms. We show how interspecies coupling can be used for high fidelity quantum non demolition state measurements with low crosstalk in qubit arrays.
Atom Based Vector Microwave Electrometry Using Rubidium Rydberg Atoms in a Vapor Cell
Sedlacek, J; Kübler, Harald; Shaffer, J P
2013-01-01
It is clearly important to pursue atomic standards for quantities like electromagnetic fields, time, length and gravity. We have recently shown, using Rydberg states, that Rb atoms in a vapor cell can serve as a practical, compact standard for microwave electric field strength. Here, we demonstrate, for the first time, that Rb atoms excited in a vapor cell can also be used for vector microwave electrometry by using Rydberg atom electromagnetically induced transparency. We describe the measurements necessary to obtain an arbitrary microwave electric field polarization at a resolution of $0.5^\\circ$. The experiments are compared to theory and found to be in excellent agreement.
Sub-wavelength microwave electric field imaging using Rydberg atoms inside atomic vapor cells
Fan, H Q; Daschner, R; Kübler, H; Shaffer, J P
2014-01-01
We have recently shown that Alkali atoms contained in a vapor cell can serve as a highly accurate standard for microwave electric field strength as well as polarization using the principles of Rydberg atom electromagnetically induced transparency. Here, we show, for the first time, that Rydberg atom electromagnetically induced transparency can be used to image microwave electric fields with unprecedented precision. The spatial resolution of the method is far into the sub-wavelength regime. The electric field resolutions are similar to those we have demonstrated in our prior experiments. Our experimental results agree with finite element calculations of test electric field patterns.
Decay rates of large-l Rydberg states of multiply charged ions approaching solid surfaces
Nedeljkovic, N. N.; Mirkovic, M. A.; Bozanic, D. K.
2008-07-01
We investigate the ionization of large-l multiply charged Rydberg ions approaching solid surfaces within the framework of decay model and applying the etalon equation method. The radial coordinate rho of the active electron is treated as a variational parameter and therefore the parabolic symmetry is preserved in this procedure. The complex eigenenergies are calculated from which the energy terms and the ionization rates are derived. We find that the large-l Rydberg states decay at approximately the same ion-surface distances as the low-l states oriented toward the vacuum and considerably closer to the surface comparing to the low-l states oriented towards the surface.
Quantum computing with atomic qubits and Rydberg interactions: progress and challenges
Saffman, M.
2016-10-01
We present a review of quantum computation with neutral atom qubits. After an overview of architectural options and approaches to preparing large qubit arrays we examine Rydberg mediated gate protocols and fidelity for two- and multi-qubit interactions. Quantum simulation and Rydberg dressing are alternatives to circuit based quantum computing for exploring many body quantum dynamics. We review the properties of the dressing interaction and provide a quantitative figure of merit for the complexity of the coherent dynamics that can be accessed with dressing. We conclude with a summary of the current status and an outlook for future progress.
Few-body interactions in frozen Rydberg gases
Faoro, Riccardo; Pelle, Bruno; Zuliani, Alexandre
2016-12-01
The strong dipole-dipole coupling and the Stark tunability make Förster resonances an attractive tool for the implementation of quantum gates. In this direction a generalization to a N-body process would be a powerful instrument to implement multi-qubit gate and it will also path the way to the understanding of many-body physics. In this review, we give a general introduction on Förster resonances, also known as two-body FRET, giving an overview of the different application in quantum engineering and quantum simulation. Then we will describe an analogous process, the quasi-forbidden FRET, which is related to the Stark mixing due to the presence of an external electric field. We will then focus on its use in a peculiar four-body FRET. The second part of this review is focused on our study of few-body interactions in a cold gas of Cs Rydberg atoms. After a detailed description of a series of quasi-forbidden resonances detected in the proximity of an allowed two-body FRET we will show our most promising result: the observation of a three-body FRET. This process corresponds to a generalization of the usual two-body FRET, where a third atom serves as a relay for the energy transport. This relay also compensates for the energy mismatch which prevents a direct two-body FRET between the donor and the acceptor, but on the other side allowed a three-body process; for this reason, the three-body FRET observed is a "Borromean" process. It can be generalized for any quantum system displaying two-body FRET from quasi-degenerate levels. We also predict N-body FRET, based on the same interaction scheme. Three-body FRET thus promises important applications in the formation of macro-trimers, implementation of few-body quantum gates, few-body entanglement or heralded entanglement.
Pulsed excitation of Rydberg-atom-pair states in an ultracold Cs gas
Saßmannshausen, Heiner; Deiglmayr, Johannes
2015-01-01
Pulsed laser excitation of a dense ultracold Cs vapor has been used to study the pairwise interactions between Cs atoms excited to $n$p$_{3/2}$ Rydberg states of principal quantum numbers in the range $n=22-36$. Molecular resonances were observed that correspond to excitation of Rydberg-atom-pair states correlated not only to the $n$p$_{3/2}+n$p$_{3/2}$ dissociation asymptotes, but also to $n$s$_{1/2}+(n+1)$s$_{1/2}$, $n$s$_{1/2}+n'$f$_{j}$, and $(n-4)$f$_{j}+(n-3)$f$_{j}$ $(j=5/2,7/2)$ dissociation asymptotes. These pair resonances are interpreted as arising from dipole-dipole, and higher long-range-interaction terms between the Rydberg atoms on the basis of i) their spectral positions, ii) their response to static and pulsed electric fields, and iii) millimeter-wave spectra between pair states correlated to different pair-dissociation asymptotes. The Rydberg-atom--pair states were found to spontaneously decay by Penning ionization and the dynamics of the ionization process were investigated during the first...
Gavryusev, V.; Signoles, A.; Ferreira-Cao, M.; Zürn, G.; Hofmann, C. S.; Günter, G.; Schempp, H.; Robert-de-Saint-Vincent, M.; Whitlock, S.; Weidemüller, M.
2016-08-01
We present combined measurements of the spatially resolved optical spectrum and the total excited-atom number in an ultracold gas of three-level atoms under electromagnetically induced transparency conditions involving high-lying Rydberg states. The observed optical transmission of a weak probe laser at the center of the coupling region exhibits a double peaked spectrum as a function of detuning, while the Rydberg atom number shows a comparatively narrow single resonance. By imaging the transmitted light onto a charge-coupled-device camera, we record hundreds of spectra in parallel, which are used to map out the spatial profile of Rabi frequencies of the coupling laser. Using all the information available we can reconstruct the full one-body density matrix of the three-level system, which provides the optical susceptibility and the Rydberg density as a function of spatial position. These results help elucidate the connection between three-level interference phenomena, including the interplay of matter and light degrees of freedom and will facilitate new studies of many-body effects in optically driven Rydberg gases.
Quantum computing with atomic qubits and Rydberg interactions: Progress and challenges
Saffman, Mark
2016-01-01
We present a review of quantum computation with neutral atom qubits. After an overview of architectural options we examine Rydberg mediated gate protocols and fidelity for two- and multi-qubit interactions. We conclude with a summary of the current status and give an outlook for future progress.
Cooperative Excitation and Many-Body Interactions in a Cold Rydberg Gas
DEFF Research Database (Denmark)
Viteau, Matthieu; Huillery, Paul; Bason, Mark George;
2012-01-01
The dipole blockade of Rydberg excitations is a hallmark of the strong interactions between atoms in these high-lying quantum states [ M. Saffman, T. G. Walker and K. Mølmer Rev. Mod. Phys. 82 2313 (2010); D. Comparat and P. Pillet J. Opt. Soc. Am. B 27 A208 (2010)]. One of the consequences of th...
Phase dependent excitation of Rydberg atoms in non-zero average fields
Magnuson, Eric; Carrat, Vincent; Gallagher, Tom
2016-05-01
The final energy of an electron excited to a high lying Rydberg state in the presence of a microwave (MW) field shows a dependence on the phase of the field at which the excitation occurs. This phase dependence is comparable to that seen in strong field experiments using attosecond pulses to probe systems perturbed by intense infrared (IR) fields. In zero average field, final energies exhibit a phase dependence at twice the frequency of the MW field. We show a phase dependence at the same frequency as the MW field emerges in the presence of a non-zero average field, parallel to the MW polarization. To isolate phase dependence at the MW frequency, we amplitude modulate the IR excitation laser and phase lock this modulation to the MW field. Li atoms are excited to states near the ionization limit in the presence of a MW field, and bound Rydberg states (n>150) are detected. In an applied average field, we observe modulation of the Rydberg signal at the MW frequency. This modulation vanishes as the average field is zeroed, but persists even in fields large enough to ionize most of the population. We compare these results to symmetry arguments and a model of classical Rydberg orbits. An experiment to determine the absolute phase of the modulation relative the MW field is discussed. This work is supported by the US Department of Energy.
A high repetition rate experimental setup for quantum non-linear optics with cold Rydberg atoms
Busche, Hannes; Ball, Simon W.; Huillery, Paul
2016-12-01
Using electromagnetically induced transparency and photon storage, the strong dipolar interactions between Rydberg atoms and the resulting dipole blockade can be mapped onto light fields to realise optical non-linearities and interactions at the single photon level. We report on the realisation of an experimental apparatus designed to study interactions between single photons stored as Rydberg excitations in optically trapped microscopic ensembles of ultracold 87Rb atoms. A pair of in-vacuum high numerical aperture lenses focus excitation and trapping beams down to 1 μm, well below the Rydberg blockade. Thanks to efficient magneto-optical trap (MOT) loading from an atomic beam generated by a 2D MOT and the ability to recycle the microscopic ensembles more than 20000 times without significant atom loss, we achieve effective repetition rates exceeding 110 kHz to obtain good photon counting statistics on reasonable time scales. To demonstrate the functionality of the setup, we present evidence of strong photon interactions including saturation of photon storage and the retrieval of non-classical light. Using in-vacuum antennae operating at up to 40 GHz, we perform microwave spectroscopy on photons stored as Rydberg excitations and observe an interaction induced change in lineshape depending on the number of stored photons.
Nonlinear modifications of photon correlations via controlled single and double Rydberg blockade
Liu, Yi-Mou; Tian, Xue-Dong; Yan, Dong; Zhang, Yan; Cui, Cui-Li; Wu, Jin-Hui
2015-04-01
We study the optical response of cold rubidium atoms driven into the four-level Y configuration exhibiting two high Rydberg levels in the regime of electromagnetically induced transparency (EIT). Atoms excited to either Rydberg level interact with each other just via self-blockade potentials (I) or also via cross blockade potentials (II). Numerical results show a few interesting quantum phenomena on the transmitted properties of a weak probe field owing to controlled single and double Rydberg blockade. In case (I), it is viable to switch between single-photon outputs with vanishing (invariable) two-photon (three-photon) correlation and photon-pair outputs with vanishing (invariable) three-photon (two-photon) correlation. Such output switch can be easily done by modulating frequencies and intensities of two strong coupling fields to create a degenerate EIT window or two separated EIT windows. In case (II), we find that two-photon and three-photon correlations decrease together at a degenerate EIT window center while increasing together between two separated EIT windows. Such consistent changes are observed because both correlations are modified by the identical polarizability degradation though depending on single and double Rydberg blockade, respectively.
Silicon as a model ion trap: Time domain measurements of donor Rydberg states
Vinh, N. Q.; Greenland, P. T.; Litvinenko, K.; Redlich, B.; van der Meer, A. F. G.; Lynch, S. A.; Warner, M.; Stoneham, A. M.; Aeppli, G.; Paul, D. J.; Pidgeon, C. R.; Murdin, B. N.
2008-01-01
One of the great successes of quantum physics is the description of the long-lived Rydberg states of atoms and ions. The Bohr model is equally applicable to donor impurity atoms in semiconductor physics, where the conduction band corresponds to the vacuum, and the loosely bound electron orbiting a s
Magic wavelengths for the 5s-18s transition in rubidium
Goldschmidt, E.A.; Norris, David Gordon; Koller, S.B.; Wyllie, R.; Brown, R.C.; Porto, J.; Safronova, M.S.; Safronova, U.I.
2015-01-01
Magic wavelengths, for which there is no differential ac Stark shift for the ground and excited state of the atom, allow trapping of excited Rydberg atoms without broadening the optical transition. This is an important tool for implementing quantum gates and other quantum information protocols with
Simons, Matt T.; Gordon, Joshua A.; Holloway, Christopher L.; Anderson, David A.; Miller, Stephanie A.; Raithel, Georg
2016-04-01
In this work, we demonstrate an approach for improved sensitivity in weak radio frequency (RF) electric-field strength measurements using Rydberg electromagnetically induced transparency (EIT) in an atomic vapor. This is accomplished by varying the RF frequency around a resonant atomic transition and extrapolating the weak on-resonant field strength from the resulting off-resonant Autler-Townes (AT) splittings. This measurement remains directly traceable to SI compared to previous techniques, precluding any knowledge of experimental parameters such as optical beam powers as is the case when using the curvature of the EIT line shape to measure weak fields. We use this approach to measure weak RF fields at 182 GHz and 208 GHz demonstrating improvement greater than a factor of 2 in the measurement sensitivity compared to on-resonant AT splitting RF electric field measurements.
Bergeson, Scott; Lyon, Mary
2016-05-01
We report measurements of the ion velocity distribution in an ultracold neutral plasma derived from a dense, cold Rydberg gas in a MOT. The Rydberg atoms are excited using a resonant two-step excitation pathway with lasers of 4 ns duration. The plasma forms spontaneously and rapidly. The rms width of the ion velocity distribution is determined by measuring laser-induced fluorescence (LIF) of the ions. The measured excitation efficiency is compared with a Monte-Carlo wavefunction calculation, and significant differences are observed. We discuss the conditions for blockaded Rydberg excitation and the subsequent spatial ordering of Rydberg atom domains. While the blockade interaction is greater than the Rabi frequency in portions of the atomic sample, no evidence for spatial ordering is observed. This research is supported in part by the Air Force Office of Scientific Research (Grant No. FA9950-12- 0308) and by the National Science Foundation (Grant No. PHY-1404488).
Bergeson, S D
2016-01-01
We report measurements of the ion velocity distribution in an ultracold neutral plasma derived from a dense, cold Rydberg gas in a MOT. The Rydberg atoms are excited using a resonant two-step excitation pathway with lasers of 4 ns duration. The plasma forms spontaneously and rapidly. The rms width of the ion velocity distribution is determined by measuring laser-induced fluorescence (LIF) of the ions. The measured excitation efficiency is compared with a Monte-Carlo wavefunction calculation, and significant differences are observed. We discuss the conditions for blockaded Rydberg excitation and the subsequent spatial ordering of Rydberg atom domains. While the blockade interaction is greater than the Rabi frequency in portions of the atomic sample, no evidence for spatial ordering is observed.
Parigi, Valentina; Stanojevic, Jovica; Hilliard, Andrew J; Nogrette, Florence; Tualle-Brouri, Rosa; Ourjoumtsev, Alexei; Grangier, Philippe
2012-01-01
We observe and measure dispersive optical non-linearities 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 non-linearities are due to the progressive appearance of a Rydberg blockaded volume within the medium. The measurements allow a direct estimation of the "blockaded fraction" of atoms within the atomic ensemble.
Mihajlov, A. A.; Sreckovic, V. A.; Ignjatovic, Lj. M.; Klyucharev, A. N.
2012-01-01
In this article the history and the current state of research of the chemiionization processes in atom-Rydberg atom collisions is presented. The principal assumptions of the model of such processes based on the dipole resonance mechanism, as well as the problems of stochastic ionization in atom-Rydberg atom collisions, are exposed. The properties of the collision kinetics in atom beams of various types used in contemporary experimentations are briefly described. Results of the calculation of ...
S. D. Bergeson; Lyon, M
2016-01-01
We report measurements of the ion velocity distribution in an ultracold neutral plasma derived from a dense, cold Rydberg gas in a MOT. The Rydberg atoms are excited using a resonant two-step excitation pathway with lasers of 4 ns duration. The plasma forms spontaneously and rapidly. The rms width of the ion velocity distribution is determined by measuring laser-induced fluorescence (LIF) of the ions. The measured excitation efficiency is compared with a Monte-Carlo wavefunction calculation, ...
Survival Of Large-l Rydberg States Of Highly Charged Ions In The Vicinity Of Metal Surfaces
Mirkovic, M. A.; Nedeljkovic, N. N.; Božanic, D. K.
2010-07-01
The probabilities for ionization of large-l multiply charged Rydberg ions approaching metallic surfaces at thermal velocities in the normal incidence geometry were calculated. The ionization process was treated within the framework of decay model using the appropriate etalon equation method for solving the complex energy eigenvalue problem. It is shown that, in contrast to corresponding low-l states, the large-l Rydberg states exhibit non-zero survival probabilities.
