Directory of Open Access Journals (Sweden)
A. Franchi
2009-01-01
Full Text Available The multiturn extraction from a circular particle accelerator is performed by trapping the beam inside stable islands of the horizontal phase space. In general, by crossing a resonance of order n, n+1 beamlets are created whenever the resonance is stable, whereas if the resonance is unstable the beam is split in n parts. Islands are generated by nonlinear magnetic fields, whereas the trapping is realized by means of a given tune variation so to cross adiabatically a resonance. Experiments at the CERN Proton Synchrotron carried out in 2007 gave the evidence of protons trapped in stable islands while crossing the one-third and one-fifth resonances. Dedicated experiments were also carried out to study the trapping process and its reversibility properties. The results of these measurement campaigns are presented and discussed in this paper.
Franchi, A; Giovannozzi, M; CERN. Geneva. BE Department
2009-01-01
The multi-turn extraction from a circular particle accelerator is performed by trapping the beam inside stable islands of the horizontal phase space. In general, by crossing a resonance of order n, n+1 beamlets are created whenever the resonance is stable, whereas if the resonance is unstable the beam is split in n parts. Islands are generated by non-linear magnetic fields, whereas the trapping is realized by means of a given tune variation so to cross adiabatically a resonance. Experiments at the CERN Proton Synchrotron carried out in 2007 gave the evidence of protons trapped in stable islands while crossing the one-third and one-fifth resonances. Dedicated experiments were also carried out to study the trapping process and its reversibility properties. The results of these measurement campaigns are presented and discussed in this paper.
Froment, P; Delbar, T; Ryckewaert, G; Tilquin, I; Vervier, J
2002-01-01
The Transmutation by Adiabatic Resonance Crossing (TARC) technique has been proposed by Rubbia (Resonance enhanced neutron captures for element activation and waste transmutation, CERN-LHC/97-0040EET, 1997; TARC collaboration, Neutron-driven nuclear transmutation by adiabatic resonance crossing, CERN-SL-99-036EET, 1999; Abanades et al., Nucl. Instr. and Meth. A 487 (2002) 577) for element activation and waste transmutation. We investigate the possibility to use this technique for the industrial production of **9**9Mo and **1**2**5Xe by resonance neutron capture in **9**8Mo and **1**2**4Xe, respectively. Their daughters, i.e. **9**9**mTc and **1**2**5I, are widely used in medical applications. The high neutron flux needed is produced by bombarding a thick Be target with 65 or 75 MeV proton beam (few microamperes). This target is placed at the centre of a large cubic lead assembly (1.6 m side, purity: 99.999%). The neutrons are progressively slowed down by elastic scattering on lead, and their energies "scan" t...
Khorshidi, Abdollah; Pazirandeh, Ali; Tenreiro, Claudio; Kadi, Yacine
2014-01-01
In this study, the transmutation adiabatic resonance crossing (TARC) concept was estimated in Mo-99 radioisotope production via radiative capture reaction in two designs. The TARC method was composed of moderating neutrons in lead or a composition of lead and water. Additionally, the target was surrounded by a moderator assembly and a graphite reflector district. Produced neutrons were investigated by (p,xn) interactions with 30 MeV and 300 mu A proton beam on tungsten, beryllium, and tantalum targets. The Mo-99 production yield was related to the moderator property, cross section, and sample positioning inside the distinct region of neutron storage as must be proper to achieve gains. Gathered thermal flux of neutrons can contribute to molybdenum isotope production. Moreover, the sample positioning to gain higher production yield was dependent on a greater flux in the length of thermal neutrons and region materials inside the moderator or reflector. When the sample radial distance from Be was 38 cm inside the...
The TARC experiment (PS211): neutron-driven nuclear transmutation by adiabatic resonance crossing
International Nuclear Information System (INIS)
Revol, J.P.; Arnould, H.; Bompas, C.A.
1999-01-01
The main purpose of the TARC experiment is to demonstrate the possibility of using Adiabatic Resonance Crossing (ARC) to destroy efficiently Long-Lived Fission Fragments (LLFFs) in accelerator-driven systems and to validate a new simulation developed in the framework of the Energy Amplifier programme. An experimental set-up was installed in a CERN PS beam line to study how neutrons produced by spallation at relatively high energy (E n ≥1 MeV) slow down quasi adiabatically with almost flat isolethargic energy distribution and reach the capture resonance energy of an element to be transmuted where they will have a high probability of being captured. Precision measurements of energy and space distributions of spallation neutrons (using 2.5 GeV/c and 3.5 GeV/c protons) slowing down in a 3.3 m x 3.3 m x 3 m lead volume and of neutron capture rates of LLFFs 99 Tc, 129 I, and several other elements were performed. An appropriate formalism and appropriate computational tools necessary for the analysis and understanding of the data were developed and validated in detail. Our direct experimental observation of ARC demonstrates the possibility to destroy, in a parasitic mode, outside the Energy Amplifier core, large amounts of 99 Tc or 129 I at a rate exceeding the production rate, thereby making it practical to reduce correspondingly the existing stockpile of LLFFs. In addition, TARC opens up new possibilities for radioactive isotope production as an alternative to nuclear reactors, in particular for medical applications, as well as new possibilities for neutron research and industrial applications. (orig.)
Arnould, H; Del Moral, R; Lacoste, V; Vlachoudis, V; Aleixandre, J; Bueno, J; Cerro, E; González, O; Tamarit, J; Andriamonje, Samuel A; Brozzi, Delecurgo; Buono, S; Carminati, F; Casagrande, Federico; Cennini, P; Collar, J I; Dumps, Ludwig; Gelès, C; Goulas, I; Fernández, R; Kadi, Y; Klapisch, Robert; Oropesa, J; Placci, Alfredo; Revol, Jean Pierre Charles; Rubbia, Carlo; Rubio, Juan Antonio; Saldaña, F; Embid, M; Gálvez, J; López, C; Pérez-Enciso, E; Poza, M; Sirvent, C; Vieira, S L; Abánades, A; García, J; Martínez-Val, J M; Perlado, M; González, E; Hussonnois, M; Le Naour, C; Trubert, D; Belle, E; Giorni, A; Heuer, R D; Loiseaux, J M; Méplan, O; Nifenecker, H; Schussler, F; Viano, J B; Angelopoulos, Angelos; Apostolakis, Alcibiades J; Karaiskos, P; Sakelliou, L; Kokkas, P; Pavlopoulos, P; Eleftheriadis, C; Kitis, G; Papadopoulos, I M; Savvidis, E; Tzima, A; Zioutas, Konstantin; Díez, S; Pérez-Navarro, A
1999-01-01
Energy and space distributions of spallation neutrons (from 2.5 and 3.57 GeV/c CERN proton beams) slowing down in a 3.3*3.3*3 m/sup 3/ lead volume and neutron capture rates on long-lived fission fragments /sup 99/Tc and /sup 129/I demonstrate that Adiabatic Resonance Crossing (ARC) can be used to eliminate efficiently such nuclear waste and validate innovative simulation. (17 refs).
Abánades, A; Andriamonje, Samuel A; Angelopoulos, Angelos; Apostolakis, Alcibiades J; Arnould, H; Belle, E; Bompas, C A; Brozzi, Delecurgo; Bueno, J; Buono, S; Carminati, F; Casagrande, Federico; Cennini, P; Collar, J I; Cerro, E; Del Moral, R; Díez, S; Dumps, Ludwig; Eleftheriadis, C; Embid, M; Fernández, R; Gálvez, J; García, J; Gelès, C; Giorni, A; González, E; González, O; Goulas, I; Heuer, R D; Hussonnois, M; Kadi, Y; Karaiskos, P; Kitis, G; Klapisch, Robert; Kokkas, P; Lacoste, V; Le Naour, C; Lèpez, C; Loiseaux, J M; Martínez-Val, J M; Méplan, O; Nifenecker, H; Oropesa, J; Papadopoulos, I M; Pavlopoulos, P; Pérez-Enciso, E; Pérez-Navarro, A; Perlado, M; Placci, A; Poza, M; Revol, Jean Pierre Charles; Rubbia, Carlo; Rubio, J A; Sakelliou, L; Saldaña, F; Savvidis, E; Schussler, F; Sirvent, C; Tamarit, J; Trubert, D; Tzima, A; Viano, J B; Vieira, S L; Vlachoudis, V; Zioutas, Konstantin; CERN. Geneva. SPS and LEP Division
2000-01-01
The results of the TARC experiment are summarized herewith, whose main purpose is to demonstrate the possibility of using Adiabatic Resonance Crossing (ARC) to destroy efficiently Long-Lived Fission Fragments (LLFFs) in accelerator-driven systems and to validate a new simulation developed in the framework of the Energy Amplifier programme. An experimental set-up was installed in a CERN PS proton beam line to study how neutrons, produced by spallation at relatively high energy (En * 1 MeV), slow down quasi adiabatically, with almost flat isolethargic energy distribution and reach the capture resonance energy of an element to be transmuted where they will have a high probability of being captured. Precision measurements of energy and space distributions of spallation neutrons (using 2.5 GeV/c and 3.5 GeV/c protons) slowing down in a 3.3 m x 3.3 m x 3 m lead volume and of neutron capture rates on LLFFs 99Tc, 129I, and several other elements were performed. An appropriate formalism and appropriate computational t...
Abánades, A; Andriamonje, Samuel A; Angelopoulos, Angelos; Apostolakis, Alcibiades J; Arnould, H; Belle, E; Bompas, C A; Brozzi, Delecurgo; Bueno, J; Buono, S; Carminati, F; Casagrande, Federico; Cennini, P; Collar, J I; Cerro, E; Del Moral, R; Díez, S; Dumps, Ludwig; Eleftheriadis, C; Embid, M; Fernández, R; Gálvez, J; García, J; Gelès, C; Giorni, A; González, E; González, O; Goulas, I; Heuer, R D; Hussonnois, M; Kadi, Y; Karaiskos, P; Kitis, G; Klapisch, Robert; Kokkas, P; Lacoste, V; Le Naour, C; López, C; Loiseaux, J M; Martínez-Val, J M; Méplan, O; Nifnecker, H; Oropesa, J; Papadopoulos, I M; Pavlopoulos, P; Pérez-Enciso, E; Pérez-Navarro, A; Perlado, M; Placci, Alfredo; Poza, M; Revol, Jean Pierre Charles; Rubbia, Carlo; Rubio, Juan Antonio; Sakelliou, L; Saldaña, F; Savvidis, E; Schussler, F; Sirvent, C; Tamarit, J; Trubert, D; Tzima, A; Viano, J B; Vieira, S L; Vlachoudis, V; Zioutas, Konstantin
2001-01-01
The Transmutation by Adiabatic Resonance Crossing (TARC) experiment was carried out as PS211 at the CERN PS from 1996 to 1999. Energy and space distributions of spallation neutrons (produced by 2.5 and 3.57 GeV/c CERN proton beams) slowing down in a 3.3*3.3*3 m/sup 3/ lead volume and neutron capture rates on long-lived fission fragments /sup 99/Tc and /sup 129/I demonstrate that Adiabatic Resonance Crossing (ARC) can be used to eliminate efficiently such nuclear waste and validate innovative simulation. (9 refs).
Abánades, A.; Aleixandre, J.; Andriamonje, S.; Angelopoulos, A.; Apostolakis, A.; Arnould, H.; Belle, E.; Bompas, C. A.; Brozzi, D.; Bueno, J.; Buono, S.; Carminati, F.; Casagrande, F.; Cennini, P.; Collar, J. I.; Cerro, E.; Del Moral, R.; Díez, S.; Dumps, L.; Eleftheriadis, C.; Embid, M.; Fernández, R.; Gálvez, J.; García, J.; Gelès, C.; Giorni, A.; González, E.; González, O.; Goulas, I.; Heuer, D.; Hussonnois, M.; Kadi, Y.; Karaiskos, P.; Kitis, G.; Klapisch, R.; Kokkas, P.; Lacoste, V.; Le Naour, C.; López, C.; Loiseaux, J. M.; Martínez-Val, J. M.; Méplan, O.; Nifenecker, H.; Oropesa, J.; Papadopoulos, I.; Pavlopoulos, P.; Pérez-Enciso, E.; Pérez-Navarro, A.; Perlado, M.; Placci, A.; Poza, M.; Revol, J.-P.; Rubbia, C.; Rubio, J. A.; Sakelliou, L.; Saldaña, F.; Savvidis, E.; Schussler, F.; Sirvent, C.; Tamarit, J.; Trubert, D.; Tzima, A.; Viano, J. B.; Vieira, S.; Vlachoudis, V.; Zioutas, K.
2002-02-01
We summarize here the results of the TARC experiment whose main purpose is to demonstrate the possibility of using Adiabatic Resonance Crossing (ARC) to destroy efficiently Long-Lived Fission Fragments (LLFFs) in accelerator-driven systems and to validate a new simulation developed in the framework of the Energy Amplifier programme. An experimental set-up was installed in a CERN PS proton beam line to study how neutrons produced by spallation at relatively high energy ( E n⩾1 MeV) slow down quasi-adiabatically with almost flat isolethargic energy distribution and reach the capture resonance energy of an element to be transmuted where they will have a high probability of being captured. Precision measurements of energy and space distributions of spallation neutrons (using 2.5 and 3.5 GeV/ c protons) slowing down in a 3.3 m×3.3 m×3 m lead volume and of neutron capture rates on LLFFs 99Tc, 129I, and several other elements were performed. An appropriate formalism and appropriate computational tools necessary for the analysis and understanding of the data were developed and validated in detail. Our direct experimental observation of ARC demonstrates the possibility to destroy, in a parasitic mode, outside the Energy Amplifier core, large amounts of 99Tc or 129I at a rate exceeding the production rate, thereby making it practical to reduce correspondingly the existing stockpile of LLFFs. In addition, TARC opens up new possibilities for radioactive isotope production as an alternative to nuclear reactors, in particular for medical applications, as well as new possibilities for neutron research and industrial applications.
Adiabatic resonant oscillations of solar neutrinos in three generations
International Nuclear Information System (INIS)
Kim, C.W.; Sze, W.K.
1987-01-01
The Mikheyev-Smirnov-Wolfenstein model of resonant solar-neutrino oscillations is discussed for three generations of leptons. Assuming adiabatic transitions, bounds for the μ- and e-neutrinos mass-squared difference Δ/sub 21,0/ are obtained as a function of the e-μ mixing angle theta 1 . The allowed region in the Δ/sub 21,0/-theta 1 plot that would solve the solar-neutrino problem is shown to be substantially larger than that of the two-generation case. In particular, the difference between the two- and three-generation cases becomes significant for theta 1 larger than --20 0
International Nuclear Information System (INIS)
Abánades, A.; Álvarez-Velarde, F.; González-Romero, E.M.; Ismailov, K.; Lafuente, A.; Nishihara, K.; Saito, M.; Stanculescu, A.; Sugawara, T.
2013-01-01
Highlights: ► TARC experiment benchmark capture rates results. ► Utilization of updated databases, included ADSLib. ► Self-shielding effect in reactor design for transmutation. ► Effect of Lead nuclear data. - Abstract: The design of Accelerator Driven Systems (ADS) requires the development of simulation tools that are able to describe in a realistic way their nuclear performance and transmutation rate capability. In this publication, we present an evaluation of state of the art Monte Carlo design tools to assess their performance concerning transmutation of long-lived fission products. This work, performed under the umbrella of the International Atomic Energy Agency, analyses two important aspects for transmutation systems: moderation on Lead and neutron captures of 99 Tc, 127 I and 129 I. The analysis of the results shows how shielding effects due to the resonances at epithermal energies of these nuclides affects strongly their transmutation rate. The results suggest that some research effort should be undertaken to improve the quality of Iodine nuclear data at epithermal and fast neutron energy to obtain a reliable transmutation estimation.
Energy Technology Data Exchange (ETDEWEB)
Abanades, A., E-mail: abanades@etsii.upm.es [Grupo de Modelizacion de Sistemas Termoenergeticos, ETSII, Universidad Politecnica de Madrid, c/Ramiro de Maeztu, 7, 28040 Madrid (Spain); Alvarez-Velarde, F.; Gonzalez-Romero, E.M. [Centro de Investigaciones Medioambientales y Tecnologicas (CIEMAT), Avda. Complutense, 40, Ed. 17, 28040 Madrid (Spain); Ismailov, K. [Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8550 (Japan); Lafuente, A. [Grupo de Modelizacion de Sistemas Termoenergeticos, ETSII, Universidad Politecnica de Madrid, c/Ramiro de Maeztu, 7, 28040 Madrid (Spain); Nishihara, K. [Transmutation Section, J-PARC Center, JAEA, Tokai-mura, Ibaraki-ken 319-1195 (Japan); Saito, M. [Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8550 (Japan); Stanculescu, A. [International Atomic Energy Agency (IAEA), Vienna (Austria); Sugawara, T. [Transmutation Section, J-PARC Center, JAEA, Tokai-mura, Ibaraki-ken 319-1195 (Japan)
2013-01-15
Highlights: Black-Right-Pointing-Pointer TARC experiment benchmark capture rates results. Black-Right-Pointing-Pointer Utilization of updated databases, included ADSLib. Black-Right-Pointing-Pointer Self-shielding effect in reactor design for transmutation. Black-Right-Pointing-Pointer Effect of Lead nuclear data. - Abstract: The design of Accelerator Driven Systems (ADS) requires the development of simulation tools that are able to describe in a realistic way their nuclear performance and transmutation rate capability. In this publication, we present an evaluation of state of the art Monte Carlo design tools to assess their performance concerning transmutation of long-lived fission products. This work, performed under the umbrella of the International Atomic Energy Agency, analyses two important aspects for transmutation systems: moderation on Lead and neutron captures of {sup 99}Tc, {sup 127}I and {sup 129}I. The analysis of the results shows how shielding effects due to the resonances at epithermal energies of these nuclides affects strongly their transmutation rate. The results suggest that some research effort should be undertaken to improve the quality of Iodine nuclear data at epithermal and fast neutron energy to obtain a reliable transmutation estimation.
Adiabatic theory of Wannier threshold laws and ionization cross sections
International Nuclear Information System (INIS)
Macek, J.H.; Ovchinnikov, S.Y.
1994-01-01
Adiabatic energy eigenvalues of H 2 + are computed for complex values of the internuclear distance R. The infinite number of bound-state eigenenergies are represented by a function ε(R) that is single valued on a multisheeted Riemann surface. A region is found where ε(R) and the corresponding eigenfunctions exhibit harmonic-oscillator structure characteristic of electron motion on a potential saddle. The Schroedinger equation is solved in the adiabatic approximation along a path in the complex R plane to compute ionization cross sections. The cross section thus obtained joins the Wannier threshold region with the keV energy region, but the exponent near the ionization threshold disagrees with well-accepted values. Accepted values are obtained when a lowest-order diabatic correction is employed, indicating that adiabatic approximations do not give the correct zero velocity limit for ionization cross sections. Semiclassical eigenvalues for general top-of-barrier motion are given and the theory is applied to the ionization of atomic hydrogen by electron impact. The theory with a first diabatic correction gives the Wannier threshold law even for this case
International Nuclear Information System (INIS)
Collins, T.
1985-08-01
A simple criterion governs the beam distortion and/or loss of protons on a fast resonance crossing. Results from numerical integrations are illustrated for simple sextupole, octupole, and 10-pole resonances
Energy Technology Data Exchange (ETDEWEB)
Collins, T.
1985-08-01
A simple criterion governs the beam distortion and/or loss of protons on a fast resonance crossing. Results from numerical integrations are illustrated for simple sextupole, octupole, and 10-pole resonances.
Adiabatic theory of nonlinear electron cyclotron resonance heating
International Nuclear Information System (INIS)
Kotel'nikov, I.A.; Stupakov, G.V.
1989-01-01
Plasma heating at electron frequency by an ordinary wave propagating at right angle to unidirectional magnetic field is treated. Injected microwave power is assumed to be so large that relativistic change of electron gyrofrequency during one flight thorugh the wave beam is much greater than inverse time of flight. The electron motion in the wave field is described using Hamiltonian formalism in adiabatic approximation. It is shown that energy coupling from the wave to electrons is due to a bifurcation of electron trajectory which results in a jumpm of the adiabatic invariant. The probability of bifurcational transition from one trajectory to another is calculated analytically and is used for the estimation of the beam power absorbed in plasma. 6 refs.; 2 figs
Cross-polarization phenomena in the NMR of fast spinning solids subject to adiabatic sweeps
Energy Technology Data Exchange (ETDEWEB)
Wi, Sungsool, E-mail: sungsool@magnet.fsu.edu, E-mail: lucio.frydman@weizmann.ac.il; Gan, Zhehong [National High Magnetic Field Laboratory, Tallahassee, Florida 32304 (United States); Schurko, Robert [Department of Chemistry and Biochemistry, University of Windsor, 401 Sunset Avenue, Windsor N9B 3P4, Ontario (Canada); Frydman, Lucio, E-mail: sungsool@magnet.fsu.edu, E-mail: lucio.frydman@weizmann.ac.il [National High Magnetic Field Laboratory, Tallahassee, Florida 32304 (United States); Department of Chemical Physics, Weizmann Institute of Sciences, 76100 Rehovot (Israel)
2015-02-14
Cross-polarization magic-angle spinning (CPMAS) experiments employing frequency-swept pulses are explored within the context of obtaining broadband signal enhancements for rare spin S = 1/2 nuclei at very high magnetic fields. These experiments employ adiabatic inversion pulses on the S-channel ({sup 13}C) to cover a wide frequency offset range, while simultaneously applying conventional spin-locking pulse on the I-channel ({sup 1}H). Conditions are explored where the adiabatic frequency sweep width, Δν, is changed from selectively irradiating a single magic-angle-spinning (MAS) spinning centerband or sideband, to sweeping over multiple sidebands. A number of new physical features emerge upon assessing the swept-CP method under these conditions, including multiple zero- and double-quantum CP transfers happening in unison with MAS-driven rotary resonance phenomena. These were examined using an average Hamiltonian theory specifically designed to tackle these experiments, with extensive numerical simulations, and with experiments on model compounds. Ultrawide CP profiles spanning frequency ranges of nearly 6⋅γB{sub 1}{sup s} were predicted and observed utilizing this new approach. Potential extensions and applications of this extremely broadband transfer conditions are briefly discussed.
Modification of optical properties by adiabatic shifting of resonances in a four-level atom
Dutta, Bibhas Kumar; Panchadhyayee, Pradipta
2018-04-01
We describe the linear and nonlinear optical properties of a four-level atomic system, after reducing it to an effective two-level atomic model under the condition of adiabatic shifting of resonances driven by two coherent off-resonant fields. The reduced form of the Hamiltonian corresponding to the two-level system is obtained by employing an adiabatic elimination procedure in the rate equations of the probability amplitudes for the proposed four-level model. For a weak probe field operating in the system, the nonlinear dependence of complex susceptibility on the Rabi frequencies and the detuning parameters of the off-resonant driving fields makes it possible to exhibit coherent control of single-photon and two-photon absorption and transparency, the evolution of enhanced Self-Kerr nonlinearity and noticeable dispersive switching. We have shown how the quantum interference results in the generic four-level model at the adiabatic limit. The present scheme describes the appearance of single-photon transparency without invoking any exact two-photon resonance.
Tiwari, Vivek; Peters, William K.; Jonas, David M.
2017-10-01
Non-adiabatic vibrational-electronic resonance in the excited electronic states of natural photosynthetic antennas drastically alters the adiabatic framework, in which electronic energy transfer has been conventionally studied, and suggests the possibility of exploiting non-adiabatic dynamics for directed energy transfer. Here, a generalized dimer model incorporates asymmetries between pigments, coupling to the environment, and the doubly excited state relevant for nonlinear spectroscopy. For this generalized dimer model, the vibrational tuning vector that drives energy transfer is derived and connected to decoherence between singly excited states. A correlation vector is connected to decoherence between the ground state and the doubly excited state. Optical decoherence between the ground and singly excited states involves linear combinations of the correlation and tuning vectors. Excitonic coupling modifies the tuning vector. The correlation and tuning vectors are not always orthogonal, and both can be asymmetric under pigment exchange, which affects energy transfer. For equal pigment vibrational frequencies, the nonadiabatic tuning vector becomes an anti-correlated delocalized linear combination of intramolecular vibrations of the two pigments, and the nonadiabatic energy transfer dynamics become separable. With exchange symmetry, the correlation and tuning vectors become delocalized intramolecular vibrations that are symmetric and antisymmetric under pigment exchange. Diabatic criteria for vibrational-excitonic resonance demonstrate that anti-correlated vibrations increase the range and speed of vibronically resonant energy transfer (the Golden Rule rate is a factor of 2 faster). A partial trace analysis shows that vibronic decoherence for a vibrational-excitonic resonance between two excitons is slower than their purely excitonic decoherence.
Directory of Open Access Journals (Sweden)
Jeong Ryeol Choi
2015-01-01
Full Text Available An adiabatic invariant, which is a conserved quantity, is useful for studying quantum and classical properties of dynamical systems. Adiabatic invariants for time-dependent superconducting qubit-oscillator systems and resonators are investigated using the Liouville-von Neumann equation. At first, we derive an invariant for a simple superconducting qubit-oscillator through the introduction of its reduced Hamiltonian. Afterwards, an adiabatic invariant for a nanomechanical resonator linearly interfaced with a superconducting circuit, via a coupling with a time-dependent strength, is evaluated using the technique of unitary transformation. The accuracy of conservation for such invariant quantities is represented in detail. Based on the results of our developments in this paper, perturbation theory is applicable to the research of quantum characteristics of more complicated qubit systems that are described by a time-dependent Hamiltonian involving nonlinear terms.
Adiabatic Siberian snake turn-on and acceleration through depolarizing resonances
International Nuclear Information System (INIS)
Koulsha, A.V.; Anferov, V.A.; Baiod, R.
1993-01-01
The authors plan to install in the IUCF Cooler Ring a rampable partial (30%) Siberian snake to test if the spin polarization is preserved during adiabatic turn-on. They also plan to use this ramped snake to accelerate polarized protons to 370 MeV while passing through two depolarizing resonances. The Siberian snake will consist of two small rampable warm solenoids placed symmetrically on either side of the exciting cold 2 T·m solenoid which would run dc at about 0.5 T·m. Ramping each warm magnet from about -0.25T·m to + 0.25 T·m. Recent experiments showed that turning on the snake in 100 msec at 370 MeV causes no serious beam loss
Wave emission by resonance crossing
International Nuclear Information System (INIS)
Tracy, E.R.; Kaufman, A.N.; Liang, Y.
1995-01-01
The emission of collective waves by a moving charged particle in a nonuniform medium is discussed. Emission occurs in a nonuniform medium when the local dispersion relation of the collective wave is satisfied. This is a form of resonance crossing. Using the Weyl symbol calculus, a local expansion of the collective wave equation driven by the particle source is derived in the neighborhood of the crossing. The collective wave dispersion manifold and the gyroballistic wave dispersion manifold can be used as a pair of local coordinates in the neighborhood of the resonance crossing, which greatly simplifies the analysis. This change of representation is carried out using a metaplectic transform (a generalization of the fourier transform). The Wigner function of the emitted wave field is then computed in the new coordinates. The Wigner function is a phase space scalar, hence the numerical value is invariant under linear canonical transformations. This invariance is invoked to finally arrive at the Wigner function in the original (physical) coordinates. The wave-action and -energy emission rates are then computed from the Wigner function. copyright 1995 American Institute of Physics
International Nuclear Information System (INIS)
Cohen, J.S.; Struensee, M.C.
1991-01-01
The improved adiabatic representation is used in calculations of elastic and isotopic-exchange cross sections for asymmetric collisions of pμ, dμ, and tμ with bare p, d, and t nuclei and with H, D, and T atoms. This formulation dissociates properly, correcting a well-known deficiency of the standard adiabatic method for muonic-atom collisions, and includes some effects at zeroth order that are normally considered nonadiabatic. The electronic screening is calculated directly and precisely within the improved adiabatic description; it is found to be about 30% smaller in magnitude than the previously used value at large internuclear distances and to deviate considerably from the asymptotic form at small distances. The reactance matrices, needed for calculations of molecular-target effects, are given in tables
Baranowski, M; Woźniak-Braszak, A; Jurga, K
2016-01-01
The paper presents the benefits of using fast adiabatic passage for the study of molecular dynamics in the solid state heteronuclear systems in the laboratory frame. A homemade pulse spectrometer operating at the frequency of 30.2MHz and 28.411MHz for protons and fluorines, respectively, has been enhanced with microcontroller direct digital synthesizer DDS controller [1-4]. This work briefly describes how to construct a low-cost and easy-to-assemble adiabatic extension set for homemade and commercial spectrometers based on recently very popular Arduino shields. The described set was designed for fast adiabatic generation. Timing and synchronization problems are discussed. The cross-relaxation experiments with different initial states of the two spin systems have been performed. Contrary to our previous work [5] where the steady-state NOE experiments were conducted now proton spins (1)H are polarized in the magnetic field B0 while fluorine spins (19)F are perturbed by selective saturation for a short time and then the system is allowed to evolve for a period in the absence of a saturating field. The adiabatic passage application leads to a reversal of magnetization of fluorine spins and increases the amplitude of the signal. Copyright © 2015 Elsevier Inc. All rights reserved.
Calculation of the resonance cross section functions
International Nuclear Information System (INIS)
Slipicevic, K.F.
1967-11-01
This paper includes the procedure for calculating the Doppler broadened line shape functions ψ and χ which are needed for calculation of resonance cross section functions. The obtained values are given in tables
Calculation of the resonance cross section functions
Energy Technology Data Exchange (ETDEWEB)
Slipicevic, K F [Institute of nuclear sciences Boris Kidric, Vinca, Beograd (Yugoslavia)
1967-11-15
This paper includes the procedure for calculating the Doppler broadened line shape functions {psi} and {chi} which are needed for calculation of resonance cross section functions. The obtained values are given in tables.
Topology of the Adiabatic Potential Energy Surfaces for theResonance States of the Water Anion
Energy Technology Data Exchange (ETDEWEB)
Haxton, Daniel J.; Rescigno, Thomas N.; McCurdy, C. William
2005-04-15
The potential energy surfaces corresponding to the long-lived fixed-nuclei electron scattering resonances of H{sub 2}O relevant to the dissociative electron attachment process are examined using a combination of ab initio scattering and bound-state calculations. These surfaces have a rich topology, characterized by three main features: a conical intersection between the {sup 2}A{sub 1} and {sup 2}B{sub 2} Feshbach resonance states; charge-transfer behavior in the OH ({sup 2}{Pi}) + H{sup -} asymptote of the {sup 2}B{sub 1} and {sup 2}A{sub 1} resonances; and an inherent double-valuedness of the surface for the {sup 2}B{sub 2} state the C{sub 2v} geometry, arising from a branch-point degeneracy with a {sup 2}B{sub 2} shape resonance. In total, eight individual seams of degeneracy among these resonances are located.
Tiwari, Vivek; Jonas, David M.
2018-02-01
Vibrational-electronic resonance in photosynthetic pigment-protein complexes invalidates Förster's adiabatic framework for interpreting spectra and energy transfer, thus complicating determination of how the surrounding protein affects pigment properties. This paper considers the combined effects of vibrational-electronic resonance and inhomogeneous variations in the electronic excitation energies of pigments at different sites on absorption, emission, circular dichroism, and hole-burning spectra for a non-degenerate homodimer. The non-degenerate homodimer has identical pigments in different sites that generate differences in electronic energies, with parameters loosely based on bacteriochlorophyll a pigments in the Fenna-Matthews-Olson antenna protein. To explain the intensity borrowing, the excited state vibrational-electronic eigenvectors are discussed in terms of the vibrational basis localized on the individual pigments, as well as the correlated/anti-correlated vibrational basis delocalized over both pigments. Compared to those in the isolated pigment, vibrational satellites for the correlated vibration have the same frequency and precisely a factor of 2 intensity reduction through vibrational delocalization in both absorption and emission. Vibrational satellites for anti-correlated vibrations have their relaxed emission intensity reduced by over a factor 2 through vibrational and excitonic delocalization. In absorption, anti-correlated vibrational satellites borrow excitonic intensity but can be broadened away by the combination of vibronic resonance and site inhomogeneity; in parallel, their vibronically resonant excitonic partners are also broadened away. These considerations are consistent with photosynthetic antenna hole-burning spectra, where sharp vibrational and excitonic satellites are absent. Vibrational-excitonic resonance barely alters the inhomogeneously broadened linear absorption, emission, and circular dichroism spectra from those for a
Integrated phononic crystal resonators based on adiabatically-terminated phononic crystal waveguides
Directory of Open Access Journals (Sweden)
Razi Dehghannasiri
2016-12-01
Full Text Available In this letter, we demonstrate a new design for integrated phononic crystal (PnC resonators based on confining acoustic waves in a heterogeneous waveguide-based PnC structure. In this architecture, a PnC waveguide that supports a single mode at the desired resonance frequencies is terminated by two waveguide sections with no propagating mode at those frequencies (i.e., have mode gap. The proposed PnC resonators are designed through combining the spatial-domain and the spatial-frequency domain (i.e., the k-domain analysis to achieve a smooth mode envelope. This design approach can benefit both membrane-based and surface-acoustic-wave-based architectures by confining the mode spreading in k-domain that leads to improved electromechanical excitation/detection coupling and reduced loss through propagating bulk modes.
Thurber, Kent R; Tycko, Robert
2012-08-28
We present theoretical calculations of dynamic nuclear polarization (DNP) due to the cross effect in nuclear magnetic resonance under magic-angle spinning (MAS). Using a three-spin model (two electrons and one nucleus), cross effect DNP with MAS for electron spins with a large g-anisotropy can be seen as a series of spin transitions at avoided crossings of the energy levels, with varying degrees of adiabaticity. If the electron spin-lattice relaxation time T(1e) is large relative to the MAS rotation period, the cross effect can happen as two separate events: (i) partial saturation of one electron spin by the applied microwaves as one electron spin resonance (ESR) frequency crosses the microwave frequency and (ii) flip of all three spins, when the difference of the two ESR frequencies crosses the nuclear frequency, which transfers polarization to the nuclear spin if the two electron spins have different polarizations. In addition, adiabatic level crossings at which the two ESR frequencies become equal serve to maintain non-uniform saturation across the ESR line. We present analytical results based on the Landau-Zener theory of adiabatic transitions, as well as numerical quantum mechanical calculations for the evolution of the time-dependent three-spin system. These calculations provide insight into the dependence of cross effect DNP on various experimental parameters, including MAS frequency, microwave field strength, spin relaxation rates, hyperfine and electron-electron dipole coupling strengths, and the nature of the biradical dopants.
Artemyev, A V; Neishtadt, A I; Zelenyi, L M; Vainchtein, D L
2010-12-01
We present an analytical and numerical study of the surfatron acceleration of nonrelativistic charged particles by electromagnetic waves. The acceleration is caused by capture of particles into resonance with one of the waves. We investigate capture for systems with one or two waves and provide conditions under which the obtained results can be applied to systems with more than two waves. In the case of a single wave, the once captured particles never leave the resonance and their velocity grows linearly with time. However, if there are two waves in the system, the upper bound of the energy gain may exist and we find the analytical value of that bound. We discuss several generalizations including the relativistic limit, different wave amplitudes, and a wide range of the waves' wavenumbers. The obtained results are used for qualitative description of some phenomena observed in the Earth's magnetosphere. © 2010 American Institute of Physics.
Multilevel parametrization of fissile nuclei resonance cross sections
International Nuclear Information System (INIS)
Lukyanov, A.A.; Kolesov, V.V.; Janeva, N.
1987-01-01
Because the resonance interference has an important influence on the resonance structure of neutron cross sections energy dependence at lowest energies, multilevel scheme of the cross section parametrization which take into account the resonance interference is used for the description with the same provisions in the regions of the interferential maximum and minimum of the resonance cross sections of the fissile nuclei
Wireless adiabatic power transfer
International Nuclear Information System (INIS)
Rangelov, A.A.; Suchowski, H.; Silberberg, Y.; Vitanov, N.V.
2011-01-01
Research highlights: → Efficient and robust mid-range wireless energy transfer between two coils. → The adiabatic energy transfer is analogous to adiabatic passage in quantum optics. → Wireless energy transfer is insensitive to any resonant constraints. → Wireless energy transfer is insensitive to noise in the neighborhood of the coils. - Abstract: We propose a technique for efficient mid-range wireless power transfer between two coils, by adapting the process of adiabatic passage for a coherently driven two-state quantum system to the realm of wireless energy transfer. The proposed technique is shown to be robust to noise, resonant constraints, and other interferences that exist in the neighborhood of the coils.
Partial cross sections near the higher resonances
International Nuclear Information System (INIS)
Falk-Vairant, P.; Valladas, G.
1961-07-01
As a continuation of the report given at the 10. Rochester Conference, recent measurements of charge-exchange cross section and π 0 production in π - -p interactions are presented here. Section 1 gives a summary of the known results for the elastic, inelastic, and charge-exchange cross sections. Section 2 presents the behavior of the cross sections in the T=1/2 state, in order to discuss the resonances at 600 and 890 MeV. Section 3 discusses the charge-exchange scattering and the interference term between the T=1/2 and T=3/2 states. Section 4 presents some comments on inelastic processes. This report is reprinted from 'Reviews of Modern Physics', Vol. 33, No. 3, 362-367, July, 1961
New resonance cross section calculational algorithms
International Nuclear Information System (INIS)
Mathews, D.R.
1978-01-01
Improved resonance cross section calculational algorithms were developed and tested for inclusion in a fast reactor version of the MICROX code. The resonance energy portion of the MICROX code solves the neutron slowing-down equations for a two-region lattice cell on a very detailed energy grid (about 14,500 energies). In the MICROX algorithms, the exact P 0 elastic scattering kernels are replaced by synthetic (approximate) elastic scattering kernels which permit the use of an efficient and numerically stable recursion relation solution of the slowing-down equation. In the work described here, the MICROX algorithms were modified as follows: an additional delta function term was included in the P 0 synthetic scattering kernel. The additional delta function term allows one more moments of the exact elastic scattering kernel to be preserved without much extra computational effort. With the improved synthetic scattering kernel, the flux returns more closely to the exact flux below a resonance than with the original MICROX kernel. The slowing-down calculation was extended to a true B 1 hyperfine energy grid calculatn in each region by using P 1 synthetic scattering kernels and tranport-corrected P 0 collision probabilities to couple the two regions. 1 figure, 6 tables
International Nuclear Information System (INIS)
Zandomeneghi, Giorgia; Meier, Beat H.