Energy Technology Data Exchange (ETDEWEB)
Donovan, Robert J., E-mail: R.Donovan@ed.ac.uk, E-mail: tr01@staffmail.ed.ac.uk; Lawley, Kenneth P., E-mail: k.p.lawley@ed.ac.uk; Ridley, Trevor, E-mail: R.Donovan@ed.ac.uk, E-mail: tr01@staffmail.ed.ac.uk [School of Chemistry, University of Edinburgh, Joseph Black Building, Edinburgh EH9 3FJ (United Kingdom)
2015-05-28
We report the identification of heavy Rydberg resonances in the ion-pair spectra of I{sub 2}, Cl{sub 2}, ICl, and IBr. Extensive vibrational progressions are analysed in terms of the energy dependence of the quantum defect δ(E{sub b}) rather than as Dunham expansions. This is shown to define the heavy Rydberg region, providing a more revealing fit to the data with fewer coefficients and leads just as easily to numbering data sets separated by gaps in the observed vibrational progressions. Interaction of heavy Rydberg states with electronic Rydberg states at avoided crossings on the inner wall of the ion-pair potential is shown to produce distinctive changes in the energy dependence of δ(E{sub b}), with weak and strong interactions readily distinguished. Heavy Rydberg behaviour is found to extend well below near-dissociation states, down to vibrational levels ∼18 000-20 000 cm{sup −1} below dissociation. The rapid semi-classical calculation of δ(E{sub b}) for heavy Rydberg states is emphasised and shows their absolute magnitude to be essentially the volume of phase space excluded from the vibrational motion by avoiding core-core penetration of the ions.
Observation of Rydberg blockade effects at very high n, n ~ 300 , using strontium n1F3 states
Zhang, Xinyue; Dunning, F. B.; Yoshida, Shuhei; Burgdörfer, Joachim
2015-05-01
Rydberg blockade at very high n, n ~ 300 , is examined using strontium n1F3 Rydberg atoms excited in a small volume defined by two tightly-focused crossed laser beams. Measurements of the number distribution of Rydberg atoms created show deviations from a Poisson distribution revealing sizeable blockade effects. The statistics of the number distribution are studied using a Monte Carlo method in which the interaction between strontium Rydberg atoms is evaluated by solving the Schrödinger equation within a two-active-electron model. The strength of blockade is analyzed in detail with respect to the alignment of two atoms relative to the laser polarizations. With careful control of the experimental parameters the probability for creating one, and only one, Rydberg atom, P(1) , in the excitation volume can be sufficiently large, P(1) > 0 . 6 , as to enable detailed studies of strongly-coupled Rydberg atom pairs. Research supported by the NSF, the Robert A. Welch Foundation, and the FWF (Austria).
Ultralong-Range Rydberg Molecules in a Divalent-Atomic System
DeSalvo, B J; Dunning, F B; Killian, T C; Sadeghpour, H R; Yoshida, S; Burgdörfer, J
2015-01-01
We report the creation of ultralong-range Sr$_2$ molecules comprising one ground-state $5s^2$ $^1S_0$ atom and one atom in a $5sns$ $^3S_1$ Rydberg state for $n$ ranging from 29 to 36. Molecules are created in a trapped ultracold atomic gas using two-photon excitation near resonant with the $5s5p$ $^3P_1$ intermediate state, and their formation is detected through ground-state atom loss from the trap. The observed molecular binding energies are fit with the aid of first-order perturbation theory that utilizes a Fermi pseudopotential with effective $s$-wave and $p$-wave scattering lengths to describe the interaction between an excited Rydberg electron and a ground-state Sr atom.
Energy Technology Data Exchange (ETDEWEB)
Miyabe, Masabumi; Ohba, Masaki; Wakaida, Ikuo [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
1997-10-01
Autoionizing Rydberg series converging to six states (0, 261.841, 633.273, 3082.011, 3427.274, 3444.235 cm{sup -1}) of Gd ion have been observed by using three-color three-step photoionization via ten different 2nd-step levels of J=0 or 1. While the perturbations with interlopers become significant in the region of n=30-35 for most of the observed series, long and well-defined series structures appeared in higher energy region. From an analysis of such unperturbed structures, the first ionization potential of Gd atom was estimated to be 49601.45 (30) cm{sup -1}. This is in good agreement with the previous value, but the accuracy is improved by about one order of magnitude. In addition, isotope effect on the ionization potential was also determined by isotope shifts of some Rydberg series. (author)
Can we measure the gravitational free fall of cold Rydberg state positronium?
Energy Technology Data Exchange (ETDEWEB)
Mills, A.P. E-mail: apmjr@citrus.ucr.edu; Leventhal, M. E-mail: leventhal@astro.umd.edu
2002-05-01
In this paper we examine the possibilities for detecting the free fall of Rydberg positronium atoms. In our scheme, cold positronium atoms are emitted from a 'point' source and excited to the n=25 circular Rydberg state with L=n-1. The positronium atoms are allowed to travel horizontally 10 m in a field free vacuum and focused onto a detector using an elliptical Van der Waals mirror. A free fall distance of order 50 {mu}m and a few detected atoms per hour are anticipated. Various extraneous influences on the positronium, such as collisions with residual gas atoms, Stark mixing in stray electric and magnetic fields, photoionization due to thermal radiation, and accelerations due to patch potentials are estimated.
Characterization of a Rydberg atom-based streak camera operating in synchroscan mode
Rella, C. W.; van der Meer, A. F. G.; Noordam, L. D.
2000-06-01
A streak camera that operates in synchroscan mode has been developed with a spectral response throughout the infrared. A gas-phase sample of Rydberg atoms is used as a photocathode. This compact device possesses 5 ps time resolution and can be used with a total infrared energy of about 1 nJ, or 10 -7 of the total macropulse energy of the FELIX free electron laser. This combination of characteristics makes it not only an attractive device for use in a variety of infrared experiments, but also a powerful tool for the study of photo-induced electron emission in atomic systems. As an example, a Rydberg-atom based electron gun which produces about 20 pulses of electrons at a 70 GHz repetition frequency has been characterized using this synchroscan streak camera.
High-order harmonic generation from Rydberg atoms driven by plasmonic-enhanced laser fields
Tikman, Y; Ciappina, M F; Chacon, A; Altun, Z; Lewenstein, M
2015-01-01
We theoretically investigate high-order harmonic generation (HHG) in Rydberg atoms driven by spatially inhomogeneous laser fields, induced, for instance, by plasmonic enhancement. It is well known that the laser intensity should to exceed certain threshold in order to generate HHG, when noble gas atoms in their ground state are used as an active medium. One way to enhance the coherent light coming from a conventional laser oscillator is to take advantage of the amplification obtained by the so-called surface plasmon polaritons, created when a low intensity laser field is focused onto a metallic nanostructure. The main limitation of this scheme is the low damage threshold of the materials employed in the nanostructures engineering. In this work we propose to use Rydberg atoms, driven by spatially inhomogeneous, plasmonic-enhanced laser fields, for HHG. We exhaustively discuss the behaviour and efficiency of these systems in the generation of coherent harmonic emission. To this aim we numerically solve the time...
Scaled-energy spectroscopy of a |M|=1 Rydberg barium atom in an electric field
Institute of Scientific and Technical Information of China (English)
Wang Lei; Quan Wei; Shen Li; Yang Hai-Feng; Shi Ting-Yun; Liu Xiao-Jun; Liu Hong-Ping; Zhan Ming-Sheng
2009-01-01
We observe strong energy-dependent quantum defects in the scaled-energy Stark spectra for |M|=1 Rydberg states of barium atoms at three scaled energies: ε= -2.000, ε= -2.500 and ε=-3.000. In an attempt to explain the observations, theoretical calculations of closed orbit theory based on a model potential including core effect are performed for non-hydrogenic atoms. While such a potential has been uniformly successful for alkali atoms with a single valence electron, it fails to match experimental results for barium atoms in the 6snp Rydberg states with two valence electrons. Our study points out that this discrepancy is due to the strong perturbation from the 5d8p state, which voids the simple approximation for constant quantum defects of principle quantum number n.
Photoassociation of Trilobite Rydberg Molecules via Resonant Spin-Orbit Coupling
Kleinbach, K. S.; Meinert, F.; Engel, F.; Kwon, W. J.; Löw, R.; Pfau, T.; Raithel, G.
2017-06-01
We report on a novel method for the photoassociation of strongly polar trilobite Rydberg molecules. This exotic ultralong-range dimer, consisting of a ground-state atom bound to the Rydberg electron via electron-neutral scattering, inherits its polar character from the admixture of high-angular-momentum electronic orbitals. The absence of low-L character hinders standard photoassociation techniques. Here, we show that for suitable principal quantum numbers the resonant coupling of the orbital motion with the nuclear spin of the perturber, mediated by electron-neutral scattering, hybridizes the trilobite molecular potential with the more conventional S -type molecular state. This provides a general path to associate trilobite molecules with large electric dipole moments, as demonstrated via high-resolution spectroscopy. We find a dipole moment of 135(45) D for the trilobite state. Our results are compared to theoretical predictions based on a Fermi model.
Absorption and Recurrence Spectra of Nonhydrogenic Rydberg Atom Near a Metal Surface
Institute of Scientific and Technical Information of China (English)
ZHOU Jun; WANG De-Hua; XUE Chun-Hua; QI Yi-Hong; LOU Sen-Yue
2008-01-01
Multielectron atoms near a metal surface are essentially more complicated than hydrogen atom with regard to theoretical treatments. By using the semicalssical closed orbit theory generalized to the multielecton atoms, we study the dynamical properties of the Rydberg lithium atom near a metal surface. The photoabsorption spectra and recurrence spectra of this system have also been calculated. Considering the effect of the ionic core potential of the Rydberg lithium atom, the number of the closed orbits increases, which leads to more peaks in the recurrence spectra than the case of hydrogen atom near a metal surface. This result shows that the core-scattered effects play an important role in nonhydrogenic atoms. This study is a new application of the dosed-orbit theory and is of potential experimental interest.
Institute of Scientific and Technical Information of China (English)
Wang De-Hua; Lin Sheng-Lu
2004-01-01
Closed orbit theory is a semiclassical technique for explaining the spectra of Rydberg atoms in external fields. By developing the closed orbit theory from two degrees of freedom to three non-separable degrees of freedom, we calculated the recurrence spectra of He Rydberg atom in perpendicular electric and magnetic fields. The closed orbits in the corresponding classical system have also been obtained. Fourier transformed spectra of He atoms have allowed direct comparison between the resonance peaks and the scaled action values of closed orbits, whereas the nonhydrogenic resonance can be explained in terms of the new orbits created by the core scattering. The semiclassical result is in good agreement with the quantum spectra, which suggests that our method is correct.
On the non-equilibrium dynamics of dissipative Rydberg gases in the presence of dephasing noise
Levi, Emanuele; Lesanovsky, Igor
2016-01-01
In the presence of strong dephasing noise the dynamics of Rydberg gases becomes effectively classical, due to the rapid decay of quantum superpositions between atomic levels. Recently a great deal of attention has been devoted to the stochastic dynamics that emerges in that limit, revealing several interesting features, including kinetically-constrained glassy behaviour, self-similarity and aggregation effects. However, the non-equilibrium physics of these systems, in particular in the regime where coherent and dissipative processes contribute on equal footing, is yet far from being understood. To explore this we study the dynamics of a small one-dimensional Rydberg lattice gas subject to dephasing noise by numerically integrating the quantum Master equation. We find indications that the main features observed in the strongly dissipative limit persist when the dissipation is not strong enough to annihilate quantum coherences at the dynamically relevant time scales. These features include a power law growth of...
Quantum control via a genetic algorithm of the field ionization pathway of a Rydberg electron
Gregoric, Vincent C.; Kang, Xinyue; Liu, Zhimin Cheryl; Rowley, Zoe A.; Carroll, Thomas J.; Noel, Michael W.
2017-08-01
Quantum control of the pathway along which a Rydberg electron field ionizes is experimentally and computationally demonstrated. Selective field ionization is typically done with a slowly rising electric field pulse. The (1/n*)4 scaling of the classical ionization threshold leads to a rough mapping between arrival time of the electron signal and principal quantum number of the Rydberg electron. This is complicated by the many avoided level crossings that the electron must traverse on the way to ionization, which in general leads to broadening of the time-resolved field ionization signal. In order to control the ionization pathway, thus directing the signal to the desired arrival time, a perturbing electric field produced by an arbitrary wave-form generator is added to a slowly rising electric field. A genetic algorithm evolves the perturbing field in an effort to achieve the target time-resolved field ionization signal.
Electro-Optomechanical Transduction & Quantum Hard-Sphere Model for Dissipative Rydberg-EIT Media
DEFF Research Database (Denmark)
Zeuthen, Emil
established the requirements for efficient performance, we turn to the question of optimization. We address this by developing a unifying equivalent-circuit formalism for electro-optomechanical transducers. This approach accommodates arbitrary linear circuits and integrates the novel optomechanical...... transduction functionality into the well-established framework of electrical engineering, thereby facilitating its implementation in potential applications such as nuclear magnetic resonance imaging and radio astronomy. We consider such optomechanical sensing of weak electrical signals and discuss how......, thus capturing the dualistic particle-wave nature of light as it manifests itself in dissipative Rydberg-EIT media. Using this approach, we analyze the saturation behavior of the transmission through one-dimensional Rydberg-EIT media in the regime of non-perturbative single-polariton EIT-decay relevant...
Ultralong-range Rydberg molecules in combined electric and magnetic fields
Kurz, Markus
2014-01-01
We investigate the impact of combined electric and magnetic fields on the structure of ultralong-range polar Rydberg molecules. Our focus is hereby on the parallel as well as the crossed field configuration taking into account both the $s$-wave and $p$-wave interactions of the Rydberg electron and the neutral ground state atom. We show the strong impact of the $p$-wave interaction on the ultralong-range molecular states for a pure $B$-field configuration. In the presence of external fields the angular degrees of freedom acquires vibrational character and we encounter two- and three-dimensional oscillatory adiabatic potential energy surfaces for the parallel and crossed field configuration, respectively. The equilibrium configurations of local potential wells can be controlled via the external field parameters for both field configurations depending of the specific degree of electronic excitation. This allows to tune the molecular alignment and orientation. The resulting electric dipole moment is in the order ...
Artificial abelian gauge potentials induced by dipole-dipole interactions between Rydberg atoms
Cesa, A
2013-01-01
We analyze the influence of dipole-dipole interactions between Rydberg atoms on the generation of abelian artificial gauge potentials and fields. When two Rydberg atoms are driven by a uniform laser field, we show that the combined atom-atom and atom-field interactions give rise to new, non-uniform, artificial gauge potentials. We identify the mechanism responsible for the emergence of these gauge potentials. Analytical expressions for the latter indicate that the strongest artificial magnetic fields are reached in the regime intermediate between the dipole blockade regime and the regime in which the atoms are sufficiently far apart such that atom-light interaction dominates over atom-atom interactions. We discuss the differences and similarities of artificial gauge fields originating from resonant dipole-dipole and van der Waals interactions. We also give an estimation of experimentally attainable artificial magnetic fields resulting from this mechanism.
A Hamiltonian for the inclusion of spin effects in long-range Rydberg molecules
Eiles, Matthew T
2016-01-01
The interaction between a Rydberg electron and a neutral atom situated inside its extended orbit is described via contact interactions for each atom-electron scattering channel. In ultracold environments, these interactions lead to ultra-long-range molecular states with binding energies typically ranging from $10$-$10^4$MHz. These energies are comparable to the relativistic and hyperfine structure of the separate atomic components. Studies of molecular formation aiming to reproduce observations with spectroscopic accuracy must therefore include the hyperfine splitting of the neutral atom and the spin-orbit splittings of both the Rydberg atom and the electron-atom interaction. Adiabatic potential energy curves that fully include these additional effects are presented for Rb$_2$ and Cs$_2$. The influence of spin degrees of freedom on the potential energy curves and molecular multipole moments probed in recent experimental work is elucidated and contrasted with other recent theoretical effort in this direction.
Demonstration of strong Rydberg blockade in three-atom systems with anisotropic interactions
Barredo, Daniel; Labuhn, Henning; Béguin, Lucas; Vernier, Aline; Nogrette, Florence; Lahaye, Thierry; Browaeys, Antoine
2014-01-01
We study the Rydberg blockade in a system of three atoms arranged in different 2D geometries (linear and triangular configurations). In the strong blockade regime, we observe high-contrast, coherent collective oscillations of the single excitation probability, and an almost perfect van der Waals blockade. Our data is consistent with a total population in doubly and triply excited states below 2%. In the partial blockade regime, we directly observe the anisotropy of the van der Waals interactions between $|nD\\rangle$ Rydberg states in the triangular configuration. A simple model, that only uses independently measured two-body van der Waals interactions, fully reproduces the dynamics of the system without any adjustable parameter. These results are extremely promising for scalable quantum information processing and quantum simulation with neutral atoms.