2004-01-01
Structural information can be extracted from one-bond residual dipolar couplings (RDC) measured in NMR spectra of systems in field-ordered media. RDC can be on the order of J-couplings if the anisotropy of alignment is ∼ 10 -2 , 10-fold stronger than that typically used for structural studies of water-soluble proteins. In such systems the performance of 1 H → 15 N polarization transfer methods of the INEPT type is not satisfactory. In this study we show the effectiveness of adiabatic-passage cross-polarization (APCP) in transferring the 1 H → 15 N polarization in the bicelle-associated peptide Leucine Enkephalin (Lenk). APCP is efficient both in static samples and in samples spun at the magic angle (MAS) or any other angle of the spinning axis to the magnetic field (variable-angle spinning, VAS). The anisotropic spectrum of an aligned static sample and the isotropic spectrum of the sample under MAS provide a set of possible values for the 1 H- 15 N RDC of phospholipid-associated Lenk. The unambiguous determination of the 1 H- 15 N RDC was accomplished by means of VAS experiments
International Nuclear Information System (INIS)
Du Luchun; Mei Dongcheng
2011-01-01
The non-adiabatic regime of stochastic resonance (SR) in a bistable system with time delay, an additive white noise and a periodic signal was investigated. The signal power amplification η was employed to characterize the SR of the system. The simulation results indicate that (i) in the case of intermediate frequency Ω of the periodic signal, the typical behavior of SR is lowered monotonically by increasing the delay time τ; in the case of large Ω, τ weakens the SR behavior and then enhances it, with a non-monotonic behavior as a function of time delay; (ii) time delay induces SR when A is above the threshold, whereas no such resonance exists in the absence of time delay; (iii) time delay induces a transition from bimodal to unimodal configuration of η; (iv) varying the particular form of time delay results in different phenomena.
Resonance capture cross section of 207Pb
Domingo-Pardo, C.; Aerts, G.; Alvarez-Pol, H.; Alvarez-Velarde, F.; Andriamonje, S.; Andrzejewski, J.; Assimakopoulos, P.; Audouin, L.; Badurek, G.; Baumann, P.; Becvar, F.; Berthoumieux, E.; Bisterzo, S.; Calvino, F.; Cano-Ott, D.; Capote, R.; Carrapico, C.; Cennini, P.; Chepel, V.; Chiaveri, E.; Colonna, N.; Cortes, G.; Couture, A.; Cox, J.; Dahlfors, M.; David, S.; Dillman, I.; Dolfini, R.; Dridi, W.; Duran, I.; Eleftheriadis, C.; Embid-Segura, M.; Ferrant, L.; Ferrari, A.; Ferreira-Marques, R.; Fitzpatrick, L.; Frais-Koelbl, H.; Fujii, K.; Furman, W.; Gallino, R.; Goncalves, I.; Gonzalez-Romero, E.; Goverdovski, A.; Gramegna, F.; Griesmayer, E.; Guerrero, C.; Gunsing, F.; Haas, B.; Haight, R.; Heil, M.; Herrera-Martinez, A.; Igashira, M.; Isaev, S.; Jericha, E.; Kadi, Y.; Kappeler, F.; Karamanis, D.; Karadimos, D.; Kerveno, M.; Ketlerov, V.; Koehler, P.; Konovalov, V.; Kossionides, E.; Krticka, M.; Lamboudis, C.; Leeb, H.; Lindote, A.; Lopes, I.; Lozano, M.; Lukic, S.; Marganiec, J.; Marrone, S.; Mastinu, P.; Mengoni, A.; Milazzo, P.M.; Moreau, C.; Mosconi, M.; Neves, F.; Oberhummer, H.; Oshima, M.; O'Brien, S.; Pancin, J.; Papachristodoulou, C.; Papadopoulos, C.; Paradela, C.; Patronis, N.; Pavlik, A.; Pavlopoulos, P.; Perrot, L.; Plag, R.; Plompen, A.; Plukis, A.; Poch, A.; Pretel, C.; Quesada, J.; Rauscher, T.; Reifarth, R.; Rosetti, M.; Rubbia, C.; Rudolf, G.; Rullhusen, P.; Salgado, J.; Sarchiapone, L.; Savvidis, I.; Stephan, C.; Tagliente, G.; Tain, J.L.; Tassan-Got, L.; Tavora, L.; Terlizzi, R.; Vannini, G.; Vaz, P.; Ventura, A.; Villamarin, D.; Vincente, M.C.; Vlachoudis, V.; Vlastou, R.; Voss, F.; Walter, S.; Wendler, H.; Wiescher, M.; Wisshak, K.
2006-01-01
The radiative neutron capture cross section of 207Pb has been measured at the CERN neutron time of flight installation n_TOF using the pulse height weighting technique in the resolved energy region. The measurement has been performed with an optimized setup of two C6D6 scintillation detectors, which allowed us to reduce scattered neutron backgrounds down to a negligible level. Resonance parameters and radiative kernels have been determined for 16 resonances by means of an R-matrix analysis in the neutron energy range from 3 keV to 320 keV. Good agreement with previous measurements was found at low neutron energies, whereas substantial discrepancies appear beyond 45 keV. With the present results, we obtain an s-process contribution of 77(8)% to the solar abundance of 207Pb. This corresponds to an r-process component of 23(8)%, which is important for deriving the U/Th ages of metal poor halo stars.
Single-level resonance parameters fit nuclear cross-sections
Drawbaugh, D. W.; Gibson, G.; Miller, M.; Page, S. L.
1970-01-01
Least squares analyses of experimental differential cross-section data for the U-235 nucleus have yielded single level Breit-Wigner resonance parameters that fit, simultaneously, three nuclear cross sections of capture, fission, and total.
An assessment of the Crossed Porro Prism Resonator
See, B. A.; Fueloep, K.; Seymour, R.
1980-08-01
Lasers with crossed porro prism resonators for military laser rangefinder and designator applications are studied. Properties of these devices are reviewed and advantages over normal mirror resonators are examined. The theory of operating is treated and the mechanical stability and other features of the laser are examined and compared to standard mirror resonators.
Kittell, Aaron W.; Camenisch, Theodore G.; Ratke, Joseph J.; Sidabras, Jason W.; Hyde, James S.
2011-01-01
A continuous wave (CW) electron paramagnetic resonance (EPR) spectrum is typically displayed as the first harmonic response to the application of 100 kHz magnetic field modulation, which is used to enhance sensitivity by reducing the level of 1/f noise. However, magnetic field modulation of any amplitude causes spectral broadening and sacrifices EPR spectral intensity by at least a factor of two. In the work presented here, a CW rapid-scan spectroscopic technique that avoids these compromises and also provides a means of avoiding 1/f noise is developed. This technique, termed non-adiabatic rapid sweep (NARS) EPR, consists of repetitively sweeping the polarizing magnetic field in a linear manner over a spectral fragment with a small coil at a repetition rate that is sufficiently high that receiver noise, microwave phase noise, and environmental microphonics, each of which has 1/f characteristics, are overcome. Nevertheless, the rate of sweep is sufficiently slow that adiabatic responses are avoided and the spin system is always close to thermal equilibrium. The repetitively acquired spectra from the spectral fragment are averaged. Under these conditions, undistorted pure absorption spectra are obtained without broadening or loss of signal intensity. A digital filter such as a moving average is applied to remove high frequency noise, which is approximately equivalent in bandwidth to use of an integrating time constant in conventional field modulation with lock-in detection. Nitroxide spectra at L- and X-band are presented. PMID:21741868
Kittell, Aaron W.; Hustedt, Eric J.; Hyde, James S.
2014-01-01
Site-directed spin-labeling electron paramagnetic resonance (SDSL EPR) provides insight into the local structure and motion of a spin probe strategically attached to a molecule. When a second spin is introduced to the system, macromolecular information can be obtained through measurement of inter-spin distances either by continuous wave (CW) or pulsed electron double resonance (ELDOR) techniques. If both methodologies are considered, inter-spin distances of 8 to 80 Å can be experimentally determined. However, there exists a region at the upper limit of the conventional X-band (9.5 GHz) CW technique and the lower limit of the four-pulse double electron-electron resonance (DEER) experiment where neither method is particularly reliable. The work presented here utilizes L-band (1.9 GHz) in combination with non-adiabatic rapid sweep (NARS) EPR to address this opportunity by increasing the upper limit of the CW technique. Because L-band linewidths are three to seven times narrower than those at X-band, dipolar broadenings that are small relative to the X-band inhomogeneous linewidth become observable, but the signal loss due to the frequency dependence of the Boltzmann factor, has made L-band especially challenging. NARS has been shown to increase sensitivity by a factor of five, and overcomes much of this loss, making L-band distance determination more feasible [1]. Two different systems are presented and distances of 18–30 Å have been experimentally determined at physiologically relevant temperatures. Measurements are in excellent agreement with a helical model and values determined by DEER. PMID:22750251
Theory of neutron resonance cross sections for safety applications
International Nuclear Information System (INIS)
Froehner, F.H.
1992-09-01
Neutron resonances exert a strong influence on the behaviour of nuclear reactors, especially on their response to the temperature changes accompanying power excursions, and also on the efficiency of shielding materials. The relevant theory of neutron resonance cross sections including the practically important approximations is reviewed, both for the resolved and the unresolved resonance region. Numerical techniques for Doppler broadening of resonances are presented, and the construction of group constants and especially of self-shielding factors for neutronics calculations is outlined. (orig.) [de
International Nuclear Information System (INIS)
Barois, Guy
1969-01-01
This research thesis aims at being a contribution to a better knowledge of the expansion process in a flow, by studying the formation of vapour in an upward adiabatic vertical flow. This self-evaporation occurs in a duct with a large cross section (10 x 10 cm) in order to make neglectable pressure losses due to friction on the wall with respect to other pressure losses. After a presentation of the characteristics of the experimental installation, the author describes the flow, outlines the influence of dissolved air on vapour bubble nucleation. He describes the method used to measure the difference between the liquid temperature and that it would have had in thermal equilibrium under a vapour pressure equal to the cross section static pressure. Different theoretical analytical studies proposed by other authors are presented, and the author proposes a model for the calculation of pressure loss associated with this self-evaporation [fr
Neutron cross sections in the unresolved resonance region
International Nuclear Information System (INIS)
Janeva, N.; Lukyanov, A.; Koyumdjieva, N.; Volev, K.
2005-01-01
In this work a development of the characteristic function model, created to reveal the resonance cross section structure in the unresolved resonance region is presented. The main advantage of this model is the calculation of resonance averaged self-shielding factors analytically. To determine average values of the cross sections and their functionals the function of joint statistical distribution of the R-matrix real and imaginary parts should be used. The characteristic function of such distribution is determined and the resonance ladder for the unresolved region is optimized to calculate the group averaged functionals in the same way as it is in the resolved resonance region. The main advantage of this model is the calculation of resonance averaged self-shielding factors analytically. The neutron width energy dependence leads to some deformation in the shape of resonances. This deformation is most apparent near the inelastic scattering threshold. For the case when the inelastic channel momentum is zero we present the formula for level shape bellow and over the inelastic threshold and the calculated resonance deformation in dependence of the position of the resonance in respect to the threshold. (authors)
Experimental study of resonance crossing with a Paul trap
Directory of Open Access Journals (Sweden)
H. Takeuchi
2012-07-01
Full Text Available The effect of resonance crossing on beam stability is studied systematically by employing a novel tabletop experimental tool and a multiparticle simulation code. A large number of ions are confined in a compact linear Paul trap to reproduce the collective beam behavior. We can prove that the ion plasma in the trap is physically equivalent to a charged-particle beam propagating through a strong focusing channel. The plasma confinement force is quickly ramped such that the trap operating point traverses linear and nonlinear resonance stop bands. Assuming a nonscaling fixed field alternating gradient accelerator composed of many identical FODO cells, we measure how much ion losses occur under diverse conditions. It is experimentally and numerically demonstrated that too slow resonance crossing leads to significant ion losses as expected. Particular attention must be paid to the linear coherent resonance excited at a quarter-integer tune. When the beam intensity is high, this type of linear stop band can seriously affect the beam quality even for rather fast resonance crossing. A scaling law is given of the emittance growth caused by the quarter-integer resonance crossing.
Capture cross section and resonance parameters of thulium-169
International Nuclear Information System (INIS)
Arbo, J.C.; Felvinci, J.P.; Melkonian, E.; Havens, W.W. Jr.
1975-01-01
The previously analyzed energy range for thulium capture resonance parameters is extended from 1 keV to 2 keV. In addition, point and group averaged thulium cross section curves are extended to above 2 keV and 181 Ta impurity levels are discussed. (SDF)
Resonance circuits for adiabatic circuits
Directory of Open Access Journals (Sweden)
C. Schlachta
2003-01-01
Full Text Available One of the possible techniques to reduces the power consumption in digital CMOS circuits is to slow down the charge transport. This slowdown can be achieved by introducing an inductor in the charging path. Additionally, the inductor can act as an energy storage element, conserving the energy that is normally dissipated during discharging. Together with the parasitic capacitances from the circuit a LCresonant circuit is formed.
Modeling laser brightness from cross Porro prism resonators
Forbes, Andrew; Burger, Liesl; Litvin, Igor Anatolievich
2006-08-01
Laser brightness is a parameter often used to compare high power laser beam delivery from various sources, and incorporates both the power contained in the particular mode, as well as the propagation of that mode through the beam quality factor, M2. In this study a cross Porro prism resonator is considered; crossed Porro prism resonators have been known for some time, but until recently have not been modeled as a complete physical optics system that allows the modal output to be determined as a function of the rotation angle of the prisms. In this paper we consider the diffraction losses as a function of the prism rotation angle relative to one another, and combine this with the propagation of the specific modes to determine the laser output brightness as a function of the prism orientation.
Display of cross sectional anatomy by nuclear magnetic resonance imaging.
Hinshaw, W S; Andrew, E R; Bottomley, P A; Holland, G N; Moore, W S
1978-04-01
High definition cross-sectional images produced by a new nuclear magnetic resonance (NMR) technique are shown. The images are a series of thin section scans in the coronal plane of the head of a rabbit. The NMR images are derived from the distribution of the density of mobile hydrogen atoms. Various tissue types can be distinguished and a clear registration of gross anatomy is demonstrated. No known hazards are associated with the technique.
Resonances in photoionization. Cross section for vibrationally excited H2
International Nuclear Information System (INIS)
Mezei, J.Zs.; Jungen, Ch.
2011-01-01
Complete text of publication follows. Diatomic molecular Hydrogen is the most abundant molecule in interstellar molecular clouds. The modeling of these environments relies on accurate cross sections for the various relevant processes. Among them, the photoionization plays a major role in the kinetics and in the energy exchanges involving H 2 . The recent discovery of vibrationally excited molecular hydrogen in extragalactic environments revealed the need for accurate evaluation of the corresponding photoionization cross sections. In the present work we report theoretical photoionization cross sections for excitation from excited vibrational levels of the ground state, dealing with the Q(N = 1) (ΔN = 0, where N is the total angular momentum of the molecule) transitions which account for roughly one third of the total photoabsorption cross section. We will focus on the v' = 1 excited level of the ground electronic state. Our calculations are based on Multichannel Quantum Defect Theory (MQDT), which allows us to take into account of the full manifold of Rydberg states and their interactions with the electronic continuum. We have carried out two types of MQDT calculations. First, we omitted all open channels and calculated energy levels, wave functions and spontaneous emission Einstein coefficients, making use of the theoretical method presented in [2]. In a second set of calculations we included the open ionization channels in the computations getting the continuum phase shifts, channel mixing coefficients and channel dipole moments and finally the photoabsorption/ photoionization cross section. The cross section is dominated by the presence of resonance structures corresponding to excitation of various vibrational levels of bound electronic states which lie above the ionization threshold. In order to assess the importance of the resonances we have calculated for each vibrational interval (the energy interval between two consecutive ionization thresholds) the
Half-integer resonance crossing in high-intensity rings
Directory of Open Access Journals (Sweden)
A. V. Fedotov
2002-02-01
Full Text Available A detailed study of the influence of space charge on the crossing of second-order resonances is presented and associated with the space-charge limit of high-intensity rings. Two-dimensional simulation studies are compared with envelope models, which agree in the finding of an increased intensity limit due to the coherent frequency shift. This result is also found for realistic bunched beams with multiturn injection painting. Characteristic features such as the influence of tune splitting, structure resonances, and the role of envelope instabilities are discussed in detail. The theoretical limits are found to be in good agreement with the performance of high-intensity proton machines.
International Nuclear Information System (INIS)
Story, J.S.
1969-09-01
The data available up to the end of November 1968 on the thermal neutron absorption cross-sections, resonance absorption integrals, and resonance parameters of silicon and its stable isotopes are collected and discussed. Estimates are given of the mean spacing of the energy levels of the compound nuclei near the neutron binding energy. It is concluded that the thermal neutron absorption cross-section and resonance absorption integral of natural silicon are not well established. The data on these two parameters are somewhat correlated, and three different assessments of the resonance integral are presented which differ over-all by a factor of 230. Many resonances have been detected by charged particle reactions which have not yet been observed in neutron cross-section measurements. One of these resonances of Si 2 8, at E n = 4 ± 5 keV might account for the large resonance integral which is derived, very uncertainly, from integral data. The principal source of the measured resonance integral of Si 3 0 has not yet been located. The thermal neutron absorption cross-section of Si 2 8 appears to result mainly from a negative energy resonance, possibly the resonance at E n = - 59 ± 5 keV detected by the Si 2 8 (d,p) reaction. (author)
Improved resonance formulas for cross sections of fissile elements
International Nuclear Information System (INIS)
Segev, M.
1978-01-01
The Adler--Adler cross-section formalism with energy-dependent parameters is a practical approximation to the R-matrix formalism, on the basis of the smallness of the s-wave neutron width in fissile elements. Attempts were made to represent experimental cross sections by the Adler--Adler formulas through an initial representation by the Reich--Moore approximation of R-matrix and a subsequent conversion of the Reich--Moore formulas to the Adler--Adler formulas. Adler and Adler foresaw difficulties in associating their formulas with approximate R-matrix theories such as those of Reich and Moore. Indeed, it is shown that, due to the nonunitarity of the Adler--Adler formalism on the one hand and the unitarity, by definition, of the Reich--Moore formalism on the other hand, the conversion from the latter to the former is ambiguous. Examples are shown to demonstrate that this ambiguity results in numerical inaccuracies, sometimes very large ones, for neutron widths that are not extremely small. Improved Adler--Adler-type formulas have been derived from the R-matrix formalism. In these formulas, the multipliers of the Breit--Wigner resonance lines exhibit more explicit energy dependence than their original counterparts, mainly in the form of additional terms in the formula for the total cross section. The conversion from Reich--Moore cross sections to the improved resonance formulas is shown to be much less ambiguous and to produce very accurate cross sections. In particular, the inaccuracies encountered with the Reich--Moore to Adler--Adler conversion are eliminated. A computer code, PEDRA, was written to perform the conversion from a given set of Reich--Moore parameters to the parameters required in the improved formulas. The numerical algorithm of this code is based on an adaptation with modifications of the numerical approach of de Saussure--Perez in the POLLA code, which converts Reich--Moore parameters to Adler--Adler parameters. 7 figures, 1 table
International Nuclear Information System (INIS)
Heinze, J.; Kowalczyk, P.; Engelke, F.
1988-01-01
Quasibound levels and shape resonances in the (B 1 Pi/sub u/ -X 1 Σ + /sub g/) band system of 39 K 2 have been recorded by crossed laser-molecular beam techniques. Using optical--optical double resonance, individual rovibrational levels (v'' = 15--18, J'' = 3--25) of the K 2 state are prepared by Franck--Condon pumping (FCP) in a supersonic nozzle beam. Excitation into quasibound levels below and above the (B 1 Pi/sub u/) state barrier is detected as molecular and atomic (K4 2 P 3 /sub // 2 →4 2 S 1 /sub // 2 only) fluorescence. The resonance transition frequencies and shapes are measured and the results are used (a) to determine the scattering resonance energies, widths, and lifetimes; (b) to compare them with values obtained by a ''maximum internal amplitude'' approach [R. J. LeRoy and R. B. Bernstein, J. Chem. Phys. 54, 5114 (1971)]; and (c) to check the agreement with exact calculations of the B state potential using the ''inverted perturbation approach (IPA).'' The bound and quasibound part of the B 1 Pi/sub u/ state including the locus (R = 8.08 +- 0.05 A) of the barrier maximum (298 +- 8 cm -1 above the adiabatic dissociation limit) is found in excellent agreement with previous results. The shape resonances are not highly sensitive to the long-range interatomic forces, here the repulsive dipole--dipole resonance interaction
Lobe, Elisabeth; Stollenwerk, Tobias; Tröltzsch, Anke
2015-01-01
In the recent years, the field of adiabatic quantum computing has gained importance due to the advances in the realisation of such machines, especially by the company D-Wave Systems. These machines are suited to solve discrete optimisation problems which are typically very hard to solve on a classical computer. Due to the quantum nature of the device it is assumed that there is a substantial speedup compared to classical HPC facilities. We explain the basic principles of adiabatic ...
Nonadiabatic exchange dynamics during adiabatic frequency sweeps.
Barbara, Thomas M
2016-04-01
A Bloch equation analysis that includes relaxation and exchange effects during an adiabatic frequency swept pulse is presented. For a large class of sweeps, relaxation can be incorporated using simple first order perturbation theory. For anisochronous exchange, new expressions are derived for exchange augmented rotating frame relaxation. For isochronous exchange between sites with distinct relaxation rate constants outside the extreme narrowing limit, simple criteria for adiabatic exchange are derived and demonstrate that frequency sweeps commonly in use may not be adiabatic with regard to exchange unless the exchange rates are much larger than the relaxation rates. Otherwise, accurate assessment of the sensitivity to exchange dynamics will require numerical integration of the rate equations. Examples of this situation are given for experimentally relevant parameters believed to hold for in-vivo tissue. These results are of significance in the study of exchange induced contrast in magnetic resonance imaging. Copyright © 2016 Elsevier Inc. All rights reserved.
International Nuclear Information System (INIS)
James, G.D.
1976-01-01
A review of the status of transactinium isotope cross sections in the resonance region and of resolved resonance parameters is given by summarising the work submitted by fourteen contributors and also by highlighting other work where notable progress has been made in our knowledge of neutron resonance phenomena. (author)
Formalism for neutron cross section covariances in the resonance region using kernel approximation
Energy Technology Data Exchange (ETDEWEB)
Oblozinsky, P.; Cho,Y-S.; Matoon,C.M.; Mughabghab,S.F.
2010-04-09
We describe analytical formalism for estimating neutron radiative capture and elastic scattering cross section covariances in the resolved resonance region. We use capture and scattering kernels as the starting point and show how to get average cross sections in broader energy bins, derive analytical expressions for cross section sensitivities, and deduce cross section covariances from the resonance parameter uncertainties in the recently published Atlas of Neutron Resonances. The formalism elucidates the role of resonance parameter correlations which become important if several strong resonances are located in one energy group. Importance of potential scattering uncertainty as well as correlation between potential scattering and resonance scattering is also examined. Practical application of the formalism is illustrated on {sup 55}Mn(n,{gamma}) and {sup 55}Mn(n,el).
Directory of Open Access Journals (Sweden)
Dave Bacon
2013-06-01
Full Text Available We describe a many-body quantum system that can be made to quantum compute by the adiabatic application of a large applied field to the system. Prior to the application of the field, quantum information is localized on one boundary of the device, and after the application of the field, this information propagates to the other side of the device, with a quantum circuit applied to the information. The applied circuit depends on the many-body Hamiltonian of the material, and the computation takes place in a degenerate ground space with symmetry-protected topological order. Such “adiabatic quantum transistors” are universal adiabatic quantum computing devices that have the added benefit of being modular. Here, we describe this model, provide arguments for why it is an efficient model of quantum computing, and examine these many-body systems in the presence of a noisy environment.
Adiabatic capture and debunching
International Nuclear Information System (INIS)
Ng, K.Y.
2012-01-01
In the study of beam preparation for the g-2 experiment, adiabatic debunching and adiabatic capture are revisited. The voltage programs for these adiabbatic processes are derived and their properties discussed. Comparison is made with some other form of adiabatic capture program. The muon g-2 experiment at Fermilab calls for intense proton bunches for the creation of muons. A booster batch of 84 bunches is injected into the Recycler Ring, where it is debunched and captured into 4 intense bunches with the 2.5-MHz rf. The experiment requires short bunches with total width less than 100 ns. The transport line from the Recycler to the muon-production target has a low momentum aperture of ∼ ±22 MeV. Thus each of the 4 intense proton bunches required to have an emittance less than ∼ 3.46 eVs. The incoming booster bunches have total emittance ∼ 8.4 eVs, or each one with an emittance ∼ 0.1 eVs. However, there is always emittance increase when the 84 booster bunches are debunched. There will be even larger emittance increase during adiabatic capture into the buckets of the 2.5-MHz rf. In addition, the incoming booster bunches may have emittances larger than 0.1 eVs. In this article, we will concentrate on the analysis of the adiabatic capture process with the intention of preserving the beam emittance as much as possible. At this moment, beam preparation experiment is being performed at the Main Injector. Since the Main Injector and the Recycler Ring have roughly the same lattice properties, we are referring to adiabatic capture in the Main Injector instead in our discussions.
Correction of multigroup cross sections for resolved resonance interference in mixed absorbers
International Nuclear Information System (INIS)
Williams, M.L.
1982-07-01
The effect that interference between resolved resonances has on averaging multigroup cross sections is examined for thermal reactor-type problems. A simple and efficient numerical scheme is presented to correct a preprocessed multigroup library for interference effects. The procedure is implemented in a design oriented lattice physics computer code and compared with rigorous numerical calculations. The approximate method for computing resonance interference correction factors is applied to obtaining fine-group cross sections for a homogeneous uranium-plutonium mixture and a uranium oxide lattice. It was found that some fine group cross sections are changed by more than 40% due to resonance interference. The change in resonance interference correction factors due to burnup of a PWR fuel pin is examined and found to be small. The effect of resolved resonance interference on collapsed broad-group cross sections for thermal reactor calculations is discussed
Energy Technology Data Exchange (ETDEWEB)
Kocic, A; Markovic, V [Institute of nuclear sciences Boris Kidric, Vinca, Beograd (Yugoslavia)
1967-04-15
Zirconium and zircaloy-2 alloy, as constructive materials, have found wide application in reactor technology, especially in heavy water systems for two reasons: a) low neutron absorption cross section, b) good mechanical properties. The thickness of the zirconium and zircaloy-2 for different applications varies from several tenths of a millimeter to about ten millimeters. Therefore, to calculate reactor systems it is desirable to know the effective neutron absorption cross section for the range of thicknesses mention above. The thermal neutron cross sections for these materials are low and no appreciable variation of the effective neutron cross section occurs even for the largest thicknesses. However, this is not true for effective resonance absorption. On the other hand, due to the lack of detailed knowledge of the zirconium resonances, calculations of the effective resonance integrals cannot be performed. Therefore it is necessary to measure the effective total and resonance absorption cross section for zirconium (author)
International Nuclear Information System (INIS)
Moldauer, P.A.
1979-01-01
The main features of the effects of S-matrix flucturations on average cross sections are reviewed with emphasis on recent developments on the enhancement of small cross sections and cross sections between directly coupled channels. Examples are given in which the effect can distort the shape of a doorway state resonance so as to reduce its observed width. 4 figures
International Nuclear Information System (INIS)
Liu, C.; Starace, A.F.
1999-01-01
Partial photodetachment and photoionization cross sections corresponding to highly excited residual atoms or ions are shown analytically to mirror one another in the neighborhood of a resonance. More precisely, any two groupings of partial cross sections are shown here to have components whose variations with energy near a resonance are equal in magnitude and opposite in direction. This work extends an analysis of Starace [Phys. Rev. A 16, 231 (1977)] for the behavior of partial cross sections near a resonance to the case when the ρ 2 parameter of Fano and Cooper [Phys. Rev. 137, A1364 (1965)] tends to zero. copyright 1999 The American Physical Society
Energy Technology Data Exchange (ETDEWEB)
Liu, C.; Starace, A.F. [Department of Physics and Astronomy, The University of Nebraska, Lincoln, Nebraska 68588-0111 (United States)
1999-03-01
Partial photodetachment and photoionization cross sections corresponding to highly excited residual atoms or ions are shown analytically to mirror one another in the neighborhood of a resonance. More precisely, any two groupings of partial cross sections are shown here to have components whose variations with energy near a resonance are equal in magnitude and opposite in direction. This work extends an analysis of Starace [Phys. Rev. A {bold 16}, 231 (1977)] for the behavior of partial cross sections near a resonance to the case when the {rho}{sup 2} parameter of Fano and Cooper [Phys. Rev. {bold 137}, A1364 (1965)] tends to zero. {copyright} {ital 1999} {ital The American Physical Society}
Computation of Resonance-Screened Cross Section by the Dorix-Speng System
Energy Technology Data Exchange (ETDEWEB)
Haeggblom, H
1968-09-15
The report describes a scheme for computation of group cross sections for fast reactors in energy regions where the resonance structure of the cross sections may be dense. A combination of the programmes Dorix and Speng is then used. Dorix calculates group cross sections for each resonance absorber separately. The interaction between resolved resonances in the same isotope is treated using a method described in a separate report. The interaction between correlated and non-correlated resonances in the unresolved region is also considered. By a Dorix calculation we obtain effective microscopic cross sections which are then read in on a library tape. This library contains both point-by-point data and group cross sections and is used in the Speng programme for computation of spectrum and/or macroscopic cross sections. The resonance interaction between different isotopes is computed in Speng by the same method as was used in the Dorix programme for non-correlated unresolved resonances. Consideration is also given to the width of the resonances compared to the energy loss by a neutron colliding with some of the scattering elements.
Computation of Resonance-Screened Cross Section by the Dorix-Speng System
International Nuclear Information System (INIS)
Haeggblom, H.
1968-09-01
The report describes a scheme for computation of group cross sections for fast reactors in energy regions where the resonance structure of the cross sections may be dense. A combination of the programmes Dorix and Speng is then used. Dorix calculates group cross sections for each resonance absorber separately. The interaction between resolved resonances in the same isotope is treated using a method described in a separate report. The interaction between correlated and non-correlated resonances in the unresolved region is also considered. By a Dorix calculation we obtain effective microscopic cross sections which are then read in on a library tape. This library contains both point-by-point data and group cross sections and is used in the Speng programme for computation of spectrum and/or macroscopic cross sections. The resonance interaction between different isotopes is computed in Speng by the same method as was used in the Dorix programme for non-correlated unresolved resonances. Consideration is also given to the width of the resonances compared to the energy loss by a neutron colliding with some of the scattering elements
Adiabatic and isothermal resistivities
International Nuclear Information System (INIS)
Fishman, R.S.
1989-01-01
The force-balance method is used to calculate the isothermal resistivity to first order in the electric field. To lowest order in the impurity potential, the isothermal resistivity disagrees with the adiabatic results of the Kubo formula and the Boltzmann equation. However, an expansion of the isothermal resistivity in powers of the impurity potential is divergent, with two sets of divergent terms. The first set arises from the density matrix of the relative electron-phonon system. The second set arises from the explicit dependence of the density matrix on the electric field, which was ignored by force-balance calculations. These divergent contributions are calculated inductively, by applying a recursion relation for the Green's functions. Using the λ 2 t→∞ limit of van Hove, I show that the resummation of these divergent terms yields the same result for the resistivity as the adiabatic calculations, in direct analogy with the work of Argyres and Sigel, and Huberman and Chester
Semi adiabatic theory of seasonal Markov processes
Energy Technology Data Exchange (ETDEWEB)
Talkner, P [Paul Scherrer Inst. (PSI), Villigen (Switzerland)
1999-08-01
The dynamics of many natural and technical systems are essentially influenced by a periodic forcing. Analytic solutions of the equations of motion for periodically driven systems are generally not known. Simulations, numerical solutions or in some limiting cases approximate analytic solutions represent the known approaches to study the dynamics of such systems. Besides the regime of weak periodic forces where linear response theory works, the limit of a slow driving force can often be treated analytically using an adiabatic approximation. For this approximation to hold all intrinsic processes must be fast on the time-scale of a period of the external driving force. We developed a perturbation theory for periodically driven Markovian systems that covers the adiabatic regime but also works if the system has a single slow mode that may even be slower than the driving force. We call it the semi adiabatic approximation. Some results of this approximation for a system exhibiting stochastic resonance which usually takes place within the semi adiabatic regime are indicated. (author) 1 fig., 8 refs.
Resonance analysis and evaluation of the 235U neutron induced cross sections
International Nuclear Information System (INIS)
Leal, L.C.
1990-06-01
Neutron cross sections of fissile nuclei are of considerable interest for the understanding of parameters such as resonance absorption, resonance escape probability, resonance self-shielding,and the dependence of the reactivity on temperature. In the present study, new techniques for the evaluation of the 235 U neutron cross sections are described. The Reich-Moore formalism of the Bayesian computer code SAMMY was used to perform consistent R-matrix multilevel analyses of the selected neutron cross-section data. The Δ 3 -statistics of Dyson and Mehta, along with high-resolution data and the spin-separated fission cross-section data, have provided the possibility of developing a new methodology for the analysis and evaluation of neutron-nucleus cross sections. The results of the analysis consists of a set of resonance parameters which describe the 235 U neutron cross sections up to 500 eV. The set of resonance parameters obtained through a R-matrix analysis are expected to satisfy statistical properties which lead to information on the nuclear structure. The resonance parameters were tested and showed good agreement with the theory. It is expected that the parametrization of the 235 U neutron cross sections obtained in this dissertation represents the current state of art in data as well as in theory and, therefore, can be of direct use in reactor calculations. 44 refs., 21 figs., 8 tabs
Baskin, Lev; Plamenevskii, Boris; Sarafanov, Oleg
2015-01-01
This volume studies electron resonant tunneling in two- and three-dimensional quantum waveguides of variable cross-sections in the time-independent approach. Mathematical models are suggested for the resonant tunneling and develop asymptotic and numerical approaches for investigating the models. Also, schemes are presented for several electronics devices based on the phenomenon of resonant tunneling. Devices based on the phenomenon of electron resonant tunneling are widely used in electronics. Efforts are directed towards refining properties of resonance structures. There are prospects for building new nanosize electronics elements based on quantum dot systems. However, the role of resonance structure can also be given to a quantum wire of variable cross-section. Instead of an "electrode - quantum dot - electrode" system, one can use a quantum wire with two narrows. A waveguide narrow is an effective potential barrier for longitudinal electron motion along a waveguide. The part of the waveguide between ...
The evaluated neutron cross sections and resonance integrals of fission products with Z = 57-62
International Nuclear Information System (INIS)
Fedorova, A.F.; Pisanko, Zh.I.; Novoselov, G.M.
1976-01-01
Neutron cross sections at a neutron velocity of V=2200 m/s, and resonance integrals for fission products with Z=57-71 are estimated. In obtaining the recommended values the results of the neutron cross sections and resonance integrals for elements used as references were normalized in accordance with the latest adjusted values. In the course of estimation, preference was given to the more accurate methods for obtaining the measured values and to the more recent investigations
Experimental determination of resonance absorption cross sections for Zircaloy-2 and zirconium
Energy Technology Data Exchange (ETDEWEB)
Kocic, A; Markovic, V [Boris Kidric Institute of Nuclear Sciences, Vinca, Beograd (Yugoslavia)
1968-05-15
The integral absorption cross section for the neutron spectrum and the thermal absorption cross section for zircaloy-2 have been determined using the pile oscillator technique. Using both values and a measured ratio of the epithermal to the thermal flux, the effective resonance integrals were obtained. After subtraction of the contributions for alloy and impurity elements, the effective resonance integrals for zirconium were evaluated. An extrapolated value of 0.91{+-}0.10 was obtained for the dilute integral. (author)
Evaluation of Cm-247 neutron cross sections in the resonance region
International Nuclear Information System (INIS)
Martinelli, T.; Menapace, E.; Motta, M.; Vaccari, M.
1980-01-01
The neutron cross sections of Cm-247 are evaluated in the resonance (resolved and unresolved) region up to 10 keV. Average resonance parameters (i.e. spacing D, fission and radiative widths, neutron strength functions) are determined for unresolved region calculations. Moreover for a better comparison with the experimental data, fission cross section is calculated up to 10 MeV. In addition, the average number of neutrons emitted per fission as a function of energy is estimated
The evaluated neutron cross sections and resonance integrals of fission products with Z=63-71
International Nuclear Information System (INIS)
Fedorova, A.F.; Pisanko, Zh.I.; Novoselov, G.M.
1976-01-01
Neutron cross sections at a neutron velocity of V=2200 m/s, and the resonance integrals for fission products with Z=63-71 are estimated. In obtaining the recommended values the results were normalized of the neutron cross sections and resonance integrals for elements used as references in accordance with the latest adjusted values. In the course of estimation, preference was given to the more accurate measuring methods and the more recent investigations. Scientific publications up to 1975 have been used
Energy Technology Data Exchange (ETDEWEB)
Olsen, Seth, E-mail: seth.olsen@uq.edu.au [School of Mathematics and Physics, The University of Queensland, Brisbane QLD 4072 (Australia)
2015-01-28
This paper reviews basic results from a theory of the a priori classical probabilities (weights) in state-averaged complete active space self-consistent field (SA-CASSCF) models. It addresses how the classical probabilities limit the invariance of the self-consistency condition to transformations of the complete active space configuration interaction (CAS-CI) problem. Such transformations are of interest for choosing representations of the SA-CASSCF solution that are diabatic with respect to some interaction. I achieve the known result that a SA-CASSCF can be self-consistently transformed only within degenerate subspaces of the CAS-CI ensemble density matrix. For uniformly distributed (“microcanonical”) SA-CASSCF ensembles, self-consistency is invariant to any unitary CAS-CI transformation that acts locally on the ensemble support. Most SA-CASSCF applications in current literature are microcanonical. A problem with microcanonical SA-CASSCF models for problems with “more diabatic than adiabatic” states is described. The problem is that not all diabatic energies and couplings are self-consistently resolvable. A canonical-ensemble SA-CASSCF strategy is proposed to solve the problem. For canonical-ensemble SA-CASSCF, the equilibrated ensemble is a Boltzmann density matrix parametrized by its own CAS-CI Hamiltonian and a Lagrange multiplier acting as an inverse “temperature,” unrelated to the physical temperature. Like the convergence criterion for microcanonical-ensemble SA-CASSCF, the equilibration condition for canonical-ensemble SA-CASSCF is invariant to transformations that act locally on the ensemble CAS-CI density matrix. The advantage of a canonical-ensemble description is that more adiabatic states can be included in the support of the ensemble without running into convergence problems. The constraint on the dimensionality of the problem is relieved by the introduction of an energy constraint. The method is illustrated with a complete active space
International Nuclear Information System (INIS)
Koyumdjieva, N.