Robust and High Fidelity Quantum Logic with the Rydberg-Dressed Blockade
Keating, Tyler; Cook, Robert; Deutsch, Ivan; Hankin, Aaron; Jau, Yuan-Yu; Biedermann, Grant
2015-05-01
We study a scheme for implementing a controlled-Z (CZ) gate between two neutral-atom qubits based on the Rydberg blockade mechanism in a manner that is robust to errors caused by atomic motion. By adiabatically dressing the ground electronic state, we can protect the gate from decoherence due to random phase errors that typically arise from atomic thermal motion. The adiabatic protocol also allows for a Doppler-free configuration with counterpropagating lasers in a σ+ /σ- orthogonal polarization geometry that further reduces motional errors due to Doppler shifts. The residual error is dominated by dipole-dipole forces acting on doubly-excited Rydberg atoms when the blockade is imperfect. For reasonable parameters, with qubits encoded into the clock states of 133Cs, we predict that our protocol could produce a CZ gate in logic.
Auto transfer to Rydberg states and indirect stabilization following double capture
Energy Technology Data Exchange (ETDEWEB)
Roncin, P.; Gaboriaud, M.N.; Barat, M. (Paris-11 Univ., 91 - Orsay (France)); Bordenave-Montesquieu, A.; Moretto-Capelle, P.; Benhenni, M. (Toulouse-3 Univ., 31 (France)); Bachau, H.; Harel, C. (Bordeaux-1 Univ., 33 (France))
1993-11-28
Two-electron capture by slow multiply charged ions colliding on rare-gas target at keV energies is known to populate doubly excited states of the projectile with large cross sections. Though these states are dominantly autoionizing, important radiative decay following double capture have been reported, among which the direct observation of the fluorescence from Rydberg states. A mechanism based on post-collisional effects was proposed, in which Rydberg states are fed from the quasi-symmetrical doubly excited states initially populated. In this paper, a quantitative analysis of this effect is developed leading to a simple model which is applied to N[sup 7+] on He and Ar collisions. (author).
Study of Microwave Multiphoton Transition of Rydberg Potassium Atom by Using B-Spline
Institute of Scientific and Technical Information of China (English)
JIN Cheng; ZHOU Xiao-Xin; ZHAO Song-Feng
2005-01-01
The B-spline expansion technique and time-dependent two-level approach are applied to study the interaction between the microwave field and potassium atoms in a static electric field. We obtain theoretical multiphoton resonance spectra that can be compared with the experimental data. We also obtain the time evolution of the final state in different microwave fields.
Institute of Scientific and Technical Information of China (English)
HU ZHENG-FA; ZHOU SHI-KANG; GONG SHUN-SHENG; ZHAN MING-SHENG
2000-01-01
The potential model method for computation of Stark structure of Cs Rydberg states atoms and oscillator strength is described,for external electric fields varying from 0 to 600V/cm.Anticrossing,l-mixing and n-mixing phenomena are observed clearly from the map of Stark.Corresponding experiment is performed under the same condition,and the two results are in good agreement with each other within the experimental uncertainty.
Absolute cross sections for charge capture from Rydberg targets by slow highly charged ions
Energy Technology Data Exchange (ETDEWEB)
DePaola, B.D.; Huang, M.; Winecki, S.; Stoeckli, M.P.; Kanai, Y. [J. R. Macdonald Laboratory, Kansas State University, Manhattan, Kansas 66506 (United States); Lundeen, S.R.; Fehrenbach, C.W.; Arko, S.A. [Department of Physics, Colorado State University, Fort Collins, Colorado 80523 (United States)
1995-09-01
A crossed beam experiment has been used to measure absolute charge capture cross sections in collisions of slow highly charged xenon ions with laser excited Rydberg atoms. The cross sections were measured for scaled projectile velocities {ital nv}{sub {ital p}} from 1.0 to 6.0, for projectile charges of 8, 16, 32, and 40, where {ital n} is the principal quantum number of the target electron. Experimental cross sections are compared with predictions of classical models.
Quasi-stationary spectrum of Rydberg atoms in the field of a highly charged ion
Energy Technology Data Exchange (ETDEWEB)
Janev, R.K.; Nedeljkovic, N.N.
1985-05-14
The complex energies of highly excited states of a hydrogen-like atom in the presence of a multicharged ion are determined for internuclear distances, corresponding to the position of energy levels close to the top of the potential barrier which separates the two Coulomb centres. The results obtained are used to determine the contribution of considered internuclear distances to the electron-capture cross section in Rydberg-atom-multicharged-ion slow collisions.
Adiabatic rapid passage two-photon excitation of a Rydberg atom
Kuznetsova, Elena; Malinovskaya, Svetlana A
2015-01-01
We considered the two-photon adiabatic rapid passage excitation of a single atom from the ground to a Rydberg state. Three schemes were analyzed: both pump and Stokes fields chirped and pulsed, only the pump field is chirped, and only the pump field is pulsed and chirped while the Stokes field is continuous wave (CW). In all three cases high transfer efficiencies $>99\\%$ were achieved for the experimentally realizable Rabi frequencies and the pulse durations of the fields.
Investigation of odd-parity Rydberg states of Eu I with autoionization detection
Institute of Scientific and Technical Information of China (English)
Xiao Ying; Dai Chang-Jian; Qin Wen-Jie
2009-01-01
Isolated-core-excitation (ICE) scheme and autoionization detection are employed to study the bound Rydberg states of europium atom. The high-lying states with odd parity have been measured using the autoionization detection method with three different excitation paths via 4f~76s6p[~8P_(5/2)], 4f~76s6p[~8P_(7/2)]and 4f~76s6p[~8P_(9/2)]intermediate states, s respectively. In this paper the spectra of bound Rydberg states of Eu atom are reported, which cover the energy regions from 36000 cm~(-1) to 38250 cm~(-1) and from 38900 cm~(-1) to 39500 cm~(-1). The study provides the information about level energy, the possible J values and relative line intensity as well as the effective principal quantum number n~* for these states. This work not only confirms the previous results of many states, but also discovers 11 new Rydberg states of Eu atom.
Observation of mesoscopic crystalline structures in a two-dimensional Rydberg gas
Schauß, Peter; Endres, Manuel; Fukuhara, Takeshi; Hild, Sebastian; Omran, Ahmed; Pohl, Thomas; Gross, Christian; Kuhr, Stefan; Bloch, Immanuel
2012-01-01
The ability to control and tune interactions in ultracold atomic gases has paved the way towards the realization of new phases of matter. Whereas experiments have so far achieved a high degree of control over short-ranged interactions, the realization of long-range interactions would open up a whole new realm of many-body physics and has become a central focus of research. Rydberg atoms are very well-suited to achieve this goal, as the van der Waals forces between them are many orders of magnitude larger than for ground state atoms. Consequently, the mere laser excitation of ultracold gases can cause strongly correlated many-body states to emerge directly when atoms are transferred to Rydberg states. A key example are quantum crystals, composed of coherent superpositions of different spatially ordered configurations of collective excitations. Here we report on the direct measurement of strong correlations in a laser excited two-dimensional atomic Mott insulator using high-resolution, in-situ Rydberg atom imag...
Philip, G.
2008-03-01
An efficient atomic jet setup offering many unprecedented advantages over a conventional heat pipe setup used in multi-photon spectroscopy, mainly of alkaline-earth metals, has been constructed by a scheme in which the sample material is encapsulated in a disposable cartridge oven located inside a thermally stabilised heat-pipe and is made to effuse in to a row of atomic beams merging to form a jet target. This novel scheme combines the advantages of both high density atomic beam with convenient geometry for orthogonal excitation and high sensitive ionisation detection capabilities of thermionic diodes, besides eliminating several problems inherent in the usual heat-pipe operation. Out of various designs, typical results are presented for a linear heat-pipe with vertical atomic jet used in two-photon spectroscopy of highly excited states of Sr I. Controlled excitations of both Rydberg and non-Rydberg states, which cannot otherwise be accessed from the ground state due to parity and spectroscopic selection rules, have been achieved by employing a weak electric field complimented by collisions. The atomic jet setup is also found very useful for the study of collisional broadening and shift of excited states and time evolution of Rydberg atoms.
Even-parity Rydberg and autoionizing states of lutetium by laser resonance-ionization spectroscopy
Li, R.; Lassen, J.; Zhong, Z. P.; Jia, F. D.; Mostamand, M.; Li, X. K.; Reich, B. B.; Teigelhöfer, A.; Yan, H.
2017-05-01
Multistep laser resonance ionization spectroscopy of lutetium (Lu) has been performed at TRIUMF's off-line laser ion source test stand. The even-parity Rydberg series 6 s2n d 2D3 /2 , 6 s2n d 2D5 /2 , and 6 s2n s 2S1 /2 were observed converging to the 6 s2 ionization potential. The experimental results have been compared to those of previous work. Fifty-one levels of Rydberg series 6 s2n d 2D5 /2 and 52 levels of Rydberg series 6 s2n s 2S1 /2 were reported. Additionally, six even-parity autoionization (AI) series converging to Lu ionic states 5 d 6 s 3D1 and 5 d 6 s 3D2 were observed. The level energies of these AI states were measured. The configurations of the AI states were assigned by relativistic multichannel theory within the framework of multichannel quantum defect theory.
An effective quantum defect theory for the diamagnetic spectrum of a barium Rydberg atom
Institute of Scientific and Technical Information of China (English)
Li Bo; Liu Hong-Ping
2013-01-01
A theoretical calculation is carried out to investigate the spectrum of a barium Rydberg atom in an external magnetic field.Using an effective approach incorporating quantum defect into the centrifugal term in the Hamiltonian,we reexamine the reported spectrum of the barium Rydberg atom in a magnetic field of 2.89 T [J.Phys.B 28 L537 (1995)].Our calculation employs B-spline basis expansion and complex coordinate rotation techniques.For single photon absorption from the ground 6s2 to 6snp Rydberg states,the spectrum is not influenced by quantum defects of channels ns and nd.The calculation is in agreement with the experimental observations until the energy reaches E =-60 cm-1.Beyond this energy,closer to the threshold,the calculated and experimental results do not agree with each other.Possible reasons for their discrepancies are discussed.Our study affirms an energy range where the diamagnetic spectrum of the barium atom can be explained thoroughly using a hydrogen model potential.
Gavryusev, V; Ferreira-Cao, M; Zürn, G; Hofmann, C S; Günter, G; Schempp, H; Robert-de-Saint-Vincent, M; Whitlock, S; Weidemüller, M
2016-01-01
We present combined measurements of the spatially-resolved optical spectrum and the total excited-atom number in an ultracold gas of three-level atoms under electromagnetically induced transparency conditions involving high-lying Rydberg states. The observed optical transmission of a weak probe laser at the center of the coupling region exhibits a double peaked spectrum as a function of detuning, whilst the Rydberg atom number shows a comparatively narrow single resonance. By imaging the transmitted light onto a charge-coupled-device camera, we record hundreds of spectra in parallel, which are used to map out the spatial profile of Rabi frequencies of the coupling laser. Using all the information available we can reconstruct the full one-body density matrix of the three-level system, which provides the optical susceptibility and the Rydberg density as a function of spatial position. These results help elucidate the connection between three-level interference phenomena, including the interplay of matter and li...
Direct observation of ultrafast many-body electron dynamics in an ultracold Rydberg gas
Takei, Nobuyuki; Sommer, Christian; Genes, Claudiu; Pupillo, Guido; Goto, Haruka; Koyasu, Kuniaki; Chiba, Hisashi; Weidemüller, Matthias; Ohmori, Kenji
2016-11-01
Many-body correlations govern a variety of important quantum phenomena such as the emergence of superconductivity and magnetism. Understanding quantum many-body systems is thus one of the central goals of modern sciences. Here we demonstrate an experimental approach towards this goal by utilizing an ultracold Rydberg gas generated with a broadband picosecond laser pulse. We follow the ultrafast evolution of its electronic coherence by time-domain Ramsey interferometry with attosecond precision. The observed electronic coherence shows an ultrafast oscillation with a period of 1 femtosecond, whose phase shift on the attosecond timescale is consistent with many-body correlations among Rydberg atoms beyond mean-field approximations. This coherent and ultrafast many-body dynamics is actively controlled by tuning the orbital size and population of the Rydberg state, as well as the mean atomic distance. Our approach will offer a versatile platform to observe and manipulate non-equilibrium dynamics of quantum many-body systems on the ultrafast timescale.
Rotational Rydberg states of polar molecules: Hund's classification and Zeeman effect
Danilyan, A. V.; Chernov, V. E.
2008-01-01
The rotational Rydberg states of polar molecules, which arise as a result of the interaction of a Rydberg electron with core rotations, are considered. A large number of angular momenta in the core-electron system lead to a considerably greater number of possible coupling schemes of these momenta compared to the number of schemes determined by the classical five Hund's cases for lower excited electron states of molecules. As a result of such detailed Hund's classification, more than 30 different coupling schemes (Hund's subcases) are constructed for rotational Rydberg states of molecules. The conditions of their realization are indicated in terms of the relative quantities of intramolecular interactions, for which analytical estimates are presented. For a large number of subcases, analytical expressions for the molecular matrix elements are found. These expressions can be useful in classification of the experimental spectra of highly excited molecules. As an application, for each of the subcases considered, analytical expressions are given, which describe the linear Zeeman effect and the Paschen-Back effect.
Krupnyj, G I; Yanovich, A A
2000-01-01
The cross sections for the sup 7 Be, sup 2 sup 2 Na and 2 sup 4 Na production in reactions on aluminium target were measured in the range of proton energy from 37 MeV up to 70 GeV on the accelerate system. On the injector the measurement of the sup 2 sup 7 Al(p, spall) sup 7 Be, sup 2 sup 7 Al(p, 3p3n) sup 2 sup 2 Na and sup 2 sup 7 Al(p, 3pn) sup 2 sup 4 Na cross sections were taken on the disposed from the accelerate by the 350, 420, 800, 1000, 1320 MeV proton beam with the spread of energy no more than 1 % and error no more than +- 5 %. On the accelerator the cross sections of the same reactions were measured in the regime of slow spread of protons from the accelerator. The numerical values of the measured cross sections and their errors, as well as ratios of cross sections of the sup 7 Be and sup 2 sup 2 Na production on aluminium to cross section of the sup 2 sup 7 Al(p, 3pn) sup 2 sup 4 Na reaction are demonstrated
Velocity-selective EIT measurement of potassium Rydberg states
Xu, Wenchao
2016-01-01
We demonstrate a velocity selection scheme that mitigates suppression of electromagnetically induced transparency (EIT) by Doppler shifts for low--high EIT probe--coupling wavelength ordering. An optical pumping beam counter-propagating with the EIT probe beam transfers atoms between hyperfine states in a velocity selective fashion. Measurement of the transmitted probe beam synchronous with chopping of the optical pumping beam enables a Doppler-free EIT signal to be detected. Transition frequencies between 5P$_{1/2}$ and $n$S$_{1/2}$ states for $n=$26, 27, and 28 in $^{39}$K are obtained via EIT spectroscopy in a heated vapor cell with a probe beam stabilized to the 4S$_{1/2}\\rightarrow$5P$_{1/2}$ transition. Using previous high-resolution measurements of the 4S$_{1/2}\\rightarrow$nS$_{1/2}$ transitions, we make a determination of the absolute frequency of the 4S$_{1/2}\\rightarrow$5P$_{1/2}$ transition. Our measurement is shifted by 560 MHz from the currently accepted value with a two-fold improvement in uncer...
von Haeften, Klaus; Laarmann, Tim; Wabnitz, Hubertus; Möller, Thomas
2005-01-01
The nature of the electronically excited states of He clusters and their relaxation mechanisms are investigated by spectroscopy using monochromatized synchrotron radiation. Time correlated fluorescence excitation and energy resolved luminescence spectra of the clusters are recorded in separate wavelength ranges. The size of the clusters and the isotopic constitution is also varied. The spectral features are analysed and discussed particularly with regard to the high lying states and their possible Rydberg nature. While Rydberg states seem not to exist in the interior region of large clusters there is experimental evidence that sharp lines in the spectrum are either due to He Rydberg atoms or excimer molecules in high vibrational states bound at the surface of large clusters or due to very small positively charged clusters with the Rydberg electron outside. The spectra of large 3He clusters exhibit a larger contribution of Rydberg lines than 4He clusters. He clusters also emit fluorescence at energies above the ionization energy of He atoms. This is attributed to the barrier for the injection of electrons into the conduction band which was found to be 1.35 eV for 4He and 0.95 eV for 3He clusters, respectively.