2006-01-01
A statistical model for the resonant cross section structure in the Unresolved Resonance Region has been developed in the framework of the R-matrix formalism in Reich Moore approach with effective accounting of the resonance parameters fluctuations. The model uses only the average resonance parameters and can be effectively applied for analyses of cross sections functional, averaged over many resonances. Those are cross section moments, transmission and self-indication functions measured through thick sample. In this statistical model the resonant cross sections structure is accepted to be periodic and the R-matrix is a function of ε=E/D with period 0≤ε≤N; R nc (ε)=π/2√(S n *S c )1/NΣ(i=1,N)(β in *β ic *ctg[π(ε i - = ε-iS i )/N]; Here S n ,S c ,S i is respectively neutron strength function, strength function for fission or inelastic channel and strength function for radiative capture, N is the number of resonances (ε i ,β i ) that obey the statistic of Porter-Thomas and Wigner's one. The simple case of this statistical model concerns the resonant cross section structure for non-fissile nuclei under the threshold for inelastic scattering - the model of the characteristic function with HARFOR program. In the above model some improvements of calculation of the phases and logarithmic derivatives of neutron channels have been done. In the parameterization we use the free parameter R l ∞ , which accounts the influence of long-distant resonances. The above scheme for statistical modelling of the resonant cross section structure has been applied for evaluation of experimental data for total, capture and inelastic cross sections for 232 Th in the URR (4-150) keV and also the transmission and self-indication functions in (4-175) keV. The set of evaluated average resonance parameters have been obtained. The evaluated average resonance parameters in the URR are consistent with those in the Resolved Resonance Region (CRP for Th-U cycle, Vienna, 2006
RFUNC, Diffusion Cross-Sections Data Analysis for Resonance Region
International Nuclear Information System (INIS)
2001-01-01
1 - Description of program or function: RFUNC is used to analyze high resolution differential elastic-scattering data from spin zero nuclides in the resonance energy region at ORELA. 2 - Method of solution: RFUNC is based upon the real R-function formalism which ignores the capture reaction channel since only resonances having neutron widths much larger than their capture widths are observed in the differential scattering data. 3 - Restrictions on the complexity of the problem: RFUNC only deals with scattering from spin zero nuclides
Behavior of partial cross sections and branching ratios in the neighborhood of a resonance
International Nuclear Information System (INIS)
Starace, A.F.
1977-01-01
Starting from the treatment of Fano for the behavior of the total cross section in a photoionization (or electron-ion scattering) experiment in the vicinity of a resonance, we present a theoretical formula for the behavior of an individual final-state channel in the neighborhood of a resonance. This result is then used to derive another theoretical formula for the behavior of the ratio of two partial cross sections (i.e., the branching ratio) in the vicinity of a resonance. This branching-ratio formula depends on the profile parameters q, GAMMA, and rho 2 for the resonance, on the branching ratio outside the resonance, and on two new parameters which are explicitly related to scattering-matrix elements and phase shifts
Change of adiabatic invariant near the separatrix
International Nuclear Information System (INIS)
Bulanov, S.V.
1995-10-01
The properties of particle motion in the vicinity of the separatrix in a phase plane are investigated. The change of adiabatic invariant value due to the separatrix crossing is evaluated as a function of a perturbation parameter magnitude and a phase of a particle for time dependent Hamiltonians. It is demonstrated that the change of adiabatic invariant value near the separatrix birth is much larger than that in the case of the separatrix crossing near the saddle point in a phase plane. The conditions of a stochastic regime to appear around the separatrix are found. The results are applied to study the longitudinal invariant behaviour of charged particles near singular lines of the magnetic field. (author). 22 refs, 9 figs
Improving the positive feedback adiabatic logic familiy
Directory of Open Access Journals (Sweden)
J. Fischer
2004-01-01
Full Text Available Positive Feedback Adiabatic Logic (PFAL shows the lowest energy dissipation among adiabatic logic families based on cross-coupled transistors, due to the reduction of both adiabatic and non-adiabatic losses. The dissipation primarily depends on the resistance of the charging path, which consists of a single p-channel MOSFET during the recovery phase. In this paper, a new logic family called Improved PFAL (IPFAL is proposed, where all n- and pchannel devices are swapped so that the charge can be recovered through an n-channel MOSFET. This allows to decrease the resistance of the charging path up to a factor of 2, and it enables a significant reduction of the energy dissipation. Simulations based on a 0.13µm CMOS process confirm the improvements in terms of power consumption over a large frequency range. However, the same simple design rule, which enables in PFAL an additional reduction of the dissipation by optimal transistor sizing, does not apply to IPFAL. Therefore, the influence of several sources of dissipation for a generic IPFAL gate is illustrated and discussed, in order to lower the power consumption and achieve better performance.
POLIDENT: A Module for Generating Continuous-Energy Cross Sections from ENDF Resonance Data
Energy Technology Data Exchange (ETDEWEB)
Dunn, M.E.; Greene, N.M.
2000-12-01
POLIDENT (Point Libraries of Data from ENDF/B Tapes) is an AMPX module that accesses the resonance parameters from File 2 of an ENDF/B library and constructs the continuous-energy cross sections in the resonance energy region. The cross sections in the resonance range are subsequently combined with the File 3 background data to construct the cross-section representation over the complete energy range. POLIDENT has the capability to process all resonance reactions that are identified in File 2 of the ENDF/B library. In addition, the code has the capability to process the single- and multi-level Breit-Wigner, Reich-Moore and Adler-Adler resonance formalisms that are identified in File 2. POLIDENT uses a robust energy-mesh-generation scheme that determines the minimum, maximum and points of inflection in the cross-section function in the resolved-resonance region. Furthermore, POLIDENT processes all continuous-energy cross-section reactions that are identified in File 3 of the ENDF/B library and outputs all reactions in an ENDF/B TAB1 format that can be accessed by other AMPX modules.
Albash, Tameem; Lidar, Daniel A.
2018-01-01
Adiabatic quantum computing (AQC) started as an approach to solving optimization problems and has evolved into an important universal alternative to the standard circuit model of quantum computing, with deep connections to both classical and quantum complexity theory and condensed matter physics. This review gives an account of the major theoretical developments in the field, while focusing on the closed-system setting. The review is organized around a series of topics that are essential to an understanding of the underlying principles of AQC, its algorithmic accomplishments and limitations, and its scope in the more general setting of computational complexity theory. Several variants are presented of the adiabatic theorem, the cornerstone of AQC, and examples are given of explicit AQC algorithms that exhibit a quantum speedup. An overview of several proofs of the universality of AQC and related Hamiltonian quantum complexity theory is given. Considerable space is devoted to stoquastic AQC, the setting of most AQC work to date, where obstructions to success and their possible resolutions are discussed.
Directory of Open Access Journals (Sweden)
J. D. Biamonte
2011-06-01
Full Text Available In his famous 1981 talk, Feynman proposed that unlike classical computers, which would presumably experience an exponential slowdown when simulating quantum phenomena, a universal quantum simulator would not. An ideal quantum simulator would be controllable, and built using existing technology. In some cases, moving away from gate-model-based implementations of quantum computing may offer a more feasible solution for particular experimental implementations. Here we consider an adiabatic quantum simulator which simulates the ground state properties of sparse Hamiltonians consisting of one- and two-local interaction terms, using sparse Hamiltonians with at most three-local interactions. Properties of such Hamiltonians can be well approximated with Hamiltonians containing only two-local terms. The register holding the simulated ground state is brought adiabatically into interaction with a probe qubit, followed by a single diabatic gate operation on the probe which then undergoes free evolution until measured. This allows one to recover e.g. the ground state energy of the Hamiltonian being simulated. Given a ground state, this scheme can be used to verify the QMA-complete problem LOCAL HAMILTONIAN, and is therefore likely more powerful than classical computing.
INTER, ENDF/B Thermal Cross-Sections, Resonance Integrals, G-Factors Calculation
International Nuclear Information System (INIS)
Dunford, Charles L.
2007-01-01
1 - Description of program or function: INTER calculates thermal cross sections, g-factors, resonance integrals, fission spectrum averaged cross sections and 14.0 MeV (or other energy) cross sections for major reactions in an ENDF-6 or ENDF-5 format data file. Version 7.01 (Jan 2005): set success flag after return from beginning. 2 - Method of solution: INTER performs integrations by using the trapezoidal rule
Absolute cross sections from the ''boomerang model'' for resonant electron-molecule scattering
International Nuclear Information System (INIS)
Dube, L.; Herzenberg, A.
1979-01-01
The boomerang model is used to calculate absolute cross sections near the 2 Pi/sub g/ shape resonance in e-N 2 scattering. The calculated cross sections are shown to satisfy detailed balancing. The exchange of electrons is taken into account. A parametrized complex-potential curve for the intermediate N 2 /sup ts-/ ion is determined from a small part of the experimental data, and then used to calculate other properties. The calculations are in good agreement with the absolute cross sections for vibrational excitation from the ground state, the absolute cross section v = 1 → 2, and the absolute total cross section
RFDR with Adiabatic Inversion Pulses: Application to Internuclear Distance Measurements
International Nuclear Information System (INIS)
Leppert, Joerg; Ohlenschlaeger, Oliver; Goerlach, Matthias; Ramachandran, Ramadurai
2004-01-01
In the context of the structural characterisation of biomolecular systems via MAS solid state NMR, the potential utility of homonuclear dipolar recoupling with adiabatic inversion pulses has been assessed via numerical simulations and experimental measurements. The results obtained suggest that it is possible to obtain reliable estimates of internuclear distances via an analysis of the initial cross-peak intensity buildup curves generated from two-dimensional adiabatic inversion pulse driven longitudinal magnetisation exchange experiments
Nettles, Charles B; Zhou, Yadong; Zou, Shengli; Zhang, Dongmao
2016-03-01
Demonstrated herein is a UV-vis Ratiometric Resonance Synchronous Spectroscopic (R2S2, pronounced as "R-two-S-two" for simplicity) technique where the R2S2 spectrum is obtained by dividing the resonance synchronous spectrum of a NP-containing solution by the solvent resonance synchronous spectrum. Combined with conventional UV-vis measurements, this R2S2 method enables experimental quantification of the absolute optical cross sections for a wide range of molecular and nanoparticle (NP) materials that range optically from pure photon absorbers or scatterers to simultaneous photon absorbers and scatterers, simultaneous photon absorbers and emitters, and all the way to simultaneous photon absorbers, scatterers, and emitters in the UV-vis wavelength region. Example applications of this R2S2 method were demonstrated for quantifying the Rayleigh scattering cross sections of solvents including water and toluene, absorption and resonance light scattering cross sections for plasmonic gold nanoparticles, and absorption, scattering, and on-resonance fluorescence cross sections for semiconductor quantum dots (Qdots). On-resonance fluorescence quantum yields were quantified for the model molecular fluorophore Eosin Y and fluorescent Qdots CdSe and CdSe/ZnS. The insights and methodology presented in this work should be of broad significance in physical and biological science research that involves photon/matter interactions.
Landahl, Andrew
2012-10-01
Quantum computers promise to exploit counterintuitive quantum physics principles like superposition, entanglement, and uncertainty to solve problems using fundamentally fewer steps than any conventional computer ever could. The mere possibility of such a device has sharpened our understanding of quantum coherent information, just as lasers did for our understanding of coherent light. The chief obstacle to developing quantum computer technology is decoherence--one of the fastest phenomena in all of physics. In principle, decoherence can be overcome by using clever entangled redundancies in a process called fault-tolerant quantum error correction. However, the quality and scale of technology required to realize this solution appears distant. An exciting alternative is a proposal called ``adiabatic'' quantum computing (AQC), in which adiabatic quantum physics keeps the computer in its lowest-energy configuration throughout its operation, rendering it immune to many decoherence sources. The Adiabatic Quantum Architectures In Ultracold Systems (AQUARIUS) Grand Challenge Project at Sandia seeks to demonstrate this robustness in the laboratory and point a path forward for future hardware development. We are building devices in AQUARIUS that realize the AQC architecture on up to three quantum bits (``qubits'') in two platforms: Cs atoms laser-cooled to below 5 microkelvin and Si quantum dots cryo-cooled to below 100 millikelvin. We are also expanding theoretical frontiers by developing methods for scalable universal AQC in these platforms. We have successfully demonstrated operational qubits in both platforms and have even run modest one-qubit calculations using our Cs device. In the course of reaching our primary proof-of-principle demonstrations, we have developed multiple spinoff technologies including nanofabricated diffractive optical elements that define optical-tweezer trap arrays and atomic-scale Si lithography commensurate with placing individual donor atoms with
Regeta, Khrystyna; Allan, Michael; Winstead, Carl; McKoy, Vincent; Mašín, Zdeněk; Gorfinkiel, Jimena D
2016-01-14
We measured differential cross sections for elastic (rotationally integrated) electron scattering on pyrimidine, both as a function of angle up to 180(∘) at electron energies of 1, 5, 10, and 20 eV and as a function of electron energy in the range 0.1-14 eV. The experimental results are compared to the results of the fixed-nuclei Schwinger variational and R-matrix theoretical methods, which reproduce satisfactorily the magnitudes and shapes of the experimental cross sections. The emphasis of the present work is on recording detailed excitation functions revealing resonances in the excitation process. Resonant structures are observed at 0.2, 0.7, and 4.35 eV and calculations for different symmetries confirm their assignment as the X̃(2)A2, Ã(2)B1, and B̃(2)B1 shape resonances. As a consequence of superposition of coherent resonant amplitudes with background scattering the B̃(2)B1 shape resonance appears as a peak, a dip, or a step function in the cross sections recorded as a function of energy at different scattering angles and this effect is satisfactorily reproduced by theory. The dip and peak contributions at different scattering angles partially compensate, making the resonance nearly invisible in the integral cross section. Vibrationally integrated cross sections were also measured at 1, 5, 10 and 20 eV and the question of whether the fixed-nuclei cross sections should be compared to vibrationally elastic or vibrationally integrated cross section is discussed.
Geometry of the Adiabatic Theorem
Lobo, Augusto Cesar; Ribeiro, Rafael Antunes; Ribeiro, Clyffe de Assis; Dieguez, Pedro Ruas
2012-01-01
We present a simple and pedagogical derivation of the quantum adiabatic theorem for two-level systems (a single qubit) based on geometrical structures of quantum mechanics developed by Anandan and Aharonov, among others. We have chosen to use only the minimum geometric structure needed for the understanding of the adiabatic theorem for this case.…
Energy Technology Data Exchange (ETDEWEB)
de Saussure, G.; Perez, R.B. (Oak Ridge National Lab., TN (USA))
1982-01-01
Several problems related to the measurement, analysis and evaluation of the neutron cross sections of the main fertile and fissile nuclides in the resonance region are reviewed. In particular the ENDF/B-V representation of these cross sections is discussed. In recent years little progress has been made in improving our knowledge of the resolved resonance parameters of the fertile nuclei. It is suggested that this absence of progress is due to a lack of adequate methodologies to deal with the systematic errors arising from uncertainties in the analysis of the measurements. The ENDF/B treatment of the unresolved resonance region is commented on and the authors recommend the validation of the unresolved resonance range evaluations with appropriate transmission and self-indication measurements.
TIMS-1, Multigroup Cross-Sections of Heavy Isotope Mixture with Resonance from ENDF/B
International Nuclear Information System (INIS)
Takano, Hideki; Ishiguro, Yukio; Matsui, Yasushi
1984-01-01
1 - Description of problem or function: TIMS-1 is a code for calculating the group constants of heavy resonant nuclei by using ENDF/ B-4 format data. This code calculates infinitely dilute cross sections and self-shielding factors as a function of composition sigma-0 temperature T and R-parameter, where R is the ratio of ato- mic number density of two different resonant nuclei. 2 - Method of solution: In the unresolved resonance region, a ladder of resonance parameters and levels is generated with Monte Carlo method. The temperature dependent cross sections are calculated with the Breit-Wigner single-level and multi-level formula. The neutron spectrum is accurately calculated by solving numerically the neutron slowing down equation using a recurrence formula for neutron slowing down source. 3 - Restrictions on the complexity of the problem: The maximum numbers of energy groups, temperatures and compositions are 60, 4 and 10 respectively
Interacting adiabatic quantum motor
Bruch, Anton; Kusminskiy, Silvia Viola; Refael, Gil; von Oppen, Felix
2018-05-01
We present a field-theoretic treatment of an adiabatic quantum motor. We explicitly discuss a motor called the Thouless motor which is based on a Thouless pump operating in reverse. When a sliding periodic potential is considered to be the motor degree of freedom, a bias voltage applied to the electron channel sets the motor in motion. We investigate a Thouless motor whose electron channel is modeled as a Luttinger liquid. Interactions increase the gap opened by the periodic potential. For an infinite Luttinger liquid the coupling-induced friction is enhanced by electron-electron interactions. When the Luttinger liquid is ultimately coupled to Fermi liquid reservoirs, the dissipation reduces to its value for a noninteracting electron system for a constant motor velocity. Our results can also be applied to a motor based on a nanomagnet coupled to a quantum spin Hall edge.
Topology hidden behind the breakdown of adiabaticity
International Nuclear Information System (INIS)
Fu, L.-B.; Chen, S.-G.
2005-01-01
For classical Hamiltonian systems, the adiabatic condition may fail at some critical points. However, the breakdown of the adiabatic condition does not always cause the adiabatic evolution to be destroyed. In this paper, we suggest a supplemental condition of the adiabatic evolution for the fixed points of classical Hamiltonian systems when the adiabatic condition breaks down at the critical points. As an example, we investigate the adiabatic evolution of the fixed points of a classical Hamiltonian system which has a number of applications
A subroutine for the calculation of resonance cross sections of U-238 in HTR fuel elements
Energy Technology Data Exchange (ETDEWEB)
Cuniberti, R; Marullo, G C
1971-02-15
In this paper, a survey of the codes used at Ispra for the calculations of resonance absorption in HTR fuel elements is presented and a subroutine for the calculation of resonance cross-sections, in a seven groups energy structure, for a HTR lattice of annular type is described. A library of homogeneous resonance integrals and a wide tabulation of lump and kernel Bell factors, and moderators efficiency is given. This paper deals mainly with the problem of taking into account the correct slowing down of neutrons in the graphite and with the derivation of Bell factors to be used in a multigroup calculation scheme.
Display of cross sectional anatomy by nuclear magnetic resonance imaging
International Nuclear Information System (INIS)
Hinshaw, W.S.; Andrew, E.R.; Bottomley, P.A.; Holland, G.N.; Moore, W.S.; Worthington, B.S.
1978-01-01
High definition cross-sectional images produced by a new nuclear magnetic resonace (NMR) technique are shown. The images are a series of thin section scans in the coronal plane of the head of a rabbit. The NMR images are derived from the distribution of the density of mobile hydrogen atoms. Various tissue types can be distinguished and a clear registration of gross anatomy is demonstrated. No known hazards are associated with the technique. (author)
Resonance parameters for measured keV neutron capture cross sections
Energy Technology Data Exchange (ETDEWEB)
Musgrove, A.R. de L
1969-05-01
All available neutron capture cross sections in the keV region ({approx} to 100 keV) have been fitted with resonance parameters. Capture cross sections for nuclides with reasonably well known average s-wave parameters, but no measured cross section, have been calculated and tabulated using p-and d- wave strength functions interpolated between fitted values. Several of these nuclides are of interest in the theory of slow nucleosynthesis of heavy elements in stars, and the product of cosmic abundance (due to the s-process) and capture cross section at 30 keV has been plotted versus mass number. (author)
Analysis of the 235U neutron cross sections in the resolved resonance range
International Nuclear Information System (INIS)
Leal, L.C.; de Saussure, G.; Perez, R.B.
1989-01-01
Using recent high-resolution measurements of the neutron transmission of 235 U and the spin-separated fission cross-section data of Moore et al., a multilevel analysis of the 235 U neutron cross sections was performed up to 300 eV. The Dyson Metha Δ 3 statistics were used to help locate small levels above 100 eV where resonances are not clearly resolved even in the best resolution measurements available. The statistical properties of the resonance parameters are discussed
Analysis of the 235U neutron cross sections in the resolved resonance range
International Nuclear Information System (INIS)
Leal, L.C.; de Saussure, G.; Perez, R.B.
1989-01-01
Using recent high-resolution measurements of the neutron transmission of 235 U and the spin-separated fission cross-section data of Moore et al., a multilevel analysis of the 235 U neutron cross sections was performed up to 300 eV. The Dyson Metha Δ 3 statistics were used to help locate small levels above 100 eV where resonances are not clearly resolved even in the best resolution measurements available. The statistical properties of the resonance parameters are discussed. 13 refs., 8 figs., 1 tab
Neutron cross section covariances in the resonance region: 52Cr, 56Fe, 58Ni
Energy Technology Data Exchange (ETDEWEB)
Oblozinsky, P.; Cho, Y.-S.; Mattoon, C.M.; Mughabghab, S.F.
2010-08-03
We evaluated covariances for neutron capture and elastic scattering cross sections on major structural materials, {sup 52}Cr, {sup 56}Fe and {sup 58}Ni, in the resonance region which extends beyond 800 keV for each of them. Use was made of the recently developed covariance formalism based on kernel approximation along with data in the Atlas of Neutron Resonances. The data of most interest for AFCI applications, elastic scattering cross section uncertainties at energies above about few hundred keV, are on the level of about 12% for {sup 52}Cr, 7-8% for {sup 56}Fe and 5-6% for {sup 58}Ni.
Resonance structure of 32S+n from measurements of neutron total and capture cross sections
International Nuclear Information System (INIS)
Halperin, J.; Johnson, C.H.; Winters, R.R.; Macklin, R.L.
1980-01-01
Neutron total and capture cross sections of 32 S have been measured up to 1100 keV neutron energy [E/sub exc/( 33 S) =9700 keV]. Spin and parity assignments have been made for 28 of the 64 resonances found in this region. Values of total radiation widths, reduced neutron widths, level spacings, and neutron strength functions have been evaluated for s/sub 1/2/, p/sub 1/2/, p/sub 3/2/, and d/sub 5/2/ levels. Single particle contributions using the valency model account for a significant portion of the total radiation width only for the p/sub 1/2/-wave resonances. A significant number of resonances can be identified with reported levels excited in 32 S(d,p) and 29 Si(α,n) reactions. A calculation of the Maxwellian average cross section appropriate to stellar interiors indicates an average capture cross section at 30 keV, sigma-bar approx. = 4.2(2) mb, a result that is relatively insensitive to the assumed stellar temperature. Direct (potential) capture and the s-wave resonance capture contributions to the thermal capture cross section do not fully account for the reported thermal cross section (530 +- 40 mb) and a bound state is invoked to account for the discrepancy
Decoherence in adiabatic quantum computation
Albash, Tameem; Lidar, Daniel A.
2015-06-01
Recent experiments with increasingly larger numbers of qubits have sparked renewed interest in adiabatic quantum computation, and in particular quantum annealing. A central question that is repeatedly asked is whether quantum features of the evolution can survive over the long time scales used for quantum annealing relative to standard measures of the decoherence time. We reconsider the role of decoherence in adiabatic quantum computation and quantum annealing using the adiabatic quantum master-equation formalism. We restrict ourselves to the weak-coupling and singular-coupling limits, which correspond to decoherence in the energy eigenbasis and in the computational basis, respectively. We demonstrate that decoherence in the instantaneous energy eigenbasis does not necessarily detrimentally affect adiabatic quantum computation, and in particular that a short single-qubit T2 time need not imply adverse consequences for the success of the quantum adiabatic algorithm. We further demonstrate that boundary cancellation methods, designed to improve the fidelity of adiabatic quantum computing in the closed-system setting, remain beneficial in the open-system setting. To address the high computational cost of master-equation simulations, we also demonstrate that a quantum Monte Carlo algorithm that explicitly accounts for a thermal bosonic bath can be used to interpolate between classical and quantum annealing. Our study highlights and clarifies the significantly different role played by decoherence in the adiabatic and circuit models of quantum computing.
The effect of background absorption on the compound cross-section in resonance scattering
International Nuclear Information System (INIS)
Frenkel, A.
1976-01-01
The effect of channel-channel correlations in the compound cross-section is studied in a model of a resonance above a compound background characterized by equal absorption in all open channels. A general rule which cannot be derived from unitarity alone is proved for the fluctuating cross-section. It provides new understanding of level-level correlations in scattering through compound nucleus states. (author)
A computer code for calculating neutron cross-sections from resonance parameter data
International Nuclear Information System (INIS)
Mill, A.J.
1979-08-01
A computer code, XSEC, has been written which calculates neutron cross-sections from resonance data. Although the program was originally written in order to identify neutron 'windows' in enriched nuclides, it may be used to evaluate the total neutron cross-section of any medium mass nuclide at intermediate energies. XSEC has proved very useful in identifying suitable nuclides for use as neutron filters at intermediate energies. (author)
Calculation of the fine spectrum and integration of the resonance cross sections in the cells
International Nuclear Information System (INIS)
Paratte, J.M.
1986-10-01
The code BOXER is used for the neutronics calculations of two-dimensional LWR arrays. During the calculation of the group constants of the cells (pin, clad and moderator), the program SLOFIN, a BOXER module, allows taking into account the self-shielding of the resonances. The resonance range is devided into two parts: - above 907 eV the cross sections are condensed into groups by the library code ETOBOX. In SLOFIN, these values are interpolated over the equivalent cross section and the temperature. The interpolation formula chosen gives an accuracy better than 1% for values of the equivalent cross section larger than 5 barns. - between 4 and 907 eV, the cross sections are given in pointwise form as a function of the lethargy. At first a list of pointwise macroscopic cross section is established. Then the fine spectrum in the cell is calculated in 2 or 3 zones by means of the collision probability theory. In the central zone one resonant pseudo-nuclide is considered for the calculation of the scattering source, while the light nuclides are explicitly treated but under the assumption of energy independent cross sections. The fine spectrum is then used as a weihting function for the condensation of the pointwise cross sections of the resonant nuclides into energy groups. The procedure was checked on the basis of the TRX-1 to -4 and BAPL-UO 2 -1 to -3 experiments which are used as benchmarks for the tests of the ENDF/B libraries. The comparisons with other calculation results show that the deviations observed are typical for the basic cross sections. The method proposed shows a good accuracy in the application range foreseen for BOXER. It is also fast enough to be used as a standard method in a cell code. (author)
Dual-band plasmonic resonator based on Jerusalem cross-shaped nanoapertures
Cetin, Arif E.; Kaya, Sabri; Mertiri, Alket; Aslan, Ekin; Erramilli, Shyamsunder; Altug, Hatice; Turkmen, Mustafa
2015-06-01
In this paper, we both experimentally and numerically introduce a dual-resonant metamaterial based on subwavelength Jerusalem cross-shaped apertures. We numerically investigate the physical origin of the dual-resonant behavior, originating from the constituting aperture elements, through finite difference time domain calculations. Our numerical calculations show that at the dual-resonances, the aperture system supports large and easily accessible local electromagnetic fields. In order to experimentally realize the aperture system, we utilize a high-precision and lift-off free fabrication method based on electron-beam lithography. We also introduce a fine-tuning mechanism for controlling the dual-resonant spectral response through geometrical device parameters. Finally, we show the aperture system's highly advantageous far- and near-field characteristics through numerical calculations on refractive index sensitivity. The quantitative analyses on the availability of the local fields supported by the aperture system are employed to explain the grounds behind the sensitivity of each spectral feature within the dual-resonant behavior. Possessing dual-resonances with large and accessible electromagnetic fields, Jerusalem cross-shaped apertures can be highly advantageous for wide range of applications demanding multiple spectral features with strong nearfield characteristics.
International Nuclear Information System (INIS)
Li Guohe; Qian Xingzhong; Pan Soufu
1998-01-01
The electron impact ionization cross sections of B-like ion N 2+ are calculated in the Coulomb-Born no exchange approximation by using R-matrix method, and the single differential cross section is given. The calculated results exhibit the Rydberg series of resonances. The resonance enhancement of the single-channel cross section is significantly greater than direct ionization cross section. It is agreement with that of Chidichimo
Studies of the Effective Total and Resonance Absorption Cross Sections for Zircaloy 2 and Zirconium
Energy Technology Data Exchange (ETDEWEB)
Hellstrand, E; Lindahl, G; Lundgren, G
1961-06-15
Using pile oscillator technique, the total absorption cross section for zircaloy 2 plates has been determined in the neutron spectrum of the reactor R1. The plate thickness was varied in six steps from 0. 2 mm to 6. 4 mm. The thermal cross section for the alloy was calculated from cross section data and the known composition of the alloy. By subtracting this value from the measured cross sections and dividing by the factor {alpha}=2/{radical}({pi}) x r x {radical}(T/T{sub 0}) the effective resonance integrals were obtained. After subtraction of a constant amount for resonance contributions from hafnium, tin etc., effective resonance integrals for zirconium could be evaluated. An extrapolated value of 0.85 {+-} 0.15 b was obtained for the infinitely dilute integral (l/v part excluded). The ratio of the resonance integral at plate thicknesses 0.2 and 6.4 mm came out as 1.65 {+-} 0.25.
International Nuclear Information System (INIS)
Holden, N.E.
1994-01-01
A re-evaluation of all thermal neutron cross sections and neutron resonance integrals has been performed, utilizing the previous database of the ''Barn Book'' and all of the more recently published experiments. Only significant changes or previously undetermined values are recorded in this report. The source for each value is also recorded in the accompanying table
Physical optics modeling of modal patterns in a crossed porro prism resonator
CSIR Research Space (South Africa)
Litvin, IA
2006-07-01
Full Text Available A physical optics model is proposed to describe the transverse modal patterns in crossed Porro prism resonators. The model departs from earlier attempts in that the prisms are modeled as non-classical rotating elements with amplitude and phase...
Simultaneous analysis of fission and capture cross section with Adler-Adler resonance formula
International Nuclear Information System (INIS)
Cao Hengdao; Qiu Guochun
1989-01-01
The method of simultaneous analysis of fission and capture cross section for fissile nuclide with Adler-Adler resonance formula and the corresponding computer code are presented. A simple and convenient method to correct parameters μ, γ simultaneously is given in order to acquire optimized parameters. The results are satisfactory
Neutron total cross-sections and resonance parameters of Mo and Ta
Indian Academy of Sciences (India)
Linear accelerator; total cross-sections; resonance parameters; SAMMY code. ... Centre for Atomic Research, Kalpakkam 603 102, India; Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang 790-784, Korea; Department of Physics, Kyungpook National University, Daegu 702-701, Korea ...
Random matrix model of adiabatic quantum computing
International Nuclear Information System (INIS)
Mitchell, David R.; Adami, Christoph; Lue, Waynn; Williams, Colin P.
2005-01-01
We present an analysis of the quantum adiabatic algorithm for solving hard instances of 3-SAT (an NP-complete problem) in terms of random matrix theory (RMT). We determine the global regularity of the spectral fluctuations of the instantaneous Hamiltonians encountered during the interpolation between the starting Hamiltonians and the ones whose ground states encode the solutions to the computational problems of interest. At each interpolation point, we quantify the degree of regularity of the average spectral distribution via its Brody parameter, a measure that distinguishes regular (i.e., Poissonian) from chaotic (i.e., Wigner-type) distributions of normalized nearest-neighbor spacings. We find that for hard problem instances - i.e., those having a critical ratio of clauses to variables - the spectral fluctuations typically become irregular across a contiguous region of the interpolation parameter, while the spectrum is regular for easy instances. Within the hard region, RMT may be applied to obtain a mathematical model of the probability of avoided level crossings and concomitant failure rate of the adiabatic algorithm due to nonadiabatic Landau-Zener-type transitions. Our model predicts that if the interpolation is performed at a uniform rate, the average failure rate of the quantum adiabatic algorithm, when averaged over hard problem instances, scales exponentially with increasing problem size
Resonant ion-pair formation in the recombination of NO+ with electrons: Cross-section determination
International Nuclear Information System (INIS)
Le Padellec, A.; Djuric, N.; Al-Khalili, A.; Danared, H.; Derkatch, A. M.; Neau, A.; Popovic, D. B.; Rosen, S.; Semaniak, J.; Thomas, R.
2001-01-01
Resonant ion-pair formation from the collisions of NO + ions with electrons was studied using the heavy-ion storage ring CRYRING at the Manne Siegbahn Laboratory of Stockholm University. The total cross section is measured for the formation of N + +O - for electron energies 8--18 eV, and the results are compared with ion-pair formation in photoionization work. A peak in the cross section is observed at 12.5 eV, with a magnitude of 8.5 x 10 -19 cm 2 . An attempt to extract the cross section for the reverse process of associative ionization is made
International Nuclear Information System (INIS)
de Saussure, G.; Leal, L.C.; Perez, R.B.
1990-01-01
In the first part of this paper, a reevaluation of the low-energy neutron cross sections of 235 U is described. This reevaluation was motivated by the discrepancy between the measured and computed temperature coefficients of reactivity and is based on recent measurements of the fission cross section and of η in the thermal and subthermal neutron energy regions. In the second part of the paper, we discuss the conversion of the Reich-Moore resonance parameters, describing the neutron cross sections of 235 U in the resolved resonance region, into equivalent Adler-Adler resonance parameters and into equivalent momentum space multipole resonance parameters. 25 refs., 4 figs., 5 tabs
International Nuclear Information System (INIS)
Saussure, G. de; Leal, L.C.; Perez, R.B.
1990-01-01
In the first part of this paper, a reevaluation of the low-energy neutron cross sections of 235 U is described. This reevaluation was motivated by the discrepancy between the measured and computed temperature coefficients of reactivity and is based on recent measurements of the fission cross section and of η in the thermal and subthermal neutron energy regions. In the second part of the paper, we discuss the conversion of the Reich-Moore resonance parameters, describing the neutron cross sections of 235 U in the resolved resonance region, into equivalent Adler-Adler resonance parameters and into equivalent momentum space multipole resonance parameters
International Nuclear Information System (INIS)
Goodrich, C.C.; Scudder, J.D.
1984-01-01
In collisionless magnetosonic shock waves, ions are commonly thought to be decelerated by dc electrostatic cross-shock electric field along the shock normal n. In a frame where ions are normally incident to the shock the change in the potential energy [qphi/sup N/] in the quasi-perpendicular geommetry is of the order of the change of the energy of normal ion flow: [qphi/sup N/]roughly-equal[1/2m/sub i/(V/sub i//sup N/xn) 2 ], which is approximately 200-500 eV at the earth's bow shock. We show that the electron energy gain, typically 1/10 this number, is consistent with such a large potential jump in this geometry. Key facts are the different paths taken by electrons an ions through the shock wave and the frame dependence of the potential jump in the geometry. In the normal incidence frame, electrons lose energy by doing work against the solar wind motional electric field E/sub M//sup N/, which partially offsets the energy gain from the cross-shock electrostatic potential energy [ephi/sub asterisk//sup N/]. In the de Hoffman-Teller frame the motional electric field vanishes; the elctrons gain the full electrostatic potential energy jump e[phi/sub asterisk//sup H//sup T/] of that frame, which is not, however, equal to the electrostatic potential energy jump e[phi/sub asterisk//sup N/] of that frame, which is not, however, equal to the electrostatic potential energy jump e[phi/sub asterisk//sup N/] in the normal incidence frame
International Nuclear Information System (INIS)
Belanova, T.S.
1994-12-01
Data on the thermal neutron fission and capture cross-sections as well as their corresponding resonance integrals are reviewed and analysed. The data are classified according to the form of neutron spectra under investigation. The weighted mean values of the cross-sections and resonance integrals for every type of neutron spectra were adopted as evaluated data. (author). 87 refs, 2 tabs
Total and fission cross-sections of 239Pu - statistical study of resonance parameters
International Nuclear Information System (INIS)
Derrien, H.; Blons, J.; Eggermann, C.; Michaudon, A.; Paya, D.; Ribon, P.
1967-01-01
The authors measured the total and fission cross-sections of 239 Pu with the linear accelerator at Saclay as a pulsed source of neutrons. The total cross-section was measured in the range from 4 to 700 eV and the best resolution used was 1.5 ns/m; the fission cross-section was measured between 4 eV and 6 keV, the best resolution having been 6 ns/m. The transmission measurements on five samples were made at the temperature of liquid nitrogen, and comparisons made with supplementary experiments at ambient temperature made it possible to determine the Doppler broadening factor (Δ = η√E). The resonances were identified from 4 to 500 eV in the total cross-section; the average level spacing was of the order of 2.4 eV. It would appear that, in this energy range, nearly all the levels were identified. The resonance parameters were determined by analysis of shape in conjunction with a least-squares programme on an IBM-7094 computer. The existence of a large number of broad resonances corresponding to very large fission widths has been shown to exist. Statistical study of the fission widths actually shows the existence of two families of resonances, one corresponding to a mean Γ f of the order of 45 meV and the other to a mean Γ/f of about 750 meV. The authors were therefore able to postulate a classification of resonances in terms of two spin states, the level population ratio in each family being: (2J 1 +1)/(2J 2 +1) = 1/3; J 1 = 0 corresponds to the broad resonances and J 2 = 1 to the narrow ones. The partial widths for radiative capture fluctuate slightly around a mean value of 40 meV. By using a multilevel programme, the authors were able to investigate the extent to which the existence of large fission widths might give rise to fictitious resonances (quasi-resonances) and perturbations and also to make a statistical study of the resonance parameters. (author) [fr
A New Scaling Law of Resonance in Total Scattering Cross Section in Gases
Raju, Gorur Govinda
2009-10-01
Electrical discharges in gases continue to be an active area of research because of industrial applications such as power systems, environmental clean up, laser technology, semiconductor fabrication etc. A fundamental knowledge of electron-gas neutral interaction is indispensable and, the total scattering cross section is one of the quantities that have been measured extensively. The energy dependence of the total cross sections shows peaks or resonance processes that are operative in the collision process. These peaks and the energies at which they occur are shown to satisfy a broad relationship involving the polarizability and the dipole moment of the target particle. Data on 62 target particles belonging to the following species are analyzed. (Eq 1) Rare gas atoms (Eq 2) Di-atomic molecules with combinations of polar, non-polar, attaching, and non-attaching properties Poly-atomic molecules with combinations of polar, non-polar, attaching, and non-attaching properties. Methods of improving the newly identified scaling law and possible application have been identified. 1 INTRODUCTION: Data on electron-neutral interactions are one of the most fundamental in the study of gaseous electronics and an immense literature, both experimental and theoretical, has become available since about the year 1920. [1-5]. In view of the central role which these data play in all facets of gas discharges and plasma science, it is felt that a critical review of available data is timely, mainly for the community of high voltage engineers and industries connected with plasma science in general. The electron-neutral interaction, often referred to as scattering in the scientific literature, is quantified by using the quantity called the total scattering cross section (QT, m^2). In the literature on cross section, total cross section and total scattering cross section are terms used synonymously and we follow the same practice. A definition may be found in reference [1]. This paper concerns
International Nuclear Information System (INIS)
Detken, Andreas; Hardy, Edme H.; Ernst, Matthias; Kainosho, Masatsune; Kawakami, Toru; Aimoto, Saburo; Meier, Beat H.