Imaging the photodissociation dynamics of the methyl radical from the 3s and 3pz Rydberg states
Marggi Poullain, Sonia; Chicharro, David V.; Zanchet, Alexandre; González, Marta G.; Rubio-Lago, Luis; Senent, María L.; García-Vela, Alberto; Bañares, Luis
2016-01-01
The photodissociation dynamics of the methyl radical from the 3s and 3pz Rydberg states have been studied using velocity map and slice ion imaging in combination with pump-probe nanosecond laser pulses. The reported translational energy and angular distributions of the H(2S) photofragment detected by (2+1) REMPI highlight different dissociation mechanisms for the 3s and 3pz Rydberg states. A narrow peak in the translational energy distribution and an anisotropic angular distribution characterizes the fast 3s photodissociation, while for the 3pz state Boltzmann-type translational energy and isotropic angular distributions are found. High level ab initio calculations have been performed in order to elucidate the photodissociation mechanisms from the two Rydberg states and to rationalize the experimental results. The calculated potential energy curves highlight a typical predissociation mechanism for the 3s state, characterized by the coupling between the 3s Rydberg state and a valence repulsive state. On the other hand, the photodissociation on the 3pz state is initiated by a predissociation process due to the coupling between the 3pz Rydberg state and a valence repulsive state and constrained, later on, by two conical intersections that allow the system to relax to lower electronic states. Such mechanism opens different reaction pathways leading to CH2 photofragments in different electronic states and inducing a transfer of energy between translational and internal modes. PMID:27296907
Imaging the photodissociation dynamics of the methyl radical from the 3s and 3pz Rydberg states.
Marggi Poullain, Sonia; Chicharro, David V; Zanchet, Alexandre; González, Marta G; Rubio-Lago, Luis; Senent, María L; García-Vela, Alberto; Bañares, Luis
2016-06-22
The photodissociation dynamics of the methyl radical from the 3s and 3pz Rydberg states have been studied using the velocity map and slice ion imaging in combination with pump-probe nanosecond laser pulses. The reported translational energy and angular distributions of the H((2)S) photofragment detected by (2+1) REMPI highlight different dissociation mechanisms for the 3s and 3pz Rydberg states. A narrow peak in the translational energy distribution and an anisotropic angular distribution characterize the fast 3s photodissociation, while for the 3pz state Boltzmann-type translational energy and isotropic angular distributions are found. High level ab initio calculations have been performed in order to elucidate the photodissociation mechanisms from the two Rydberg states and to rationalize the experimental results. The calculated potential energy curves highlight a typical predissociation mechanism for the 3s state, characterized by the coupling between the 3s Rydberg state and a valence repulsive state. On the other hand, the photodissociation on the 3pz state is initiated by a predissociation process due to the coupling between the 3pz Rydberg state and a valence repulsive state and constrained, later on, by two conical intersections that allow the system to relax to lower electronic states. Such a mechanism opens up different reaction pathways leading to CH2 photofragments in different electronic states and inducing a transfer of energy between translational and internal modes.
Resonant charge transfer of hydrogen Rydberg atoms incident at a Cu(100) projected band-gap surface
Gibbard, J A; Kohlhoff, M; Rennick, C J; So, E; Ford, M; Softley, T P
2015-01-01
The charge transfer (ionization) of hydrogen Rydberg atoms (principal quantum number $n=25-34$) incident at a Cu(100) surface is investigated. Unlike fully metallic surfaces, where the Rydberg electron energy is degenerate with the conduction band of the metal, the Cu(100) surface has a projected bandgap at these energies, and only discrete image states are available through which charge transfer can take place. Resonant enhancement of charge transfer is observed at hydrogen principal quantum numbers for which the Rydberg energy matches the energy of one of the image states. The integrated surface ionization signals show clear periodicity as the energies of states with increasing $n$ come in and out of resonance with the image states. The velocity dependence of the surface ionization dynamics is also investigated. Decreased velocity of the incident H atom leads to a greater mean distance of ionization and a lower field required to extract the ion. The surface-ionization profiles (signal versus applied field) ...
Radiative lifetimes of Rydberg 6pnd J=2 states of Pb Ⅰ by multichannel quantum defect theory
Institute of Scientific and Technical Information of China (English)
Dai Zhen-Wen; Jiang Hong-Mei; Sun Gui-Juan; Jiang Zhan-Kui
2004-01-01
Energy levels of the odd-parity 6pnd J=2 Rydberg states of Pb Ⅰ are analysed by the multichannel quantum defect theory (MQDT) in the frame of a five-channel three-limit calculation model. With optimal MQDT parameters, channel admixture coefficients are obtained and used to calculate the theoretical lifetimes of the levels by comparing to the previously measured lifetimes. The predicted lifetimes for higher-lying Rydberg states are given and discussed. These predicted lifetimes are very different from those obtained by the four-channel two-limit model previously used, which means that introduction of the additional interacting channel is important for studying the 6pnd J=2 Rydberg statesof Pb Ⅰ.
Energy levels of perturbed 6pnd J = 2 Rydberg states of Pb I by multichannel quantum defect theory
Institute of Scientific and Technical Information of China (English)
DAI; Zhenwen; (戴振文); JIANG; Hongmei; (蒋红玫); LIU; Jingyao; (刘靖尧); PENG; Weixian; (彭慰先); JIANG; Zhankui; (蒋占魁)
2003-01-01
Energy levels of the odd-parity 6pnd J = 2 Rydberg states of atomic lead are analyzed by the multichannel quantum defect theory (MQDT) with previous experimental energy levels. The 6pnd (6 ≤n ≤ 63) J = 2 Rydberg energy levels are calculated and optimal MQDT parameters were obtained. Using these parameters, admixture coefficients for each level are calculated to designate the level denotations. The results show that strong channel mixings exist for the levels near the 6p6d (3/2)[5/2]2o and 6p6d (3/2)[3/2]2o pertubers. The five-channel model different from that in literature is used to predict 21 energy positions of 6pnd (1/2)[3/2]2o levels and to determine the denotations of all the 6pnd J = 2 Rydberg states under 59788 cm-1 for Pb I.
Direct Electron Impact Excitation of Rydberg-Valence States of Molecular Nitrogen
Malone, C. P.; Johnson, P. V.; Liu, X.; Ajdari, B.; Muleady, S.; Kanik, I.; Khakoo, M. A.
2012-12-01
Collisions between electrons and neutral N2 molecules result in emissions that provide an important diagnostic probe for understanding the ionospheric energy balance and the effects of space weather in upper atmospheres. Also, transitions to singlet ungerade states cause N2 to be a strong absorber of solar radiation in the EUV spectral range where many ro-vibrational levels of these Rydberg-valence (RV) states are predissociative. Thus, their respective excitation and emission cross sections are important parameters for understanding the [N]/[N2] ratio in the thermosphere of nitrogen dominated atmospheres. The following work provides improved constraints on absolute and relative excitation cross sections of numerous RV states of N2, enabling more physically accurate atmospheric modeling. Here, we present recent integral cross sections (ICSs) for electron impact excitation of RV states of N2 [6], which were based on the differential cross sections (DCSs) derived from electron energy-loss (EEL) spectra of [5]. This work resulted in electronic excitation cross sections over the following measured vibrational levels: b 1Πu (v‧=0-14), c3 1Πu (v‧=0-3), o3 1Πu (v‧=0-3), b‧ 1Σu+ (v‧=0-10), c‧4 1Σu+ (v‧=0-3), G 3Πu (v‧=0-3), and F 3Πu (v‧=0-3). We further adjusted the cross sections of the RV states by extending the vibronic contributions to unmeasured v‧-levels via the relative excitation probabilities (REPs) as discussed in [6]. This resulted in REP-scaled ICSs over the following vibrational levels for the singlet ungerade states: b(0-19), c3(0-4), o3(0-4), b‧(0-16), and c‧4(0-8). Comparison of the ICSs of [6] with available EEL based measurements, theoretical calculations, and emission based work generally shows good agreement within error estimations, except with the recent reevaluation provided by [1]. Further, we have extended these results, using the recent EEL data of [3], to include the unfolding of better resolved features above ~13
Khatri, Indu; Goyal, Arun; Diouldé Ba, Mamadou; Faye, Maurice; Sow, Malick; Sakho, Ibrahima; Singh, A. K.; Mohan, Man; Wagué, Ahmadou
2017-01-01
Resonance energies and total natural width of the 3pns 1P° and 3pnd 1P° Rydberg series of Mg-like (Z=13-26) ions are reported. Resonance energies of the Mg-like Al+ belonging to the 3pns 3P°→ 2 p63 p 1/2 0 2P and 3pns 3P°→ 2 p63 p3/2 0 3P transitions are also tabulated. The calculations are made in the framework of the Screening constant by unit nuclear charge (SCUNC) formalism. Excellent agreements between experiments at ALS and R-matrix calculations are obtained for both 3pns 1,3P° and 3pnd 1P° Rydberg series of the Mg-like Al+ ions. The present results for Mg-like Si2+, S4+, Cl5+, and Ar6+, compared with the only existing R-matrix calculations indicate lack of accuracy in the Mg-like Si2+ data obtained from noniterative formulation of the eigenchannel R-matrix method. New precise data for Mg-like P3+, K7+, Ca8+, Sc9+, Ti10+, V11+, Cr12+, Mn13+, and Fe14+ ions are presented as useful guidelines for investigators focusing their challenge on the Photoionization of Mg-like heavy charged ions in connection with their application in laboratory, astrophysics, and plasma physics.
On the Use of a Mixed Gaussian/Finite-Element Basis Set for the Calculation of Rydberg States
Thuemmel, Helmar T.; Langhoff, Stephen (Technical Monitor)
1996-01-01
Configuration-interaction studies are reported for the Rydberg states of the helium atom using mixed Gaussian/finite-element (GTO/FE) one particle basis sets. Standard Gaussian valence basis sets are employed, like those, used extensively in quantum chemistry calculations. It is shown that the term values for high-lying Rydberg states of the helium atom can be obtained accurately (within 1 cm -1), even for a small GTO set, by augmenting the n-particle space with configurations, where orthonormalized interpolation polynomials are singly occupied.
Evolution from a molecular Rydberg gas to an ultracold plasma in a seeded supersonic expansion of NO
Morrison, J P; Keller, J S; Grant, E R
2008-01-01
We report the spontaneous formation of a plasma from a gas of cold Rydberg molecules. Double-resonant laser excitation promotes nitric oxide, cooled to 1 K in a seeded supersonic molecular beam, to single Rydberg states extending as deep as 80 cm$^{-1}$ below the lowest ionization threshold. The density of excited molecules in the illuminated volume is as high as 1 x 10$^{13}$ cm$^{-3}$. This population evolves to produce prompt free electrons and a durable cold plasma of electrons and intact NO$^{+}$ ions.
Scaled-energy spectroscopy of helium \\|M\\|=1 Rydberg atoms in a static electric field
Kips, Annemieke; Vassen, Wim; Hogervorst, Wim; Dando, Paul A.
1998-10-01
We present scaled-energy spectra on helium Rydberg atoms in a static electric field. \\|M\\|=1 states were studied in excitation from the 2 1S0 metastable state. Spectra were recorded for ɛ=-2.940(4), ɛ=-2.350(4), both below the saddle point, and ɛ=-1.760(4), above the saddle point. Closed-orbit theory was applied to interpret the spectra. A recent extension to closed-orbit theory, incorporating core effects, was used. This significantly improved agreement between experiment and theory.
The Stark effect in atomic Rydberg states through a quantum defect approach
Menéndez, J. M.; Martín, I.; Velasco, A. M.
A basis set of quantum defect orbitals (QDOs) has been adopted for the diagonalization of the Hamiltonian matrix of nonhydrogenic atoms in the presence of an external electric field, so that the Stark structure of the Rydberg states has been possible to determine. The presently obtained Stark maps are in excellent agreement with those resulting from theory and experiment, as reported in the literature for a few representative atoms. The adequacy of the Stark quantum defect orbital (SQDO) procedure for accurately dealing with properties related to the Stark effect in atoms is suggested.
Unified theory of bound and scattering molecular Rydberg states as quantum maps
Dietz, Barbara; Lombardi, Maurice; Seligman, Thomas H.
2004-08-01
Using a representation of multichannel quantum defect theory in terms of a quantum Poincaré map for bound Rydberg molecules, we apply Jung's scattering map to derive a generalized quantum map, that includes the continuum. We show that this representation not only simplifies the understanding of the method, but moreover produces considerable numerical advantages. Finally we show under what circumstances the usual semi-classical approximations yield satisfactory results. In particular we see that singularities that cause problems in semi-classics are irrelevant to the quantum map.
Electric field sensing near the surface microstructure of an atom chip using cold Rydberg atoms
Carter, J D; Martin, J D D
2012-01-01
The electric fields near the heterogeneous metal/dielectric surface of an atom chip were measured using cold atoms. The atomic sensitivity to electric fields was enhanced by exciting the atoms to Rydberg states that are 10^8 times more polarizable than the ground state. We attribute the measured fields to charging of the insulators between the atom chip wires. Surprisingly, it is observed that these fields may be dramatically lowered with appropriate voltage biasing, suggesting configurations for the future development of hybrid quantum systems.
STARK STRUCTURE OF THE RYDBERG STATES OF ALKALINE-EARTH ATOMS
Institute of Scientific and Technical Information of China (English)
郅妙婵; 戴长建; 李士本
2001-01-01
The Stark effects of the Rydberg states in the alkaline-earth atoms are studied theoretically. Using a method similar to the treatment of alkali atoms, the properties of the Stark states of Mg, Ca, Sr and Ba atoms in the regions far away from the perturbers are investigated. The Stark maps for Mg (n=16, M=0), Ca (n=10, M=0), Sr (n=12,M=0) and Ba (n=13, |M|=0,1) are presented. Topics such as the general methods of calculation, the treatment of fine structure, and the structure of level anti-crossings are discussed. The comparison between the theoretical and experimental Stark maps is satisfactory.
Majkic, M. D.; Nedeljkovic, N. N.; Galijas, S. M. D.
2010-07-01
We elaborated the time-symmetric, two-state vector model to investigate the intermediate stages of the electron capture into the Rydberg states of multiply charged ions interacting with solid surface under the grazing incidence geometry. The neutralization distances for the ions XeZ+ interacting with Al-surface are calculated, for core charges Z ?[5,30]. The corresponding mean neutralization distances are in agreement with the data deduced from the measured kinetic energy gain due to the image acceleration of the ions.
Intermolecular Vibrations of the Complex of NO in the nsσ Rydberg States and Ar
Tsuji, Kazuhide; Shibuya, Kazuhiko; Obi, Kinichi
1995-01-01
The resonance enhanced multiphoton ionization method has been applied to the study of NO-Ar van der Waals complex in the nsσ (n = 3,4) Rydberg states. We have assigned the intermolecular vibrations appearing in the Ã—X˜ excitation spectrum of the complex. The bending structure appeared only with the excitation of the stretching mode in the Ã state, which was interpreted by intermolecular forces. The E˜-Ã excitation spectra were independent of the initial intermolecular level in the Ã state an...
Quantum repeater with Rydberg-blocked atomic ensembles in fiber-coupled cavities
DEFF Research Database (Denmark)
Brion, Etienne; Carlier, F.; Akulin, M.
2012-01-01
We propose and analyze a quantum repeater architecture in which Rydberg-blocked atomic ensembles inside optical cavities are linked by optical fibers. Entanglement generation, swapping, and purification are achieved through collective laser manipulations of the ensembles and photon transmission....... Successful transmission and storage of entanglement are heralded by ionization events rather than by photon detection signals used in previous proposals. We demonstrate how the high charge detection efficiency allows for a shortened average entanglement generation time, and we analyze an implementation...... of our scheme with ensembles of Cs atoms....
Energy Technology Data Exchange (ETDEWEB)
Bordenave-Montesquieu, A.; Moretto-Capelle, P.; Gonzalez, A.; Benhenni, M. (Toulouse-3 Univ., 31 (France)); Bachau, H.; Sanchez, I. (Bordeaux-1 Univ., 33 - Talence (France). Lab. des Collisions Atomiques)
1994-09-28
A high resolution electron spectrometry of the (3lnl') Ryberg series populated in N[sup 7+] + He and Ne[sup 10+] + He collisions at 10 q keV, 10[sup o] allows us to observe, for the first time by this method, two post-collisional effects. First, it is found with nitrogen ions that, when n increases from n = 4 to 9, the L-distribution peaks more and more on the high angular momentum states. This is qualitatively understood as a Stark deformation of the Rydberg orbit by the Coulomb field of the receding ion. Also, in the n range where the double capture process populates symmetrical 4l4l' states (n>9), an enhancement of the intensities of the 3lnl' Rydberg lines is observed for both collisonal systems. This is thought to be a signature of the so-called auto transfer to Rydberg states effect. The transfer of population from the 3l4l' to the 3lnl' states is found to be favoured against a direct autoionization of these 4l4l' states into the n = 2 continuum. These experimental findings together with preliminary spectroscopic calculations concerning the configuration interaction of the Ne[sup 8+] (4l4l') states with the Ne[sup 8+](3lnl') Rydberg series are also discussed within the context of the electron stabilization which follows a double capture. (Author).
Atomic loss and gain as a resource for nonequilibrium phase transitions in optical lattices
Everest, B.; Marcuzzi, M.; Lesanovsky, I.
2016-02-01
Recent breakthroughs in the experimental manipulation of strongly interacting atomic Rydberg gases in lattice potentials have opened an avenue for the study of many-body phenomena. Considerable efforts are currently being undertaken to achieve clean experimental settings that show a minimal amount of noise and disorder and are close to zero temperature. A complementary direction investigates the interplay between coherent and dissipative processes. Recent experiments have revealed a glimpse into the emergence of a rich nonequilibrium behavior stemming from the competition of laser excitation, strong interactions, and radiative decay of Rydberg atoms. The aim of the present theoretical work is to show that local incoherent loss and gain of atoms can in fact be the source of interesting out-of-equilibrium dynamics. This perspective opens up paths for the exploration of nonequilibrium critical phenomena and, more generally, phase transitions, some of which so far have been rather difficult to study. To demonstrate the richness of the encountered dynamical behavior we consider here three examples. The first two feature local atom loss and gain together with an incoherent excitation of Rydberg states. In this setting either a continuous or a discontinuous phase transition emerges with the former being reminiscent of genuine nonequilibrium transitions of stochastic processes with multiple absorbing states. The third example considers the regime of coherent laser excitation. Here the many-body dynamics is dominated by an equilibrium transition of the "model A" universality class.
High teleportation rates using cold-atom-ensemble-based quantum repeaters with Rydberg blockade
Solmeyer, Neal; Li, Xiao; Quraishi, Qudsia
2016-04-01
We present a simplified version of a repeater protocol in a cold neutral-atom ensemble with Rydberg excitations optimized for two-node entanglement generation and describe a protocol for quantum teleportation. Our proposal draws from previous proposals [B. Zhao et al., Phys. Rev. A 81, 052329 (2010), 10.1103/PhysRevA.81.052329; Y. Han et al., Phys. Rev. A 81, 052311 (2010), 10.1103/PhysRevA.81.052311] that described efficient and robust protocols for long-distance entanglement with many nodes. Using realistic experimental values, we predict an entanglement generation rate of ˜25 Hz and a teleportation rate of ˜5 Hz . Our predicted rates match the current state-of-the-art experiments for entanglement generation and teleportation between quantum memories. With improved efficiencies we predict entanglement generation and teleportation rates of ˜7.8 and ˜3.6 kHz, respectively, representing a two-order-of-magnitude improvement over the currently realized values. Cold-atom ensembles with Rydberg excitations are promising candidates for repeater nodes because collective effects in the ensemble can be used to deterministically generate a long-lived ground-state memory which may be efficiently mapped onto a directionally emitted single photon.
Electromagnetically induced transparency with Rydberg atoms across the Breit-Rabi regime
Naber, J B; Heuvell, H B van Linden van den; Spreeuw, R J C
2016-01-01
We present experimental results on the influence of magnetic fields and laser polarization on electromagnetically induced transparency (EIT) using Rydberg levels of $^{87}$Rb atoms. The measurements are performed in a room temperature vapor cell with two counter-propagating laser beams at 480nm and 780nm in a ladder-type energy level scheme. We measure the EIT spectrum of a range of $ns_{1/2}$ Rydberg states for $n=19-27$, where the hyperfine structure can still be resolved. Our measurements span the range of magnetic fields from the low field linear Zeeman regime to the high field Paschen-Back regimes. The observed spectra are very sensitive to small changes in magnetic fields and the polarization of the laser beams. We model our observations using optical Bloch equations that take into account the full multi-level structure of the atomic states involved and the decoupling of the electronic $J$ and nuclear $I$ angular momenta in the Breit-Rabi regime. The numerical model yields excellent agreement with the o...
Handshake electron transfer from hydrogen Rydberg atoms incident at a series of metallic thin films
Gibbard, Jemma A
2016-01-01
Thin metallic films have a 1D quantum well along the surface normal direction, which yields particle-in-a-box style electronic quantum states. However the quantum well is not infinitely deep and the wavefunctions of these states penetrate outside the surface where the electron is bound by its own image-charge attraction. Therefore a series of discrete, vacant states reach out from the thin film into the vacuum increasing the probability of electron transfer from an external atom or molecule to the thin film, especially for the resonant case where the quantum well energy matches that of the Rydberg atom. We show that `handshake' electron transfer from a highly excited Rydberg atom to these thin-film states is experimentally measurable. Thicker films, have a wider 1D box, changing the energetic distribution and image-state contribution to the thin film wavefunctions, resulting in more resonances. Calculations successfully predict the number of resonances and the nature of the thin-film wavefunctions for a given...
Paris-Mandoki, Asaf; Tresp, Christoph; Mirgorodskiy, Ivan; Hofferberth, Sebastian
2016-01-01
F\\"orster resonances provide a highly flexible tool to tune both the strength and the angular shape of interactions between two Rydberg atoms. We give a detailed explanation about how F\\"orster resonances can be found by searching through a large range of possible quantum number combinations. We apply our search method to $SS$, $SD$ and $DD$ pair states of $^{87}$Rb with principal quantum numbers from 30 to 100, taking into account the fine structure splitting of the Rydberg states. We find various strong resonances between atoms with a large difference in principal quantum numbers. We quantify the strength of these resonances by introducing a figure of merit $\\tilde C_3$ which is independent of the magnetic quantum number and geometry to classify the resonances by interaction strength. We further predict to what extent interaction exchange is possible on different resonances and point out limitations of the coherent hopping process. Finally, we discuss the angular dependence of the dipole-dipole interaction ...
Photoionization microscopy of Rydberg hydrogen atom in a non-uniform electrical field
Shao-Hao, Cheng; De-Hua, Wang; Zhao-Hang, Chen; Qiang, Chen
2016-06-01
In this paper, we investigate the photoionization microscopy of the Rydberg hydrogen atom in a gradient electric field for the first time. The observed oscillatory patterns in the photoionization microscopy are explained within the framework of the semiclassical theory, which can be considered as a manifestation of interference between various electron trajectories arriving at a given point on the detector plane. In contrast with the photoionization microscopy in the uniform electric field, the trajectories of the ionized electron in the gradient electric field will become chaotic. An infinite set of different electron trajectories can arrive at a given point on the detector plane, which makes the interference pattern of the electron probability density distribution extremely complicated. Our calculation results suggest that the oscillatory pattern in the electron probability density distribution depends sensitively on the electric field gradient, the scaled energy and the position of the detector plane. Through our research, we predict that the interference pattern in the electron probability density distribution can be observed in an actual photoionization microscopy experiment once the external electric field strength and the position of the electron detector plane are reasonable. This study provides some references for the future experimental research on the photoionization microscopy of the Rydberg atom in the non-uniform external fields. Project supported by the National Natural Science Foundation of China (Grant No. 11374133) and the Project of Shandong Provincial Higher Educational Science and Technology Program, China (Grant No. J13LJ04).
Ellipticity dependence of neutral Rydberg excitation of atoms in strong laser fields
Zhao, Lei; Dong, Jingwei; Lv, Hang; Yang, Tianxiang; Lian, Yi; Jin, Mingxing; Xu, Haifeng; Ding, Dajun; Hu, Shilin; Chen, Jing
2016-11-01
Rydberg state excitation (RSE) of different atoms in elliptically polarized strong 800 nm laser fields is investigated experimentally, and the results are compared with calculations of the strong-field approximation (SFA) model and the semiclassical model. It is observed that the RSE probability declines with increasing laser ellipticity for all of the He, Ar, and Kr atoms. While the measured ellipticity dependence of He RSE is very consistent with the predictions of both the SFA and semiclassical calculations, the width of the ellipticity dependence for Ar and Kr atoms is wider than that of the SFA model but closer to the semiclassical calculations. Analysis indicates that unlike a tunneling-plus-rescattering process, the decline of the RSE yield with increasing ellipticity can be attributed to a decrease of electrons with low kinetic energy that could be captured in the Rydberg states by the Coulomb potential. It indicates that the atomic RSE process could be related to the very low or near-zero energy structure in the photoelectron spectrum in strong laser fields, which would stimulate further experimental and theoretical studies to reveal their underlying mechanisms.
A new formula for the statistical weight for a sequence of Rydberg levels in an atom or ion
Eriksson, M.; Lennerstad, H.
2017-07-01
We present a new formula for the total statistical weight of all Rydberg levels Gion (nl, nh ) for which the principal quantum number n is between higher, nh , and a lower, nl , limits. This formula can be used for all atoms in the periodic table and for all corresponding ions.
Kips, A.; Vassen, W.; Hogervorst, W.; Dando, P.A.
1998-01-01
We present scaled-energy spectra on helium Rydberg atoms in a static electric field. /M/ = 1 states were studied in excitation from the 2 S-1(0) metastable state. Spectra were recorded for epsilon = -2.940(4), epsilon = -2.350(4), both below the saddle point, and epsilon = -1.760(4), above the saddl
Non-Elastic Processes in Atom Rydberg-Atom Collisions: Review of State of Art and Problems
Indian Academy of Sciences (India)
A. A. Mihajlov; V. A. Srećković; Lj. M. Ignjatović; A. N. Klyucharev; M. S. Dimitrijević; N. M. Sakan
2015-12-01
Inour previous research, it has been demonstrated that inelastic processes in atom Rydberg-atom collisions, such as chemi-ionization and ($n-n'$) mixing, should be considered together. Here we will review the present state-of-the-art and the actual problems. In this context, we will consider the influence of the ($n-n'$)-mixing during a symmetric atom Rydberg-atom collision processes on the intensity of chemi-ionization process. It will be taken into account H(1s) + H*() collisional systems, where the principal quantum number is $n \\gg 1$. It will be demonstrated that the inclusion of ($n-n'$) mixing in the calculation, influences significantly on the values of chemi-ionization rate coefficients, particularly in the lower part of the block of the Rydberg states. Different possible channels of the ($n-n'$)-mixing influence on chemi-ionization rate coefficients will be demonstrated. The possibility of interpretation of the ($n-n'$)-mixing influence will be considered on the basis of two existing methods for describing the inelastic processes in symmetrical atom Rydberg-atom collisions.
Energy Technology Data Exchange (ETDEWEB)
Gudmundsdóttir, Hildur [Science Institute and Faculty of Physical Sciences VR-III, University of Iceland, 107 Reykjavík (Iceland); Zhang, Yao; Weber, Peter M. [Department of Chemistry, Brown University, Providence, Rhode Island 02912 (United States); Jónsson, Hannes [Science Institute and Faculty of Physical Sciences VR-III, University of Iceland, 107 Reykjavík (Iceland); Department of Chemistry, Brown University, Providence, Rhode Island 02912 (United States)
2014-12-21
Theoretical calculations of Rydberg excited states of molecular clusters consisting of N,N-dimethylisopropylamine molecules using a Perdew-Zunger self-interaction corrected energy functional are presented and compared with results of resonant multiphoton ionization measurements. The binding energy of the Rydberg electron in the monomer is calculated to be 2.79 eV and 2.27 eV in the 3s and 3p state, respectively, which compares well with measured values of 2.88 eV and 2.21 eV. Three different stable configurations of the dimer in the ground state were found using an energy functional that includes van der Waals interaction. The lowest ground state energy conformation has the two N-atoms widely separated, by 6.2 Å, while the Rydberg state energy is lowest for a configuration where the N-atoms of the two molecules come close together, separated by 3.7 Å. This conformational change is found to lower the Rydberg electron binding energy by 0.2 eV. The self-interaction corrected functional gives a highly localized hole on one of the two molecules, unlike results obtained using the PBE functional or the hybrid B3LYP functional which give a delocalized hole. For the trimer, the self-interaction corrected calculation gives a Rydberg electron binding energy lowered further by 0.13 eV as compared with the dimer. The calculated results compare well with trends observed in experimental measurements. The reduction of the Rydberg electron binding energy with cluster size can be ascribed to an effective delocalization of the positive charge of the hole by the induced and permanent dipole moments of the neighboring molecules. A further decrease observed to occur on a time scale of tens of ps can be ascribed to a structural rearrangement of the clusters in the Rydberg state where molecules rotate to orient their dipoles in response to the formation of the localized hole.
Multi-photon excitation spectra of the 3snl (l = 0, 1, 2 and 3) Rydberg states of magnesium
Energy Technology Data Exchange (ETDEWEB)
Rafiq, M; Kalyar, M A; Baig, M A [Atomic and Molecular Physics Laboratory, Department of Physics, Quaid-i-Azam University, Islamabad 45320 (Pakistan)
2007-08-14
New experimental data on the highly excited l = 0, 1, 2 and 3 Rydberg states of magnesium have been acquired using two-photon and two-step laser excitation technique in conjunction with a thermionic diode ion detector. The new observations include even parity 3sns {sup 1}S{sub 0} (8 {<=} n {<=} 24) and 3snd {sup 1}D{sub 2} (7 {<=} n {<=} 62) Rydberg states approached directly from the 3s{sup 2} {sup 1}S{sub 0} ground state via two-photon excitation, and the odd parity 3snp {sup 1}P{sub 1} (20 {<=} n {<=} 61) and 3snf {sup 1}F{sub 3} (14 {<=} n {<=} 66) Rydberg states accessed by the two-step excitation process via 3s4s {sup 1}S{sub 0} and 3s3d {sup 1}D{sub 2} intermediate states. The Rydberg relation fit to the new data of the np {sup 1}P{sub 1} and nf {sup 1}F{sub 3} series yields the binding energies of the 3s4s {sup 1}S{sub 0} and 3s3d {sup 1}D{sub 2} levels as 18 167.702 cm{sup -1} and 15 267.972 cm{sup -1}, respectively. By adding the binding energies to the corresponding energies of the aforementioned levels, a precise value of the first ionization potential of magnesium is determined as 61 671.04 {+-} 0.04 cm{sup -1}. Using this ionization potential value, the quantum defects for the ns {sup 1}S{sub 0}, np {sup 1}P{sub 1}, nd {sup 1}D{sub 2} and nf {sup 1}F{sub 3} Rydberg series have been determined as 1.526(2), 1.046(2), 0.602(2) and 0.049(2) cm{sup -1} respectively.
Palmer, Michael H.; Ridley, Trevor; Vrønning Hoffmann, Søren; Jones, Nykola C.; Coreno, Marcello; de Simone, Monica; Grazioli, Cesare; Zhang, Teng; Biczysko, Malgorzata; Baiardi, Alberto; Peterson, Kirk A.
2016-03-01
New photoelectron (PE) and ultra violet (UV) and vacuum UV (VUV) spectra have been obtained for chlorobenzene by synchrotron study with higher sensitivity and resolution than previous work and are subjected to detailed analysis. In addition, we report on the mass-resolved (2 + 1) resonance enhanced multiphoton ionization (REMPI) spectra of a jet-cooled sample. Both the VUV and REMPI spectra have enabled identification of a considerable number of Rydberg states for the first time. The use of ab initio calculations, which include both multi-reference multi-root doubles and singles configuration interaction (MRD-CI) and time dependent density functional theoretical (TDDFT) methods, has led to major advances in interpretation of the vibrational structure of the ionic and electronically excited states. Franck-Condon (FC) analyses of the PE spectra, including both hot and cold bands, indicate much more complex envelopes than previously thought. The sequence of ionic states can be best interpreted by our multi-configuration self-consistent field computations and also by comparison of the calculated vibrational structure of the B and C ionic states with experiment; these conclusions suggest that the leading sequence is the same as that of iodobenzene and bromobenzene, namely: X2B1(3b1-1) < A2A2(1a2-1) < B2B2(6b2-1) < C2B1(2b1-1). The absorption onset near 4.6 eV has been investigated using MRD-CI and TDDFT calculations; the principal component of this band is 1B2 and an interpretation based on the superposition of FC and Herzberg-Teller contributions has been performed. The other low-lying absorption band near 5.8 eV is dominated by a 1A1 state, but an underlying weak 1B1 state (πσ∗) is also found. The strongest band in the VUV spectrum near 6.7 eV is poorly resolved and is analyzed in terms of two ππ∗ states of 1A1 (higher oscillator strength) and 1B2 (lower oscillator strength) symmetries, respectively. The calculated vertical excitation energies of these two
Palmer, Michael H.; Ridley, Trevor; Vrønning Hoffmann, Søren; Jones, Nykola C.; Coreno, Marcello; de Simone, Monica; Grazioli, Cesare; Zhang, Teng; Biczysko, Malgorzata; Baiardi, Alberto; Peterson, Kirk A.