2001-01-01
The application of adiabatic polarization-transfer experiments to resonance assignment in solid, uniformly 13 C- 15 N-labelled polypeptides is demonstrated for the cyclic decapeptide antamanide. A homonuclear correlation experiment employing the DREAM sequence for adiabatic dipolar transfer yields a complete assignment of the C α and aliphatic side-chain 13 C resonances to amino acid types. The same information can be obtained from a TOBSY experiment using the recently introduced P9 1 12 TOBSY sequence, which employs the J couplings as a transfer mechanism. A comparison of the two methods is presented. Except for some aromatic phenylalanine resonances, a complete sequence-specific assignment of the 13 C and 15 N resonances in antamanide is achieved by a series of selective or broadband adiabatic triple-resonance experiments. Heteronuclear transfer by adiabatic-passage Hartmann-Hahn cross polarization is combined with adiabatic homonuclear transfer by the DREAM and rotational-resonance tickling sequences into two- and three-dimensional experiments. The performance of these experiments is evaluated quantitatively
International Nuclear Information System (INIS)
Curati, Walter L.; Oatridge, Angela; Herlihy, Amy H.; Hajnal, Joseph V.; Puri, Basant K.; Bydder, Graeme M.
2001-01-01
AIM: The aim of this study was to compare the performance of three fluid attenuated inversion recovery (FLAIR) pulse sequences for control of cerebrospinal fluid (CSF) and blood flow artifacts in imaging of the brain. The first of these sequences had an initial sinc inversion pulse which was followed by conventional k-space mapping. The second had an initial sinc inversion pulse followed by k-space re-ordered by inversion time at each slice position (KRISP) and the third had an adiabatic initial inversion pulse followed by KRISP. MATERIALS AND METHODS: Ten patients with established disease were studied with all three pulse sequences. Seven were also studied with the adiabatic KRISP sequence after contrast enhancement. Their images were evaluated for patient motion artifact, CSF and blood flow artifact as well as conspicuity of the cortex, meninges, ventricular system, brainstem and cerebellum. The conspicuity of lesions and the degree of enhancement were also evaluated. RESULTS: Both the sinc and adiabatic KRISP FLAIR sequences showed better control of CSF and blood flow artifacts than the conventional FLAIR sequence. In addition the adiabatic KRISP FLAIR sequence showed better control of CSF artifact at the inferior aspect of the posterior fossa. The lesion conspicuity was similar for each of the FLAIR sequences as was the degree of contrast enhancement to that shown with a T 1 weighted spin echo sequence. CONCLUSION: The KRISP FLAIR sequence controls high signal artifacts from CSF flow and blood flow and the adiabatic pulse controls high signal artifacts due to inadequate inversion of the CSF magnetization at the periphery of the head transmitter coil. The KRISP FLAIR sequence also improves cortical and meningeal definition as a result of an edge enhancement effect. The effects are synergistic and can be usefully combined in a single pulse sequence. Curati, W.L. et al. (2001)
Decoherence in a scalable adiabatic quantum computer
International Nuclear Information System (INIS)
Ashhab, S.; Johansson, J. R.; Nori, Franco
2006-01-01
We consider the effects of decoherence on Landau-Zener crossings encountered in a large-scale adiabatic-quantum-computing setup. We analyze the dependence of the success probability--i.e., the probability for the system to end up in its new ground state--on the noise amplitude and correlation time. We determine the optimal sweep rate that is required to maximize the success probability. We then discuss the scaling of decoherence effects with increasing system size. We find that those effects can be important for large systems, even if they are small for each of the small building blocks
International Nuclear Information System (INIS)
Alhassid, Y.; Bush, B.; Yale Univ., New Haven, CT
1990-01-01
The effects of time-dependent shape fluctuations on the giant dipole resonance (GDR) in hot rotating nuclei are investigated. Using the framework of the Landau theory of shape transitions we develop a realistic macroscopic stochastic model to describe the quadrupole time-dependent shape fluctuations and their coupling to the dipole degrees of freedom. In the adiabatic limit the theory reduces to a previous adiabatic theory of static fluctuations in which the GDR cross section is calculated by averaging over the equilibrium distribution with the unitary invariant metric. Nonadiabatic effects are investigated in this model and found to cause structural changes in the resonance cross section and motional narrowing. Comparisons with experimental data are made and deviations from the adiabatic calculations can be explained. In these cases it is possible to determine from the data the damping of the quadrupole motion at finite temperature. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Haeggblom, H
1969-02-15
In order to investigate some aspects of the 'Intermediate Resonance Approximation' developed by Goldstein and Cohen, comparative calculations have been made using this method together with more accurate methods. The latter are as follows: a) For homogeneous materials the slowing down equation is solved in the fundamental mode approximation with the computer programme SPENG. All cross sections are given point by point. Because the spectrum can be calculated for at most 2000 energy points, the energy regions where the resonances are accurately described are limited. Isolated resonances in the region 100 to 240 eV are studied for {sup 238}U/Fe and {sup 238}U/Fe/Na mixtures. In the regions 161 to 251 eV and 701 to 1000 eV, mixtures of {sup 238}U and Na are investigated. {sup 239}Pu/Na and {sup 239}Pu/{sup 238}U/Na mixtures are studied in the region 161 to 251 eV. b) For heterogeneous compositions in slab geometry the integral transport equation is solved using the FLIS programme in 22 energy groups. Thus, only one resonance can be considered in each calculation. Two resonances are considered, namely those belonging to {sup 238}U at 190 and 937 eV. The compositions are lattices of {sup 238}U and Fe plates. The computer programme DORIX is used for the calculations using the Intermediate Resonance Approximation. Calculations of reaction rates and effective cross sections are made at 0, 300 and 1100 deg K for homogeneous media and at 300 deg K for heterogeneous media. The results are compared to those obtained by using the programmes SPENG and FLIS and using the narrow resonance approximation.
Testing of cross-section functionals in the unresolved resonance region
International Nuclear Information System (INIS)
Koshcheev, V.N.; Krivtsov, A.S.; Sinitsa, V.V.; Ukraintsev, V.F.
1994-01-01
The results of a comparison of the GRUCON, MMK and NJOY data processing codes in the treatment of evaluated neutron data in the unresolved resonance region are presented. The sets of average resonance parameters of 238 U and 239 Pu isotopes, which have been published by Munos-Cobos et al., and Ribon et al., were used in this exercise. Average cross-sections, self-shielding factors and Doppler broadening self-shielding factors are compared with the original results presented by the above-mentioned authors. Conclusions regarding the reliability of the neutron data processing codes are made. (author). 6 refs, 7 tabs
Compact beam splitters in coupled waveguides using shortcuts to adiabaticity
Chen, Xi; Wen, Rui-Dan; Shi, Jie-Long; Tseng, Shuo-Yen
2018-04-01
There are various works on adiabatic (three) waveguide coupler devices but most are focused on the quantum optical analogies and the physics itself. We successfully apply shortcuts to adiabaticity techniques to the coupled waveguide system with a suitable length for integrated optics devices. Especially, the counter-diabatic driving protocol followed by unitary transformation overcomes the previously unrealistic implemention, and is used to design feasible and robust 1 × 2 and 1 × 3 beam splitters for symmetric and asymmetric three waveguide couplers. Numerical simulations with the beam propagation method demonstrate that these shortcut designs for beam splitters are shorter than the adiabatic ones, and also have a better tolerance than parallel waveguides resonant beam splitters with respect to spacing errors and wavelength variation.
Contribution to the study of the unresolved resonance range of the neutrons cross sections
International Nuclear Information System (INIS)
Noguere, Gilles
2014-01-01
This document presents the statistical description of neutron cross sections in the unresolved resonance range. The modeling of the total cross section and of the 'shape - elastic' cross section is based on the 'average R-Matrix' formalism. The partial cross sections describing the radiative capture, elastic scattering, inelastic scattering and fission process are calculated using the Hauser-Feshbach formalism with width fluctuation corrections. In the unresolved resonance range, these models depend on the average resonance parameters (neutron strength function Sc, mean level spacing D c , average partial reaction widths Γ c , channel radius a c , effective radius R' and distant level parameter R-bar c ∞ ). The codes (NJOY, CALENDF...) dedicated to the processing of nuclear data libraries (JEFF, ENDF/B, JENDL, CENDL, BROND... ) use the average parameters to take into account the self-shielding phenomenon for the simulation of the neutron transport in Monte-Carlo (MCNP, TRIPOLI... ) and deterministic (APOLLO, ERANOS...) codes. The evaluation work consists in establishing a consistent set of average parameters as a function of the total angular momentum J of the system and of the orbital moment of the incident neutron l. The work presented in this paper aims to describe the links between the S-Matrix and the 'average R-Matrix' formalism for the calculation of Sc, R-bar c ∞ , ac and R'. (author) [fr
Interplay between electric and magnetic effect in adiabatic polaritonic systems
Alabastri, Alessandro; Toma, Andrea; Liberale, Carlo; Chirumamilla, Manohar; Giugni, Andrea; De Angelis, Francesco De; Das, Gobind; Di Fabrizio, Enzo M.; Proietti Zaccaria, Remo
2013-01-01
We report on the possibility of realizing adiabatic compression of polaritonic wave on a metallic conical nano-structure through an oscillating electric potential (quasi dynamic regime). By comparing this result with an electromagnetic wave excitation, we were able to relate the classical lighting-rod effect to adiabatic compression. Furthermore, we show that while the magnetic contribution plays a marginal role in the formation of adiabatic compression, it provides a blue shift in the spectral region. In particular, magnetic permeability can be used as a free parameter for tuning the polaritonic resonances. The peculiar form of adiabatic compression is instead dictated by both the source and the metal permittivity. The analysis is performed by starting from a simple electrostatic system to end with the complete electromagnetic one through intermediate situations such as the quasi-electrostatic and quasi-dynamic regimes. Each configuration is defined by a particular set of equations which allows to clearly determine the individual role played by the electric and magnetic contribution in the generation of adiabatic compression. We notice that these findings can be applied for the realization of a THz nano-metric generator. © 2013 Optical Society of America.
International Nuclear Information System (INIS)
de Saussure, G.; Perez, R.B.
1981-01-01
Several aspects of the measurement, analysis and evaluation of the cross sections of the fertile and fissile nuclides in the resonance regions are discussed. In the resolved range, for the fertile nuclides it is thought that the principal requirement for improved evaluations is for a practical methodology to deal with systematic errors and their correlations. For the fissile nuclides 235 U and 239 Pu, the ENDF/B-V evaluations are not consistent with ENDF/B procedures recommendations and fall short of the goals of resonance analysis. New evaluations of these two isotopes should be performed. In the unresolved resonance region it is shown that the ENDF/B representation is ambiguous and is not theoretically justified. A better representation may be desirable, and a validation of the representation with experimental self-shielding and transmission measurements is certainly required. 105 references
Atlas of giant dipole resonances. Parameters and graphs of photonuclear reaction cross sections
International Nuclear Information System (INIS)
Varlamov, A.V.; Varlamov, V.V.; Rudenko, D.S.; Stepanov, M.E.
1999-01-01
Parameters of giant dipole resonances (GDR) observed in photonuclear reaction cross sections using various beams of incident photons are presented. Data, given for 200 stable isotopes from 2 H to 243 Am including their natural compositions, were collected from papers published over the years 1951-1996. GDR parameters, such as energy positions, amplitudes and widths, are included into the table and organized by element, isotope and reaction. Graphs of the majority of the photonuclear reaction cross sections, included in the international nuclear data library EXFOR by the end of 1998, are presented. The graphs are provided for 182 stable isotopes and natural compositions. (author)
Review of the microscopic cross sections for the americium isotopes in the resolved resonance region
International Nuclear Information System (INIS)
Browne, J.C.
1978-01-01
The differential cross section measurements for 241 Am, /sup 242m/Am and 243 Am are reviewed in the energy range from 0.5 eV to 10 keV. Parameters extracted from resonance analysis, such as the neutron strength function, the average level spacing, the average capture and fission widths, are compared for the various measurements. The average capture and fission cross sections from 100 eV to 10 keV are directly compared. The status of the data set is discussed with suggestions for further measurements. 24 references
X-ray resonant Raman scattering cross sections of Mn, Fe, Cu and Zn
International Nuclear Information System (INIS)
Sanchez, Hector Jorge; Valentinuzzi, MarIa Cecilia; Perez, Carlos
2006-01-01
X-ray fluorescence spectra present singular characteristics produced by the different scattering processes. When atoms are irradiated with incident energy lower and close to an absorption edge, scattering peaks appear due to an inelastic process known as resonant Raman scattering. It constitutes an important contribution to the background of the fluorescent line. The resonant Raman scattering must be taken into account in the determination of low concentration contaminants, especially when the elements have proximate atomic numbers. The values of the mass attenuation coefficients experimentally obtained when materials are analysed with monochromatic x-ray beams under resonant conditions differ from the theoretical values (between 5% and 10%). This difference is due, in part, to the resonant Raman scattering. Monochromatic synchrotron radiation was used to study the Raman effect on pure samples of Mn, Fe, Cu and Zn. Energy scans were carried out in different ranges of energy near the absorption edge of the target element. As the Raman peak has a non-symmetric shape, theoretical models for the differential cross section, convoluted with the instrument function, were used to determine the RRS cross section as a function of the incident energy
Unresolved resonance range cross section, probability tables and self shielding factor
International Nuclear Information System (INIS)
Sublet, J.Ch.; Blomquist, R.N.; Goluoglu, S.; Mac Farlane, R.E.
2009-07-01
The performance and methodology of 4 processing codes have been compared in the unresolved resonance range of a selected set of isotopes. Those isotopes have been chosen to encompass most cases encountered in the unresolved energy range contained in major libraries like Endf/B-7 or Jeff-3.1.1. The code results comparison is accompanied by data format and formalism examinations and processing code fine-interpretation study. After some improvements, the results showed generally good agreement, although not perfect with infinite dilute cross-sections. However, much larger differences occur when shelf-shielded effective cross-sections are compared. The infinitely dilute cross-section are often plot checked but it is the probability table derived and shelf-shielded cross sections that are used and interpreted in criticality and transport calculations. This suggests that the current evaluation data format and formalism, in the unresolved resonance range should be tightened up, ambiguities removed. In addition production of the shelf shielded cross-sections should be converged to a much greater accuracy. (author)
Energy Technology Data Exchange (ETDEWEB)
Barbosa, Alessandra Souza [Departamento de Física, Universidade Federal do Paraná, CP 19044, 81531-990 Curitiba, Paraná (Brazil); Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Varella, Márcio T. do N. [Instituto de Física, Universidade de São Paulo, Rua do Matão 1731, 05508-090 São Paulo, SP (Brazil); Sanchez, Sergio d’A.; Bettega, Márcio H. F., E-mail: bettega@fisica.ufpr.br [Departamento de Física, Universidade Federal do Paraná, CP 19044, 81531-990 Curitiba, Paraná (Brazil); Ameixa, João; Limão-Vieira, Paulo; Ferreira da Silva, Filipe [Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Blanco, Francisco [Departamento de Física Atómica, Molecular y Nuclear, Facultad de Ciencias Físicas, Universidad Complutense de Madrid, E-28040 Madrid (Spain); and others
2016-08-28
In this work, we report theoretical and experimental cross sections for elastic scattering of electrons by chlorobenzene (ClB). The theoretical integral and differential cross sections (DCSs) were obtained with the Schwinger multichannel method implemented with pseudopotentials (SMCPP) and the independent atom method with screening corrected additivity rule (IAM-SCAR). The calculations with the SMCPP method were done in the static-exchange (SE) approximation, for energies above 12 eV, and in the static-exchange plus polarization approximation, for energies up to 12 eV. The calculations with the IAM-SCAR method covered energies up to 500 eV. The experimental differential cross sections were obtained in the high resolution electron energy loss spectrometer VG-SEELS 400, in Lisbon, for electron energies from 8.0 eV to 50 eV and angular range from 7{sup ∘} to 110{sup ∘}. From the present theoretical integral cross section (ICS) we discuss the low-energy shape-resonances present in chlorobenzene and compare our computed resonance spectra with available electron transmission spectroscopy data present in the literature. Since there is no other work in the literature reporting differential cross sections for this molecule, we compare our theoretical and experimental DCSs with experimental data available for the parent molecule benzene.
Thermal neutron capture and resonance integral cross sections of {sup 45}Sc
Energy Technology Data Exchange (ETDEWEB)
Van Do, Nguyen; Duc Khue, Pham; Tien Thanh, Kim [Institute of Physics, Vietnam Academy of Science and Technology, 10 Dao Tan, Hanoi (Viet Nam); Thi Hien, Nguyen [Institute of Physics, Vietnam Academy of Science and Technology, 10 Dao Tan, Hanoi (Viet Nam); Department of Physics and Center for High Energy Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Kim, Guinyun, E-mail: gnkim@knu.ac.kr [Department of Physics and Center for High Energy Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Kim, Kwangsoo [Department of Physics and Center for High Energy Physics, Kyungpook National University, Daegu 702-701 (Korea, Republic of); Shin, Sung-Gyun; Cho, Moo-Hyun [Department of Advanced Nuclear Engineering, Pohang University of Science and Technology, Pohang 790-784 (Korea, Republic of); Lee, Manwoo [Research Center, Dongnam Institute of Radiological and Medical Science, Busan 619-953 (Korea, Republic of)
2015-11-01
The thermal neutron cross section (σ{sub 0}) and resonance integral (I{sub 0}) of the {sup 45}Sc(n,γ){sup 46}Sc reaction have been measured relative to that of the {sup 197}Au(n,γ){sup 198}Au reaction by means of the activation method. High-purity natural scandium and gold foils without and with a cadmium cover of 0.5 mm thickness were irradiated with moderated pulsed neutrons produced from the Pohang Neutron Facility (PNF). The induced activities in the activated foils were measured with a high purity germanium (HPGe) detector. In order to improve the accuracy of the experimental results the counting losses caused by the thermal (G{sub th}) and resonance (G{sub epi}) neutron self-shielding, the γ-ray attenuation (F{sub g}) and the true γ-ray coincidence summing effects were made. In addition, the effect of non-ideal epithermal spectrum was also taken into account by determining the neutron spectrum shape factor (α). The thermal neutron cross-section and resonance integral of the {sup 45}Sc(n,γ){sup 46}Sc reaction have been determined relative to the reference values of the {sup 197}Au(n,γ){sup 198}Au reaction, with σ{sub o,Au} = 98.65 ± 0.09 barn and I{sub o,Au} = 1550 ± 28 barn. The present thermal neutron cross section has been determined to be σ{sub o,Sc} = 27.5 ± 0.8 barn. According to the definition of cadmium cut-off energy at 0.55 eV, the present resonance integral cross section has been determined to be I{sub o,Sc} = 12.4 ± 0.7 barn. The present results are compared with literature values and discussed.
International Nuclear Information System (INIS)
Anaf, J.; Chalhoub, E.S.
1989-01-01
A program (RESQ) based on quadratures that evaluates, from ENDF/B data, the resolved resonance contribution in group-averaged cross sections (capture, fission and scattering) was developed. Single and Multilevel Breit-Wigner parameters are accepted. Constant weighting function and zero Kelvin were considered. To assure convergence, different quadrature orders may be analysed. Results are compared with other codes' reconstruction and integration methods. (author) [pt
Ainslie, M.A.; Leighton, T.G.
2009-01-01
The scattering cross-section σs of a gas bubble of equilibrium radius R0 in liquid can be written in the form σs =4π R02 / [(ω12 / ω2 -1)2 + δ2], where ω is the excitation frequency, ω1 is the resonance frequency, and δ is a frequency-dependent dimensionless damping coefficient. A persistent
Display of cross sectional anatomy by nuclear magnetic resonance imaging. 1978.
Hinshaw, W S; Andrew, E R; Bottomley, P A; Holland, G N; Moore, W S
1995-12-01
High definition cross-sectional images produced by a new nuclear magnetic resonance (NMR) technique are shown. The images are a series of thin section scans in the coronal plane of the head of a rabbit. The NMR images are derived from the distribution of the density of mobile hydrogen atoms. Various tissue types can be distinguished and a clear registration of gross anatomy is demonstrated. No known hazards are associated with the technique.
Alperovich, Z.; Buchinsky, O.; Greenstein, S.; Ishaaya, A. A.
2017-08-01
We investigate the misalignment sensitivity in a crossed-Porro resonator configuration when coherently combining two pulsed multimode Nd:YAG laser channels. To the best of our knowledge, this is the first reported study of this configuration. The configuration is based on a passive intra-cavity interferometric combiner that promotes self-phase locking and coherent combining. Detailed misalignment sensitivity measurements are presented, examining both translation and angular deviations of the end prisms and combiner, and are compared to the results for standard flat end-mirror configurations. The results show that the most sensitive parameter in the crossed-Porro resonator configuration is the angular tuning of the intra-cavity interferometric combiner, which is ~±54 µrad. In comparison, with the flat end mirror configuration, the most sensitive parameter in the resonator is the angular tuning of the output coupler, which is ~±11 µrad. Thus, with the crossed-Porro configuration, we obtain significantly reduced sensitivity. This ability to reduce the misalignment sensitivity in coherently combined solid-state configurations may be beneficial in paving their way into practical use in a variety of demanding applications.
Adiabatic temperature change from non-adiabatic measurements
Czech Academy of Sciences Publication Activity Database
Carvalho, A.M.G.; Mejía, C.S.; Ponte, C.A.; Silva, L.E.L.; Kaštil, Jiří; Kamarád, Jiří; Gomes, A.M.
2016-01-01
Roč. 122, č. 3 (2016), s. 1-5, č. článku 246. ISSN 0947-8396 Institutional support: RVO:68378271 Keywords : magnetocaloric effect * adiabatic temperature change * calorimetric device * gadolinium Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.455, year: 2016
Adiabatic/diabatic polarization beam splitter
Energy Technology Data Exchange (ETDEWEB)
DeRose, Christopher; Cai, Hong
2017-09-12
The various presented herein relate to an on-chip polarization beam splitter (PBS), which is adiabatic for the transverse magnetic (TM) mode and diabatic for the transverse electric (TE) mode. The PBS comprises a through waveguide and a cross waveguide, wherein an electromagnetic beam comprising TE mode and TM mode components is applied to an input port of the through waveguide. The PBS can be utilized to separate the TE mode component from the TM mode component, wherein the TE mode component exits the PBS via an output port of the through waveguide, and the TM mode component exits the PBS via an output port of the cross waveguide. The PBS has a structure that is tolerant to manufacturing variations and exhibits high polarization extinction ratios over a wide bandwidth.
Adiabatic quantum pumping and charge quantization
International Nuclear Information System (INIS)
Kashcheyevs, V; Aharony, A.; Entin-Wohlmanl, O.
2004-01-01
Full Text:Modern techniques for coherent manipulation of electrons at the nano scale (electrostatic gating, surface acoustic waves) allow for studies of the adiabatic quantum pumping effect - a directed current induced by a slowly varying external perturbation. Scattering theory of pumping predicts transfer of an almost integer number of electrons per cycle if instantaneous transmission is determined by a sequence of resonances. We show that this quantization can be explained in terms of loading/unloading quasi-bound virtual states, and derive a tool for analyzing quantized pumping induced by a general potential. This theory is applied to a simple model of pumping due to surface acoustic waves. The results reproduce all the qualitative features observed in actual experiments
International Nuclear Information System (INIS)
Meftah, B.; Karam, R.A.
1984-01-01
Agreement between calculations and measurements within prescribed limits of error is always the test of engineering design analysis. Large and puzzling discrepancies do exist between several measured and calculated important integral reactor parameters. A thorough and exhaustive investigation of the methods used in reactor analysis revealed that in the generation of effective resonance cross sections no anisotropy effects are considered in the resonances. This is true in the integral transport and fundamental-mode codes. The neglect of anisotropy introduces errors at two levels: (1) the effective group cross sections such as σsub(c), σsub(f) and σsub(s); and (2) the diffusion coefficients and P 1 and higher components of the scattering cross sections. The study showed that the inclusion of linear scattering anisotropy increases, in general, the cell effective capture cross section of 238 U in both ZPR-6/5 and TRX-3 reactors. The increase was up to 2% in TRX-3 and 0.5% in ZPR-6/5. The effect on the multiplication factor was -0.003% Δk/k for ZPR-6/5 and -0.05% Δk/k for TRX-3. (author)
Quantum adiabatic Markovian master equations
International Nuclear Information System (INIS)
Albash, Tameem; Zanardi, Paolo; Boixo, Sergio; Lidar, Daniel A
2012-01-01
We develop from first principles Markovian master equations suited for studying the time evolution of a system evolving adiabatically while coupled weakly to a thermal bath. We derive two sets of equations in the adiabatic limit, one using the rotating wave (secular) approximation that results in a master equation in Lindblad form, the other without the rotating wave approximation but not in Lindblad form. The two equations make markedly different predictions depending on whether or not the Lamb shift is included. Our analysis keeps track of the various time and energy scales associated with the various approximations we make, and thus allows for a systematic inclusion of higher order corrections, in particular beyond the adiabatic limit. We use our formalism to study the evolution of an Ising spin chain in a transverse field and coupled to a thermal bosonic bath, for which we identify four distinct evolution phases. While we do not expect this to be a generic feature, in one of these phases dissipation acts to increase the fidelity of the system state relative to the adiabatic ground state. (paper)
Transitionless driving on adiabatic search algorithm
Energy Technology Data Exchange (ETDEWEB)
Oh, Sangchul, E-mail: soh@qf.org.qa [Qatar Environment and Energy Research Institute, Qatar Foundation, Doha (Qatar); Kais, Sabre, E-mail: kais@purdue.edu [Qatar Environment and Energy Research Institute, Qatar Foundation, Doha (Qatar); Department of Chemistry, Department of Physics and Birck Nanotechnology Center, Purdue University, West Lafayette, Indiana 47907 (United States)
2014-12-14
We study quantum dynamics of the adiabatic search algorithm with the equivalent two-level system. Its adiabatic and non-adiabatic evolution is studied and visualized as trajectories of Bloch vectors on a Bloch sphere. We find the change in the non-adiabatic transition probability from exponential decay for the short running time to inverse-square decay in asymptotic running time. The scaling of the critical running time is expressed in terms of the Lambert W function. We derive the transitionless driving Hamiltonian for the adiabatic search algorithm, which makes a quantum state follow the adiabatic path. We demonstrate that a uniform transitionless driving Hamiltonian, approximate to the exact time-dependent driving Hamiltonian, can alter the non-adiabatic transition probability from the inverse square decay to the inverse fourth power decay with the running time. This may open up a new but simple way of speeding up adiabatic quantum dynamics.
International Nuclear Information System (INIS)
Bosted, P. E.; Christy, M. E.
2008-01-01
An empirical fit is described to measurements of inclusive inelastic electron-deuteron cross sections in the kinematic range of four-momentum transfer 0≤Q 2 2 and final state invariant mass 1.1 p of longitudinal to transverse cross sections for the proton, and the assumption R p =R n . The underlying fit parameters describe the average cross section for a free proton and a free neutron, with a plane-wave impulse approximation used to fit to the deuteron data. Additional fit parameters are used to fill in the dip between the quasi-elastic peak and the Δ(1232) resonance. The mean deviation of data from the fit is 3%, with less than 4% of the data points deviating from the fit by more than 10%
Thermal neutron capture cross sections resonance integrals and g-factors
International Nuclear Information System (INIS)
Mughabghab, S.F.
2003-02-01
The thermal radiative capture cross sections and resonance integrals of elements and isotopes with atomic numbers from 1 to 83 (as well as 232 Th and 238 U) have been re-evaluated by taking into consideration all known pertinent data published since 1979. This work has been undertaken as part of an IAEA co-ordinated research project on 'Prompt capture gamma-ray activation analysis'. Westcott g-factors for radiative capture cross sections at a temperature of 300K were computed by utilizing the INTER code and ENDF-B/VI (Release 8) library files. The temperature dependence of the Westcott g-factor is illustrated for 113 Cd, 124 Xe and 157 Gd at temperatures of 150, 294 and 400K. Comparisons have also been made of the newly evaluated capture cross sections of 6 Li, 7 Li, 12 C and 207 Pb with those determined by the k 0 method. (author)
Kotlarchyk, Michael; Thurston, George M
2016-12-28
In this work we study the potential for utilizing the scattering of polarized neutrons from nuclei whose spin has been modulated using nuclear magnetic resonance (NMR). From first principles, we present an in-depth development of the differential scattering cross sections that would arise in such measurements from a hypothetical target system containing nuclei with non-zero spins. In particular, we investigate the modulation of the polarized scattering cross sections following the application of radio frequency pulses that impart initial transverse rotations to selected sets of spin-1/2 nuclei. The long-term aim is to provide a foundational treatment of the scattering cross section associated with enhancing scattering signals from selected nuclei using NMR techniques, thus employing minimal chemical or isotopic alterations, so as to advance the knowledge of macromolecular or liquid structure.
Studies in Chaotic adiabatic dynamics
International Nuclear Information System (INIS)
Jarzynski, C.
1994-01-01
Chaotic adiabatic dynamics refers to the study of systems exhibiting chaotic evolution under slowly time-dependent equations of motion. In this dissertation the author restricts his attention to Hamiltonian chaotic adiabatic systems. The results presented are organized around a central theme, namely, that the energies of such systems evolve diffusively. He begins with a general analysis, in which he motivates and derives a Fokker-Planck equation governing this process of energy diffusion. He applies this equation to study the open-quotes goodnessclose quotes of an adiabatic invariant associated with chaotic motion. This formalism is then applied to two specific examples. The first is that of a gas of noninteracting point particles inside a hard container that deforms slowly with time. Both the two- and three-dimensional cases are considered. The results are discussed in the context of the Wall Formula for one-body dissipation in nuclear physics, and it is shown that such a gas approaches, asymptotically with time, an exponential velocity distribution. The second example involves the Fermi mechanism for the acceleration of cosmic rays. Explicit evolution equations are obtained for the distribution of cosmic ray energies within this model, and the steady-state energy distribution that arises when this equation is modified to account for the injection and removal of cosmic rays is discussed. Finally, the author re-examines the multiple-time-scale approach as applied to the study of phase space evolution under a chaotic adiabatic Hamiltonian. This leads to a more rigorous derivation of the above-mentioned Fokker-Planck equation, and also to a new term which has relevance to the problem of chaotic adiabatic reaction forces (the forces acting on slow, heavy degrees of freedom due to their coupling to light, fast chaotic degrees)
TERRESTRIAL PLANET FORMATION DURING THE MIGRATION AND RESONANCE CROSSINGS OF THE GIANT PLANETS
International Nuclear Information System (INIS)
Lykawka, Patryk Sofia; Ito, Takashi
2013-01-01
The newly formed giant planets may have migrated and crossed a number of mutual mean motion resonances (MMRs) when smaller objects (embryos) were accreting to form the terrestrial planets in the planetesimal disk. We investigated the effects of the planetesimal-driven migration of Jupiter and Saturn, and the influence of their mutual 1:2 MMR crossing on terrestrial planet formation for the first time, by performing N-body simulations. These simulations considered distinct timescales of MMR crossing and planet migration. In total, 68 high-resolution simulation runs using 2000 disk planetesimals were performed, which was a significant improvement on previously published results. Even when the effects of the 1:2 MMR crossing and planet migration were included in the system, Venus and Earth analogs (considering both orbits and masses) successfully formed in several runs. In addition, we found that the orbits of planetesimals beyond a ∼ 1.5-2 AU were dynamically depleted by the strengthened sweeping secular resonances associated with Jupiter's and Saturn's more eccentric orbits (relative to the present day) during planet migration. However, this depletion did not prevent the formation of massive Mars analogs (planets with more than 1.5 times Mars's mass). Although late MMR crossings (at t > 30 Myr) could remove such planets, Mars-like small mass planets survived on overly excited orbits (high e and/or i), or were completely lost in these systems. We conclude that the orbital migration and crossing of the mutual 1:2 MMR of Jupiter and Saturn are unlikely to provide suitable orbital conditions for the formation of solar system terrestrial planets. This suggests that to explain Mars's small mass and the absence of other planets between Mars and Jupiter, the outer asteroid belt must have suffered a severe depletion due to interactions with Jupiter/Saturn, or by an alternative mechanism (e.g., rogue super-Earths)
Investigation of the 93Nb neutron cross-sections in resonance energy range
International Nuclear Information System (INIS)
Grigoriev, Yu.V.; Kitaev, V.Ya.; Zhuravlev, B.V.; Sinitsa, V.V.; Borzakov, S.B.; Faikov-Stanchik, H.; Ilchev, G.; Mezentseva, Zh.V.; Panteleev, Ts.Ts.; Kim, G.N.
2002-01-01
The results of gamma-ray multiplicity spectra and transmission measurements for 93 Nb in energy range 21.5 eV-100 keV are presented. Gamma spectra from 1 to 7 multiplicity were measured on the 501 m and 121 m flight paths of the IBR-30 using a 16-section scintillation detector with a NaI(Tl) crystals of a total volume of 36 l and a 16-section liquid scintillation detector of a total volume of 80 l for metallic samples of 50, 80 mm in diameter and 1, 1.5 mm thickness with 100% 93 Nb. Besides, the total and scattering cross-section of 93 Nb were measured by means batteries of B-10 and He-3 counters on the 124 m, 504 m and 1006 m flight paths of the IBR-30. Spectra of multiplicity distribution were obtained for resolved resonances in the energy region E=30-6000 eV and for energy groups in the energy region E=21.5 eV- 100 keV. They were used for determination of the average multiplicity, resonance parameters and capture cross-section in energy groups and for low-laying resonances of 93 Nb. Standard capture cross-sections of 238 U and experimental gamma-ray multiplicity spectra were also used for determination of capture cross section 93 Nb in energy groups. Similar values were calculated using the ENDF/B-6 and JENDL-3 evaluated data libraries with the help of the GRUKON computer program. Within the limits of experimental errors there is observed an agreement between the experiment and calculation, but in some groups the experimental values differ from the calculated ones. (author)
Investigation of the sup 9 sup 3 Nb neutron cross-sections in resonance energy range
Grigoriev, Y V; Faikov-Stanchik, H; Ilchev, G; Kim, G N; Kitaev, V Ya; Mezentseva, Z V; Panteleev, T; Sinitsa, V V; Zhuravlev, B V
2001-01-01
The results of gamma-ray multiplicity spectra and transmission measurements for sup 9 sup 3 Nb in energy range 21.5 eV-100 keV are presented. Gamma spectra from 1 to 7 multiplicity were measured on the 501 m and 121 m flight paths of the IBR-30 using a 16-section scintillation detector with a NaI(Tl) crystals of a total volume of 36 l and a 16-section liquid scintillation detector of a total volume of 80 l for metallic samples of 50, 80 mm in diameter and 1, 1.5 mm thickness with 100% sup 9 sup 3 Nb. Besides, the total and scattering cross-section of sup 9 sup 3 Nb were measured by means batteries of B-10 and He-3 counters on the 124 m, 504 m and 1006 m flight paths of the IBR-30. Spectra of multiplicity distribution were obtained for resolved resonances in the energy region E=30-6000 eV and for energy groups in the energy region E=21.5 eV- 100 keV. They were used for determination of the average multiplicity, resonance parameters and capture cross-section in energy groups and for low-laying resonances of sup...
Ion Motion in the Adiabatic Focuser
International Nuclear Information System (INIS)
Henestroza, E.; Sessler, A.M.; Yu, S.S.
2006-01-01
In this paper we numerically study the effect of ion motion in an adiabatic focuser, motivated by a recent suggestion that ion motion in an adiabatic focuser might be significant and even preclude operation of the focuser as previously envisioned. It is shown that despite ion motion the adiabatic focuser should work as well as originally envisioned
Crossed-coil detection of two-photon excited nuclear quadrupole resonance
Eles, Philip T.; Michal, Carl A.
2005-08-01
Applying a recently developed theoretical framework for determining two-photon excitation Hamiltonians using average Hamiltonian theory, we calculate the excitation produced by half-resonant irradiation of the pure quadrupole resonance of a spin-3/2 system. This formalism provides expressions for the single-quantum and double-quantum nutation frequencies as well as the Bloch-Siegert shift. The dependence of the excitation strength on RF field orientation and the appearance of the free-induction signal along an axis perpendicular to the excitation field provide an unmistakable signature of two-photon excitation. We demonstrate single- and double-quantum excitation in an axially symmetric system using 35Cl in a single crystal of potassium chlorate ( ωQ = 28 MHz) with crossed-coil detection. A rotation plot verifies the orientation dependence of the two-photon excitation, and double-quantum coherences are observed directly with the application of a static external magnetic field.
Solid-state effects on thermal-neutron cross sections and on low-energy resonances
International Nuclear Information System (INIS)
Harvey, J.A.; Mook, H.A.; Hill, N.W.; Shahal, O.
1982-01-01
The neutron total cross sections of several single crystals (Si, Cu, sapphire), several polycrystalline samples (Cu, Fe, Be, C, Bi, Ta), and a fine-powder copper sample have been measured from 0.002 to 5 eV. The Cu powder and polycrystalline Fe, Be and C data exhibit the expected abrupt changes in cross section. The cross section of the single crystal of Si is smooth with only small broad fluctuations. The data on two single Cu crystals, the sapphire crystal, cast Bi, and rolled samples of Ta and Cu have many narrow peaks approx. 10 -3 eV wide. High resolution (0.3%) transmission measurements were made on the 1.057-eV resonance in 240 Pu and the 0.433-eV resonance in 180 Ta, both at room and low temperatures to study the effects of crystal binding. Although the changes in Doppler broadening with temperature were apparent, no asymmetries due to a recoilless contribution were observed
Quantum state specific reactant preparation in a molecular beam by rapid adiabatic passage
Chadwick, Helen; Hundt, P. Morten; van Reijzen, Maarten E.; Yoder, Bruce L.; Beck, Rainer D.
2014-01-01
Highly efficient preparation of molecules in a specific rovibrationally excited state for gas/surface reactivity measurements is achieved in a molecular beam using tunable infrared (IR) radiation from a single mode continuous wave optical parametric oscillator (cw-OPO). We demonstrate that with appropriate focusing of the IR radiation, molecules in the molecular beam crossing the fixed frequency IR field experience a Doppler tuning that can be adjusted to achieve complete population inversion of a two-level system by rapid adiabatic passage (RAP). A room temperature pyroelectric detector is used to monitor the excited fraction in the molecular beam and the population inversion is detected and quantified using IR bleaching by a second IR-OPO. The second OPO is also used for complete population transfer to an overtone or combination vibration via double resonance excitation using two spatially separated RAP processes.
Adiabatic theorem and spectral concentration
International Nuclear Information System (INIS)
Nenciu, G.