2016-05-01
New photoelectron spectra (PES) and ultra violet (UV) and vacuum UV (VUV) absorption spectra of fluorobenzene recorded at higher resolution than previously, have been combined with mass-resolved (2 + 1) and (3 + 1) resonance enhanced multiphoton ionization (REMPI) spectra; this has led to the identification of numerous Rydberg states. The PES have been compared with earlier mass-analyzed threshold ionization and photoinduced Rydberg ionization (PIRI) spectra to give an overall picture of the ionic state sequence. The analysis of these spectra using both equations of motion with coupled cluster singles and doubles (EOM-CCSD) configuration interaction and time dependent density functional theory (TDDFT) calculations have been combined with vibrational analysis of both the hot and cold bands of the spectra, in considerable detail. The results extend several earlier studies on the vibronic coupling leading to conical intersections between the X2B1 and A2A2 states, and a further trio (B, C, and D) of states. The conical intersection of the X and A states has been explicitly identified, and its structure and energetics evaluated. The energy sequence of the last group is only acceptable to the present study if given as B2B2
Energy Technology Data Exchange (ETDEWEB)
Kivimäki, A., E-mail: kivimaki@iom.cnr.it [CNR—Istituto Officina dei Materiali (IOM), Laboratorio TASC, 34149 Trieste (Italy); Coreno, M. [CNR—Istituto di Struttura della Materia (ISM), Basovizza Area Science Park, 34149 Trieste (Italy); Miotti, P.; Frassetto, F.; Poletto, L. [CNR—Istituto di Fotonica e Nanotecnologie (IFN), via Trasea 7, 35131 Padova (Italy); Stråhlman, C. [MAX IV Laboratory, Lund University, P.O. Box 118, 22100 Lund (Sweden); Simone, M. de [CNR—Istituto Officina dei Materiali (IOM), Laboratorio TASC, 34149 Trieste (Italy); Richter, R. [Elettra-Sincrotrone Trieste, Area Science Park Basovizza, 34149 Trieste (Italy)
2016-05-15
Highlights: • The soft X-ray emission spectrum of SF{sub 6} changes at the S 2p → 4e{sub g} shape resonance. • The emission band around 172 eV indicates the population of the 6a{sub 1g} orbital. • Shake-up processes accompanying S 2p ionization can explain the new emissions. • Field ionization of neutral high Rydberg (HR) fragments reveals F and S atoms. • The yield of neutral HR fragments increases at the S 2p → 4e{sub g} shape resonance. - Abstract: We have studied the nature of the S 2p → 4e{sub g} shape resonance in the SF{sub 6} molecule by performing two different experiments. Soft X-ray emission spectra measured at the 4e{sub g} shape resonance reveal features that do not originate from the S 2p{sup −1} states. One of the features can be assigned to the 6a{sub 1g} → S 2p transition. The 6a{sub 1g} orbital, which is empty in the molecular ground state, can be populated either in core–valence double excitations or in S 2p shake-up transitions. Both these channels are considered. We have also studied the fragmentation of SF{sub 6} molecule after the decay of the S 2p core-hole states by observing neutral fragments in high-Rydberg states, where an electron occupies an orbital with n ≥ 20 (n is the principal quantum number). Such neutral fragments become, in relative terms, more abundant at the S 2p → 4e{sub g} shape resonance with respect to the S 2p → 2t{sub 2g} shape resonance, which is a pure one-electron phenomenon.
Electrostatic trapping and in situ detection of Rydberg atoms above chip-based transmission lines
Lancuba, P.; Hogan, S. D.
2016-04-01
Beams of helium atoms in Rydberg-Stark states with principal quantum number n = 48 and electric dipole moments of 4600 D have been decelerated from a mean initial longitudinal speed of 2000 m s-1 to zero velocity in the laboratory-fixed frame-of-reference in the continuously moving electric traps of a transmission-line decelerator. In this process accelerations up to -1.3× {10}7 m s-2 were applied, and changes in kinetic energy of {{Δ }}{E}{kin}=1.3× {10}-20 J ({{Δ }}{E}{kin}/e=83 meV) per atom were achieved. Guided and decelerated atoms, and those confined in stationary electrostatic traps, were detected in situ by pulsed electric field ionisation. The results of numerical calculations of particle trajectories within the decelerator have been used to characterise the observed deceleration efficiencies, and aid in the interpretation of the experimental data.
Institute of Scientific and Technical Information of China (English)
LI ChunYan; WANG TingTing; ZHEN JunFeng; ZHANG Qun; CHEN Yang
2009-01-01
Kr atoms were produced in their metastable states 4p55s [3/2]2 and 4p55s' [1/2]0 in a pulsed DC discharge in a beam, and subsequently excited to the even-parity autoionizing Rydberg states 4p5np' [3/2]1,2, [1/2]1 and 4p5nf' [5/2]3 using single photon excitation. The excitation spectra of the even-parity autoionizing resonance series from the metastable Kr were obtained by recording the autoionized Kr+ ions with time-of-flight ion detection in the photon energy range of 29000-40000 cm-1. A wealth of autoionizing resonances were newly observed, from which more precise and more systematic spec-troscopic data of the level energy and quantum defects were derived.
Institute of Scientific and Technical Information of China (English)
Chun-yan Li; Ting-ting Wang; Jun-feng Zhen; Qun Zhang; Yang Chen
2008-01-01
Xenon atoms were produced in their metastable states 5p56s[3/2]2 and 5p56s'[1/2]0 in a pulsed DC discharge in a beam, and subsequently excited to the even-parity autoionizing Rydberg states 5p5np' [3/2] 1 ,[1/2]1, t, and 5p5 nf'[5/2]3 using single photon excitation. The excitation spectra of the even-parity autoionizing resonance series from the metastable 129Xe were obtained by recording the autoionized Xe+ with time-of-flight ion detection in the photon energy range of 28000-42000 cm-1. A wealth of autoionizing resonances were newly observed, from which more precise and systematic spectroscopic data of the level energies and quantum defects were derived.
The fine structure splitting of the level of lithium in Rydberg states
Institute of Scientific and Technical Information of China (English)
胡先权; 胡文江; 孔春阳
2002-01-01
The Hamiltonian of the four-body problem for a lithium atom is expanded in series. The level shift and levelformula of a lithium atom in Rydberg states are achieved by means of the calculation of polarization of the atomic core(including the contribution of dipole, quadrupole and octupole components). We also consider the effect of relativitytheory, the orbital angular momentum L and the spin angular momentum S coupling scheme (LS coupling) and high-order correction of the effective potential to the level shift. The fine structure splitting (N＝5-12, L＝4-9, J＝L±l/2)and level intervals in B ydberg states have been calculated by the above-mentioned formula and compared with recentexperimental data.
Three-body bound states in dipole-dipole interacting Rydberg atoms
Kiffner, Martin; Jaksch, Dieter
2013-01-01
We show that the dipole-dipole interaction between three identical Rydberg atoms can give rise to bound trimer states. The microscopic origin of these states is fundamentally different from Efimov physics. Two stable trimer configurations exist where the atoms form the vertices of an equilateral triangle in a plane perpendicular to a static electric field. The triangle edge length typically exceeds $R\\approx 2\\,\\mu\\text{m}$, and each configuration is two-fold degenerate due to Kramers' degeneracy. The depth of the potential wells and the triangle edge length can be controlled by external parameters. We establish the Borromean nature of the trimer states, analyze the quantum dynamics in the potential wells and describe methods for their production and detection.
Semiclassical Calculation of Recurrence Spectra of He Rydberg Atom in Strong External Fields
Institute of Scientific and Technical Information of China (English)
WANG De-Hua; DING Shi-Liang; LIN Sheng-Lu
2004-01-01
Using core-scattered closed-orbit theory and region-splitting iterative method, we calculated the scaled recurrence spectra of helium atom in parallel electric and magnetic fields. Closed orbits in the corresponding classical system have also been obtained. When we search the closed orbits, in order to remove the Coulomb singularity of the classical Hamiltonian motion equations, we implement the Kustaanheimo-Stiefel transformation, which transforms the system from a three-dimensional to a four-dimensional one. The Fourier transformed spectrum of helium atom has allowed direct comparison between peaks in such plot and the scaled action values of closed orbits. The results are compared with those of the hydrogen case, which shows that the core-scattered effects play an important role in the recurrence spectra of the multi-electron Rydberg atom.
Institute of Scientific and Technical Information of China (English)
WANG De-Hua; DING Shi-Liang
2003-01-01
Closed-orbit theory is a semiclassical technique for explaining the spectra of Rydberg atoms in external fields. Using the closed-orbit theory and classical perturbation theory, we calculate the scaled recurrence spectra of Lithium atom in magnetic field plus a weak perpendicular electric field. The results show when the crossed electric field is added, the recurrence spectra are weakened greatly. As the scaled electric field f increases, the peaks of the recurrence spectra lose strength. Some recurrences are very sensitive and fall off rapidly as f increases; others persist till much higher f . As the electric field is stronger, some of the peaks revive. This phenomenon, caused by the interference among the electron waves that return to the nucleus, can be computed from the azimuthal dependence of the classical closed orbits.
Generalized local frame transformation theory for Rydberg atoms in external fields
Giannakeas, P; Robicheaux, F
2016-01-01
A rigorous theoretical framework is developed for a generalized local frame transformation theory (GLFT). A first test application to the photoionization spectra of Rydberg atoms in an external electric field demonstrates dramatic improvement over the first version of the local frame transformation theory developed initially by Fano and Harmin. This revised GLFT theory yields non-trivial corrections because it now includes the full on-shell Hilbert space without adopting the truncations in the original theory. Comparisons of the semi-analytical GLFT Stark spectra with {\\it ab initio} numerical simulations yields errors in the range of a few tens of MHz, an improvement over the original Fano-Harmin theory whose errors are 10-100 times larger. Our analysis provides a systematic pathway to precisely describe the corresponding photoabsorption spectra that should be accurate enough to meet most modern experimental standards.
Electrostatic trapping and in situ detection of Rydberg atoms above chip-based transmission lines
Lancuba, P
2016-01-01
Beams of helium atoms in Rydberg-Stark states with principal quantum number $n=48$ and electric dipole moments of 4600~D have been decelerated from a mean initial longitudinal speed of 2000~m/s to zero velocity in the laboratory-fixed frame-of-reference in the continuously moving electric traps of a transmission-line decelerator. In this process accelerations up to $-1.3\\times10^{7}$~m/s$^2$ were applied, and changes in kinetic energy of $\\Delta E_{\\mathrm{kin}}=1.3\\times10^{-20}$~J ($\\Delta E_{\\mathrm{kin}}/e = 83$~meV) per atom were achieved. Guided and decelerated atoms, and those confined in stationary electrostatic traps, were detected in situ by pulsed electric field ionisation. The results of numerical calculations of particle trajectories within the decelerator have been used to characterise the observed deceleration efficiencies, and aid in the interpretation of the experimental data.
A comparative analysis of binding in ultralong-range Rydberg molecules
Fey, Christian; Schmelcher, Peter; Rittenhouse, Seth T; Sadeghpour, Hossein R
2015-01-01
We perform a comparative analysis of different computational approaches employed to explore the electronic structure of ultralong-range Rydberg molecules. Employing the Fermi pseudopotential approach, where the interaction is approximated by an $s$-wave bare delta function potential, one encounters a non-convergent behavior in basis set diagonalization. Nevertheless, the energy shifts within the first order perturbation theory coincide with those obtained by an alternative approach relying on Green's function calculation with the quantum defect theory. A pseudopotential that yields exactly the results obtained with the quantum defect theory, i.e. beyond first order perturbation theory, is the regularized delta function potential. The origin of the discrepancies between the different approaches is analytically motivated.
Emergence of a Metallic Quantum Solid Phase in a Rydberg-Dressed Fermi Gas.
Li, Wei-Han; Hsieh, Tzu-Chi; Mou, Chung-Yu; Wang, Daw-Wei
2016-07-15
We examine possible low-temperature phases of a repulsively Rydberg-dressed Fermi gas in a three-dimensional free space. It is shown that the collective density excitations develop a roton minimum, which is softened at a wave vector smaller than the Fermi wave vector when the particle density is above a critical value. The mean field calculation shows that, unlike the insulating density wave states often observed in conventional condensed matters, a self-assembled metallic density wave state emerges at low temperatures. In particular, the density wave state supports a Fermi surface and a body-centered-cubic crystal order at the same time with the estimated critical temperature being about one tenth of the noninteracting Fermi energy. Our results suggest the emergence of a fermionic quantum solid that should be observable in the current experimental setup.
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
Kr atoms were produced in their metastable states 4p55s [3/2]2 and 4p55s’ [1/2]0 in a pulsed DC dis-charge in a beam,and subsequently excited to the even-parity autoionizing Rydberg states 4p5np’ [3/2]1,2,[1/2]1 and 4p5nf’ [5/2]3 using single photon excitation.The excitation spectra of the even-parity autoionizing resonance series from the metastable Kr were obtained by recording the autoionized Kr+ ions with time-of-flight ion detection in the photon energy range of 29000-40000 cm1.A wealth of autoionizing resonances were newly observed,from which more precise and more systematic spec-troscopic data of the level energy and quantum defects were derived.
[Constant scaled-energy spectroscopy of Rydberg atoms in a static electric field].
Cao, Jun-wen; Liu, Xiao-jun; Zhao, Zhi; Zhan, Ming-sheng
2002-02-01
In the past years, scaled energy spectroscopy is under active investigation because this method can simplify the analysis of atomic spectra in the external field based on classic mechanics. A fully computer-controlled experimental system to study the constant scaled-energy spectroscopy was established and described in this paper. The excitation energy E and the strength of the external electric field F were controlled synchronously to keep the scaled-energy epsilon = E/square root of F constant. With this system, constant scaled-energy spectra of Strontium Rydberg atoms at epsilon = -3.0 in a static electric field were successfully recorded for the first time, and the recurrence spectra were obtained by a Fourier transform.
Detecting and imaging single Rydberg electrons in a Bose-Einstein condensate
Karpiuk, Tomasz; Rzążewski, Kazimierz; Balewski, Jonathan B; Krupp, Alexander T; Gaj, Anita; Löw, Robert; Hofferberth, Sebastian; Pfau, Tilman
2014-01-01
The quantum mechanical states of electrons in atoms and molecules are discrete spatial orbitals, which are fundamental for our understanding of atoms, molecules, and solids. They determine a wide range of basic atomic properties, ranging from the coupling to external fields to the whole field of chemistry. Nevertheless, the manifestation of electron orbitals in experiments so far has been rather indirect. In a detailed theoretical model, we analyze the impact of a single Rydberg electron onto a Bose-Einstein condensate and compare the results to experimental data. Based on this validated model we propose a method to optically image the shape of single electron orbitals using electron-phonon coupling in a Bose-Einstein condensate. This scheme requires only established and readily available experimental techniques and allows to directly capture textbook-like spatial images of single electronic orbitals in a single shot experiment.
Excitation of high orbital angular momentum Rydberg states with Laguerre-Gauss beams
Rodrigues, J D; Mendonça, J T
2015-01-01
We consider the excitation of Rydberg states through photons carrying an intrinsic orbital angular momentum degree of freedom. Laguerre-Gauss modes, with a helical wave-front structure, correspond to such a set of laser beams, which carry some units of orbital angular momentum in their propagation direction. We demonstrate that, in a proper geometrical setting, this orbital angular momentum can be transferred to the internal degrees of freedom of the atoms, thus violating the standard dipolar selection rules. Higher orbital angular momentum states become accessible through a single photon excitation process. We investigate how the spacial structure of the Laguerre-Gauss beam affects the radial coupling strength, assuming the simplest case of hydrogen-like wavefunctions. Finally we discuss a generalization of the angular momentum coupling, in order to include the effects of the fine and hyperfine splitting, in the context of the Wigner-Eckart theorem.
Sub- and super-luminal light propagation using a Rydberg state
Bharti, Vineet
2016-01-01
We present a theoretical study to investigate sub- and super-luminal light propagation in a rubidium atomic system consisting of a Rydberg state by using density matrix formalism. The analysis is performed in a 4-level vee+ladder system interacting with a weak probe, and strong control and switching fields. The dispersion and absorption profiles are shown for stationary atoms as well as for moving atoms by carrying out Doppler averaging at room temperature. We also present the group index variation with control Rabi frequency and observe that a transparent medium can be switched from sub- to super-luminal propagation in the presence of switching field. Finally, the transient response of the medium is discussed, which shows that the considered 4-level scheme has potential applications in absorptive optical switching.
Institute of Scientific and Technical Information of China (English)
WANGDe-Hua; DINGShi-Liang
2003-01-01
Closed-orbit theory is a semiclassical technique for explaining the spectra of Rydberg atoms in external fields. Using the dosed-orblt theory and classical perturbation theory, we calculate the scaled recurrence spectra of Lithium atom in magnetic field plus a weak perpendicular electric field. The results show when the crossed electric field is added, the recurrence spectra are weakened greatly. As the scaled electric field f increases, the peaks of the recurrence spectra lose strength. Some recurrences are very sensitive and fall off rapidly as f increases, others persist till much higher f. As the electric field is stronger, some of the peaks revive. This phenomenon, caused by the interference among the electron waves that return to the nucleus, can be computed from the azimuthal dependence of the classical closed orbits.
Absorption and Recurrence Spectra of Sodium Rydberg Atom in a Strong External Magnetic Field
Institute of Scientific and Technical Information of China (English)
WANG De-Hua; LIN Sheng-Lu
2004-01-01
Using core-scattered closed-orbit theory, we calculate the photoabsorption and the scaled recurrence spectra of sodium Rydberg atom in strong magnetic field below ionization threshold. The non-Coulombic nature of the ionic core have been modified by a model potential, which includes an attractive Coulomb potential and a short-ranged core potential. A family of core-scattered nonhydrogenic closed orbits have also been discovered. The Fourier transformed spectra of sodium atom have allowed direct comparison between peaks in such plot and the scaled action values of closed orbits. The new peaks in the recurrence spectra of sodium atom have been considered as effects caused by the core scattering of returning waves at the ionic core. The results are compared with those of hydrogen case, which show that the core-scattered effects play an important role in alkali-metal atoms.
Absorption and Recurrence Spectra of Sodium Rydberg Atom in a Strong External Magnetic Field
Institute of Scientific and Technical Information of China (English)
WANGDe-Hua; LINSheng-Lu
2004-01-01
Using core-scattered closed-orbit theory, we calculate the photoabsorption and the scaled recurrence spectra of sodium Rydberg atom in strong magnetic fied below ionization threshoM. The non-Coulombic nature of the ionic core have been modified by a model potential, which includes an attractive Coulomb potential and a short-ranged core potential. A family of core-scattered nonhydrogenic closed orbits have also been discovered. The Fourier transformed spectra of sodium atom have allowed direct comparison between peaks in such plot and the scaled action values of closed orbits. The new peaks in the recurrence spectra of sodium atom have been considered as effects caused by the core scattering of returning waves at the ionic core. The results are compared with those of hydrogen case, which show that the core-scattered effects play an important role in alkali-metal atoms.
Application of electric field ionization method to detect the high-lying Rydberg states of Eu I
Institute of Scientific and Technical Information of China (English)
Jun Xie; Changjian Dai; Ming Li
2011-01-01
@@ The 4f76s(9S)np 8PJ (J = 5/2, 7/2, 9/2) Rydberg series converging to the first ionization limit 4f76s 9S4 of the Eu atom using the three-step laser excitation and electric-field-ionization (EFI) method are studied.First, the Eu atom is excited from the 4f76s2 8So7/2 ground state to the 4f76s7s 8So7/2 state through the 4f76s6p 10P9/2 state by the first two dye lasers.Next, it is populated to many higher-n members of the 4f76s(9S)np 8pJ Rydberg series by the third dye laser whose wavelength is scanned within a certain range.%The 4f76s(9S)np 8PJ (J = 5/2, 7/2, 9/2) Rydberg series converging to the first ionization limit 4f76s 9S4 of the Eu atom using the three-step laser excitation and electric-field-ionization (EFI) method are studied.First, the Eu atom is excited from the 4f76s2 8S7o/2 ground state to the 4f76s7s 8S7o/2 state through the 4f76s6p 10P9/2 state by the first two dye lasers. Next, it is populated to many higher-n members of the 4f76s(9S)np 8pJ Rydberg series by the third dye laser whose wavelength is scanned within a certain range.Finally, the atom in these higher-n states is ionized by the external pulsed electric field. With the field strength up to 2 kV/cm, we can detect the atom in 4f76s(9S)np 8pJ states with n ≥ 40. With the given laser line width, the level energies of Rydberg states with n as high as 72 can be determined. We not only confirm the previous data on the 4f76s(9S) np 8pJ Rydberg series, but also extend the n-value assignment significantly by detecting more states.
Tunable two-dimensional arrays of single Rydberg atoms for realizing quantum Ising models.
Labuhn, Henning; Barredo, Daniel; Ravets, Sylvain; de Léséleuc, Sylvain; Macrì, Tommaso; Lahaye, Thierry; Browaeys, Antoine
2016-06-30
Spin models are the prime example of simplified many-body Hamiltonians used to model complex, strongly correlated real-world materials. However, despite the simplified character of such models, their dynamics often cannot be simulated exactly on classical computers when the number of particles exceeds a few tens. For this reason, quantum simulation of spin Hamiltonians using the tools of atomic and molecular physics has become a very active field over the past years, using ultracold atoms or molecules in optical lattices, or trapped ions. All of these approaches have their own strengths and limitations. Here we report an alternative platform for the study of spin systems, using individual atoms trapped in tunable two-dimensional arrays of optical microtraps with arbitrary geometries, where filling fractions range from 60 to 100 per cent. When excited to high-energy Rydberg D states, the atoms undergo strong interactions whose anisotropic character opens the way to simulating exotic matter. We illustrate the versatility of our system by studying the dynamics of a quantum Ising-like spin-1/2 system in a transverse field with up to 30 spins, for a variety of geometries in one and two dimensions, and for a wide range of interaction strengths. For geometries where the anisotropy is expected to have small effects on the dynamics, we find excellent agreement with ab initio simulations of the spin-1/2 system, while for strongly anisotropic situations the multilevel structure of the D states has a measurable influence. Our findings establish arrays of single Rydberg atoms as a versatile platform for the study of quantum magnetism.
Ionization Potentials and Quantum Defects of 1s2np2P Rydberg States of Lithium Atom
Institute of Scientific and Technical Information of China (English)
CHEN Chao
2008-01-01
In this work,ionization potentials and quantum effects of 1s2np2p Rydberg states of lithium are calculated based on the calibrated quantum defect function.Energy levels and quantum defects for 1s2np2P bound states and their adjacent continuum states are calculated with the R-matrix theory,and then the quantum defect function of the 1s2np (n ≥ 7) channel is obtained,which varies smoothly with the energy based on the quantum defect theory.The accurate quantum defect of the 1s27p2P state derived from the experimental data is used to calibrate the original quantum defect function.The new function is used to calculate ionization potentials and quantum effects of 1s2np2P (n ≥ 7) Rydberg states.Present calculations are in agreement with recent experimental data in whole.
Shemansky, D. E.; Hall, D. T.; Ajello, J. M.
1985-01-01
The cross sections sigma R 1 (2p) for excitation of H Ly-alpha emission produced by electron impact on H2 is reexamined. A more accurate estimate for sigma R 1 (2p) is obtained based on Born approximation estimates of the H2 Rydberg system cross sections using measured relative excitation functions. The obtained value is (8.18 + or -1.2) x 10 to the -18th sq cm at 100 eV, a factor of 0.69 below the value universally applied to cross section measurements over the past decade. Cross sections for the H2 Rydberg systems fixed in magnitude by the Born approximation have also been obtained using experimentally determined excitation functions. Accurate analytic expressions for these cross sections allow the direct calculation of rate coefficients.
Adiabatic potential energy curves of long-range Rydberg molecules: Two-electron R-matrix approach
Tarana, Michal
2016-01-01
We introduce a computational method developed for study of long-range molecular Rydberg states of such systems that can be approximated by two electrons in a model potential of the atomic cores. Only diatomic molecules are considered. The method is based on a two-electron \\rmath approach inside a sphere centered on one of the atoms. The wave function is then connected to a Coulomb region outside the sphere via multichannel version of the Coulomb Green's function. This approach is put into a test by its application to a study of Rydberg states of the hydrogen molecule for internuclear distances $R$ from 20 to 400 bohrs and energies corresponding to $n$ from 3 to 22. The results are compared with previous quantum chemical calculations (lower quantum numbers $n$) and computations based on contact potential models (higher quantum numbers $n$).
Energy Technology Data Exchange (ETDEWEB)
Yang, Yang [Department of Chemistry, Duke University, Durham, North Carolina 27708 (United States); Aggelen, Helen van [Department of Chemistry, Duke University, Durham, North Carolina 27708 (United States); Department of Inorganic and Physical Chemistry, Ghent University, 9000 Ghent (Belgium); Yang, Weitao, E-mail: weitao.yang@duke.edu [Department of Chemistry and Department of Physics, Duke University, Durham, North Carolina 27708 (United States)
2013-12-14
Double, Rydberg, and charge transfer (CT) excitations have been great challenges for time-dependent density functional theory (TDDFT). Starting from an (N ± 2)-electron single-determinant reference, we investigate excitations for the N-electron system through the pairing matrix fluctuation, which contains information on two-electron addition/removal processes. We adopt the particle-particle random phase approximation (pp-RPA) and the particle-particle Tamm-Dancoff approximation (pp-TDA) to approximate the pairing matrix fluctuation and then determine excitation energies by the differences of two-electron addition/removal energies. This approach captures all types of interesting excitations: single and double excitations are described accurately, Rydberg excitations are in good agreement with experimental data and CT excitations display correct 1/R dependence. Furthermore, the pp-RPA and the pp-TDA have a computational cost similar to TDDFT and consequently are promising for practical calculations.
Institute of Scientific and Technical Information of China (English)
BIAN Xue-Bin; LIU Hong-Ping; SHI Ting-Yun
2008-01-01
A robust time-dependent approach to the high-resolution photoabsorption spectrum of Rydberg atoms in magnetic fields is presented. Traditionally we have to numerically diagonalize a huge matrix to solve the eigen-problem and then to obtain the spectral information. This matrix operation requires high-speed computers with large memories. Alternatively we present a unitary but very easily parallelized time-evolution method in an inexpensive way, which is very accurate and stable even in long-time scale evolution. With this method, we perform the spectral calculation of hydrogen atom in magnetic field, which agrees well with the experimental observation. It can be extended to study the dynamics of Rydberg atoms in more complicated cases such as in combined electric and magnetic fields.
Simons, Matt T; Holloway, Christopher L
2016-01-01
We demonstrate simultaneous electromagnetically-induced transparency (EIT) with cesium (Cs) and rubidium (Rb) Rydberg atoms in the same vapor cell with coincident (overlapping) optical fields. Each atomic system can detect radio frequency (RF) electric (E) field strengths through modification of the EIT signal (Autler-Townes (AT) splitting), which leads to a direct SI traceable RF E-field measurement. We show that these two systems can detect the same the RF E-field strength simultaneously, which provides a direct in situ comparison of Rb and Cs RF measurements in Rydberg atoms. In effect, this allows us to perform two independent measurements of the same quantity in the same laboratory, providing two different immediate and independent measurements. This gives two measurements that helps rule out systematic effects and uncertainties in this E-field metrology approach, which are important when establishing an international measurement standard for an E-field strength and is a necessary step for this method to...
Yang, Yang; van Aggelen, Helen; Yang, Weitao
2013-12-14
Double, Rydberg, and charge transfer (CT) excitations have been great challenges for time-dependent density functional theory (TDDFT). Starting from an (N ± 2)-electron single-determinant reference, we investigate excitations for the N-electron system through the pairing matrix fluctuation, which contains information on two-electron addition/removal processes. We adopt the particle-particle random phase approximation (pp-RPA) and the particle-particle Tamm-Dancoff approximation (pp-TDA) to approximate the pairing matrix fluctuation and then determine excitation energies by the differences of two-electron addition/removal energies. This approach captures all types of interesting excitations: single and double excitations are described accurately, Rydberg excitations are in good agreement with experimental data and CT excitations display correct 1/R dependence. Furthermore, the pp-RPA and the pp-TDA have a computational cost similar to TDDFT and consequently are promising for practical calculations.
Mihajlov, A A; Ignjatovic, Lj M; Klyucharev, A N; 10.1007/s10876-011-0438-7
2012-01-01
In this article the history and the current state of research of the chemiionization processes in atom-Rydberg atom collisions is presented. The principal assumptions of the model of such processes based on the dipole resonance mechanism, as well as the problems of stochastic ionization in atom-Rydberg atom collisions, are exposed. The properties of the collision kinetics in atom beams of various types used in contemporary experimentations are briefly described. Results of the calculation of the chemi-ionization rate coefficients are given and discussed for the range of the principal quantum number values 5 < n < 25. The role of the chemi-ionization processes in astrophysical and laboratory low-temperature plasmas, and the contemporary methods of their investigation are described. Also the directions of further research of chemi-ionization processes are discussed in this article.
Bhowmick, Arup; Sahoo, Sushree S.; Mohapatra, Ashok K.
2016-08-01
We discuss the optical-heterodyne-detection technique to study the absorption and dispersion of a probe beam propagating through a medium with a narrow resonance. The technique has been demonstrated for Rydberg electromagnetically induced transparency in rubidium thermal vapor and the optical nonlinearity of a probe beam with variable intensity has been studied. A quantitative comparison of the experimental result with a suitable theoretical model is presented. The limitations and the working regime of the technique are discussed.
2011-02-25
Rydberg gas in a magneto - optical trap . We also demonstrated a novel technique for reducing the relative velocities of neighboring atoms in an atomic...beam to enable the exploration of coherent interactions between atoms and/or molecules that are not easily laser cooled or optically trapped . II...spectroscopy of isolated atoms. New laser and electro- optic technology and techniques serve as the key tools for active manipulation of inter- and intra
Energy Technology Data Exchange (ETDEWEB)
Aptekarev, A I [Keldysh Institute of Applied Mathematics, Russian Academy of Sciences and Moscow State University Lomonosov (Russian Federation); Dehesa, J S; Martinez-Finkelshtein, A; Yanez, R J [Instituto Carlos I de Fisica Teorica y Computacional, Universidad de Granada, 18071-Granada (Spain)], E-mail: aptekaa@keldysh.ru, E-mail: dehesa@ugr.es, E-mail: andrei@ual.es, E-mail: ryanez@ugr.es
2010-04-09
The radial position (
Božnic, D. K.; Nedeljkovic, N. N.
2010-07-01
We analyze the ionization dynamics of slow hydrogenlike Rydberg atoms (principal quantum number n >> 1 ) approaching solid surface in a weak electric field. The recently obtained etalon-equation method results for the simulation of experimental signal are used to investigate the influence of the initial velocity distribution. It is demonstrated that an agreement with the experimental signal can be obtained with the broadened velocity distributions.
Non-Elastic Processes in Atom Rydberg-Atom Collisions: Review of State of Art and Problems
Mihajlov, A A; Ignjatović, Lj M; Klyucharev, A N; Dimitrijević, M S; Sakan, N M
2016-01-01
In our previous research, it has been demonstrated that such inelastic processes in atom Rydberg-atom collisions, as chemi-ionization and (n-n') mixing, should be considered together. Here we will review the present state of the art and the actual problems will be discussed. In this context, we will consider the influence of the (n-n')-mixing during a symmetric atom Rydberg-atom collision processes on the intensity of chemi-ionization process. It will be taken into account H(1s) + H*(n) collisional systems, where the principal quantum number n $>>$ 1. It will be demonstrated that the inclusion of (n-n') mixing in the calculation, influences significantly on the values of chemi-ionization rate coefficients, particularly in the lower part of the block of the Rydberg states. Different possible channels of the (n-n')-mixing influence on chemi-ionization rate coefficients will be demonstrated. The possibility of interpretation of the (n-n')-mixing influence will be considered on the basis of two existing methods f...
Tarana, Michal; Čurík, Roman
2016-05-01
We introduce a computational method developed for study of long-range molecular Rydberg states of such systems that can be approximated by two electrons in a model potential of the atomic cores. The method is based on a two-electron R-matrix approach inside a sphere centered on one of the atoms. The wave function is then connected to a Coulomb region outside the sphere via a multichannel version of the Coulomb Green's function. This approach is applied to a study of Rydberg states of Rb2 for internuclear separations R from 40 to 320 bohrs and energies corresponding to n from 7 to 30. We report bound states associated with the low-lying 3Po resonance and with the virtual state of the rubidium atom that turn into ion-pair-like bound states in the Coulomb potential of the atomic Rydberg core. The results are compared with previous calculations based on single-electron models employing a zero-range contact-potential and short-range modele potential. Czech Science Foundation (Project No. P208/14-15989P).