1981-01-01
The spectral concentration of arbitrary order, for the Stark effect is proved to exist for a large class of Hamiltonians appearing in nonrelativistic and relativistic quantum mechanics. The results are consequences of an abstract theorem about the spectral concentration for self-ad oint operators. A general form of the adiabatic theorem of quantum mechanics, generalizing an earlier result of the author as well as some results of Lenard, is also proved [ru
Solid state nuclear magnetic resonance studies of cross polarization from quadrupolar nuclei
Energy Technology Data Exchange (ETDEWEB)
De Paul, Susan M. [Univ. of California, Berkeley, CA (United States)
1997-08-01
The development of solid-state Nuclear Magnetic Resonance (NMR) has, to a large extent, focused on using spin-1/2 nuclei as probes to investigate molecular structure and dynamics. For such nuclei, the technique of cross polarization is well-established as a method for sensitivity enhancement. However, over two-thirds of the nuclei in the periodic table have a spin-quantum number greater than one-half and are known as quadrupolar nuclei. Such nuclei are fundamental constituents of many inorganic materials including minerals, zeolites, glasses, and gels. It is, therefore, of interest to explore the extent to which polarization can be transferred from quadrupolar nuclei. In this dissertation, solid-state NMR experiments involving cross polarization from quadrupolar nuclei to spin-1/2 nuclei under magic-angle spinning (MAS) conditions are investigated in detail.
Plasma heating by adiabatic compression
International Nuclear Information System (INIS)
Ellis, R.A. Jr.
1972-01-01
These two lectures will cover the following three topics: (i) The application of adiabatic compression to toroidal devices is reviewed. The special case of adiabatic compression in tokamaks is considered in more detail, including a discussion of the equilibrium, scaling laws, and heating effects. (ii) The ATC (Adiabatic Toroidal Compressor) device which was completed in May 1972, is described in detail. Compression of a tokamak plasma across a static toroidal field is studied in this device. The device is designed to produce a pre-compression plasma with a major radius of 17 cm, toroidal field of 20 kG, and current of 90 kA. The compression leads to a plasma with major radius of 38 cm and minor radius of 10 cm. Scaling laws imply a density increase of a factor 6, temperature increase of a factor 3, and current increase of a factor 2.4. An additional feature of ATC is that it is a large tokamak which operates without a copper shell. (iii) Data which show that the expected MHD behavior is largely observed is presented and discussed. (U.S.)
Investigation of the 232Th neutron cross-sections in resonance energy range
International Nuclear Information System (INIS)
Grigoriev, Yu.V.; Kitaev, V.Ya.; Sinitsa, V.V.; Zhuravlev, B.V.; Borzakov, S.B.; Faikov-Stanchik, H.; Ilchev, G.L.; Panteleev, Ts.Ts.; Kim, G.N.
2001-01-01
The alternative path in the development of atomic energy is the uranium-thorium cycle. In connection with this, the measurements of the 232 Th neutron capture and total cross-sections and its resonance self-shielding coefficients in resonance energy range are necessary because of their low accuracy. In this work, the results of the investigations of the thorium-232 neutron cross-sections are presented. The measurements have been carried out on the gamma-ray multisection liquid detector and neutron detector as a battery of boron counters on the 120 m flight path of the pulsed fast reactor IBR-30. As the filter samples were used the metallic disks of various thickness and diameter of 45 mm. Two plates from metallic thorium with thickness of 0.2 mm and with the square of 4.5x4.5 cm 2 were used as the radiator samples. The group neutron total and capture cross-sections within the accuracy of 2-7% in the energy range of (10 eV-10 keV) were obtained from the transmissions and the sum spectra of g-rays from the fourth multiplicity to the seventh one. The neutron capture group cross-sections of 238 U were used as the standard for obtaining of thorium ones. Analogous values were calculated on the GRUCON code with the ENDF/B-6, JENDL-3 evaluated data libraries. Within the limits of experimental errors an agreement between the experiment and calculation is observed, but in some groups the experimental values are larger than the calculated ones. (author)
Andrianova, Olga; Lomakov, Gleb; Manturov, Gennady
2017-09-01
The neutron transmission experiments are one of the main sources of information about the neutron cross section resonance structure and effect in the self-shielding. Such kind of data for niobium and silicon nuclides in energy range 7 keV to 3 MeV can be obtained from low-resolution transmission measurements performed earlier in Russia (with samples of 0.027 to 0.871 atom/barn for niobium and 0.076 to 1.803 atom/barn for silicon). A significant calculation-to-experiment discrepancy in energy range 100 to 600 keV and 300 to 800 keV for niobium and silicon, respectively, obtained using the evaluated nuclear data library ROSFOND, were found. The EVPAR code was used for estimation the average resonance parameters in energy range 7 to 600 keV for niobium. For silicon a stochastic optimization method was used to modify the resolved resonance parameters in energy range 300 to 800 keV. The improved ROSFOND evaluated nuclear data files were tested in calculation of ICSBEP integral benchmark experiments.
DEFF Research Database (Denmark)
Petersen, Nils Holger
2014-01-01
A chapter in a book about terminology within the field of medievalism: the chapter discusses the resonance of medieval music and ritual in modern (classical) music culture and liturgical practice.......A chapter in a book about terminology within the field of medievalism: the chapter discusses the resonance of medieval music and ritual in modern (classical) music culture and liturgical practice....
Accurate Cross Sections for Excitation of Resonance Transitions in Atomic Oxygen
Tayal, S. S.
2004-01-01
Electron collision excitation cross sections for the resonance 2p(sup)4 (sup 3)P-2p(sup 3)3s (sup 3)S(sup 0), 2p(sup 4) (sup 3)P-2p(sup 3)3d (sup 3)D(sup 0), 2p4 (sup 3)P-2p(sup 3)3s (sup 3)D(sup 0), 2p(sup 4) (sup 3)P-2p(sup 3)3s (sup 3)P(sup 0) and 2p(sup 4) (sup 3)P-2s2p(sup 5) (sup 3)P(sup 0) transitions have been calculated by using the R matrix with a pseudostates approach for incident electron energies from near threshold to 100 eV. The excitation of these transition sgives rise to strong atomic oxygen emission features at 1304, 1027, 989, 878, and 792 Angstrom in the spectra of several planetary atmospheres. We included 22 spectroscopic bound and autoionizing states and 30 pseudostates in the close-coupling expansion. The target wave functions are chosen to properly account for the important correlation and relaxation effects. The effect of coupling to the continuum is included through the use of pseudostates. The contribution of the ionization continuum is significant for resonance transitions. Measured absolute direct excitation cross sections of 0 I are reported by experimental groups from the Jet Propulsion Laboratory and Johns Hopkins University. Good agreement is noted for the 2p(sup)4 (sup 3)P-2p(sup 3)3s (sup 3)S(sup 0) transition (lambda 1304 Ang) with measured cross sections from both groups that agree well with each other. There is disagreement between experiments for other transitions. Our results support the measured cross sections from the Johns Hopkins University for the 2p(sup 4) (sup 3)P-2p(sup 3)3d (sup 3)D(sup 0) and 2p4 (sup 3)P-2p(sup 3)3s (sup 3)D(sup 0) transitions, while for the 2p4 (sup 3)P-2p(sup 3)3s (sup 3)D(sup 0) transition the agreement is switched to the measured cross sections from the Jet Propulsion Laboratory.
Adiabatic Wankel type rotary engine
Kamo, R.; Badgley, P.; Doup, D.
1988-01-01
This SBIR Phase program accomplished the objective of advancing the technology of the Wankel type rotary engine for aircraft applications through the use of adiabatic engine technology. Based on the results of this program, technology is in place to provide a rotor and side and intermediate housings with thermal barrier coatings. A detailed cycle analysis of the NASA 1007R Direct Injection Stratified Charge (DISC) rotary engine was performed which concluded that applying thermal barrier coatings to the rotor should be successful and that it was unlikely that the rotor housing could be successfully run with thermal barrier coatings as the thermal stresses were extensive.
A Phase Matching, Adiabatic Accelerator
Energy Technology Data Exchange (ETDEWEB)
Lemery, Francois [Hamburg U.; Flöttmann, Klaus [DESY; Kärtner, Franz [CFEL, Hamburg; Piot, Philippe [Northern Illinois U.
2017-05-01
Tabletop accelerators are a thing of the future. Reducing their size will require scaling down electromagnetic wavelengths; however, without correspondingly high field gradients, particles will be more susceptible to phase-slippage – especially at low energy. We investigate how an adiabatically-tapered dielectric-lined waveguide could maintain phase-matching between the accelerating mode and electron bunch. We benchmark our simple model with CST and implement it into ASTRA; finally we provide a first glimpse into the beam dynamics in a phase-matching accelerator.
Cross-linkable liposomes stabilize a magnetic resonance contrast-enhancing polymeric fastener.
Smith, Cartney E; Kong, Hyunjoon
2014-04-08
Liposomes are commonly used to deliver drugs and contrast agents to their target site in a controlled manner. One of the greatest obstacles in the performance of such delivery vehicles is their stability in the presence of serum. Here, we demonstrate a method to stabilize a class of liposomes that load gadolinium, a magnetic resonance (MR) contrast agent, as a model cargo on their surfaces. We hypothesized that the sequential adsorption of a gadolinium-binding chitosan fastener on the liposome surface followed by covalent cross-linking of the lipid bilayer would provide enhanced stability and improved MR signal in the presence of human serum. To investigate this hypothesis, liposomes composed of diyne-containing lipids were assembled and functionalized via chitosan conjugated with a hydrophobic anchor and diethylenetriaminepentaacetic acid (DTPA). This postadsorption cross-linking strategy served to stabilize the thermodynamically favorable association between liposome and polymeric fastener. Furthermore, the chitosan-coated, cross-linked liposomes proved more effective as delivery vehicles of gadolinium than uncross-linked liposomes due to the reduced liposome degradation and chitosan desorption. Overall, this study demonstrates a useful method to stabilize a broad class of particles used for systemic delivery of various molecular payloads.
International Nuclear Information System (INIS)
Bhat, M.R.; Ozer, O.
1982-01-01
1 - Description of problem or function: RESEND generates infinitely- dilute, un-broadened, point cross sections in the ENDF format by combining ENDF File 3 background cross sections with points calculated from ENDF File 2 resonance parameter data. ADLER calculates total, capture, and fission cross sections from the corresponding Adler-Adler parameters in the ENDF/B File 2 Version II data and also Doppler-broadens cross sections. 2 - Method of solution: RESEND calculations are done in two steps by two separate sections of the program. The first section does the resonance calculation and stores the results on a scratch file. The second section combines the data from the scratch file with background cross sections and prints the results. ADLER uses the Adler-Adler formalism. 3 - Restrictions on the complexity of the problem: RESEND expects its input to be a standard mode BCD ENDF file (Version II/III). Since the output is also a standard mode BCD ENDF file, the program is limited by the six significant figure accuracy inherent in the ENDF formats. (If the cross section has been calculated at two points so close in energy that only their least significant figures differ, that interval is assumed to have converged, even if other convergence criteria may not be satisfied.) In the unresolved range the cross sections have been averaged over a Porter-Thomas distribution. In some regions the calculated resonance cross sections may be negative. In such cases the standard convergence criterion would cause an unnecessarily large number of points to be produced in the region where the cross section becomes zero. For this reason an additional input convergence criterion (AVERR) may be used. If the absolute value of the cross section at both ends of an interval is determined to be less than AVERR then the interval is assumed to have converged. There are no limitations on the total number of points generated. The present ENDF (Version II/III) formats restrict the total number of
International Nuclear Information System (INIS)
Madjet, Mohamed E.; Renger, Thomas; Hopper, Dale E.; McCune, Matthew A.; Chakraborty, Himadri S.; Rost, Jan-M.; Manson, Steven T.
2010-01-01
A theoretical study of the subshell photoionization of the Xe atom endohedrally confined in C 60 is presented. Powerful hybridization of the Xe 5s state with the bottom edge of C 60 π band is found that induces strong structures in the 5s ionization, causing the cross section to differ significantly from earlier results that omit this hybridization. The hybridization also affects the angular distribution asymmetry parameter of Xe 5p ionization near the Cooper minimum. The 5p cross section, on the other hand, is greatly enhanced by borrowing considerable oscillator strength from the C 60 giant plasmon resonance via the atom-fullerene dynamical interchannel coupling. Beyond the C 60 plasmon energy range the atomic subshell cross sections display confinement-induced oscillations in which, over the large 4d shape resonance region, the dominant 4d oscillations induce their ''clones'' in all degenerate weaker channels known as correlation confinement resonances.
Dimova, E.; Steflekova, V.; Karatodorov, S.; Kyoseva, E.
2018-03-01
We propose a way of achieving efficient and robust second-harmonic generation. The technique proposed is similar to the adiabatic population transfer in a two-state quantum system with crossing energies. If the phase mismatching changes slowly, e.g., due to a temperature gradient along the crystal, and makes the phase match for second-harmonic generation to occur, then the energy would be converted adiabatically to the second harmonic. As an adiabatic technique, the second-harmonic generation scheme presented is stable to variations in the crystal parameters, as well as in the input light, crystal length, input intensity, wavelength and angle of incidence.
Directory of Open Access Journals (Sweden)
Peter Keefe
2004-03-01
Full Text Available Abstract: The nature of the thermodynamic behavior of Type I superconductor particles, having a cross section less than the Ginzburg-Landau temperature dependent coherence length is discussed for magnetic field induced adiabatic phase transitions from the superconductive state to the normal state. Argument is advanced supporting the view that when the adiabatic magneto-caloric process is applied to particles, the phase transition is characterized by a decrease in entropy in violation of traditional formulations of the Second Law, evidenced by attainment of a final process temperature below that which would result from an adiabatic magneto-caloric process applied to bulk dimensioned specimens.
Sum rule for bremsstrahlung cross section for 6Li in the resonating-group method
International Nuclear Information System (INIS)
Lodhi, M.A.K.; Wood, K.E.
1982-01-01
In the method of resonating-group structure, the wave function of 6 Li is assumed to have a single channel of alpha and deuteron substructures in the ground state. It is shown that the intercluster exchange of nucleons is an important effect which causes significant change in the root mean square radius and the dipole transition cross section. Due to lack of symmetry in space coordinates of 6 Li, the dipole operator is not identical to the mean square operator for this sum rule calculation and is expected to display like behavior in similar systems. It is also shown that the deuteron substructure in this nucleus is substantially larger than the alpha substructure. (orig.)
Recent developments pertinent to processing of ENDF/B-6 type resonance cross section data
International Nuclear Information System (INIS)
Hwang, R. N.
1998-01-01
In view of our increasing dependence on computations rather than construction and operation of more costly experimental facilities, the rigor and accuracy achievable by calculational methods certainly deserve more attention. This is particularly so for the Monte Carlo methods which are generally regarded as the ultimate computational standard for the entire nuclear community around the globe. One obvious question that one may raise is whether the numerical algorithms deployed to process cross sections accurately reflect the rigor of the state-of-the-art nuclear data. The case in point is particularly essential in the resolved and the unresolved resonance regions, which constitute the most demanding task in all processing codes for reactor applications. For the resolved energy region, the point-wise cross sections are highly fluctuating functions of energy and temperature. In light of the availability of a large body of resonance data spanning over the much expanded energy ranges for most of major nuclides, critical examinations and improvement where appropriate, of the existing methods are apparently in order. For the unresolved energy region, improvement of traditional methods based on statistical approaches for treating the self-shielding effects is also desirable. From the perspective of the Monte Carlo approach, an alternative means for generating the probability tables without the inevitable difficulties associated with statistical uncertainties and/or those with concerns of uniqueness is needed. The accuracy considerations provide the motivation for the recent efforts at ANL to upgrade the existing VIMB processing code developed in early 70's in order to deal processing codes with these issues. Various tasks of upgrading are still at various stages of development. The purpose of this paper is to present an up-to-date account of the work in progress
International Nuclear Information System (INIS)
Deutchman, P.A.; Norbury, J.W.; Townsend, L.W.
1985-01-01
A quantal many-body formalism is presented that investigates pion production through the coherent formation of a nucleonic isobar in the projectile and its subsequent decay to various pion charge states along with concomitant excitation of the target to a coherent spin-isospin giant resonance via a peripheral collision of relativistic heavy ions. Total cross sections as a function of the incident energy per nucleon and Lorentz-invariant differential cross sections as a function of pion energy and angle are calculated. It is shown that the pion angular distributions, in coincidence with the target giant resonance excitations, might provide a well-defined signature for these coherent processes
Neutron Cross section Covariances in the Resonance region: 50,53Cr, 54,57Fe and 60Ni
Energy Technology Data Exchange (ETDEWEB)
Oblozinsky, P.; Cho,Y.-S.; Mattoon,C.M.; Mughabghab,S.F.
2010-11-23
We evaluated covariances in the neutron resonance region for capture and elastic scattering cross sections on minor structural materials, {sup 50,53}Cr, {sup 54,57}Fe and {sup 60}Ni. Use was made of the recently developed covariance formalism based on kernel approximation along with data in the Atlas of Neutron Resonances. Our results of most interest for advanced fuel cycle applications, elastic scattering cross section uncertainties at energies around 100 keV, are on the level of about 7-10%.
International Nuclear Information System (INIS)
Badnell, N.R.; Pindzola, M.S.; Griffin, D.C.
1991-01-01
The total inelastic cross section for electron-ion scattering may be found in the independent-processes approximation by adding the resonant cross section to the nonresonant background cross section. We study the validity of this approximation for electron excitation of multiply charged ions. The resonant-excitation cross section is calculated independently using distorted waves for various Li-like and Na-like ions using (N+1)-electron atomic-structure methods previously developed for the calculation of dielectronic-recombination cross sections. To check the effects of interference between the two scattering processes, we also carry out detailed close-coupling calculations for the same atomic ions using the R-matrix method. For low ionization stages, interference effects manifest themselves sometimes as strong window features in the close-coupling cross section, which are not present in the independent-processes cross section. For higher ionization stages, however, the resonance features found in the independent-processes approximation are found to be in good agreement with the close-coupling results
Keefe, Peter
2004-01-01
Abstract: The nature of the thermodynamic behavior of Type I superconductor particles, having a cross section less than the Ginzburg-Landau temperature dependent coherence length is discussed for magnetic field induced adiabatic phase transitions from the superconductive state to the normal state. Argument is advanced supporting the view that when the adiabatic magneto-caloric process is applied to particles, the phase transition is characterized by a decrease in entropy in violation of tradi...
International Nuclear Information System (INIS)
Robinson, G.S.
1985-12-01
MIRANDA is the cross-section generation module of the AUS neutronics code system used to prepare multigroup cross-section data which are pertinent to a particular study from a general purpose multigroup library of cross sections. Libraries have been prepared from ENDF/B which are suitable for thermal and fast fission reactors and for fusion blanket studies. The libraries include temperature dependent data, resonance cross sections represented by subgroup parameters and may contain photon as well as neutron data. The MIRANDA module includes a multiregion resonance calculation in slab, cylinder or cluster geometry, a homogeneous B L flux solution, and a group condensation facility. This report documents the modifications to an earlier version of MIRANDA and provides a complete user's manual
PIPER Continuous Adiabatic Demagnetization Refrigerator
Kimball, Mark O.; Shirron, Peter J.; Canavan, Edgar R.; James, Bryan L.; Sampson, Michael A.; Letmate, Richard V.
2017-01-01
We report upon the development and testing of a 4-stage adiabatic demagnetization refrigerator (ADR) capable of continuous cooling at 0.100 Kelvin. This cooler is being built to cool the detector array aboard NASA's Primordial Inflation Polarization Explorer (PIPER) observatory. The goal of this balloon mission is to measure the primordial gravitational waves that should exist if the theory of cosmological inflation is correct. At altitude, the ADR will hold the array of transition-edge sensors at 100 mK continuously while periodically rejecting heat to a 1.2 K pumped helium bath. During testing on ground, the array is held at the same temperature but heat is rejected to a 4.2 K helium bath indicating the flexibility in this coolers design.
Mid-range adiabatic wireless energy transfer via a mediator coil
International Nuclear Information System (INIS)
Rangelov, A.A.; Vitanov, N.V.
2012-01-01
A technique for efficient mid-range wireless energy transfer between two coils via a mediator coil is proposed. By varying the coil frequencies, three resonances are created: emitter–mediator (EM), mediator–receiver (MR) and emitter–receiver (ER). If the frequency sweeps are adiabatic and such that the EM resonance precedes the MR resonance, the energy flows sequentially along the chain emitter–mediator–receiver. If the MR resonance precedes the EM resonance, then the energy flows directly from the emitter to the receiver via the ER resonance; then the losses from the mediator are suppressed. This technique is robust against noise, resonant constraints and external interferences. - Highlights: ► Efficient and robust mid-range wireless energy transfer via a mediator coil. ► The adiabatic energy transfer is analogous to adiabatic passage in quantum optics. ► Wireless energy transfer is insensitive to any resonant constraints. ► Wireless energy transfer is insensitive to noise in the neighborhood of the coils.
DEFF Research Database (Denmark)
an impetus or drive to that account: change, innovation, rupture, or discontinuity. Resonances: Historical Essays on Continuity and Change explores the historiographical question of the modes of interrelation between these motifs in historical narratives. The essays in the collection attempt to realize...
International Nuclear Information System (INIS)
Anaf, J.; Chalhoub, E.S.
1990-01-01
The procedures for calculating contributions of resolved and unresolved resonances and background cross sections, in XLACS code, were revised. Constant weighting function and zero Kelvin temperature were considered. Discrepancies found were corrected and now the validated XLACS code generates results that are correct and in accordance with its originally established procedures. (author)
BRIGITTE-KA, ENDF/B to KEDAK Data Conversion with Resonance Cross-Sections Tables Generator
International Nuclear Information System (INIS)
Stein, Eckhard; Schepers, J.C.; Vandeplas, P.
1976-01-01
1 - Nature of physical problem solved: The program translates evaluated nuclear data from the ENDF representation (3) into the KEDAK representation (5). Nearly all nuclear data desired by the user to be present on KEDAK will be produced. 2 - Method of solution: The retrieval and processing codes of ENDF (4) have been used, but some have been modified. Point-wise cross sections are calculated from resonance parameters. In the resolved resonance region all resonances are taken into account for each energy point. In order to guarantee linear interpolation with an error less than eps in the resolved resonance region, an energy mesh constructed by using the UNICORN code (6) is refined by adding points, if a cross section value calculated from the resonance parameters differs appreciably from the value calculated by interpolation. The various ENDF interpolation rules are reduced to the linear-linear rule used by KEDAK. Pointwise cross sections are calculated from the given parameters (e.g. the angular distributions). Some data of ENDF/B MF=5 (energy distributions of secondary neutrons) are also converted. 3 - Restrictions on the complexity of the problem: Because variable dimensioning is used for nearly all arrays, there are only few restrictions. These are the following: - One (natural) element may have up to 10 isotopes. - Five different L-states (L=0,1,2,3,4) are allowed in the resolved Breit-Wigner resonance parameter set. - Three different L-states and 5 different J-states for each L-state are allowed in the unresolved Breit-Wigner resonance parameter set. - One hundred points are allowed as primary energy grid for energy distributions of secondary neutrons
International Nuclear Information System (INIS)
Leal, L.C.; de Saussure, G.; Perez, R.B.
1990-01-01
The URR computer code has been developed to calculate cross-section probability tables, Bondarenko self-shielding factors, and self-indication ratios for fertile and fissile isotopes in the unresolved resonance region. Monte Carlo methods are utilized to select appropriate resonance parameters and to compute the cross sections at the desired reference energy. The neutron cross sections are calculated by the single-level Breit-Wigner formalism with s-, p-, and d-wave contributions. The cross-section probability tables are constructed by sampling by Doppler broadened cross-sections. The various self-shielding factors are computer numerically as Lebesgue integrals over the cross-section probability tables
Rapid adiabatic passage in quantum dots: Influence of scattering and dephasing
DEFF Research Database (Denmark)
Schuh, K.; Jahnke, F.; Lorke, Michael
2011-01-01
Theoretical investigations for the realization of population inversion of semiconductor quantum dot ground-state transitions by means of adiabatic passage with chirped optical pulses are presented. While the inversion due to Rabi oscillations depends sensitively on the resonance condition...... to describe carrier scattering and dephasing in the corresponding simulations and allow to quantify the conditions to simultaneously invert an ensamble of quantum dots....
International Nuclear Information System (INIS)
Hwang, R.N.; Toppel, B.J.; Henryson, H. II.
1980-10-01
Motivated by a need for an economical yet rigorous tool which can address the computation of the structural material Doppler effect, an extremely efficient improved RABANL capability has been developed utilizing the fact that the Doppler broadened line shape functions become essentially identical to the natural line shape functions or Lorentzian limits beyond about 100 Doppler widths from the resonance energy, or when the natural width exceeds about 200 Doppler widths. The computational efficiency has been further enhanced by preprocessing or screening a significant number of selected resonances during library preparation into composition and temperature independent smooth background cross sections. The resonances which are suitable for such pre-processing are those which are either very broad or those which are very weak. The former contribute very little to the Doppler effect and their self-shielding effect can readily be averaged into slowly varying background cross section data, while the latter contribute very little to either the Doppler or to self-shielding effects. To illustrate the accuracy and efficiency of the improved RABANL algorithms and resonance screening techniques, calculations have been performed for two systems, the first with a composition typical of the STF converter region and the second typical of an LMFBR core composition. Excellent agreement has been found for RABANL compared to the reference Monte Carlo solution obtained using the code VIM, and improved results have also been obtained for the narrow resonance approximation in the ultra-fine-group option of MC 2 -2
Muon level crossing resonance spectroscopy applied to free-radical formation
International Nuclear Information System (INIS)
Venkateswaran, K.; Barnabas, M.V.; Walker, D.C.
1989-01-01
Muon Level Crossing Resonance Spectroscopy has been used to explore two aspects of muonium chemistry: unique free radicals and muonated radical yields. (1) A variety of new free-radicals have been seen by LCR. For instance, in thioacetamide the only radical produced from muonium is the S sm-bullet radical formed when Mu adds to the C of the C=S bond. In allylbenzene a whole range of radicals form with substantial yields (two side-chain and three ring additions); whereas in styrene, 85% of the radicals have Mu bonded to the end C of the side-chain and there is no meta-adduct at all. (2) Absolute yields of the radicals formed by interaction of muonium atoms in water with acrylamide as a solute (and with benzene in n-hexane) have shown that all muons not directly incorporated into diamagnetic molecules (such as MuH) appear as muonated free radicals. i.e. the missing fraction is found
FPSPH DFPSPF, Line Shape Function for Doppler Broadened Resonance Cross-Sections Calculation
International Nuclear Information System (INIS)
Ribon, P.
1982-01-01
1 - Description of problem or function: In the computation of Doppler- broadened resonance cross sections, use is made of the symmetric and anti-symmetric line shape functions. These functions usually denoted as Psi and Phi (Psi and Chi in Anglo-Saxon formalism) are defined in terms of the real and imaginary parts of the error function for complex arguments. They are the product of the convolution of a Gaussian function with the symmetric and anti-symmetric Breit-Wigner functions, respectively. FPSPH and DFPSPH compute these functions. 2 - Method of solution: For (1+x 2 ) > 20 Beta 2 , the calculation is based upon the asymptotic expansion: Psi+(i*Phi) = 1/(1-ix)*(1-t+3t 2 -3.5t 3 +3.5+7t 4 ---), with: t = 1/(2z 2 ); z = (1-ix)/Beta. The half-plane (Beta,x) is split in several parts, and use is made of PADE approximants. For 1 + x 2 2 , the calculation is based upon the relation with the erf function: Psi + i*Phi = SQRT(Pi)/Beta*(e (z 2 ) )*(1-erf(z)) (z = (1-ix)/Beta, and erf(z) being calculated from its analytic expansion: erf(z) = 2/SQRT(Pi)*z*e (-z 2 ) *(1+z 2 /3+z 4 /(3*5) + z 6 /(3*5*7)+---). PADE approximants are used to compute the expansion and e z 2
Energy consumption for shortcuts to adiabaticity
Torrontegui, E.; Lizuain, I.; González-Resines, S.; Tobalina, A.; Ruschhaupt, A.; Kosloff, R.; Muga, J. G.
2017-08-01
Shortcuts to adiabaticity let a system reach the results of a slow adiabatic process in a shorter time. We propose to quantify the "energy cost" of the shortcut by the energy consumption of the system enlarged by including the control device. A mechanical model where the dynamics of the system and control device can be explicitly described illustrates that a broad range of possible values for the consumption is possible, including zero (above the adiabatic energy increment) when friction is negligible and the energy given away as negative power is stored and reused by perfect regenerative braking.
Quantum entangling power of adiabatically connected Hamiltonians
International Nuclear Information System (INIS)
Hamma, Alioscia; Zanardi, Paolo
2004-01-01
The space of quantum Hamiltonians has a natural partition in classes of operators that can be adiabatically deformed into each other. We consider parametric families of Hamiltonians acting on a bipartite quantum state space. When the different Hamiltonians in the family fall in the same adiabatic class, one can manipulate entanglement by moving through energy eigenstates corresponding to different values of the control parameters. We introduce an associated notion of adiabatic entangling power. This novel measure is analyzed for general dxd quantum systems, and specific two-qubit examples are studied
International Nuclear Information System (INIS)
Walker, D.C.; Barnabas, M.V.; Venkateswaran, K.
1988-11-01
Benzene is used here as a scavenger of muonium to produce the muonated cyclohexadienyl radical in dilute solutions in n-hexane. The radical was identified by level crossing resonance spectroscopy (LCR) by observing the proton resonance of the -CHMu group occurring at 2.059T. Its yield is found to equal the sum of the muonium atom yield and the 'missing' muon yield in hexane (total 35% of the incident muons). Consequently, the complete dispersement of muons in different chemical associations is now accounted for in a saturated hydrocarbon liquid, and is seen to be similar to that in water
Thermoelectric Effects under Adiabatic Conditions
Directory of Open Access Journals (Sweden)
George Levy
2013-10-01
Full Text Available This paper investigates not fully explained voltage offsets observed by several researchers during the measurement of the Seebeck coefficient of high Z materials. These offsets, traditionally attributed to faulty laboratory procedures, have proven to have an irreducible component that cannot be fully eliminated in spite of careful laboratory procedures. In fact, these offsets are commonly observed and routinely subtracted out of commercially available Seebeck measurement systems. This paper offers a possible explanation based on the spontaneous formation of an adiabatic temperature gradient in the presence of a force field. The diffusion-diffusion heat transport mechanism is formulated and applied to predict two new thermoelectric effects. The first is the existence of a temperature gradient across a potential barrier in a semiconductor and the second is the Onsager reciprocal of the first, that is, the presence of a measureable voltage that arises across a junction when the temperature gradient is forced to zero by a thermal clamp. Suggested future research includes strategies for utilizing the new thermoelectric effects.
Adiabatic quantum computing with spin qubits hosted by molecules.
Yamamoto, Satoru; Nakazawa, Shigeaki; Sugisaki, Kenji; Sato, Kazunobu; Toyota, Kazuo; Shiomi, Daisuke; Takui, Takeji
2015-01-28
A molecular spin quantum computer (MSQC) requires electron spin qubits, which pulse-based electron spin/magnetic resonance (ESR/MR) techniques can afford to manipulate for implementing quantum gate operations in open shell molecular entities. Importantly, nuclear spins, which are topologically connected, particularly in organic molecular spin systems, are client qubits, while electron spins play a role of bus qubits. Here, we introduce the implementation for an adiabatic quantum algorithm, suggesting the possible utilization of molecular spins with optimized spin structures for MSQCs. We exemplify the utilization of an adiabatic factorization problem of 21, compared with the corresponding nuclear magnetic resonance (NMR) case. Two molecular spins are selected: one is a molecular spin composed of three exchange-coupled electrons as electron-only qubits and the other an electron-bus qubit with two client nuclear spin qubits. Their electronic spin structures are well characterized in terms of the quantum mechanical behaviour in the spin Hamiltonian. The implementation of adiabatic quantum computing/computation (AQC) has, for the first time, been achieved by establishing ESR/MR pulse sequences for effective spin Hamiltonians in a fully controlled manner of spin manipulation. The conquered pulse sequences have been compared with the NMR experiments and shown much faster CPU times corresponding to the interaction strength between the spins. Significant differences are shown in rotational operations and pulse intervals for ESR/MR operations. As a result, we suggest the advantages and possible utilization of the time-evolution based AQC approach for molecular spin quantum computers and molecular spin quantum simulators underlain by sophisticated ESR/MR pulsed spin technology.
Perturbative treatment of possible failures in the adiabatic theorem
International Nuclear Information System (INIS)
Vertesi, T.; Englman, R.
2005-01-01
-dependent Hamiltonian H a (t) for which it is presumed that the AT is satisfied and from this Hamiltonian they construct a dual Hamiltonian, H b (t) = -U a† (t)H a (t)U a† (t), where U a (t) is the time evolution operator for the original Hamiltonian, H a (t). Then it is demonstrated that the AT can be very inaccurate for the dual Hamiltonian H b (t). We argue in a perturbational analysis, that in the dual b-system the breakdown of the application of the AT can be traced to the appearance of some nonzero terms and is related to two time scales in the Hamiltonian H b (t). The Hamiltonian H(t) in equation depends only on one time scale (t/T ), then from our analytical investigations follows that AT implies a good estimate for the required run-time T of quantum adiabatic algorithms regardless of the existing inconsistency in the AT. On the other hand, in the case of resonance, when some frequency in the Hamiltonian is nearly equal to one of the transition frequencies of the system, the Hamiltonian has intrinsically two time scales giving rise to possible failure in the application of the adiabatic theorem. (author)
Magnus approximation in the adiabatic picture
International Nuclear Information System (INIS)
Klarsfeld, S.; Oteo, J.A.
1991-01-01
A simple approximate nonperturbative method is described for treating time-dependent problems that works well in the intermediate regime far from both the sudden and the adiabatic limits. The method consists of applying the Magnus expansion after transforming to the adiabatic basis defined by the eigenstates of the instantaneous Hamiltonian. A few exactly soluble examples are considered in order to assess the domain of validity of the approximation. (author) 32 refs., 4 figs
Hierarchical theory of quantum adiabatic evolution
International Nuclear Information System (INIS)
Zhang, Qi; Wu, Biao; Gong, Jiangbin
2014-01-01
Quantum adiabatic evolution is a dynamical evolution of a quantum system under slow external driving. According to the quantum adiabatic theorem, no transitions occur between nondegenerate instantaneous energy eigenstates in such a dynamical evolution. However, this is true only when the driving rate is infinitesimally small. For a small nonzero driving rate, there are generally small transition probabilities between the energy eigenstates. We develop a classical mechanics framework to address the small deviations from the quantum adiabatic theorem order by order. A hierarchy of Hamiltonians is constructed iteratively with the zeroth-order Hamiltonian being determined by the original system Hamiltonian. The kth-order deviations are governed by a kth-order Hamiltonian, which depends on the time derivatives of the adiabatic parameters up to the kth-order. Two simple examples, the Landau–Zener model and a spin-1/2 particle in a rotating magnetic field, are used to illustrate our hierarchical theory. Our analysis also exposes a deep, previously unknown connection between classical adiabatic theory and quantum adiabatic theory. (paper)
Symmetry of the Adiabatic Condition in the Piston Problem
Anacleto, Joaquim; Ferreira, J. M.
2011-01-01
This study addresses a controversial issue in the adiabatic piston problem, namely that of the piston being adiabatic when it is fixed but no longer so when it can move freely. It is shown that this apparent contradiction arises from the usual definition of adiabatic condition. The issue is addressed here by requiring the adiabatic condition to be…
International Nuclear Information System (INIS)
de Saussure, G.; Olsen, D.K.; Perez, R.B.
1976-01-01
The ENDF/B-IV prescription fails to represent correctly the 238 U total (and scattering) cross section between the levels of the resolved range. It is shown how this representation can be improved by properly accounting for the contribution of levels outside the resolved region to the cross section at energies inside the resolved region, and by substituting the more precise multilevel Breit-Wigner formula for the presently used single-level formula. The importance of computing accurately the minima in the total cross section is illustrated by comparing values of the self-shielded capture resonance integral computed with ENDF/B-IV and with a more accurate cross section model
{sup 41}K(n, {gamma}){sup 42}K thermal and resonance integral cross section measurements
Energy Technology Data Exchange (ETDEWEB)
Ferreira, F.A. Jr.; Maidana, N.L.; Vanin, V.R. [Sao Paulo Univ., SP (Brazil). Lab. do Acelerador Linear; Dias, M.S.; Koskinas, M.F. [IPEN-CNEN, Sao Paulo, SP (Brazil). Lab. de Metrolgia Nuclear; Lopez-Pino, N. [Instituto Superior de Tecnolgias y Ciencias Aplicadas (InSTEC), Habana (Cuba)
2012-07-01
We measured the {sup 41}K thermal neutron absorption and resonance integral cross sections after the irradiation of KNO{sub 3} samples near the core of the IEA-R1 IPEN pool-type research reactor. Bare and cadmium-covered targets were irradiated in pairs with Au-Al alloy flux-monitors. The residual activities were measured by gamma-ray spectroscopy with a HPGe detector, with special care to avoid the {sup 42}K decay {beta}{sup -} emission effects on the spectra. The gamma-ray self-absorption was corrected with the help of MCNP simulations. We applied the Westcott formalism in the average neutron flux determination and calculated the depression coefficients for thermal and epithermal neutrons due to the sample thickness with analytical approximations. We obtained 1.57(4) b and 1.02(4) b, for thermal and resonance integral cross sections, respectively, with correlation coefficient equal to 0.39.
Energy Technology Data Exchange (ETDEWEB)
Majumdar, A.; Zuiderweg, E.R.P. [Univ. of Michigan, Ann Arbor, MI (United States)
1994-12-01
Heteronuclear multiple-pulse-based Cross Polarization (HECP) between scalar coupled spins is gaining an important role in high-resolution multidimensional NMR of isotopically labeled biomolecules, especially in experiments involving net magnetization transfer. It has generally been observed that in these situations, the performance of HECP is superior to that of INEPT-based sequences. In particular, HECP-based three-dimensional HCCH spectroscopy is more efficient than the INEPT version of the same experiment. Differences in sensitivity have been intuitively attributed to relaxation effects and technical factors such as radiofrequency (rf) inhomogeneity We present theoretical analyses and computer simulations to probe the effects of these factors. Relaxation effects were treated phenomenologically; we found that relaxation differences are relatively small (up to 25%) between pulsed-free-precession (INEPT) and HECP-although always in favor of HECP. We explored the rf effects by employing a Gaussian distribution of rf amplitude over sample volume. We found that inhomogeneity effects significantly favor HECP over INEPT, especially under conditions of {open_quotes}matched {close_quotes} inhomogeneity in the two rf coils. The differences in favor of HECP indicate that an extension of HECP to triple resonance experiments (TRCP) in I -> S -> Q net transfers might yield better results relative to analogous INEPT-based net transfers. We theoretically analyze the possibilities of TRCP and find that transfer functions are critically dependent on the ratio J{sub IS}/J{sub SQ}. When J{sub IS} equals J{sub SQ}, we find that 100% transfer is possible for truly simultaneous TRCP and this transfer is obtained in a time 1.41 /J. The TRCP time requirement compares favorably with optimally concatenated INEPT-transfers, where net transfer I -> S -> Q is complete at 1.5 /J.
International Nuclear Information System (INIS)
Zhan Jie; Gong Honghan
2013-01-01
An increasing amount of neuroimaging studies recently demonstrated activation of visual cortex in both blind and sighted participants when performing a variety of tactile tasks such as Braille reading and tactile object recognition, which indicates that visual cortex not only receives visual information, but may participate in tactile perception. To address these cross-modal changes of visual cortex and the neurophysiological mechanisms, many researchers conducted explosive studies using functional magnetic resonance imaging (fMRI) and have made some achievements. This review focuses on cross-modal activation of visual cortex and the underlying mechanisms during tactile perception in both blind and sighted individuals. (authors)
International Nuclear Information System (INIS)
Kun, S.Yu.
1985-01-01
On the basis of the symmetrized Simonius representation of the S matrix statistical properties of its fluctuating component in the presence of direct reactions are investigated. The case is considered where the resonance levels are strongly overlapping and there is a lot of open channels, assuming that compound-nucleus cross sections which couple different channels are equal. It is shown that using the averaged unitarity condition on the real energy axis one can eliminate both resonance-resonance and channel-channel correlations from partial r transition amplitudes. As a result, we derive the basic points of the Epicson fluctuation theory of nuclear cross sections, independently of the relation between the resonance overlapping and the number of open channels, and the validity of the Hauser-Feshbach model is established. If the number of open channels is large, the time of uniform population of compound-nucleus configurations, for an open excited nuclear system, is much smaller than the Poincare time. The life time of compound nucleus is discussed
Kolesniková, Lucie; Koucký, Jan; Kania, Patrik; Uhlíková, Tereza; Beckers, Helmut; Urban, Štěpán
2018-01-01
The resonance crossing of rotational levels with different fine-structure components and different k rotational quantum numbers was observed in the rotational spectra of the symmetric top fluorosulfate radical FSO3rad. Detailed measurements were performed to analyze these weak resonances as well as the A1-A2 splittings of the K = 3 and K = 6 transitions. The resonance level crossing enabled the experimental determination of "forbidden" parameters, the rotational A and the centrifugal distortion DK constants as well as the corresponding resonance off-diagonal matrix element.
Adiabatic regularization of power spectra in nonminimally coupled chaotic inflation
Energy Technology Data Exchange (ETDEWEB)
Alinea, Allan L., E-mail: alinea@het.phys.sci.osaka-u.ac.jp [Department of Physics, Osaka University, Toyonaka, Osaka 560-0043 (Japan)
2016-10-01
We investigate the effect of adiabatic regularization on both the tensor- and scalar-perturbation power spectra in nonminimally coupled chaotic inflation. Similar to that of the minimally coupled general single-field inflation, we find that the subtraction term is suppressed by an exponentially decaying factor involving the number of e -folds. By following the subtraction term long enough beyond horizon crossing, the regularized power spectrum tends to the ''bare'' power spectrum. This study justifies the use of the unregularized (''bare'') power spectrum in standard calculations.
Assessment of total efficiency in adiabatic engines
Mitianiec, W.
2016-09-01
The paper presents influence of ceramic coating in all surfaces of the combustion chamber of SI four-stroke engine on working parameters mainly on heat balance and total efficiency. Three cases of engine were considered: standard without ceramic coating, fully adiabatic combustion chamber and engine with different thickness of ceramic coating. Consideration of adiabatic or semi-adiabatic engine was connected with mathematical modelling of heat transfer from the cylinder gas to the cooling medium. This model takes into account changeable convection coefficient based on the experimental formulas of Woschni, heat conductivity of multi-layer walls and also small effect of radiation in SI engines. The simulation model was elaborated with full heat transfer to the cooling medium and unsteady gas flow in the engine intake and exhaust systems. The computer program taking into account 0D model of engine processes in the cylinder and 1D model of gas flow was elaborated for determination of many basic engine thermodynamic parameters for Suzuki DR-Z400S 400 cc SI engine. The paper presents calculation results of influence of the ceramic coating thickness on indicated pressure, specific fuel consumption, cooling and exhaust heat losses. Next it were presented comparisons of effective power, heat losses in the cooling and exhaust systems, total efficiency in function of engine rotational speed and also comparison of temperature inside the cylinder for standard, semi-adiabatic and full adiabatic engine. On the basis of the achieved results it was found higher total efficiency of adiabatic engines at 2500 rpm from 27% for standard engine to 37% for full adiabatic engine.
Adiabatic approximation in the ultrastrong-coupling regime of an oscillator and two qubits
Energy Technology Data Exchange (ETDEWEB)
Yang, Ping; Zou, Ping [Laboratory of Nanophotonic Functional Materials and Devices, SIPSE and LQIT, South China Normal University, Guangzhou 510006 (China); Zhang, Zhi-Ming, E-mail: zmzhang@scnu.edu.cn [Laboratory of Nanophotonic Functional Materials and Devices, SIPSE and LQIT, South China Normal University, Guangzhou 510006 (China)
2012-10-01
We present a system composed of two flux qubits and a transmission-line resonator. Instead of using the rotating wave approximation (RWA), we analyze the system by the adiabatic approximation methods under two opposite extreme conditions. Basic properties of the system are calculated and compared under these two different conditions. Relative energy-level spectrum of the system in the adiabatic displaced oscillator basis is shown, and the theoretical result is compared with the numerical solution. -- Highlights: ► Our work shows that the adiabatic approximations may work also in the ultrastrong coupling limit. ► Both of the approximation methods are valid in a large range of coupling strength, including the ultrastrong coupling regime. ► The results of the approximate formula meet well the exact numerical solution.
Dobado, Antonio; Guo, Feng-Kun; Llanes-Estrada, Felipe J.
2015-12-01
We are exploring a generic strongly-interacting Electroweak Symmetry Breaking Sector (EWSBS) with the low-energy effective field theory for the four experimentally known particles (W±L, ZL, h) and its dispersion-relation based unitary extension. In this contribution we provide simple estimates for the production cross-section of pairs of the EWSBS bosons and their resonances at proton-proton colliders as well as in a future e-e+ (or potentially a μ-μ+) collider with a typical few-TeV energy. We examine the simplest production mechanisms, tree-level production through a W (dominant when quantum numbers allow) and the simple effective boson approximation (in which the electroweak bosons are considered as collinear partons of the colliding fermions). We exemplify with custodial isovector and isotensor resonances at 2 TeV, the energy currently being discussed because of a slight excess in the ATLAS 2-jet data. We find it hard, though not unthinkable, to ascribe this excess to one of these WLWL rescattering resonances. An isovector resonance could be produced at a rate smaller than, but close to earlier CMS exclusion bounds, depending on the parameters of the effective theory. The ZZ excess is then problematic and requires additional physics (such as an additional scalar resonance). The isotensor one (that would describe all charge combinations) has smaller cross-section. Supported by the Spanish Excellence Network on Hadronic Physics FIS2014-57026-REDT, by Spanish Grants Universidad Complutense UCM:910309 and Ministerio de Economia y Competitividad MINECO:FPA2011-27853-C02-01, MINECO:FPA2014-53375-C2-1-P, by the Deutsche Forschungsgemeinschaft and National Natural Science Foundation of China through Funds Provided to the Sino-German CRC 110 “Symmetries and the Emergence of Structure in QCD” (NSFC Grant No. 11261130311) and by NSFC (Grant No. 11165005)
Energy Technology Data Exchange (ETDEWEB)
Sokolowski, E K; Bladh, R
1969-02-15
Pile oscillator measurements of heavy-water solutions of As, B, Mn and In have been carried out in two different neutron spectra in the R0 reactor. For B, Mn and In the 2200 m/s cross section values recommended in BNL-325 are given to within 1.5 % or less, while for As the stated uncertainty is 5 %. In the present work the BNL values for B, Mn and In were used to derive weighted mean calibration constants for the reactor, which were then in turn used for obtaining self-consistent cross section values for all four elements. The values thus obtained for B, Mn and In were within experimental error of the recommended BNL values. The absorption cross section for As is in good agreement with a recently published value for the activation cross section. The value for the resonance integral of As, derived from the present measurements, is in better agreement with calculations from resonance parameters than values reported earlier.
International Nuclear Information System (INIS)
Sokolowski, E.K.; Bladh, R.
1969-02-01
Pile oscillator measurements of heavy-water solutions of As, B, Mn and In have been carried out in two different neutron spectra in the R0 reactor. For B, Mn and In the 2200 m/s cross section values recommended in BNL-325 are given to within 1.5 % or less, while for As the stated uncertainty is 5 %. In the present work the BNL values for B, Mn and In were used to derive weighted mean calibration constants for the reactor, which were then in turn used for obtaining self-consistent cross section values for all four elements. The values thus obtained for B, Mn and In were within experimental error of the recommended BNL values. The absorption cross section for As is in good agreement with a recently published value for the activation cross section. The value for the resonance integral of As, derived from the present measurements, is in better agreement with calculations from resonance parameters than values reported earlier
Quantum adiabatic approximation and the geometric phase
International Nuclear Information System (INIS)
Mostafazadeh, A.
1997-01-01
A precise definition of an adiabaticity parameter ν of a time-dependent Hamiltonian is proposed. A variation of the time-dependent perturbation theory is presented which yields a series expansion of the evolution operator U(τ)=summation scr(l) U (scr(l)) (τ) with U (scr(l)) (τ) being at least of the order ν scr(l) . In particular, U (0) (τ) corresponds to the adiabatic approximation and yields Berry close-quote s adiabatic phase. It is shown that this series expansion has nothing to do with the 1/τ expansion of U(τ). It is also shown that the nonadiabatic part of the evolution operator is generated by a transformed Hamiltonian which is off-diagonal in the eigenbasis of the initial Hamiltonian. This suggests the introduction of an adiabatic product expansion for U(τ) which turns out to yield exact expressions for U(τ) for a large number of quantum systems. In particular, a simple application of the adiabatic product expansion is used to show that for the Hamiltonian describing the dynamics of a magnetic dipole in an arbitrarily changing magnetic field, there exists another Hamiltonian with the same eigenvectors for which the Schroedinger equation is exactly solvable. Some related issues concerning geometric phases and their physical significance are also discussed. copyright 1997 The American Physical Society
Adiabatic process reversibility: microscopic and macroscopic views
International Nuclear Information System (INIS)
Anacleto, Joaquim; Pereira, Mario G
2009-01-01
The reversibility of adiabatic processes was recently addressed by two publications. In the first (Miranda 2008 Eur. J. Phys. 29 937-43), an equation was derived relating the initial and final volumes and temperatures for adiabatic expansions of an ideal gas, using a microscopic approach. In that relation the parameter r accounts for the process reversibility, ranging between 0 and 1, which corresponds to the free and reversible expansion, respectively. In the second (Anacleto and Pereira 2009 Eur. J. Phys. 30 177-83), the authors have shown that thermodynamics can effectively and efficiently be used to obtain the general law for adiabatic processes carried out by an ideal gas, including compressions, for which r≥1. The present work integrates and extends the aforementioned studies, providing thus further insights into the analysis of the adiabatic process. It is shown that Miranda's work is wholly valid for compressions. In addition, it is demonstrated that the adiabatic reversibility coefficient given in terms of the piston velocity and the root mean square velocity of the gas particles is equivalent to the macroscopic description, given just by the quotient between surroundings and system pressure values. (letters and comments)
Representation of the neutron cross sections in the unresolved resonance region
International Nuclear Information System (INIS)
de Saussure, G.; Perez, R.B.
1975-01-01
Some limitations of the statistical approach to the representation of cross sections in the unresolved region are discussed and it is suggested that the actual Doppler-broadened cross sections should be used instead. 5 figures
International Nuclear Information System (INIS)
Van'kov, A.A.; Blokhin, A.I.; Manokhin, V.N.; Kravchenko, I.V.
1985-01-01
This paper analyses the reasons for the differences which exist between group-averaged evaluated cross-section data from different evaluated data files for U235, U238 and Pu239 in the unresolved resonance energy region. (author)
Evaluated 182,183,184,186W Neutron Cross Sections and Covariances in the Resolved Resonance Region
International Nuclear Information System (INIS)
Pigni, Marco T; Leal, Luiz C
2015-01-01
Oak Ridge National Laboratory (ORNL) has recently completed the resonance parameter evaluation of four tungsten isotopes, i.e., 182,183,184,186 W, in the neutron energy range of thermal up to several keV. This nuclear data work was performed with support from the US Nuclear Criticality Safety Program (NCSP) in an effort to provide improved tungsten cross section and covariance data for criticality safety analyses. The evaluation methodology uses the Reich-Moore approximation of the R-matrix formalism of the code SAMMY to fit high-resolution measurements performed in 2010 and 2012 at the Geel linear accelerator facility (GELINA), as well as other experimental data sets on natural tungsten available in the EXFOR library. In the analyzed energy range, this work nearly doubles the resolved resonance region (RRR) present in the latest US nuclear data library ENDF/B-VII.1. In view of the interest in tungsten for distinct types of nuclear applications and the relatively homogeneous distribution of the isotopic tungsten - namely, 182 W(26.5%), 183 W(14.31%), 184 W(30.64%), and 186 W(28.43%) - the completion of these four evaluations represents a significant contribution to the improvement of the ENDF library. This paper presents an overview of the evaluated resonance parameters and related covariances for total and capture cross sections on the four tungsten isotopes.
International Nuclear Information System (INIS)
Nakagawa, Tsuneo
1984-10-01
RESENDD is a computer program to calculate resonance cross sections from evaluated resonance parameters in the ENDF/B format. This program was improved from RESEND by modifying the multi-level Breit-Wigner formula, adding a function of Doppler broadening, and so on. This report explains functions of RESENDD and describes input data. Some examples are also given. (author)
Adiabatic quantum search algorithm for structured problems
International Nuclear Information System (INIS)
Roland, Jeremie; Cerf, Nicolas J.
2003-01-01
The study of quantum computation has been motivated by the hope of finding efficient quantum algorithms for solving classically hard problems. In this context, quantum algorithms by local adiabatic evolution have been shown to solve an unstructured search problem with a quadratic speedup over a classical search, just as Grover's algorithm. In this paper, we study how the structure of the search problem may be exploited to further improve the efficiency of these quantum adiabatic algorithms. We show that by nesting a partial search over a reduced set of variables into a global search, it is possible to devise quantum adiabatic algorithms with a complexity that, although still exponential, grows with a reduced order in the problem size
Experimental study on the adiabatic shear bands
International Nuclear Information System (INIS)
Affouard, J.
1984-07-01
Four martensitic steels (Z50CDV5 steel, 28CND8 steel, 35NCDV16 steel and 4340 steel) with different hardness between 190 and 600 Hsub(B) (Brinell hardness), have been studied by means of dynamic compressive tests on split Hopkinson pressure bar. Microscopic observations show that the fracture are associated to the development of adiabatic shear bands (except 4340 steel with 190 Hsub(B) hardness). By means of tests for which the deformation is stopped at predetermined levels, the measurement of shear and hardness inside the band and the matrix indicates the chronology of this phenomenon: first the localization of shear, followed by the formation of adiabatic shear band and ultimatly crack initiation and propagation. These results correlated with few simulations by finite elements have permitted to suggest two mecanisms of deformation leading to the formation of adiabatic shear bands in this specific test [fr
Exciton spectrum of surface-corrugated quantum wells: the adiabatic self-consistent approach
International Nuclear Information System (INIS)
Atenco A, N.; Perez R, F.; Makarov, N.M.
2005-01-01
A theory for calculating the relaxation frequency ν and the shift δ ω of exciton resonances in quantum wells with finite potential barriers and adiabatic surface disorder is developed. The adiabaticity implies that the correlation length R C for the well width fluctuations is much larger than the exciton radius a 0 (R C >> a 0 ). Our theory is based on the self-consistent Green's function method, and therefore takes into account the inherent action of the exciton scattering on itself. The self-consistent approach is shown to describe quantitatively the sharp exciton resonance. It also gives the qualitatively correct resonance picture for the transition to the classical limit, as well as within the domain of the classical limit itself. We present and analyze results for h h-exciton in a GaAs quantum well with Al 0.3 Ga 0.7 As barriers. It is established that the self-consistency and finite height of potential barriers significantly influence on the line-shape of exciton resonances, and make the values of ν and δ ω be quite realistic. In particular, the relaxation frequency ν for the ground-state resonance has a broad, almost symmetric maximum near the resonance frequency ω 0 , while the surface-induced resonance shift δ ω vanishes near ω 0 , and has different signs on the sides of the exciton resonance. (Author) 43 refs., 4 figs
Adiabatic supernova expansion into the circumstellar medium
International Nuclear Information System (INIS)
Band, D.L.; Liang, E.P.
1987-01-01
We perform one dimensional numerical simulations with a Lagrangian hydrodynamics code of the adiabatic expansion of a supernova into the surrounding medium. The early expansion follows Chevalier's analytic self-similar solution until the reverse shock reaches the ejecta core. We follow the expansion as it evolves towards the adiabatic blast wave phase. Some memory of the earlier phases of expansion is retained in the interior even when the outer regions expand as a blast wave. We find the results are sensitive to the initial configuration of the ejecta and to the placement of gridpoints. 6 refs., 2 figs
Collapse and equilibrium of rotating, adiabatic clouds
International Nuclear Information System (INIS)
Boss, A.P.
1980-01-01
A numerical hydrodynamics computer code has been used to follow the collapse and establishment of equilibrium of adiabatic gas clouds restricted to axial symmetry. The clouds are initially uniform in density and rotation, with adiabatic exponents γ=5/3 and 7/5. The numerical technique allows, for the first time, a direct comparison to be made between the dynamic collapse and approach to equilibrium of unconstrained clouds on the one hand, and the results for incompressible, uniformly rotating equilibrium clouds, and the equilibrium structures of differentially rotating polytropes, on the other hand
Superconducting system for adiabatic quantum computing
Energy Technology Data Exchange (ETDEWEB)
Corato, V [Dipartimento di Ingegneria dell' Informazione, Second University of Naples, 81031 Aversa (Italy); Roscilde, T [Department of Physics and Astronomy, University of Southern California, Los Angeles, CA 90089-0484 (Canada); Ruggiero, B [Istituto di Cibernetica ' E.Caianiello' del CNR, I-80078, Pozzuoli (Italy); Granata, C [Istituto di Cibernetica ' E.Caianiello' del CNR, I-80078, Pozzuoli (Italy); Silvestrini, P [Dipartimento di Ingegneria dell' Informazione, Second University of Naples, 81031 Aversa (Italy)
2006-06-01
We study the Hamiltonian of a system of inductively coupled flux qubits, which has been theoretically proposed for adiabatic quantum computation to handle NP problems. We study the evolution of a basic structure consisting of three coupled rf-SQUIDs upon tuning the external flux bias, and we show that the adiabatic nature of the evolution is guaranteed by the presence of the single-SQUID gap. We further propose a scheme and the first realization of an experimental device suitable for verifying the theoretical results.
International Nuclear Information System (INIS)
Pauly, N.; Dubus, A.; Roesler, M.
2003-01-01
For incident protons with velocities around 1 a.u., electron capture and loss processes are known to play an important role. In particular, electron emission as well as electronic stopping power are strongly influenced by the charge changing processes. Several different electron capture and loss processes have been identified [Solid State Phys. 43 (1990) 229], i.e. Auger valence band processes, shell processes and resonant coherent processes. In the latter, the incident projectile undergoes a periodic excitation due to the periodic crystalline potential so that an electron can be lost or captured. In the literature, several different choices have been made for the crystalline potential. It is precisely the aim of the present work to review and compare the various potentials used in the literature and to show the influence of this choice on the resonant coherent electron capture and loss cross sections
International Nuclear Information System (INIS)
Zandrino, F.; Sardanelli, F.; Molinari, G.; Masperone, M.A.; Smeraldi, A.; Odaglia, G.
2000-01-01
To evaluate left ventricular myocardial mass and function as well as ostial coronary artery cross-sectional area in endurance athletes, an athlete group of 12 highly trained rowers and a control group of 12 sedentary healthy subjects underwent MR examination. An ECG-gated breath-hold cine gradient-echo sequence was used to calculate myocardial mass, end-diastolic and end-systolic volumes, stroke volume, and cardiac output, all related to body surface area, as well as ejection fraction. A 3D fat-saturated ECG- and respiratory-triggered navigator echo sequence was used to evaluate coronary arteries: left main (LM), left anterior descending (LAD), left circumflex (LCx), and right coronary artery (RCA). Cross-sectional area was calculated and divided for body surface area. Myocardial mass was found significantly larger in athlete group than in control group (p = 0.0078), the same being for end-diastolic volume (p = 0.0078), stroke volume (p = 0.0055), LM (p = 0.0066) and LAD (p = 0.0129). No significant difference was found for all the remaining parameters. Significant correlation with myocardial mass was found for LM (p < 0.001) and LAD (p = 0.0340), not for LCx and RCA. Magnetic resonance imaging is a useful tool in evaluating the myocardial hypertrophy and function of athlete's heart. Magnetic resonance angiography is a valuable noninvasive method to visualize the correlated cross-sectional area increase of the left coronary artery system. (orig.)
International Nuclear Information System (INIS)
Leal, L.C.; de Saussure, G.; Perez, R.B.
1989-01-01
The URR computer code has been developed to calculate cross-section probability tables, Bondarenko self-shielding factors, and self- indication ratios for fertile and fissile isotopes in the unresolved resonance region. Monte Carlo methods are utilized to select appropriate resonance parameters and to compute the cross sections at the desired reference energy. The neutron cross sections are calculated by the single-level Breit-Wigner formalism with s-, p-, and d-wave contributions. The cross-section probability tables are constructed by sampling the Doppler broadened cross-section. The various shelf-shielded factors are computed numerically as Lebesgue integrals over the cross-section probability tables. 6 refs
International Nuclear Information System (INIS)
Korobov, V.I.; Melezhik, V.S.; Ponomarev, L.I.
1992-01-01
A numerical scheme for solving the problem of slow collisions in the three-body adiabatic approach is applied for calculation of muon transfer rates in collisions of hydrogen isotope atoms on bare nuclei. It is demonstrated that the multichannel adiabatic approach allows one to reach high accuracy results (∼3%) estimating the cross sections of charge transfer processes which are the best ones up to date. The method is appliable in a wide range of energies (0.001-50 eV) which is of interest for analysis of muon catalysed fusion experiments. 20 refs.; 3 figs.; 5 tabs
Resolved nuclear hyperfine structure of muonium in CuCl by means of muon level-crossing resonance
International Nuclear Information System (INIS)
Schneider, J.W.; Keller, H.; Odermatt, W.; Puempin, B.; Savic, I.M.; Simmler, H.; Dodds, S.A.; Estle, T.L.; Duvarney, R.C.; Chow, K.; Kadono, R.; Kiefl, R.F.; Li, Q.; Riseman, T.M.; Zhou, H.; Lichti, R.L.; Schwab, C.
1991-01-01
Detailed muon level-crossing resonance measurements of Mu I and Mu II centres in single crystals of CuCl are presented. The hyperfine and nuclear hyperfine parameters of the closest two shells of nuclei are remarkably similar for the two centres, indicating that both are located at the same tetrahedral interstitial site with four Cu nearest neighbours and six Cl next-nearest neighbours. About 30% of the total unpaired-electron spin density is located on the muon, about 60% on the four nearest neighbours and the rest on the six next-nearest neighbours, with nothing observable for any other shell. (orig.)
Pulsed adiabatic structure and complete population transfer
International Nuclear Information System (INIS)
Shore, B.W.
1992-10-01
Population can be transferred between atomic or molecular energy states in a variety of ways. The basic idea of adiabatic transfer, discussed in many textbooks, is as follows. One begins with an atom that is in some single energy state (an eigenstate of an initial Hamiltonian). This energy state is one of many possible states, known variously as the unperturbed states or basis states or diabatic states. Next one begins to change the Hamiltonian very slowly. The changes may occur in either the diagonal elements (the basis state energies) or in the off-diagonal elements (interactions between basis states). If there are off-diagonal elements then the Hamiltonian will no longer commute with the original one. Because the Hamiltonian is no longer the one that was used to define the original basis states, it will cause these states to become mixed. However, if the change is sufficiently slow, the system can remain in a single eigenstate of the changing Hamiltonian -- an adiabatic state, composed of a combination of basis states. Finally, at some later time, one examines the system once again in the original basis. One finds that the population has undergone a change, and now resides in a different unperturbed state. One has produced population transfer. There are many illustrative examples of adiabatic passage, both theory and experiment. The author mentions briefly two common examples, inelastic collisions between atoms, and the static Stark effect in Rydberg atoms, before continuing with the main objective, a discussion of adiabatic passage induced by laser pulses
Post-adiabatic analysis of atomic collisions
International Nuclear Information System (INIS)
Klar, H.; Fano, U.
1976-01-01
The coupling between adiabatic channels can be partially transformed away. The transformation need not induce any transition between channnels; but it correlates the radial wave functions and their gradients with the channel functions and it depresses the lower effective potentials, as the energy increases, in accordance with empirical evidence
Connection between adiabaticity and the mirror mode
International Nuclear Information System (INIS)
Cohen, R.H.
1976-01-01
The size of magnetic moment jumps of a particle in a long, thin equilibrium magnetic mirror field is shown to be related to the complex zeroes of the mirror mode parameter B + 4πdP/sub perpendicular//dB. A consequence is that adiabaticity places a lower limit on β than does the mirror mode
Predicting the effect of relaxation during frequency-selective adiabatic pulses
Pfaff, Annalise R.; McKee, Cailyn E.; Woelk, Klaus
2017-11-01
Adiabatic half and full passages are invaluable for achieving uniform, B1-insensitive excitation or inversion of macroscopic magnetization across a well-defined range of NMR frequencies. To accomplish narrow frequency ranges with adiabatic pulses (computer-calculated data with experimental results demonstrates that, in non-viscous, small-molecule fluids, it is possible to model magnetization and relaxation by considering standard T1 and T2 relaxation in the traditional rotating frame. The proposed model is aimed at performance optimizations of applications in which these pulses are employed. It differs from previous reports which focused on short high-power adiabatic pulses and relaxation that is governed by dipole-dipole interactions, cross polarization, or chemical exchange.
Adiabatic burst evaporation from bicontinuous nanoporous membranes
Ichilmann, Sachar; Rücker, Kerstin; Haase, Markus; Enke, Dirk
2015-01-01
Evaporation of volatile liquids from nanoporous media with bicontinuous morphology and pore diameters of a few 10 nm is an ubiquitous process. For example, such drying processes occur during syntheses of nanoporous materials by sol–gel chemistry or by spinodal decomposition in the presence of solvents as well as during solution impregnation of nanoporous hosts with functional guests. It is commonly assumed that drying is endothermic and driven by non-equilibrium partial pressures of the evaporating species in the gas phase. We show that nearly half of the liquid evaporates in an adiabatic mode involving burst-like liquid-to-gas conversions. During single adiabatic burst evaporation events liquid volumes of up to 107 μm3 are converted to gas. The adiabatic liquid-to-gas conversions occur if air invasion fronts get unstable because of the built-up of high capillary pressures. Adiabatic evaporation bursts propagate avalanche-like through the nanopore systems until the air invasion fronts have reached new stable configurations. Adiabatic cavitation bursts thus compete with Haines jumps involving air invasion front relaxation by local liquid flow without enhanced mass transport out of the nanoporous medium and prevail if the mean pore diameter is in the range of a few 10 nm. The results reported here may help optimize membrane preparation via solvent-based approaches, solution-loading of nanopore systems with guest materials as well as routine use of nanoporous membranes with bicontinuous morphology and may contribute to better understanding of adsorption/desorption processes in nanoporous media. PMID:25926406
International Nuclear Information System (INIS)
Mayinger, F.
1982-01-01
The author starts by discussing the gas-fluidic mixture, its application and its special characteristics. The conservation theorems for these mixtures are then presented, including the continuity equation, the impulse equation, and energy balance. The type of flow in vertical channels, vertical downwards flow and flow in horizontal and inclined tubes is discussed followed by a short section on local volumetric steam contents and slip. The expressions for the slip and for the local volumetric steam contents are explained before discussing phase separation in nonflowing fluids. Pressure loss in tubes and channels is followed by discussion of pressure loss in various types of moulded bodies with particular reference to fuel rod bundles. In conclusion the author discusses pressure wave expansion, critical discharge and cross exchange in sub-divided channels. (A.N.K.)
International Nuclear Information System (INIS)
Cullen, D.E.
1979-01-01
Program RECENT reconstructs energy-dependent neutron total, elastic, capture, and fission cross sections from a combination of resonance parameters and tabulated background cross sections in the ENDF/B format. Entire evaluations, not just cross sections, are written to the result file, which is in ENDF/B format. The output includes the original resonance parameters in a form that can be used in Doppler broadening and self-shielding calculations. A listing of the source deck is available on request. 5 figures, 5 tables
International Nuclear Information System (INIS)
Peter Bosted; M. E. Christy
2007-01-01
An empirical fit is described to measurements of inclusive inelastic electron-deuteron cross sections in the kinematic range of four-momentum transfer 0 (le) Q 2 2 and final state invariant mass 1.2 p of longitudinal to transverse cross sections for the proton, and the assumption R p =R n . The underlying fit parameters describe the average cross section for proton and neutron, with a plane-wave impulse approximation (PWIA) used to fit to the deuteron data. Pseudo-data from MAID 2007 were used to constrain the average nucleon cross sections for W<1.2 GeV. The mean deviation of data from the fit is 3%, with less than 5% of the data points deviating from the fit by more than 10%
Applied neutron resonance theory
International Nuclear Information System (INIS)
Froehner, F.H.
1980-01-01
Utilisation of resonance theory in basic and applications-oriented neutron cross section work is reviewed. The technically important resonance formalisms, principal concepts and methods as well as representative computer programs for resonance parameter extraction from measured data, evaluation of resonance data, calculation of Doppler-broadened cross sections and estimation of level-statistical quantities from resonance parameters are described. (author)
Applied neutron resonance theory
International Nuclear Information System (INIS)
Froehner, F.H.
1978-07-01
Utilisation of resonance theory in basic and applications-oriented neutron cross section work is reviewed. The technically important resonance formalisms, principal concepts and methods as well as representative computer programs for resonance parameter extraction from measured data, evaluation of resonance data, calculation of Doppler-broadened cross sections and estimation of level-statistical quantities from resonance parameters are described. (orig.) [de
Efimov Trimers near the Zero-crossing of a Feshbach Resonance
DEFF Research Database (Denmark)
Zinner, Nikolaj Thomas
2012-01-01
Near a Feshbach resonance, the two-body scattering length can assume any value. When it approaches zero, the next-order term given by the effective range is known to diverge. We consider the question of whether this divergence (and the vanishing of the scattering length) is accompanied by an anom...... by an anomalous solution of the three-boson Schr\\"odinger equation similar to the one found at infinite scattering length by Efimov. Within a simple zero-range model, we find no such solutions, and conclude that higher-order terms do not support Efimov physics.......Near a Feshbach resonance, the two-body scattering length can assume any value. When it approaches zero, the next-order term given by the effective range is known to diverge. We consider the question of whether this divergence (and the vanishing of the scattering length) is accompanied...
Differential Cross-Sections for pi- p --> gamma n in the First Resonance Region
Guex-Le Lan, Huong; Hilscher, H; Joseph, C L; Schmitt, H; Tran, M T; Truöl, P; Vaucher, B; Winkelmann, E; Zupancic, Crtomir; Joseph, C L no 1; Tran, M T no 1; Vaucher, B no 1; Winkelmann, E no 1; Bayer, W no 2; Hilscher, H no 2; Schmitt, H no 2; Zupancic, C no 2; Truöl, P no 3; Guex, L H no 1
1975-01-01
Differential cross-sections for negative pion radiative capture on protons at c.m. angles of 60°, 90°, and 120° have been measured at nine incident laboratory energies between 110 and 270 MeV. Comparison with measured cross-sections for pion photoproduction and with conventional multipole analyses shows neither evidence for a violation of time reversal invariance nor for an isotensor component of the electromagnetic current of hardrons. Record added 1974-09-01, las
Numerical Study of a Crossed Loop Coil Array for Parallel Magnetic Resonance Imaging
International Nuclear Information System (INIS)
Hernandez, J.; Solis, S. E.; Rodriguez, A. O.
2008-01-01
A coil design has been recently proposed by Temnikov (Instrum Exp Tech. 2005;48;636-637), with higher experimental signal-to-noise ratio than that of the birdcage coil. It is also claimed that it is possible to individually tune it with a single chip capacitor. This coil design shows a great resemble to the gradiometer coil. These results motivated us to numerically simulate a three-coil array for parallel magnetic resonance imaging and in vivo magnetic resonance spectroscopy with multi nuclear capability. The magnetic field was numerical simulated by solving Maxwell's equations with the finite element method. Uniformity profiles were calculated at the midsection for one single coil and showed a good agreement with the experimental data. Then, two more coils were added to form two different coil arrays: coil elements were equally distributed by an angle of a 30 deg. angle. Then, uniformity profiles were calculated again for all cases at the midsection. Despite the strong interaction among all coil elements, very good field uniformity can be achieved. These numerical results indicate that this coil array may be a good choice for magnetic resonance imaging parallel imaging
Non-adiabatic perturbations in multi-component perfect fluids
Energy Technology Data Exchange (ETDEWEB)
Koshelev, N.A., E-mail: koshna71@inbox.ru [Ulyanovsk State University, Leo Tolstoy str 42, 432970 (Russian Federation)
2011-04-01
The evolution of non-adiabatic perturbations in models with multiple coupled perfect fluids with non-adiabatic sound speed is considered. Instead of splitting the entropy perturbation into relative and intrinsic parts, we introduce a set of symmetric quantities, which also govern the non-adiabatic pressure perturbation in models with energy transfer. We write the gauge invariant equations for the variables that determine on a large scale the non-adiabatic pressure perturbation and the rate of changes of the comoving curvature perturbation. The analysis of evolution of the non-adiabatic pressure perturbation has been made for several particular models.
Non-adiabatic perturbations in multi-component perfect fluids
International Nuclear Information System (INIS)
Koshelev, N.A.
2011-01-01
The evolution of non-adiabatic perturbations in models with multiple coupled perfect fluids with non-adiabatic sound speed is considered. Instead of splitting the entropy perturbation into relative and intrinsic parts, we introduce a set of symmetric quantities, which also govern the non-adiabatic pressure perturbation in models with energy transfer. We write the gauge invariant equations for the variables that determine on a large scale the non-adiabatic pressure perturbation and the rate of changes of the comoving curvature perturbation. The analysis of evolution of the non-adiabatic pressure perturbation has been made for several particular models
3He(γ,pd) cross sections with tagged photons below the Δ resonance
International Nuclear Information System (INIS)
Kolb, N.R.; Cairns, E.B.; Hackett, E.D.; Korkmaz, E.; Nakano, T.; Opper, A.K.; Quraan, M.A.; Rodning, N.L.; Rozon, F.M.; Asai, J.; Feldman, G.; Hallin, E.; O'Rielly, G.V.; Pywell, R.E.; Skopik, D.M.
1994-01-01
The reaction cross section for 3 He(γ,pd) has been measured using the Saskatchewan-Alberta Large Acceptance Detector (SALAD) with tagged photons in the energy range from 166 to 213 MeV. The energy and angle of the proton and the deuteron were measured with SALAD while the tagger determined the photon energy. Differential cross sections have been determined for 40 degree p * <150 degree. The results are in agreement with the Bonn and Saclay photodisintegration measurements. The most recent photodisintegration measurement performed at Bates is higher by a factor of 1.3, which is just within the combined errors of the experiments. The proton capture results differ by a factor of 1.7 from the present experiment. Comparisons are made with microscopic calculations of the cross sections
3He(γ,pd) cross sections with tagged photons below the Δ resonance
Kolb, N. R.; Cairns, E. B.; Hackett, E. D.; Korkmaz, E.; Nakano, T.; Opper, A. K.; Quraan, M. A.; Rodning, N. L.; Rozon, F. M.; Asai, J.; Feldman, G.; Hallin, E.; O'rielly, G. V.; Pywell, R. E.; Skopik, D. M.
1994-05-01
The reaction cross section for 3He(γ,pd) has been measured using the Saskatchewan-Alberta Large Acceptance Detector (SALAD) with tagged photons in the energy range from 166 to 213 MeV. The energy and angle of the proton and the deuteron were measured with SALAD while the tagger determined the photon energy. Differential cross sections have been determined for 40°<θ*p<150°. The results are in agreement with the Bonn and Saclay photodisintegration measurements. The most recent photodisintegration measurement performed at Bates is higher by a factor of 1.3, which is just within the combined errors of the experiments. The proton capture results differ by a factor of 1.7 from the present experiment. Comparisons are made with microscopic calculations of the cross sections.
Energy Technology Data Exchange (ETDEWEB)
Parikh, Kushal R.; Kraft, Kate H.; Ivancic, Vesna; Smith, Ethan A.; Dillman, Jonathan R. [Section of Pediatric Radiology, Mott Children' s Hospital, Department of Radiology, University of Michigan Health System, Ann Arbor, MI (United States); Hammer, Matthew R. [University of Texas Southwestern, Department of Radiology, Dallas, TX (United States)
2015-11-15
MR Urography (MRU) is an increasingly used imaging modality for the evaluation of pediatric genitourinary obstruction. To determine whether pediatric MR urography (MRU) reliably detects crossing vessels in the setting of suspected ureteropelvic junction (UPJ) obstruction. The clinical significance of these vessels was also evaluated. We identified pediatric patients diagnosed with UPJ obstruction by MRU between May 2009 and June 2014. MRU studies were evaluated by two pediatric radiologists for the presence or absence of crossing vessels. Ancillary imaging findings such as laterality, parenchymal thinning/scarring, trapped fluid in the proximal ureter, and presence of renal parenchymal edema were also evaluated. Imaging findings were compared to surgical findings. We used the Mann-Whitney U test to compare continuous data and the Fisher exact test to compare proportions. Twenty-four of 25 (96%) UPJ obstructions identified by MRU were surgically confirmed. MRU identified crossing vessels in 10 of these cases, with 9 cases confirmed intraoperatively (κ = 0.92 [95% CI: 0.75, 1.0]). Crossing vessels were determined to be the primary cause of UPJ obstruction in 7/9 children intraoperatively, while in two children the vessels were deemed incidental and noncontributory to the urinary tract obstruction. There was no significant difference in age or the proportions of ancillary findings when comparing children without and with obstructing vessels. MRU allows detection of crossing vessels in pediatric UPJ obstruction. Although these vessels are the primary cause of obstruction in some children, they are incidental and non-contributory in others. Our study failed to convincingly identify any significant predictors (e.g., age or presence of renal parenchymal edema) that indicate when a crossing vessel is the primary cause of obstruction. (orig.)