Levi, Emanuele; Gutiérrez, Ricardo; Lesanovsky, Igor
2016-09-01
In the presence of strong dephasing noise the dynamics of Rydberg gases becomes effectively classical, due to the rapid decay of quantum superpositions between atomic levels. Recently a great deal of attention has been devoted to the stochastic dynamics that emerges in that limit, revealing several interesting features, including kinetically constrained glassy behaviour, self-similarity and aggregation effects. However, the non-equilibrium physics of these systems, in particular in the regime where coherent and dissipative processes contribute on equal footing, is yet far from being understood. To explore this we study the dynamics of a small one-dimensional Rydberg lattice gas subject to dephasing noise by numerically integrating the quantum master equation. We interpolate between the coherent and the strongly dephased regime by defining a generalised concept of a blockade length. We find indications that the main features observed in the strongly dissipative limit persist when the dissipation is not strong enough to annihilate quantum coherences at the dynamically relevant time scales. These features include the existence of a time-dependent Rydberg blockade radius, and a growth of the density of excitations which is compatible with the power-law behaviour expected in the classical limit.
Dynamics of Bloch State Positronium Emission from MOF Targets Studied via Rydberg TOF Spectroscopy
Piñeiro Escalera, Alina; Jones, Adric; Mills, Allen
2016-05-01
Recent advances in the efficient production and detection of Rydberg positronium (Ps) have made it possible to perform energy- and angle- resolved time-of-flight (TOF) spectroscopy with Ps. We report here TOF measurements of Ps emission from the metal-oxide framework (MOF) targets, MOF-5 and ZIF-8. MOFs are a recently synthesized class of chemical structures, characterized by high long-range order and large surface area to volume ratios (i.e., they are highly porous and uniform, crystalline materials). Ps is found to be emitted predominantly in a series of monoenergetic peaks, providing clear evidence of Ps Bloch states. Measuring the relative populations of the monoenergetic peaks, as a function of implantation energy and target temperature, provides insight into the target-dependent dynamics of Bloch state Ps. Work supported by the U.S. National Science Foundation Grants No. PHY 1206100 and No. PHY 1040590 and the National Science Foundation Graduate Research Fellowship Progam (NSF-GRFP). DOE BES DE-FG02-13ER46972 (MOF-5 synthesis and characterization).
Facilitation Dynamics and Localization Phenomena in Rydberg Lattice Gases with Position Disorder
Marcuzzi, Matteo; Minář, Jiří; Barredo, Daniel; de Léséleuc, Sylvain; Labuhn, Henning; Lahaye, Thierry; Browaeys, Antoine; Levi, Emanuele; Lesanovsky, Igor
2017-02-01
We explore the dynamics of Rydberg excitations in an optical tweezer array under antiblockade (or facilitation) conditions. Because of the finite temperature the atomic positions are randomly spread, an effect that leads to quenched correlated disorder in the interatomic interaction strengths. This drastically affects the facilitation dynamics as we demonstrate experimentally on the elementary example of two atoms. To shed light on the role of disorder in a many-body setting we show that here the dynamics is governed by an Anderson-Fock model, i.e., an Anderson model formulated on a lattice with sites corresponding to many-body Fock states. We first consider a one-dimensional atom chain in a limit that is described by a one-dimensional Anderson-Fock model with disorder on every other site, featuring both localized and delocalized states. We then illustrate the effect of disorder experimentally in a situation in which the system maps on a two-dimensional Anderson-Fock model on a trimmed square lattice. We observe a clear suppression of excitation propagation, which we ascribe to the localization of the many-body wave functions in Hilbert space.
Dynamics of a Rydberg hydrogen atom near a metal surface in the electron-extraction scheme
Energy Technology Data Exchange (ETDEWEB)
Iñarrea, Manuel [Área de Física Aplicada, Universidad de La Rioja, Logroño (Spain); Lanchares, Víctor [Departamento de Matemáticas y Computación, Universidad de La Rioja, Logroño, La Rioja (Spain); Palacián, Jesús [Departamento de Ingeniería Matemática e Informática, Universidad Pública de Navarra, Pamplona (Spain); Pascual, Ana I. [Departamento de Matemáticas y Computación, Universidad de La Rioja, Logroño, La Rioja (Spain); Salas, J. Pablo, E-mail: josepablo.salas@unirioja.es [Área de Física Aplicada, Universidad de La Rioja, Logroño (Spain); Yanguas, Patricia [Departamento de Ingeniería Matemática e Informática, Universidad Pública de Navarra, Pamplona (Spain)
2015-01-23
We study the classical dynamics of a Rydberg hydrogen atom near a metal surface in the presence of a constant electric field in the electron-extraction situation [1], e.g., when the field attracts the electron to the vacuum. From a dynamical point of view, this field configuration provides a dynamics richer than in the usual ion-extraction scheme, because, depending on the values of field and the atom–surface distance, the atom can be ionized only towards the metal surface, only to the vacuum or to the both sides. The evolution of the phase space structure as a function of the atom–surface distance is explored in the bound regime of the atom. In the high energy regime, the ionization mechanism is also investigated. We find that the classical results of this work are in good agreement with the results obtained in the wave-packet propagation study carried out by So et al. [1]. - Highlights: • We study a classical hydrogen atom near a metal surface plus a electric field. • We explore the phase space structure as a function of the field strength. • We find most of the electronic orbits are oriented along the field direction. • We study the ionization of the atom for several atom–surface distances. • This classical study is in good agreement with the quantum results.
Ionization of Rydberg atoms by the kicks of half-cycle pulses
Indian Academy of Sciences (India)
Chatterjee Supriya; Saha Aparna; Talukdar B
2016-04-01
We present a quantum mechanical model to study the ionization of quasione dimensional Rydberg atoms interacting with half-cycle pulses (HCPs) and use it to demonstrate the inadequacy of semiclassical approaches to calculate ionization probabilities of such atoms subject to the impact of more than one HCP. For a single-kicked atom both models correctly reproduce the experimentally observed ‘s-curve’ as can be seen by plotting the ionization probability $P$ as a function of momentum transfer $q_1$.We demonstrate that for a twice-kicked atom, the semiclassical model yields numbers for $P$ which are not physically realizable. For fixed values of momentum transfers $q_1$and $q_2$, in a twice-kicked atom, the ionization probability as a function of time delay between the kicks exhibits periodic decay and revival. The results of the semiclassical approach appear to agree with the quantum mechanical values at the times of revival of P, else these show considerable deviation. We attempt to provide a physical explanation for the limitation of the semiclassical approach.
Entangling atomic spins with a Rydberg-dressed spin-flip blockade
Jau, Y.-Y.; Hankin, A. M.; Keating, T.; Deutsch, I. H.; Biedermann, G. W.
2016-01-01
Controlling the quantum entanglement between parts of a many-body system is key to unlocking the power of quantum technologies such as quantum computation, high-precision sensing, and the simulation of many-body physics. The spin degrees of freedom of ultracold neutral atoms in their ground electronic state provide a natural platform for such applications thanks to their long coherence times and the ability to control them with magneto-optical fields. However, the creation of strong coherent coupling between spins has been challenging. Here we demonstrate a strong and tunable Rydberg-dressed interaction between spins of individually trapped caesium atoms with energy shifts of order 1 MHz in units of Planck’s constant. This interaction leads to a ground-state spin-flip blockade, whereby simultaneous hyperfine spin flips of two atoms are inhibited owing to their mutual interaction. We employ this spin-flip blockade to rapidly produce single-step Bell-state entanglement between two atoms with a fidelity >=81(2)%.
Electron Capture from Linear Stark Rydberg States above the Matching Velocity
Ciocca, M.; Creasey, C.; MacAdam, K. B.
1998-05-01
The relative cross section for electron capture by singly charged ions from linear Stark Rydberg states of Na has been measured, both as a function of the angle of impact and of projectile velocity. The target, the topmost state of the n = 24 Stark manifold, was prepared by two-step laser excitation from the Na ground state, via 3p_3/2, in an electric field F_Stark= 160 V/cm. By means of a device perfected in our laboratory (the "Stark Barrel"), we aligned the target by adiabatically switching the electric field, after excitation, down to a preset low value and a desired direction in the plane determined by the ion and Na beams. Thermionic emission ion sources of Li and Na were operated at accelerating voltages 400-2000 V to allow study of electron capture in the reduced velocity range v = 1.0 - 2.5. This augments an earlier study by Homan footnote D. M. Homan, Ph. D. Dissertation, University of Kentucky 1997, unpublished. at lower velocities.
Handshake electron transfer from hydrogen Rydberg atoms incident at a series of metallic thin films.
Gibbard, J A; Softley, T P
2016-06-21
Thin metallic films have a 1D quantum well along the surface normal direction, which yields particle-in-a-box style electronic quantum states. However the quantum well is not infinitely deep and the wavefunctions of these states penetrate outside the surface where the electron is bound by its own image-charge attraction. Therefore a series of discrete, vacant states reach out from the thin film into the vacuum increasing the probability of electron transfer from an external atom or molecule to the thin film, especially for the resonant case where the quantum well energy matches that of the atom. We show that "handshake" electron transfer from a highly excited Rydberg atom to these thin-film states is experimentally measurable. Thicker films have a wider 1D box, changing the energetic distribution and image-state contribution to the thin film wavefunctions, resulting in more resonances. Calculations successfully predict the number of resonances and the nature of the thin-film wavefunctions for a given film thickness.
The dynamical properties of Rydberg hydrogen atom near a metal surface
Institute of Scientific and Technical Information of China (English)
GE Meihua; ZHANG Yanhui; WANG Dehua; DU Mengli; LIN Shenglu
2005-01-01
The dynamical properties of Rydberg hydrogen atom near a metal surface are presented by using the methods of phase space analysis and closed orbit theory. Transforming the coordinates of the Hamiltonian, we find that the phase space of the system is divided into vibrational and rotational region. Both the Poincaré surface of section and the closed orbit theory verify the same conclusion clearly. In this paper we choose the atomic principal quantum number as n = 20. The dynamical character of the exited hydrogen atom depends sensitively on the atom-surface distance d. When d is sufficiently large, the atom-surface potential can be expressed by the traditional van der Waals force and the system is integrable. When d becomes smaller, there exists a critical value dc. For d > dc, the system is near-integrable and the motion is regular. While chaotic motion appears for d < dc, and the system tends to be non-integrable. The trajectories become unstable and the electron might be captured onto the metal surface.
Generalized local frame transformation theory for Rydberg atoms in external fields
Giannakeas, Panagiotis; Robicheaux, Francis; Greene, Chris H.
2016-05-01
In this work a rigorous theoretical framework is developed generalizing the local frame transformation theory (GLFT) and it is applied to the photoionization spectra of Rydberg atoms in an external electric field. The resulting development is compared with previous theoretical treatments, including the first version of local frame transformation theory, developed initially by Fano and Harmin. Our revised version of the theory yields non-trivial corrections because we now take into account the full Hilbert space on the energy shell without adopting truncations utilized by the original Fano-Harmin theory. The semi-analytical calculations from GLFT approach are compared with ab initio numerical simulations yielding errors of few tens of MHz whereas the errors in the original Fano-Harmin theory are one or two orders of magnitude larger. Our analysis provides a systematic pathway to precisely describe the corresponding photoabsorption spectra that should be accurate enough to meet modern experimental standards. This work was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Award numbers DE-SC0010545 (for PG and CHG) and DE-SC0012193 (for FR).
Energy Technology Data Exchange (ETDEWEB)
Lombardi, M.; Seligman, T.H. (Laboratoire de Spectrometrie Physique-Universite Joseph Fourier de Grenoble, Boite Postale No. 87, 38402 Saint Martin d' Heres, CEDEX (France))
1993-05-01
We study Rydberg molecules taking into account the interaction between the rotational motion of the nuclei and the radial motion of the electron. This situation can be treated to a good approximation in quantum mechanics by the multichannel quantum-defect method which in turn has a well-defined classical limit. We are able to calculate very long sequences of levels and the corresponding amplitudes of wave packets. This allows us to study the statistical properties of both in detail. Our interest focuses on aspects of quantum chaos'' that can be particularly well understood in this case. Our main result is that, in a completely chaotic classical situation, where statistics of quantum-level spacings follow the expected universal Gaussian-orthogonal-ensemble behavior, and statistics of line intensities display the expected universal Porter-Thomas behavior, nonuniversal properties are explicitly contained in correlations between intensities and spacings, determined by the time needed for the classical system to mix on a length scale given by the quantum wavelength.
Formation and decay of the Rydberg states of multiply charged ions interacting with solid surfaces
Energy Technology Data Exchange (ETDEWEB)
Mirkovic, M A; Nedeljkovic, N N; Bozanic, D K, E-mail: gmirkomarko@sezampro.rs
2010-11-01
Processes of formation and decay of the Rydberg states of multiply charged ions escaping solid surfaces with intermediate velocities (v {approx} 1 a.u.) represent complex quantum events that require a detailed quantum description. We have developed a two-state vector model for the population process, with the functions {Psi}{sub 1} and {Psi}{sub 2} for definition of the state of a single active electron. The electron exchange between the solid and the moving ion is described by a mixed flux through a plane positioned between them. For the low values of the angular momentum quantum numbers l the radial electronic coordinate {rho} can be neglected, whereas for the large-l values a wide space region around the projectile trajectory was taken into account. The reionization of the previously populated states is considered as a decay of the wave function {Psi}{sub 2}. The corresponding decay rates are obtained by an appropriate etalon equation method: in the large-l case the radial electronic coordinate {rho} is treated as a variational parameter. The theoretical predictions based on that population-reionization mechanism are compared with the available beam-foil experimental data, as well as the experimental data obtained in the interaction of multiply charged ions with micro-capillary foil. Generally, the model reproduces the experimentally observed non-linear trend of the l distributions from l = 0 to l{sub max} = n - 1.
Study of Energy Levels and Decay Mechanisms for Singlet Rydberg States of Molecular Nitrogen.
1987-09-15
using optogalvanic spectroscopy in an rf discharge by Suzuki and Kakimoto . 3 7 Subsequently Miyazaki, Scheingraber, and Vida13 8 measured transitions...positions for each of the transitions observed. Also shown are the line positions determined by Suzuki and Kakimoto 3 7 4.. for the same transitions through...cgOZu 4- g"O’ transitions are those of Suzuki and Kakimoto .37 The intervals for the 3)E Sall (0) IE transitions were calculated from the term values
Morisawa, Yusuke; Tachibana, Shin; Ehara, Masahiro; Ozaki, Yukihiro
2012-12-01
Attenuated total reflection far-ultraviolet (ATR-FUV) spectra containing Rydberg states of n-alkanes (C(m)H(2m+2); m varies in the range 5-9) and branched alkanes observed in the liquid phase were investigated by quantum chemical calculations with the aim of elucidating electronic transitions from σ orbitals of liquid n- and branched alkanes. New assignments are proposed based on the time-dependent density functional theory (TD-DFT) and symmetry-adapted cluster configuration interaction (SAC-CI) calculations, and the differences in these spectra are analyzed in detail. The FUV spectra of n-alkanes show a broad asymmetric feature near 8.3 eV. The strong band at ∼8.3 eV shows a red shift with a significant increase in intensity as the carbon chain length increases, which is attributed to the overlapping transitions from the third (or fourth) highest occupied molecular orbitals HOMO-2 (or HOMO-3) and HOMO-1 to Rydberg 3p(y) by the TD-DFT and SAC-CI calculations. This band was previously assigned to the overlap of two peaks arising from the transition from the HOMO to 3p and from the HOMO-1 to 3s based on their term values. Although the most intense transition, T1, is from HOMO-2 for m = 5 and 6 and HOMO-3 for m varying in the range of 7-9, the shape of Kohn-Sham molecular orbital for T1 is similar among the all-alkanes investigated. The theoretical result also has demonstrated that the red shift originates in both stabilization of the Rydberg 3p(y) and destabilization of the occupied orbitals. The intensity of the shoulder at 7.7 eV drastically increases in the spectra of the branched alkanes, especially for those with quaternary carbon atoms such as 2,2-dimethyl butane. This increase in intensity is caused by a reduction in symmetry in the branched alkanes, which leads the forbidden transitions to Rydberg 3s to allowed transitions. In this way, the present study has provided new insight into the existence of their Rydberg transitions and the shape of the relevant
Institute of Scientific and Technical Information of China (English)
WANG Xiao-Lu; LIU Ling-Tao; GAO Xiang; SHEN Chun; LI Jia-Ming
2008-01-01
@@ Using a simplified multi-configuration Dirac-Fock (SMCDF) scheme based on the multi-configuration Dirac-Fock (MCDF) theory, we study the systematic variations of the fine-structure splittings of n2 D3/2,5/2 Rydberg series along the sodium-like isoelectronic sequence, i.e.the fine-structure orderings vary with increasing atomic number Z.The competition between the spin-orbit interactions and the exchange interactions due to relativistic effects of the nd orbital wavefunctions well explain such variations.Furthermore, the effect of Breit interactions which plays the secondary role is studied.