The Decent Care Movement: Subsidiarity, Pragmatic Solidarity, and Cross-Cultural Resonance.
Niforatos, Joshua D
2016-02-01
Decent Care is the World Health Organization and The Ford Foundation's joint effort to articulate a healthcare paradigm that makes a patient's voice equal to the voice of the healthcare provider. In this article, the six tenants of Decent Care are outlined with particular emphasis on subsidiarity. Liberation theology's preferential option for the poor maxim is presented and compared with other major world religions to demonstrate the cross-cultural focus of "decency." The power of this paradigm is in its emphasis and proclamation of human flourishing in a healthcare setting, generally speaking, and more specifically, human flourishing in the presence of affliction from chronic disease or dying cross-culturally.
Empirical Fit to Precision Inclusive Electron-Proton Cross Sections in the Resonance Region
International Nuclear Information System (INIS)
M.E. Christy; Peter Bosted
2007-01-01
An empirical fit is described to measurements of inclusive inelastic electron-proton cross sections in the kinematic range of four-momentum transfer 0 (le) Q 2 2 and final state invariant mass 1.1 2 ∼ 7.5 GeV 2 , and photoproduction data at Q 2 = 0. Compared to previous fits, the present fit covers a wider kinematic range, fits both transverse and longitudinal cross sections, and features smooth transitions to the photoproduction data at Q 2 =0 and DIS data at high Q 2 and W
Adiabatic Quantum Optimization for Associative Memory Recall
Directory of Open Access Journals (Sweden)
Hadayat eSeddiqi
2014-12-01
Full Text Available Hopfield networks are a variant of associative memory that recall patterns stored in the couplings of an Ising model. Stored memories are conventionally accessed as fixed points in the network dynamics that correspond to energetic minima of the spin state. We show that memories stored in a Hopfield network may also be recalled by energy minimization using adiabatic quantum optimization (AQO. Numerical simulations of the underlying quantum dynamics allow us to quantify AQO recall accuracy with respect to the number of stored memories and noise in the input key. We investigate AQO performance with respect to how memories are stored in the Ising model according to different learning rules. Our results demonstrate that AQO recall accuracy varies strongly with learning rule, a behavior that is attributed to differences in energy landscapes. Consequently, learning rules offer a family of methods for programming adiabatic quantum optimization that we expect to be useful for characterizing AQO performance.
Adiabatic Quantum Optimization for Associative Memory Recall
Seddiqi, Hadayat; Humble, Travis
2014-12-01
Hopfield networks are a variant of associative memory that recall patterns stored in the couplings of an Ising model. Stored memories are conventionally accessed as fixed points in the network dynamics that correspond to energetic minima of the spin state. We show that memories stored in a Hopfield network may also be recalled by energy minimization using adiabatic quantum optimization (AQO). Numerical simulations of the underlying quantum dynamics allow us to quantify AQO recall accuracy with respect to the number of stored memories and noise in the input key. We investigate AQO performance with respect to how memories are stored in the Ising model according to different learning rules. Our results demonstrate that AQO recall accuracy varies strongly with learning rule, a behavior that is attributed to differences in energy landscapes. Consequently, learning rules offer a family of methods for programming adiabatic quantum optimization that we expect to be useful for characterizing AQO performance.
ADIABATIC HEATING OF CONTRACTING TURBULENT FLUIDS
International Nuclear Information System (INIS)
Robertson, Brant; Goldreich, Peter
2012-01-01
Turbulence influences the behavior of many astrophysical systems, frequently by providing non-thermal pressure support through random bulk motions. Although turbulence is commonly studied in systems with constant volume and mean density, turbulent astrophysical gases often expand or contract under the influence of pressure or gravity. Here, we examine the behavior of turbulence in contracting volumes using idealized models of compressed gases. Employing numerical simulations and an analytical model, we identify a simple mechanism by which the turbulent motions of contracting gases 'adiabatically heat', experiencing an increase in their random bulk velocities until the largest eddies in the gas circulate over a Hubble time of the contraction. Adiabatic heating provides a mechanism for sustaining turbulence in gases where no large-scale driving exists. We describe this mechanism in detail and discuss some potential applications to turbulence in astrophysical settings.
Adiabatic Theorem for Quantum Spin Systems
Bachmann, S.; De Roeck, W.; Fraas, M.
2017-08-01
The first proof of the quantum adiabatic theorem was given as early as 1928. Today, this theorem is increasingly applied in a many-body context, e.g., in quantum annealing and in studies of topological properties of matter. In this setup, the rate of variation ɛ of local terms is indeed small compared to the gap, but the rate of variation of the total, extensive Hamiltonian, is not. Therefore, applications to many-body systems are not covered by the proofs and arguments in the literature. In this Letter, we prove a version of the adiabatic theorem for gapped ground states of interacting quantum spin systems, under assumptions that remain valid in the thermodynamic limit. As an application, we give a mathematical proof of Kubo's linear response formula for a broad class of gapped interacting systems. We predict that the density of nonadiabatic excitations is exponentially small in the driving rate and the scaling of the exponent depends on the dimension.
Adiabatic invariance with first integrals of motion
Adib, Artur B.
2002-10-01
The construction of a microthermodynamic formalism for isolated systems based on the concept of adiabatic invariance is an old but seldom appreciated effort in the literature, dating back at least to P. Hertz [Ann. Phys. (Leipzig) 33, 225 (1910)]. An apparently independent extension of such formalism for systems bearing additional first integrals of motion was recently proposed by Hans H. Rugh [Phys. Rev. E 64, 055101 (2001)], establishing the concept of adiabatic invariance even in such singular cases. After some remarks in connection with the formalism pioneered by Hertz, it will be suggested that such an extension can incidentally explain the success of a dynamical method for computing the entropy of classical interacting fluids, at least in some potential applications where the presence of additional first integrals cannot be ignored.
Ramsey numbers and adiabatic quantum computing.
Gaitan, Frank; Clark, Lane
2012-01-06
The graph-theoretic Ramsey numbers are notoriously difficult to calculate. In fact, for the two-color Ramsey numbers R(m,n) with m, n≥3, only nine are currently known. We present a quantum algorithm for the computation of the Ramsey numbers R(m,n). We show how the computation of R(m,n) can be mapped to a combinatorial optimization problem whose solution can be found using adiabatic quantum evolution. We numerically simulate this adiabatic quantum algorithm and show that it correctly determines the Ramsey numbers R(3,3) and R(2,s) for 5≤s≤7. We then discuss the algorithm's experimental implementation, and close by showing that Ramsey number computation belongs to the quantum complexity class quantum Merlin Arthur.
Trapped Ion Quantum Computation by Adiabatic Passage
International Nuclear Information System (INIS)
Feng Xuni; Wu Chunfeng; Lai, C. H.; Oh, C. H.
2008-01-01
We propose a new universal quantum computation scheme for trapped ions in thermal motion via the technique of adiabatic passage, which incorporates the advantages of both the adiabatic passage and the model of trapped ions in thermal motion. Our scheme is immune from the decoherence due to spontaneous emission from excited states as the system in our scheme evolves along a dark state. In our scheme the vibrational degrees of freedom are not required to be cooled to their ground states because they are only virtually excited. It is shown that the fidelity of the resultant gate operation is still high even when the magnitude of the effective Rabi frequency moderately deviates from the desired value.
Adiabatic perturbation theory in quantum dynamics
Teufel, Stefan
2003-01-01
Separation of scales plays a fundamental role in the understanding of the dynamical behaviour of complex systems in physics and other natural sciences. A prominent example is the Born-Oppenheimer approximation in molecular dynamics. This book focuses on a recent approach to adiabatic perturbation theory, which emphasizes the role of effective equations of motion and the separation of the adiabatic limit from the semiclassical limit. A detailed introduction gives an overview of the subject and makes the later chapters accessible also to readers less familiar with the material. Although the general mathematical theory based on pseudodifferential calculus is presented in detail, there is an emphasis on concrete and relevant examples from physics. Applications range from molecular dynamics to the dynamics of electrons in a crystal and from the quantum mechanics of partially confined systems to Dirac particles and nonrelativistic QED.
Zhou, Xing-Yu; Wang, Ya-Di; Xia, Li-Gang
2017-08-01
A detailed theoretical derivation of the cross sections of e+e- → e+e- and e+e- → μ + μ - around the J/ψ resonance is reported. The resonance and interference parts of the cross sections, related to J/ψ resonance parameters, are calculated. Higher-order corrections for vacuum polarization and initial-state radiation are considered. An arbitrary upper limit of radiative correction integration is involved. Full and simplified versions of analytic formulae are given with precision at the level of 0.1% and 0.2%, respectively. Moreover, the results obtained in the paper can be applied to the case of the ψ(3686) resonance. Supported by National Natural Science Foundation of China (11275211) and Istituto Nazionale di Fisica Nucleare, Italy
International Nuclear Information System (INIS)
Harvey, J.A.; Hill, N.W.; Larson, N.M.; Larson, D.C.
1991-01-01
High-resolution neutron transmission measurements have been made on several thicknesses of nitrogen gas samples from 0.5 eV to 50 MeV at the Oak Ridge Electron Linear Accelerator (ORELA). A preliminary R-matrix analysis has been done for resonances up to 800 keV. An R-matrix analysis of previous data was done by LANL and ENDF/B-VI, including the lowest energy resonance in 14 N at 433 keV. They found a spin of 3/2 (with ell = 1) and a peak cross section of 7.0 b. Analysis of the present data yield a spin of 7/2 (requiring ell ≥ 2) and a peak cross section of 11.5 b for this resonance. These results are important for transport calculations of neutrons through air. Scattering measurements are planned to determine the parity of this resonance. 6 refs., 2 figs
International Nuclear Information System (INIS)
Maric, Dj.M.; Meier, P.F.; Vogel, S.; Davis, E.A.
1991-01-01
The possibility of studying impurity passivation complexes in semiconductors by quadrupole resonance spectroscopy is examined. The problem is illustrated for the case of boron in silicon passivated with hydrogen or, equivalently, with muonium, since the radioactive light isotope in principle offers a greater sensitivity for detection of the spectra. Ab initio calculations on suitable cluster models of the passivation complexes provide estimates of the electric field gradients at the quadrupolar nuclei, and thereby predictions of the quadrupole resonance frequencies. Detection via cross-relaxation techniques is proposed, notably muon level crossing resonance (μLCR), and illustrated by calculation of the time dependence of the muon polarization function. Possible reasons for the absence of quadrupolar resonances in μLCR spectra recorded in exploratory experiments are discussed; these include the existence of a local tunnelling mode for the lighter isotope. (author)
Adiabatic graph-state quantum computation
International Nuclear Information System (INIS)
Antonio, B; Anders, J; Markham, D
2014-01-01
Measurement-based quantum computation (MBQC) and holonomic quantum computation (HQC) are two very different computational methods. The computation in MBQC is driven by adaptive measurements executed in a particular order on a large entangled state. In contrast in HQC the system starts in the ground subspace of a Hamiltonian which is slowly changed such that a transformation occurs within the subspace. Following the approach of Bacon and Flammia, we show that any MBQC on a graph state with generalized flow (gflow) can be converted into an adiabatically driven holonomic computation, which we call adiabatic graph-state quantum computation (AGQC). We then investigate how properties of AGQC relate to the properties of MBQC, such as computational depth. We identify a trade-off that can be made between the number of adiabatic steps in AGQC and the norm of H-dot as well as the degree of H, in analogy to the trade-off between the number of measurements and classical post-processing seen in MBQC. Finally the effects of performing AGQC with orderings that differ from standard MBQC are investigated. (paper)
Ohmic ignition of Neo-Alcator tokamak with adiabatic compression
International Nuclear Information System (INIS)
Inoue, Nobuyuki; Ogawa, Yuichi
1992-01-01
Ohmic ignition condition on axis of the DT tokamak plasma heated by minor radius and major radius adiabatic compression is studied assuming parabolic profiles for plasma parameters, elliptic plasma cross section, and Neo-Alcator confinement scaling. It is noticeable that magnetic compression reduces the necessary total plasma current for Ohmic ignition device. Typically in compact ignition tokamak of the minor radius of 0.47 m, major radius of 1.5 m and on-axis toroidal field of 20 T, the plasma current of 6.8 MA is sufficient for compression plasma, while that of 11.7 MA is for no compression plasma. Another example with larger major radius is also described. In such a device the large flux swing of Ohmic transformer is available for long burn. Application of magnetic compression saves the flux swing and thereby extends the burn time. (author)
3He(γ,pp)n cross sections with tagged photons below the Δ resonance energy
Kolb, N. R.; Feldman, G.; O'rielly, G. V.; Pywell, R. E.; Skopik, D. M.; Hackett, E. D.; Quraan, M. A.; Rodning, N. L.
1996-11-01
Cross sections have been measured for the 3He(γ,pp)n reaction with tagged photons in the range Eγ =161-208 MeV using the Saskatchewan-Alberta Large Acceptance Detector (SALAD). The protons were detected over a range of polar angles of 40°-140° and azimuthal angles of 0°-360° with an energy threshold of 40 MeV. Comparisons are made with a microscopic calculation which includes one-, two-, and three-nucleon absorption mechanisms. One- and two-nucleon processes, including final-state interactions, are unable to account for the measured cross sections. The addition of three-nucleon absorption diagrams gives roughly the right strength, but the distribution in phase space is in disagreement with the data.
3He(γ,pp)n cross sections with tagged photons below the Δ resonance energy
International Nuclear Information System (INIS)
Kolb, N.R.; Feldman, G.; ORielly, G.V.; Pywell, R.E.; Skopik, D.M.; Hackett, E.D.; Quraan, M.A.; Rodning, N.L.
1996-01-01
Cross sections have been measured for the 3 He(γ,pp)n reaction with tagged photons in the range E γ =161 endash 208 MeV using the Saskatchewan-Alberta Large Acceptance Detector (SALAD). The protons were detected over a range of polar angles of 40 degree endash 140 degree and azimuthal angles of 0 degree endash 360 degree with an energy threshold of 40 MeV. Comparisons are made with a microscopic calculation which includes one-, two-, and three-nucleon absorption mechanisms. One- and two-nucleon processes, including final-state interactions, are unable to account for the measured cross sections. The addition of three-nucleon absorption diagrams gives roughly the right strength, but the distribution in phase space is in disagreement with the data. copyright 1996 The American Physical Society
International Nuclear Information System (INIS)
Qian Dongbin; Guo Yuhui; Zhang Dacheng; Chinese Academy of Sciences, Beijing; Ma Xinwen; Zhao Zhizheng; Wang Yanyu; Zu Kailing
2006-01-01
A CAMAC data acquisition system for measuring ionization cross section in laser multi-step resonant ionization experiment is described. The number of scalers in the front-end CAMAC can be adjusted by changing the data read-out table files. Both continuous and manual acquisition models are available, and there is a wide adjustable range from 1 ms to 800 s with the acquisition time unit. The long-term stability, Δt/t, for the data acquisition system with an acquisition time unit of 100 s was measured to be better than ±0.01%, thus validating its reliability in long-term online experimental data acquisition. The time response curves for three electrothermal power-meters were also measured by this DAQ system. (authors)
McConnell, R; Kolthammer, WS; Richerme, P; Müllers, A; Walz, J; Grzonka, D; Zielinski, M; Fitzakerley, D; George, MC; Hessels, EA; Storry, CH; Weel, M
2016-01-01
Lasers are used to control the production of highly excited positronium atoms (Ps*). The laser light excites Cs atoms to Rydberg states that have a large cross section for resonant charge-exchange collisions with cold trapped positrons. For each trial with 30 million trapped positrons, more than 700 000 of the created Ps* have trajectories near the axis of the apparatus, and are detected using Stark ionization. This number of Ps* is 500 times higher than realized in an earlier proof-of-principle demonstration (2004 Phys. Lett. B 597 257). A second charge exchange of these near-axis Ps* with trapped antiprotons could be used to produce cold antihydrogen, and this antihydrogen production is expected to be increased by a similar factor.
Pion-nucleus total cross sections in the (3, 3) resonance region
International Nuclear Information System (INIS)
Carroll, A.S.; Chiang, I.; Dover, C.B.; Kycia, T.F.; Li, K.K.; Mazur, P.O.; Michael, D.N.; Mockett, P.M.; Rahm, D.C.; Rubinstein, R.
1976-01-01
The results of total cross section measurements are presented for π +- on targets of natural Li, C, Al, Fe, Sn, and Pb in the region of 65--320 MeV laboratory kinetic energy. The data are fitted with a simple phenomenological model, which allows one to extract the A dependence of the peak energy and the width which characterize the pion-nucleus interaction
International Nuclear Information System (INIS)
Segev, M.
1996-01-01
The last three years have witnessed an increasing interest in the in-rod distribution of resonance absorption and of temperature. High burnup, especially beyond the 'classical' limit of 30 GWd/T, is expected to generate uneven in-rod isotope distributions with consequences for fuel rod integrity and reactor Doppler feedback. There are recent indications that, even for a freshly loaded uranium-oxide rod, proper account of the U 238 in-rod absorption rate distribution results in a doppler coefficient some 15% lower in magnitude than its routinely calculated value. Presently a special form of application is made of the Bogart approach. This approach is based on the fact that, as a fuel rod is filled in from the outside, its resonance capture rate increases monotonically, despite file decreasing effective capture cross section for the thickness annulus. Bogart used His observation to derive a differential equation for the in-rod absorption distribution. Presently we capitalize on the idea in a discrete form. (author)
Energy Technology Data Exchange (ETDEWEB)
Segev, M [Ben-Gurion Univ. of the Negev, Beersheba (Israel). Dept. of Nuclear Engineering
1996-12-01
The last three years have witnessed an increasing interest in the in-rod distribution of resonance absorption and of temperature. High burnup, especially beyond the `classical` limit of 30 GWd/T, is expected to generate uneven in-rod isotope distributions with consequences for fuel rod integrity and reactor Doppler feedback. There are recent indications that, even for a freshly loaded uranium-oxide rod, proper account of the U{sup 238} in-rod absorption rate distribution results in a doppler coefficient some 15% lower in magnitude than its routinely calculated value. Presently a special form of application is made of the Bogart approach. This approach is based on the fact that, as a fuel rod is filled in from the outside, its resonance capture rate increases monotonically, despite file decreasing effective capture cross section for the thickness annulus. Bogart used His observation to derive a differential equation for the in-rod absorption distribution. Presently we capitalize on the idea in a discrete form. (author).
Chen, Ye-Hong; Xia, Yan; Song, Jie; Chen, Qing-Qin
2015-10-28
Berry's approach on "transitionless quantum driving" shows how to set a Hamiltonian which drives the dynamics of a system along instantaneous eigenstates of a reference Hamiltonian to reproduce the same final result of an adiabatic process in a shorter time. In this paper, motivated by transitionless quantum driving, we construct shortcuts to adiabatic passage in a three-atom system to create the Greenberger-Horne-Zeilinger states with the help of quantum Zeno dynamics and of non-resonant lasers. The influence of various decoherence processes is discussed by numerical simulation and the result proves that the scheme is fast and robust against decoherence and operational imperfection.
International Nuclear Information System (INIS)
Alekseev, A.A.; Bergman, A.A.; Berlev, A.I.; Koptelov, E.A.; Egorov, A.S.; Samylin, B.F.; Trufanov, A.M.; Fursov, B.I.; Shorin, V.S.
2012-01-01
The neutron induced fission cross sections of Am and Cm isotopes were measured relative to 239 Pu in the neutron energy range from 1 eV to 20 keV at the INR RAS lead slowing down spectrometer LSDS-100. The fission resonance integrals were also estimated using the measured cross section data. The results have been compared with the available experimental and evaluated data. This analysis has shown the present status of the measured fission cross sections and the necessity to revise the evaluated cross sections libraries for the minor actinides. (author)
Xu, Joanna Xiuzhu; Hu, Juan; Zhang, Dongmao
2018-05-25
Presented herein is the ratiometric bandwidth-varied polarized resonance synchronous spectroscopy (BVPRS2) method for quantification of material optical activity spectra. These include the sample light absorption and scattering cross-section spectrum, the scattering depolarization spectrum, and the fluorescence emission cross-section and depolarization spectrum in the wavelength region where the sample both absorbs and emits. This ratiometric BVPRS2 spectroscopic method is a self-contained technique capable of quantitatively decoupling material fluorescence and light scattering signal contribution to its ratiometric BVPRS2 spectra through the linear curve-fitting of the ratiometric BVPRS2 signal as a function of the wavelength bandwidth used in the PRS2 measurements. Example applications of this new spectroscopic method are demonstrated with materials that can be approximated as pure scatterers, simultaneous photon absorbers/emitters, simultaneous photon absorbers/scatterers, and finally simultaneous photon absorbers/scatterers/emitters. Because the only instruments needed for this ratiometric BVPRS2 technique are the conventional UV-vis spectrophotometer and spectrofluorometer, this work should open doors for routine decomposition of material UV-vis extinction spectrum into its absorption and scattering component spectra. The methodology and insights provided in this work should be of broad significance to all chemical research that involves photon/matter interactions.
International Nuclear Information System (INIS)
Borella, A.
2005-01-01
Chapter 1 describes the motivation of the measurements (accelerator driven systems, stellar nucleosynthesis, neutron induced reactions on 206 Pb), the present status of the neutron capture data for 206 Pb and 209 Bi and the structure of this work. In Chapter 2 the basic reaction theory underlying this work is described. The neutron induced reaction mechanism and formalism are explained. The parameterisation of the cross section in terms of R-matrix theory is discussed and we put particular emphasis on the statistical behaviour of the resonance parameters and the impact of the angular distribution of gamma rays following neutron capture. The relation between experimental observables and the resonance parameters is discussed together with general comments related to resonance shape analysis. Chapter 3 is focused on the determination of resonance parameters for 206 Pb. We performed high-resolution transmission and capture measurements at the Time-Of-Flight (TOF) facility GELINA of the IRMM at Geel (B) and determined the resonance parameters. For nuclei like 206 Pb, where the total width is dominated by Γ n , the capture area allows to determine G . Transmission measurements were carried out to determine Γ n , and the statistical factor g of resonances. Before performing a Resonance Shape Analysis (RSA) on the transmission and capture data, we verified the neutron flux and resolution at GELINA. We also compared the characteristics of GELINA with those of the n-TOF facility at CERN. A special emphasis is placed on the total energy detection technique using C 6 D 6 detectors. This technique was applied for the determination of the capture cross section. To reduce systematic bias effects on the capture cross section, the response of the detectors was determined by Monte Carlo simulations, which has been validated by experiments. Using these response functions the partial capture cross sections for individual resonances of 206 Pb have been deduced, by unfolding the
International Nuclear Information System (INIS)
Anaf, J.; Chalhoub, E.S.
1988-12-01
The NJOY and LINEAR/RECENT/GROUPIE calculational procedures for the resolved and unresolved resonance contributions and background cross sections are evaluated. Elastic scattering, fission and capture multigroup cross sections generated by these codes and the previously validated ETOG-3Q, ETOG-3, FLANGE-II and XLACS are compared. Constant weighting function and zero Kelvin temperature are considered. Discrepancies are presented and analysed. (author) [pt
International Nuclear Information System (INIS)
Anaf, J.; Chalhoub, E.S.
1991-01-01
The NJOY and LINEAR/RECENT/GROUPIE calculational procedures for the resolved and unresolved resonance contributions and background cross sections are evaluated. Elastic scattering, fission and capture multigroup cross sections generated by these codes and the previously validated ETOG-3Q, ETOG-3, FLANGE-II and XLACS are compared. Constant weighting function and zero Kelvin temperature are considered. Discrepancies are presented and analyzed. (author)
Gupta, Ranjana; Joshi, Sandeep; Mittal, Amit; Luthra, Ishita; Mittal, Puneet; Verma, Vibha
2015-01-01
Acquired Dyke-Davidoff-Masson syndrome, also known as hemispheric atrophy, is characterized by loss of volume of one cerebral hemisphere from an insult in early life. Crossed cerebellar diaschisis refers to dysfunction/atrophy of cerebellar hemisphere which is secondary to contralateral supratentorial insult. We describe magnetic resonance imaging findings in two cases of acquired Dyke-Davidoff-Masson syndrome with crossed cerebro-cerebellar diaschisis.
Kittell, Aaron W.; Hyde, James S.
2015-01-01
Non-adiabatic rapid passage (NARS) electron paramagnetic resonance (EPR) spectroscopy was introduced by Kittell, A.W., Camenisch, T.G., Ratke, J.J. Sidabras, J.W., Hyde, J.S., 2011 as a general purpose technique to collect the pure absorption response. The technique has been used to improve sensitivity relative to sinusoidal magnetic field modulation, increase the range of inter-spin distances that can be measured under near physiological conditions, and enhance spectral resolution in copper (II) spectra. In the present work, the method is extended to CW microwave power saturation of spin-labeled T4 Lysozyme (T4L). As in the cited papers, rapid triangular sweep of the polarizing magnetic field was superimposed on slow sweep across the spectrum. Adiabatic rapid passage (ARP) effects were encountered in samples undergoing very slow rotational diffusion as the triangular magnetic field sweep rate was increased. The paper reports results of variation of experimental parameters at the interface of adiabatic and non-adiabatic rapid sweep conditions. Comparison of the forward (up) and reverse (down) triangular sweeps is shown to be a good indicator of the presence of rapid passage effects. Spectral turning points can be distinguished from spectral regions between turning points in two ways: differential microwave power saturation and differential passage effects. Oxygen accessibility data are shown under NARS conditions that appear similar to conventional field modulation data. However, the sensitivity is much higher, permitting, in principle, experiments at substantially lower protein concentrations. Spectral displays were obtained that appear sensitive to rotational diffusion in the range of rotational correlation times of 10−3 to 10−7 s in a manner that is analogous to saturation transfer spectroscopy. PMID:25917132
Bond selective chemistry beyond the adiabatic approximation
Energy Technology Data Exchange (ETDEWEB)
Butler, L.J. [Univ. of Chicago, IL (United States)
1993-12-01
One of the most important challenges in chemistry is to develop predictive ability for the branching between energetically allowed chemical reaction pathways. Such predictive capability, coupled with a fundamental understanding of the important molecular interactions, is essential to the development and utilization of new fuels and the design of efficient combustion processes. Existing transition state and exact quantum theories successfully predict the branching between available product channels for systems in which each reaction coordinate can be adequately described by different paths along a single adiabatic potential energy surface. In particular, unimolecular dissociation following thermal, infrared multiphoton, or overtone excitation in the ground state yields a branching between energetically allowed product channels which can be successfully predicted by the application of statistical theories, i.e. the weakest bond breaks. (The predictions are particularly good for competing reactions in which when there is no saddle point along the reaction coordinates, as in simple bond fission reactions.) The predicted lack of bond selectivity results from the assumption of rapid internal vibrational energy redistribution and the implicit use of a single adiabatic Born-Oppenheimer potential energy surface for the reaction. However, the adiabatic approximation is not valid for the reaction of a wide variety of energetic materials and organic fuels; coupling between the electronic states of the reacting species play a a key role in determining the selectivity of the chemical reactions induced. The work described below investigated the central role played by coupling between electronic states in polyatomic molecules in determining the selective branching between energetically allowed fragmentation pathways in two key systems.
Coherent photon scattering cross sections for helium near the delta resonance
International Nuclear Information System (INIS)
Delli Carpini, D.; Booth, E.C.; Miller, J.P.; Igarashi, R.; Bergstrom, J.; Caplan, H.; Doss, M.; Hallin, E.; Rangacharyulu, C.; Skopik, D.; Lucas, M.A.; Nathan, A.M.; Wells, D.P.
1991-01-01
The angular distributions for coherent photon scattering from 4 He were measured at average laboratory bremsstrahlung energies of 187, 235, and 280 MeV. The experiment was performed at the Saskatchewan Accelerator Laboratory using the new high duty factor electron beam. The scattered photons were observed with a high-resolution NaI(Tl) total absorption scintillation detector. These measurements are intended to investigate modification of the Δ properties inside the nuclear medium and the treatment of nonresonant contributions to the scattering cross sections. The results are compared to theoretical calculations in the isobar-hole model. Clear deviations from the theory are evident at all energies, especially at 187 MeV
Accuracy versus run time in an adiabatic quantum search
International Nuclear Information System (INIS)
Rezakhani, A. T.; Pimachev, A. K.; Lidar, D. A.
2010-01-01
Adiabatic quantum algorithms are characterized by their run time and accuracy. The relation between the two is essential for quantifying adiabatic algorithmic performance yet is often poorly understood. We study the dynamics of a continuous time, adiabatic quantum search algorithm and find rigorous results relating the accuracy and the run time. Proceeding with estimates, we show that under fairly general circumstances the adiabatic algorithmic error exhibits a behavior with two discernible regimes: The error decreases exponentially for short times and then decreases polynomially for longer times. We show that the well-known quadratic speedup over classical search is associated only with the exponential error regime. We illustrate the results through examples of evolution paths derived by minimization of the adiabatic error. We also discuss specific strategies for controlling the adiabatic error and run time.
Intermittent strong transport of the quasi-adiabatic plasma state.
Kim, Chang-Bae; An, Chan-Yong; Min, Byunghoon
2018-06-05
The dynamics of the fluctuating electrostatic potential and the plasma density couched in the resistive-drift model at nearly adiabatic state are simulated. The linear modes are unstable if the phase difference between the potential and the density are positive. Exponential growth of the random small perturbations slows down due to the nonlinear E × B flows that work in two ways. They regulate the strength of the fluctuations by transferring the energy from the energy-producing scale to neighboring scales and reduce the cross phase at the same time. During quasi-steady relaxation sporadic appearance of very strong turbulent particle flux is observed that is characterized by the flat energy spectrum and the broad secondary peak in the mesoscale of the order of the gyro-radius. Such boost of the transport is found to be caused by presence of relatively large cross phase as the E × B flows are not effective in cancelling out the cross phase.
High-fidelity adiabatic inversion of a {sup 31}P electron spin qubit in natural silicon
Energy Technology Data Exchange (ETDEWEB)
Laucht, Arne, E-mail: a.laucht@unsw.edu.au; Kalra, Rachpon; Muhonen, Juha T.; Dehollain, Juan P.; Mohiyaddin, Fahd A.; Hudson, Fay; Dzurak, Andrew S.; Morello, Andrea [Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales 2052 (Australia); McCallum, Jeffrey C.; Jamieson, David N. [Centre for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Melbourne, Victoria 3010 (Australia)
2014-03-03
The main limitation to the high-fidelity quantum control of spins in semiconductors is the presence of strongly fluctuating fields arising from the nuclear spin bath of the host material. We demonstrate here a substantial improvement in single-qubit inversion fidelities for an electron spin qubit bound to a {sup 31}P atom in natural silicon, by applying adiabatic sweeps instead of narrow-band pulses. We achieve an inversion fidelity of 97%, and we observe signatures in the spin resonance spectra and the spin coherence time that are consistent with the presence of an additional exchange-coupled donor. This work highlights the effectiveness of simple adiabatic inversion techniques for spin control in fluctuating environments.
Accuracy of the adiabatic-impulse approximation for closed and open quantum systems
Tomka, Michael; Campos Venuti, Lorenzo; Zanardi, Paolo
2018-03-01
We study the adiabatic-impulse approximation (AIA) as a tool to approximate the time evolution of quantum states when driven through a region of small gap. Such small-gap regions are a common situation in adiabatic quantum computing and having reliable approximations is important in this context. The AIA originates from the Kibble-Zurek theory applied to continuous quantum phase transitions. The Kibble-Zurek mechanism was developed to predict the power-law scaling of the defect density across a continuous quantum phase transition. Instead, here we quantify the accuracy of the AIA via the trace norm distance with respect to the exact evolved state. As expected, we find that for short times or fast protocols, the AIA outperforms the simple adiabatic approximation. However, for large times or slow protocols, the situation is actually reversed and the AIA provides a worse approximation. Nevertheless, we found a variation of the AIA that can perform better than the adiabatic one. This counterintuitive modification consists in crossing the region of small gap twice. Our findings are illustrated by several examples of driven closed and open quantum systems.
Exciton spectrum of surface-corrugated quantum wells: the adiabatic self-consistent approach
Energy Technology Data Exchange (ETDEWEB)
Atenco A, N.; Perez R, F. [lnstituto de Fisica, Universidad Autonoma de Puebla, A.P. J-48, 72570 Puebla (Mexico); Makarov, N.M. [lnstituto de Ciencias, Universidad Autonoma de Puebla, Priv. 17 Norte No 3417, Col. San Miguel Hueyotlipan, 72050 Puebla (Mexico)
2005-07-01
A theory for calculating the relaxation frequency {nu} and the shift {delta} {omega} of exciton resonances in quantum wells with finite potential barriers and adiabatic surface disorder is developed. The adiabaticity implies that the correlation length R{sub C} for the well width fluctuations is much larger than the exciton radius a{sub 0} (R{sub C} >> a{sub 0}). Our theory is based on the self-consistent Green's function method, and therefore takes into account the inherent action of the exciton scattering on itself. The self-consistent approach is shown to describe quantitatively the sharp exciton resonance. It also gives the qualitatively correct resonance picture for the transition to the classical limit, as well as within the domain of the classical limit itself. We present and analyze results for h h-exciton in a GaAs quantum well with Al{sub 0.3} Ga{sub 0.7}As barriers. It is established that the self-consistency and finite height of potential barriers significantly influence on the line-shape of exciton resonances, and make the values of {nu} and {delta} {omega} be quite realistic. In particular, the relaxation frequency {nu} for the ground-state resonance has a broad, almost symmetric maximum near the resonance frequency {omega}{sub 0}, while the surface-induced resonance shift {delta} {omega} vanishes near {omega}{sub 0}, and has different signs on the sides of the exciton resonance. (Author) 43 refs., 4 figs.
Photoionization by a bichromatic field: Adiabatic theory
International Nuclear Information System (INIS)
Pazdzersky, V.A.; Yurovsky, V.A.
1995-01-01
Atom photoionization by the superposition of a fundamental field and its second harmonic is considered. The finite analytical expressions for the photoionization probability are obtained using the adiabatic approximation. They demonstrate that the photoelectron angular distribution has a polar symmetry when the electrical field strength has a maximal polar asymmetry and the distribution is asymmetrical when the field is symmetrical. A strict proof of the polar symmetry of the photoionization probability in the case of the electrical field with maximal asymmetry is deduced using the Keldysh-Faisal-Reiss theories. The obtained results are in agreement with the experimental data available
Neutron generator based on adiabatic trap
International Nuclear Information System (INIS)
Golovin, I.N.; Zhil'tsov, V.A.; Panov, D.A.; Skovoroda, A.A.; Shatalov, G.E.; Shcherbakov, A.G.
1988-01-01
A possibility of 14 MeV neutron generator (NG) production on the basis of axial-symmetric adiabatic trap with MHD cusped armature for the testing of materials and elements of the DT reactor first wall and blanket structure is discussed. General requirements to NG are formulated. It is shown that the NG variant discussed meets the requirements formulated. Approximate calculation of the NG parameters has shown that total energy consumption by the generator does not exceed 220 MW at neutron flux specific capacity of 2.5 MW/m 2 and radiation test area of 5-6 m 2
Phase avalanches in near-adiabatic evolutions
International Nuclear Information System (INIS)
Vertesi, T.; Englman, R.
2006-01-01
In the course of slow, nearly adiabatic motion of a system, relative changes in the slowness can cause abrupt and high magnitude phase changes, ''phase avalanches,'' superimposed on the ordinary geometric phases. The generality of this effect is examined for arbitrary Hamiltonians and multicomponent (>2) wave packets and is found to be connected (through the Blaschke term in the theory of analytic signals) to amplitude zeros in the lower half of the complex time plane. Motion on a nonmaximal circle on the Poincare-sphere suppresses the effect. A spectroscopic transition experiment can independently verify the phase-avalanche magnitudes
On adiabatic perturbations in the ekpyrotic scenario
International Nuclear Information System (INIS)
Linde, A.; Mukhanov, V.; Vikman, A.
2010-01-01
In a recent paper, Khoury and Steinhardt proposed a way to generate adiabatic cosmological perturbations with a nearly flat spectrum in a contracting Universe. To produce these perturbations they used a regime in which the equation of state exponentially rapidly changed during a short time interval. Leaving aside the singularity problem and the difficult question about the possibility to transmit these perturbations from a contracting Universe to the expanding phase, we will show that the methods used in Khoury are inapplicable for the description of the cosmological evolution and of the process of generation of perturbations in this scenario
Adiabatic and non-adiabatic electron oscillations in a static electric field
International Nuclear Information System (INIS)
Wahlberg, C.
1977-03-01
The influence of a static electric field on the oscillations of a one-dimensional stream of electrons is investigated. In the weak field limit the oscillations are adiabatic and mode coupling negligible, but becomes significant if the field is tronger. The latter effect is believed to be of importance for the stability of e.g. potential double layers
The differential cross section of the 12C(p,p)12C reaction near the resonance at energy 1.726 MeV
International Nuclear Information System (INIS)
Duvanov, S.M.; Kobzev, A.P.
1996-01-01
New experimental results on the differential cross section of the 12 C(p,p) 12 C reaction near the separate resonance at 1726 keV were obtained for the 170 deg scattering angle. The cross section measured with a thin target has been used for computer simulation of the spectra measured for a defined initial proton energy for two thick targets. The precision measurements of the proton energies have been carried out using the resonance of 27 Al(p,γ) 28 Si reaction at 1726.0 keV. The energy scale of the excitation function of the 12 C(p,p) 12 C reaction near the resonance at 1726 keV has been defined more exactly. It will improve the precision of depth profiling of carbon in solids. 11 refs., 5 figs., 1 tab
Adiabatic theory of Wannier threshold laws and ionization cross sections
International Nuclear Information System (INIS)
Macek, J.H.; Ovchinnikov, S.Yu.
1994-01-01
The Wannier threshold law for three-particle fragmentation is reviewed. By integrating the Schroedinger equation along a path where the reaction coordinate R is complex, anharmonic corrections to the simple power law are obtained. These corrections are found to be non-analytic in the energy E, in contrast to the expected analytic dependence upon E
Adiabatic theory of Wannier threshold laws and ionization cross sections
International Nuclear Information System (INIS)
Macek, J.H.; Ovchinnikov, S.Y.
1995-01-01
The Wannier threshold law for three-particle fragmentation is reviewed. By integrating the Schroedinger equation along a path where the reaction coordinate R is complex, anharmonic corrections to the simple power law are obtained. These corrections are found to be non-analytic in the energy E, in contrast to the expected analytic dependence upon E. copyright 1995 American Institute of Physics
Adiabatic evolution of decoherence-free subspaces and its shortcuts
Wu, S. L.; Huang, X. L.; Li, H.; Yi, X. X.
2017-10-01
The adiabatic theorem and shortcuts to adiabaticity for time-dependent open quantum systems are explored in this paper. Starting from the definition of dynamical stable decoherence-free subspace, we show that, under a compact adiabatic condition, the quantum state remains in the time-dependent decoherence-free subspace with an extremely high purity, even though the dynamics of the open quantum system may not be adiabatic. The adiabatic condition mentioned here in the adiabatic theorem for open systems is very similar to that for closed quantum systems, except that the operators required to change slowly are the Lindblad operators. We also show that the adiabatic evolution of decoherence-free subspaces depends on the existence of instantaneous decoherence-free subspaces, which requires that the Hamiltonian of open quantum systems be engineered according to the incoherent control protocol. In addition, shortcuts to adiabaticity for adiabatic decoherence-free subspaces are also presented based on the transitionless quantum driving method. Finally, we provide an example that consists of a two-level system coupled to a broadband squeezed vacuum field to show our theory. Our approach employs Markovian master equations and the theory can apply to finite-dimensional quantum open systems.
International Nuclear Information System (INIS)
Hamel, D.; Wilkin, G.B.
1979-09-01
Group cross sections in the resolved resonance region are commonly computed for each nuclide independently of other resonance nuclides present in the fuel mixture. While this technique is usually entirely adequate for uranium fuel cycles, it is necessary to establish its legitimacy for closed thorium fuel cycles topped with fissile uranium or plutonium by analysis of a number of representative cases. At the same time cross sections originating from WIMS (Winfrith Improved Multigroup Scheme) calculations are compared with values computed in this study. In this context, particular attention is paid to the adequacy of the lower boundary for the WIMS resonance treatment. All calculations are based on heavy nuclide cross sections from the ENDF/B-IV data compilaton (Evaluated Nuclear Data File). Appreciable interaction effects have been determined for all nuclides except for 232 Th. In most cases, these are due to the strong 232 Th resonance doublet at 21.8 eV and 23.5 eV but some effects also result from resonances of 234 U (5.19 eV, 48.75 eV), 236 U (5.45 eV), 242 Pu (2.67 eV) and others. The influence of mutual interaction on the infinite lattice multiplicaton factor is very small in comparison to the effects of self-shielding. WIMS cross sections do not always compare well with the values computed in the study, but discrepancies are in most cases related to the different sources of data. Interaction effects are not explicitly taken into account in WIMS. Several nuclides ( 233 Pa, 233 U, 240 Pu, 242 Pu) show appreciable self-shielding below the WIMS resonance region and are therefore not treated adequately. The impact of these discrepancies on the multiplication factor is relatively small, however, because of error cancellation. (author)
Charvet, Christine J; Hof, Patrick R; Raghanti, Mary Ann; Van Der Kouwe, Andre J; Sherwood, Chet C; Takahashi, Emi
2017-04-01
The isocortex of primates is disproportionately expanded relative to many other mammals, yet little is known about what the expansion of the isocortex entails for differences in cellular composition and connectivity patterns in primates. Across the depth of the isocortex, neurons exhibit stereotypical patterns of projections. Upper-layer neurons (i.e., layers II-IV) project within and across cortical areas, whereas many lower-layer pyramidal neurons (i.e., layers V-VI) favor connections to subcortical regions. To identify evolutionary changes in connectivity patterns, we quantified upper (i.e., layers II-IV)- and lower (i.e., layers V-VI)-layer neuron numbers in primates and other mammals such as rodents and carnivores. We also used MR tractography based on high-angular resolution diffusion imaging and diffusion spectrum imaging to compare anterior-to-posterior corticocortical tracts between primates and other mammals. We found that primates possess disproportionately more upper-layer neurons as well as an expansion of anterior-to-posterior corticocortical tracts compared with other mammals. Taken together, these findings demonstrate that primates deviate from other mammals in exhibiting increased cross-cortical connectivity. J. Comp. Neurol. 525:1075-1093, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.
An Adiabatic Phase-Matching Accelerator
Energy Technology Data Exchange (ETDEWEB)
Lemery, Francois [DESY; Floettmann, Klaus [DESY; Piot, Philippe [Northern Illinois U.; Kaertner, Franz X. [Hamburg U.; Assmann, Ralph [DESY
2017-12-22
We present a general concept to accelerate non-relativistic charged particles. Our concept employs an adiabatically-tapered dielectric-lined waveguide which supports accelerating phase velocities for synchronous acceleration. We propose an ansatz for the transient field equations, show it satisfies Maxwell's equations under an adiabatic approximation and find excellent agreement with a finite-difference time-domain computer simulation. The fields were implemented into the particle-tracking program {\\sc astra} and we present beam dynamics results for an accelerating field with a 1-mm-wavelength and peak electric field of 100~MV/m. The numerical simulations indicate that a $\\sim 200$-keV electron beam can be accelerated to an energy of $\\sim10$~MeV over $\\sim 10$~cm. The novel scheme is also found to form electron beams with parameters of interest to a wide range of applications including, e.g., future advanced accelerators, and ultra-fast electron diffraction.
Quantum Adiabatic Algorithms and Large Spin Tunnelling
Boulatov, A.; Smelyanskiy, V. N.
2003-01-01
We provide a theoretical study of the quantum adiabatic evolution algorithm with different evolution paths proposed in this paper. The algorithm is applied to a random binary optimization problem (a version of the 3-Satisfiability problem) where the n-bit cost function is symmetric with respect to the permutation of individual bits. The evolution paths are produced, using the generic control Hamiltonians H (r) that preserve the bit symmetry of the underlying optimization problem. In the case where the ground state of H(0) coincides with the totally-symmetric state of an n-qubit system the algorithm dynamics is completely described in terms of the motion of a spin-n/2. We show that different control Hamiltonians can be parameterized by a set of independent parameters that are expansion coefficients of H (r) in a certain universal set of operators. Only one of these operators can be responsible for avoiding the tunnelling in the spin-n/2 system during the quantum adiabatic algorithm. We show that it is possible to select a coefficient for this operator that guarantees a polynomial complexity of the algorithm for all problem instances. We show that a successful evolution path of the algorithm always corresponds to the trajectory of a classical spin-n/2 and provide a complete characterization of such paths.
Compton, N.; Taylor, C. E.; Hicks, K.; Cole, P.; Zachariou, N.; Ilieva, Y.; Nadel-Turonski, P.; Klempt, E.; Nikonov, V. A.; Sarantsev, A. V.; Adhikari, K. P.; Adhikari, S.; Akbar, Z.; Anefalos Pereira, S.; Avakian, H.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Camp, M.; Cao, Frank Thanh; Cao, T.; Carman, D. S.; Celentano, A.; Charles, G.; Chetry, T.; Ciullo, G.; Clark, L.; Cole, P. L.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Filippi, A.; Fleming, J. A.; Fradi, A.; Gavalian, G.; Ghandilyan, Y.; Giovanetti, K. L.; Girod, F. X.; Glazier, D. I.; Gleason, C.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Heddle, D.; Holtrop, M.; Hughes, S. M.; Hyde, C. E.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jenkins, D.; Jo, H. S.; Joo, K.; Joosten, S.; Keller, D.; Khachatryan, G.; Khachatryan, M.; Khandaker, M.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Kuleshov, S. V.; Lanza, L.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; McKinnon, B.; Meyer, C. A.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Movsisyan, A.; Munevar, E.; Munoz Camacho, C.; Murdoch, G.; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Ripani, M.; Ritchie, B. G.; Rizzo, A.; Rosner, G.; Sabatié, F.; Salgado, C.; Schumacher, R. A.; Sharabian, Y. G.; Simonyan, A.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stankovic, I.; Stepanyan, S.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Torayev, B.; Trivedi, A.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Wei, X.; Wood, M. H.; Zachariou, N.; Zhang, J.; CLAS Collaboration
2017-12-01
We report the first measurement of differential and total cross sections for the γ d →K0Λ (p ) reaction, using data from the CLAS detector at the Thomas Jefferson National Accelerator Facility. Data collected during two separate experimental runs were studied with photon-energy coverage 0.8-3.6 GeV and 0.5- 2.6 GeV, respectively. The two measurements are consistent giving confidence in the method and determination of systematic uncertainties. The cross sections are compared with predictions from the KAON-MAID theoretical model (without kaon exchange), which deviate from the data at higher W and at forward kaon angles. These data, along with previously published cross sections for K+Λ photoproduction, provide essential constraints on the nucleon resonance spectrum. A first partial wave analysis was performed that describes the data without the introduction of new resonances.
Energy Technology Data Exchange (ETDEWEB)
Errea, L.F.; Mendez, L.; Riera, A.
1986-07-15
We study the characteristics of charge exchange processes in ion--atom collisions, induced by a strong laser field whose wavelength is resonant to the splitting at a pseudocrossing of two molecular adiabatic energies, where the transition dipole has a sharp maximum. To calculate the charge exchange cross section we use a semiclassical approach and a molecular expansion for the electronic wave function. Using the formalism of Macias and Riera, and of Ho, Chu, and Laughlin, the properties and practical advantages of field-free and dressed molecular wave functions in that expansion are studied in detail. In practice we have found the former basis to be more advantageous from the computational point of view. A limitation of the Floquet approach of Ho et al. is obtained. As an illustration, we treat O/sup 8 +/+H(1s) charge exchange collisions in presence of a laser field whose frequency is quasiresonant with the energy splitting at the pseudocrossing between the 7isigma and the 6hsigma energy curves. The importance of the (usually neglected) diagonal ac Stark terms is stressed.
International Nuclear Information System (INIS)
Errea, L.F.; Mendez, L.; Riera, A.
1986-01-01
We study the characteristics of charge exchange processes in ion--atom collisions, induced by a strong laser field whose wavelength is resonant to the splitting at a pseudocrossing of two molecular adiabatic energies, where the transition dipole has a sharp maximum. To calculate the charge exchange cross section we use a semiclassical approach and a molecular expansion for the electronic wave function. Using the formalism of Macias and Riera, and of Ho, Chu, and Laughlin, the properties and practical advantages of field-free and dressed molecular wave functions in that expansion are studied in detail. In practice we have found the former basis to be more advantageous from the computational point of view. A limitation of the Floquet approach of Ho et al. is obtained. As an illustration, we treat O 8+ +H(1s) charge exchange collisions in presence of a laser field whose frequency is quasiresonant with the energy splitting at the pseudocrossing between the 7isigma and the 6hsigma energy curves. The importance of the (usually neglected) diagonal ac Stark terms is stressed
Asteroseismology of white dwarf stars. I - Adiabatic results
Energy Technology Data Exchange (ETDEWEB)
Bradley, P.A.; Winget, D.E. (Texas, University (USA) McDonald Observatory, Austin (USA))
1991-02-01
A preliminary investigation of the asteroseismological properties of chemically stratified evolutionary DA and DB white dwarf models is reported. The period and kinetic energy distributions for nonradial g-modes of spherical harmonic indices l = 1-3 are computed in the adiabatic approximation, and the effects of varying the total stellar masss and the surface layer masses on the pulsation properties are studied using an extensive grid of models. Significant resonant mode trapping due to chemical stratification is found. Modes trapped in the outer layers have much lower kinetic energies; these minima also show up as minima in the period spacing between modes of consecutive radial overtone k. Mode trapping occurs at the same or nearly the same value of k for different l-values. Thus, l-values of trapped modes may be identified on the basis of their period ratios. It is shown that observational identification of these period ratios can be used to constrain the mass of the star and its surface layer. 68 refs.
Dependence of adiabatic population transfer on pulse profile
Indian Academy of Sciences (India)
Control of population transfer by rapid adiabatic passage has been an established technique wherein the exact amplitude profile of the shaped pulse is considered to be insignificant. We study the effect of ultrafast shaped pulses for two-level systems, by density-matrix approach. However, we find that adiabaticity depends ...
Kinetic Theory Derivation of the Adiabatic Law for Ideal Gases.
Sobel, Michael I.
1980-01-01
Discusses how the adiabatic law for ideal gases can be derived from the assumption of a Maxwell-Boltzmann (or any other) distribution of velocities--in contrast to the usual derivations from thermodynamics alone, and the higher-order effect that leads to one-body viscosity. An elementary derivation of the adiabatic law is given. (Author/DS)
Teleportation of an Unknown Atomic State via Adiabatic Passage
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
We propose a scheme for teleporting an unknown atomic state via adiabatic passage. Taking advantage of adiabatic passage, the atom has no probability of being excited and thus the atomic spontaneous emission is suppressed.We also show that the fidelity can reach 1 under certain condition.
Adiabatic Compression Sensitivity of AF-M315E
2015-07-01
Brand for their technical expertise and guidance. He also wishes to thank Mr. Stephen McKim from NASA Goddard Space Flight Center for his assistance...Wilson, D. B., and Stoltzfus, J. M. "Adiabatic Compression of Oxygen: Real Fluid Temperatures," 2000. 10Ismail, I. M. K., and Hawkins , T. W. "Adiabatic
Constraints on the Adiabatic Temperature Change in Magnetocaloric Materials
DEFF Research Database (Denmark)
Nielsen, Kaspar Kirstein; Bahl, Christian Robert Haffenden; Smith, Anders
2010-01-01
The thermodynamics of the magnetocaloric effect implies constraints on the allowed variation in the adiabatic temperature change for a magnetocaloric material. An inequality for the derivative of the adiabatic temperature change with respect to temperature is derived for both first- and second...
Quantum Adiabatic Optimization and Combinatorial Landscapes
Smelyanskiy, V. N.; Knysh, S.; Morris, R. D.
2003-01-01
In this paper we analyze the performance of the Quantum Adiabatic Evolution (QAE) algorithm on a variant of Satisfiability problem for an ensemble of random graphs parametrized by the ratio of clauses to variables, gamma = M / N. We introduce a set of macroscopic parameters (landscapes) and put forward an ansatz of universality for random bit flips. We then formulate the problem of finding the smallest eigenvalue and the excitation gap as a statistical mechanics problem. We use the so-called annealing approximation with a refinement that a finite set of macroscopic variables (verses only energy) is used, and are able to show the existence of a dynamic threshold gamma = gammad, beyond which QAE should take an exponentially long time to find a solution. We compare the results for extended and simplified sets of landscapes and provide numerical evidence in support of our universality ansatz.
Quantum tunneling in the adiabatic Dicke model
International Nuclear Information System (INIS)
Chen Gang; Chen Zidong; Liang Jiuqing
2007-01-01
The Dicke model describes N two-level atoms interacting with a single-mode bosonic field and exhibits a second-order phase transition from the normal to the superradiant phase. The energy levels are not degenerate in the normal phase but have degeneracy in the superradiant phase, where quantum tunneling occurs. By means of the Born-Oppenheimer approximation and the instanton method in quantum field theory, the tunneling splitting, inversely proportional to the tunneling rate for the adiabatic Dicke model, in the superradiant phase can be evaluated explicitly. It is shown that the tunneling splitting vanishes as exp(-N) for large N, whereas for small N it disappears as √(N)/exp(N). The dependence of the tunneling splitting on the relevant parameters, especially on the atom-field coupling strength, is also discussed
The adiabatic approximation in multichannel scattering
International Nuclear Information System (INIS)
Schulte, A.M.
1978-01-01
Using two-dimensional models, an attempt has been made to get an impression of the conditions of validity of the adiabatic approximation. For a nucleon bound to a rotating nucleus the Coriolis coupling is neglected and the relation between this nuclear Coriolis coupling and the classical Coriolis force has been examined. The approximation for particle scattering from an axially symmetric rotating nucleus based on a short duration of the collision, has been combined with an approximation based on the limitation of angular momentum transfer between particle and nucleus. Numerical calculations demonstrate the validity of the new combined method. The concept of time duration for quantum mechanical collisions has also been studied, as has the collective description of permanently deformed nuclei. (C.F.)
Adiabatic equilibrium models for direct containment heating
International Nuclear Information System (INIS)
Pilch, M.; Allen, M.D.
1991-01-01
Probabilistic risk assessment (PRA) studies are being extended to include a wider spectrum of reactor plants than was considered in NUREG-1150. There is a need for simple direct containment heating (DCH) models that can be used for screening studies aimed at identifying potentially significant contributors to overall risk in individual nuclear power plants. This paper presents two adiabatic equilibrium models suitable for the task. The first, a single-cell model, places a true upper bound on DCH loads. This upper bound, however, often far exceeds reasonable expectations of containment loads based on CONTAIN calculations and experiment observations. In this paper, a two cell model is developed that captures the major mitigating feature of containment compartmentalization, thus providing more reasonable estimates of the containment load
Adiabatically steered open quantum systems: Master equation and optimal phase
International Nuclear Information System (INIS)
Salmilehto, J.; Solinas, P.; Ankerhold, J.; Moettoenen, M.
2010-01-01
We introduce an alternative way to derive the generalized form of the master equation recently presented by J. P. Pekola et al. [Phys. Rev. Lett. 105, 030401 (2010)] for an adiabatically steered two-level quantum system interacting with a Markovian environment. The original derivation employed the effective Hamiltonian in the adiabatic basis with the standard interaction picture approach but without the usual secular approximation. Our approach is based on utilizing a master equation for a nonsteered system in the first superadiabatic basis. It is potentially efficient in obtaining higher-order equations. Furthermore, we show how to select the phases of the adiabatic eigenstates to minimize the local adiabatic parameter and how this selection leads to states which are invariant under a local gauge change. We also discuss the effects of the adiabatic noncyclic geometric phase on the master equation.
Design of ternary clocked adiabatic static random access memory
International Nuclear Information System (INIS)
Wang Pengjun; Mei Fengna
2011-01-01
Based on multi-valued logic, adiabatic circuits and the structure of ternary static random access memory (SRAM), a design scheme of a novel ternary clocked adiabatic SRAM is presented. The scheme adopts bootstrapped NMOS transistors, and an address decoder, a storage cell and a sense amplifier are charged and discharged in the adiabatic way, so the charges stored in the large switch capacitance of word lines, bit lines and the address decoder can be effectively restored to achieve energy recovery during reading and writing of ternary signals. The PSPICE simulation results indicate that the ternary clocked adiabatic SRAM has a correct logic function and low power consumption. Compared with ternary conventional SRAM, the average power consumption of the ternary adiabatic SRAM saves up to 68% in the same conditions. (semiconductor integrated circuits)
Generalized shortcuts to adiabaticity and enhanced robustness against decoherence
Santos, Alan C.; Sarandy, Marcelo S.
2018-01-01
Shortcuts to adiabaticity provide a general approach to mimic adiabatic quantum processes via arbitrarily fast evolutions in Hilbert space. For these counter-diabatic evolutions, higher speed comes at higher energy cost. Here, the counter-diabatic theory is employed as a minimal energy demanding scheme for speeding up adiabatic tasks. As a by-product, we show that this approach can be used to obtain infinite classes of transitionless models, including time-independent Hamiltonians under certain conditions over the eigenstates of the original Hamiltonian. We apply these results to investigate shortcuts to adiabaticity in decohering environments by introducing the requirement of a fixed energy resource. In this scenario, we show that generalized transitionless evolutions can be more robust against decoherence than their adiabatic counterparts. We illustrate this enhanced robustness both for the Landau-Zener model and for quantum gate Hamiltonians.
Adiabatic logic future trend and system level perspective
Teichmann, Philip
2012-01-01
Adiabatic logic is a potential successor for static CMOS circuit design when it comes to ultra-low-power energy consumption. Future development like the evolutionary shrinking of the minimum feature size as well as revolutionary novel transistor concepts will change the gate level savings gained by adiabatic logic. In addition, the impact of worsening degradation effects has to be considered in the design of adiabatic circuits. The impact of the technology trends on the figures of merit of adiabatic logic, energy saving potential and optimum operating frequency, are investigated, as well as degradation related issues. Adiabatic logic benefits from future devices, is not susceptible to Hot Carrier Injection, and shows less impact of Bias Temperature Instability than static CMOS circuits. Major interest also lies on the efficient generation of the applied power-clock signal. This oscillating power supply can be used to save energy in short idle times by disconnecting circuits. An efficient way to generate the p...
Design of ternary clocked adiabatic static random access memory
Pengjun, Wang; Fengna, Mei
2011-10-01
Based on multi-valued logic, adiabatic circuits and the structure of ternary static random access memory (SRAM), a design scheme of a novel ternary clocked adiabatic SRAM is presented. The scheme adopts bootstrapped NMOS transistors, and an address decoder, a storage cell and a sense amplifier are charged and discharged in the adiabatic way, so the charges stored in the large switch capacitance of word lines, bit lines and the address decoder can be effectively restored to achieve energy recovery during reading and writing of ternary signals. The PSPICE simulation results indicate that the ternary clocked adiabatic SRAM has a correct logic function and low power consumption. Compared with ternary conventional SRAM, the average power consumption of the ternary adiabatic SRAM saves up to 68% in the same conditions.
Adiabatic Rearrangement of Hollow PV Towers
Directory of Open Access Journals (Sweden)
Eric A Hendricks
2010-10-01
Full Text Available Diabatic heating from deep moist convection in the hurricane eyewall produces a towering annular structure of elevated potential vorticity (PV. This structure has been referred to as a hollow PV tower. The sign reversal of the radial gradient of PV satisfies the Charney-Stern necessary condition for combined barotropic-baroclinic instability. For thin enough annular structures, small perturbations grow exponentially, extract energy from the mean flow, and lead to hollow tower breakdown, with significant vortex structural and intensity change. The three-dimensional adiabatic rearrangements of two prototypical hurricane-like hollow PV towers (one thick and one thin are examined in an idealized framework. For both hollow towers, dynamic instability causes air parcels with high PV to be mixed into the eye preferentially at lower levels, where unstable PV wave growth rates are the largest. Little or no mixing is found to occur at upper levels. The mixing at lower and middle levels is most rapid for the breakdown of the thin hollow tower, consistent with previous barotropic results. For both hollow towers, this advective rearrangement of PV affects the tropical cyclone structure and intensity in a number of ways. First, the minimum central pressure and maximum azimuthal mean velocity simultaneously decrease, consistent with previous barotropic results. Secondly, isosurfaces of absolute angular momentum preferentially shift inward at low levels, implying an adiabatic mechanism by which hurricane eyewall tilt can form. Thirdly, a PV bridge, similar to that previously found in full-physics hurricane simulations, develops as a result of mixing at the isentropic levels where unstable PV waves grow most rapidly. Finally, the balanced mass field resulting from the PV rearrangement is warmer in the eye between 900 and 700 hPa. The location of this warming is consistent with observed warm anomalies in the eye, indicating that in certain instances the hurricane
International Nuclear Information System (INIS)
Buechner, J.M.
1989-01-01
For a number of problems in the Plasma Astrophysics it is necessary to know the laws, which govern the non adiabatic charged particle dynamics in strongly curves magnetic field reversals. These are, e.q., the kinetic theory of the microscopic and macroscopicstability of current sheets in collionless plasma, of microturbulence, causing anomalous resistivity and dissipating currents, the problem of spontaneous reconnection, the formation of non Maxwellian distribution functions, particle acceleration and the use of particles as a diagnostic tool ('tracers'). To find such laws we derived from the differential equations of motion discrete mappings. These mappings allow an investigation of the motion after the break down of the adiabaticity of the magnetic moment. (author). 32 refs.; 5 figs.; 1 tab
Approximations to the non-adiabatic particle response in toroidal geometry
International Nuclear Information System (INIS)
Schep, T.J.; Braams, B.J.
1981-08-01
The non-adiabatic part of the particle response to low-frequency electromagnetic modes with long parallel wavelengths is discussed. Analytic approximations to the kernels of the integrals that relate the amplitudes of the perturbed potentials to the non-adiabatic part of the perturbed density in an axisymmetric toroidal configuration are presented and the results are compared with numerical calculations. It is shown that both in the plane slab and in toroidal geometry the kernel contains a logarithmic singularity. This singularity is associated with particles with vanishing parallel velocity so that, in toroidal geometry, it is related with the behaviour of trapped particles near their turning points. In contrast to the plane slab, in toroidal geometry this logarithmic singularity is mainly real and associated with non-resonant particles. Apart from this logarithmic term, the kernel contains a complex regular part arising from resonant as well as from non-resonant particles. The analytic approximations that will be presented make the dispersion relation of drift-type modes in toroidal geometry amenable to analytic as well as to simpler numerical calculation of the growth rate and of the spatial mode structure
Quantum theory of NMR adiabatic pulses and their applications
International Nuclear Information System (INIS)
Ke, Y.
1993-01-01
Recently explosive developments of in vivo NMR spectroscopy (NMRS) and imaging (NMRI) in biological and medical sciences have resulted in the establishment of NMR as one of the most advanced major technique in life sciences. These developments have created huge demands for a variety of NMR adiabatic pulses with play a very important role in NMR experiments in vivo. In order to develop new NMR adiabatic pulses, a rigorous systematical quantum theory for this kind of pulses is greatly needed. Providing such a theory is one of the important goals of this dissertation. Quantum density matrix theory and product operator method have been used throughout this dissertation. Another goal, which is the major goal of this thesis research, is to use the quantum theory as a guide to develop new NMR adiabatic pulses and their applications. To fill this goal, a technique to construct a new type of adiabatic pulses, narrow band selective adiabatic pulses, has been invented, which is described through the example of constructing an adiabatic DANTE inversion pulse. This new adiabatic pulse is the first narrow band selective adiabatic pulses: Adiabatic homonuclear and heteronuclear spectral editing sequences. Unique to the first pulse sequence is a B 1 -field filter which is built by using two non-refocusing adiabatic full passage pulses to refocus the wanted signal and dephase unwanted signals. This extra filter greatly enhance the editing efficiency. Unlike commonly used heteronuclear spectral editing sequences which depend on the polarization transfer or spectral subtraction by phase cycling techniques, the second pulse sequences accomplishes the editing of heteronuclear J-coupled signals based on the fact that this sequence is transparent to the uncoupled spins and is equivalent a 90 degrees excitation pulse to the heteronuclear J-coupled spins. Experimental results have confirmed the ability of spectral editing with these two new sequences
Rotational excitation of H2O by para-H2 from an adiabatically reduced dimensional potential.
Scribano, Yohann; Faure, Alexandre; Lauvergnat, David
2012-03-07
Cross sections and rate coefficients for low lying rotational transitions in H(2)O colliding with para-hydrogen pH(2) are computed using an adiabatic approximation which reduces the dimensional dynamics from a 5D to a 3D problem. Calculations have been performed at the close-coupling level using the recent potential of Valiron et al. [J. Chem. Phys. 129, 134306 (2008)]. A good agreement is found between the reduced adiabatic calculations and the 5D exact calculations, with an impressive time saving and memory gain. This adiabatic reduction of dimensionality seems very promising for scattering studies involving the excitation of a heavy target molecule by a light molecular projectile. © 2012 American Institute of Physics
Chaotic jumps in the generalized first adiabatic invariant in current sheets
International Nuclear Information System (INIS)
Brittnacher, M.J.; Whipple, E.C.
1991-01-01
In attempting to develop a fluidlike model of plasma dynamics in a current sheet, kinetic effects due to chaotic non-adiabatic particle motion must be included in any realistic description. Using drift variables, derived by the Kruskal averaging procedure, to construct distribution functions may provide an approach in which to develop the fluid description. However, the drift motion is influenced by abrupt changes in the value of the generalized first adiabatic invariant J. In this letter, the authors indicate how the changes in J derived from separatrix crossing theory can be incorporated into the drift variable approach to generating distribution functions. In particular, the authors propose a method to determine distribution functions for an ensemble of particles following interactions with the tail current sheet by treating the interaction as a scattering problem characterized by changes in the invariant
Resonance phenomenon in classical cepheids
International Nuclear Information System (INIS)
Takeuti, Mine; Aikawa, Toshiki
1981-01-01
To investigate resonance phenomenon in classical cepheids, the non-linear radial oscillation of stars is studied based on the assumption that the non-adiabatic perturbation is expressed in terms of van der Pol's type damping. Two- and three-wave resonance in this system is applied to classical cepheids to describe their bump and double-mode behavior. The phase of bump and the depression of amplitude are explained for bump cepheids. The double-periodicity is shown by the enhancement of the third overtone in three-wave resonance. Non-linear effect on resonant period is also discussed briefly. (author)
International Nuclear Information System (INIS)
Laporta, V.; Chakrabarti, K.; Celiberto, R.; Janev, R. K.; Mezei, J. Zs.; Niyonzima, S.; Tennyson, J.; Schneider, I.F.
2017-01-01
A theoretical study of resonant vibrational excitation, dissociative recombination and dissociative excitation processes of the beryllium monohydride cation, BeH"+ , induced by electron impact, is reported. Full sets of ro-vibrationally-resolved cross sections and of the corresponding Maxwellian rate coefficients are presented for the three processes. Particular emphasis is given to the high-energy behaviour. Potential curves of "2σ"+, "2σ and "2δ symmetries and the corresponding resonance widths, obtained from R-matrix calculations, provide the input for calculations which use a local complex-potential model for resonant collisions in each of the three symmetries. Rotational motion of nuclei and isotopic effects are also discussed. The relevant results are compared with those obtained using a multichannel quantum defect theory method. Full results are available from the Phys4Entry database.
Crossing a Nonlinear Resonance
Indian Academy of Sciences (India)
IAS Admin
Fermi's theory for the acceleration of cosmic rays [2] as- sumes that the ... The most well-known example goes back to the Lorentz–. Einstein .... inside and reflecting from the boundary according to ..... Here the chaotic layers of different.
Energy Technology Data Exchange (ETDEWEB)
Adams, A., E-mail: Alina.Adams@itmc.rwth-aachen.de [Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Templergraben 55, 52056 Aachen (Germany); Piechatzek, A.; Schmitt, G. [Institut für Instandhaltung und Korrosionsschutztechnik gGmbH, Kalkofen 4, 58638 Iserlohn (Germany); Siegmund, G. [ExxonMobil Production Germany, Riethorst 12, 30659 Hannover (Germany)
2015-08-05
The potential of single-sided Nuclear Magnetic Resonance (NMR) to monitor truly non-invasive changes in polymer materials during aging under aggressive media is for the first time evaluated. For this, the NMR method is used in combination with other condition monitoring methods including mechanical measurements, mass uptake, and differential scanning calorimetry. It is validated by studying for the first time the aging kinetics of silane cross-linked polyethylene (PEX) exposed to media used in oil and gas production and transportation, including aliphatic and aromatic hydrocarbons, sulphur solvents, and corrosion inhibitors in combination with CO{sub 2} and H{sub 2}S. All investigated parameters changed, with the strongest effects detected for the NMR chain mobility and in the presence of hydrocarbons. Furthermore, a universal linear correlation curve could be established between the depression of the tensile strength and the chain mobility. This result represents a fundamental step towards establishing single-sided NMR as a new analytical tool for in situ condition monitoring of polyethylene working under sour conditions. The proposed approach can be easily extended to other polymer materials. - Highlights: • The changes in PEX exposed to sour media were quantified for the first time. • The strongest morphological changes in PEX were detected under exposure to hydrocarbon media. • The chain mobility measured truly non-destructively by single-sided NMR showed the highest sensitivity to the aging process. • A universal linear correlation curve was found between the chain mobility and the tensile strength. • Single-sided NMR was validated as a condition monitoring tool.
Ghiasi, Mohammad S; Arjmand, Navid; Shirazi-Adl, Aboulfazl; Farahmand, Farzam; Hashemi, Hassan; Bagheri, Sahar; Valizadeh, Mahsa
2016-03-01
Iatrogenic injuries to paraspinal muscles during the posterior lumbar surgery (PLS) cause a reduction in their cross-sectional areas (CSAs) and contractile densities over time post-surgery. This study aims to quantify such alterations. Pre- and postoperative CSAs (~6 months interval) of all paraspinal muscles were measured in six patients undergoing PLS using a 3-T magnetic resonance (MR) scanner to quantify the alterations in geometrical and tissue effective contractile (non-fatty) CSAs of these muscles at all lumbar levels. To examine the presence of any confounding effects on recorded changes within ~7-month period, measurements were also carried out on ten healthy volunteers. In the healthy population, an important (~22%) portion of CSA of the erector spinae (ES) was noncontractile at the lower lumbar levels. Negligible variations over time in both the total geometrical (<1.7% in average) and contractile (<1.2%) CSAs of muscles were observed in the healthy group (i.e., no confounding effect). Following PLS, significant reductions were observed in the geometrical CSA of only multifidus (MF) muscle by ~14 and 11% as well as in its contractile CSA by ~26 and 14% at the L5-S1 and L4-L5 levels, respectively. The total CSA of ES at lower lumbar levels shows substantial noncontractile contents in both healthy and patient populations. Biomechanical models of the spine should hence account for the noncontractile contents using only the effective contractile muscle CSAs. Postoperative variations in CSAs of paraspinal muscles may have profound effects on patterns of muscle activities, spinal loading, and stability.
International Nuclear Information System (INIS)
Brunhoeber, H.
2001-11-01
The interference terms R LT and R TT that contribute to the cross section of the charged pion electroproduction have been determined in an electron scattering experiment at the accelerator facility ELSA by detecting the outgoing neutron of the nπ + -decay channel by a large acceptance Time-of-Flight spectrometer covering the Δ + (1232) resonance region at the four momentum transfers of 0.638 GeV 2 and 0.8 GeV 2 . (orig.)
Piecewise adiabatic following in non-Hermitian cycling
Gong, Jiangbin; Wang, Qing-hai
2018-05-01
The time evolution of periodically driven non-Hermitian systems is in general nonunitary but can be stable. It is hence of considerable interest to examine the adiabatic following dynamics in periodically driven non-Hermitian systems. We show in this work the possibility of piecewise adiabatic following interrupted by hopping between instantaneous system eigenstates. This phenomenon is first observed in a computational model and then theoretically explained, using an exactly solvable model, in terms of the Stokes phenomenon. In the latter case, the piecewise adiabatic following is shown to be a genuine critical behavior and the precise phase boundary in the parameter space is located. Interestingly, the critical boundary for piecewise adiabatic following is found to be unrelated to the domain for exceptional points. To characterize the adiabatic following dynamics, we also advocate a simple definition of the Aharonov-Anandan (AA) phase for nonunitary cyclic dynamics, which always yields real AA phases. In the slow driving limit, the AA phase reduces to the Berry phase if adiabatic following persists throughout the driving without hopping, but oscillates violently and does not approach any limit in cases of piecewise adiabatic following. This work exposes the rich features of nonunitary dynamics in cases of slow cycling and should stimulate future applications of nonunitary dynamics.
Non-adiabatic perturbations in Ricci dark energy model
International Nuclear Information System (INIS)
Karwan, Khamphee; Thitapura, Thiti
2012-01-01
We show that the non-adiabatic perturbations between Ricci dark energy and matter can grow both on superhorizon and subhorizon scales, and these non-adiabatic perturbations on subhorizon scales can lead to instability in this dark energy model. The rapidly growing non-adiabatic modes on subhorizon scales always occur when the equation of state parameter of dark energy starts to drop towards -1 near the end of matter era, except that the parameter α of Ricci dark energy equals to 1/2. In the case where α = 1/2, the rapidly growing non-adiabatic modes disappear when the perturbations in dark energy and matter are adiabatic initially. However, an adiabaticity between dark energy and matter perturbations at early time implies a non-adiabaticity between matter and radiation, this can influence the ordinary Sachs-Wolfe (OSW) effect. Since the amount of Ricci dark energy is not small during matter domination, the integrated Sachs-Wolfe (ISW) effect is greatly modified by density perturbations of dark energy, leading to a wrong shape of CMB power spectrum. The instability in Ricci dark energy is difficult to be alleviated if the effects of coupling between baryon and photon on dark energy perturbations are included
The new classification of elementary particle resonance mass spectra
International Nuclear Information System (INIS)
Gareev, F.A.; Barabanov, M.Yu.; Kazacha, G.S.
1997-01-01
Elementary particle resonances have been systematically analyzed from the first principles: the conservation laws of energy-momentum and Ehrenfest adiabatic invariant. As a result, resonance decay product momenta and masses of resonances were established to be quantized. Radial excited states of resonances were revealed. These observations give us a possibility to formulate the strategy of experimental searches for new resonances and to systematize already known ones. (author)
Are the reactions of quinones on graphite adiabatic?
International Nuclear Information System (INIS)
Luque, N.B.; Schmickler, W.
2013-01-01
Outer sphere electron transfer reactions on pure metal electrodes are often adiabatic and hence independent of the electrode material. Since it is not clear, whether adiabatic electron transfer can also occur on a semi-metal like graphite, we have re-investigated experimental data presented in a recent communication by Nissim et al. [Chemical Communications 48 (2012) 3294] on the reactions of quinones on graphite. We have supplemented their work by DFT calculations and conclude, that these reactions are indeed adiabatic. This contradicts the assertion of Nissim et al. that the rates are proportional to the density of states at the Fermi level
Approximability of optimization problems through adiabatic quantum computation
Cruz-Santos, William
2014-01-01
The adiabatic quantum computation (AQC) is based on the adiabatic theorem to approximate solutions of the Schrödinger equation. The design of an AQC algorithm involves the construction of a Hamiltonian that describes the behavior of the quantum system. This Hamiltonian is expressed as a linear interpolation of an initial Hamiltonian whose ground state is easy to compute, and a final Hamiltonian whose ground state corresponds to the solution of a given combinatorial optimization problem. The adiabatic theorem asserts that if the time evolution of a quantum system described by a Hamiltonian is l
Modeling non-adiabatic photoexcited reaction dynamics in condensed phases
International Nuclear Information System (INIS)
Coker, D.F.
2003-01-01
Reactions of photoexcited molecules, ions, and radicals in condensed phase environments involve non-adiabatic dynamics over coupled electronic surfaces. We focus on how local environmental symmetries can effect non-adiabatic coupling between excited electronic states and thus influence, in a possibly controllable way, the outcome of photo-excited reactions. Semi-classical and mixed quantum-classical non-adiabatic molecular dynamics methods, together with semi-empirical excited state potentials are used to probe the dynamical mixing of electronic states in different environments from molecular clusters, to simple liquids and solids, and photo-excited reactions in complex reaction environments such as zeolites
Adiabatic quantum algorithm for search engine ranking.
Garnerone, Silvano; Zanardi, Paolo; Lidar, Daniel A
2012-06-08
We propose an adiabatic quantum algorithm for generating a quantum pure state encoding of the PageRank vector, the most widely used tool in ranking the relative importance of internet pages. We present extensive numerical simulations which provide evidence that this algorithm can prepare the quantum PageRank state in a time which, on average, scales polylogarithmically in the number of web pages. We argue that the main topological feature of the underlying web graph allowing for such a scaling is the out-degree distribution. The top-ranked log(n) entries of the quantum PageRank state can then be estimated with a polynomial quantum speed-up. Moreover, the quantum PageRank state can be used in "q-sampling" protocols for testing properties of distributions, which require exponentially fewer measurements than all classical schemes designed for the same task. This can be used to decide whether to run a classical update of the PageRank.
Adiabatic liquid piston compressed air energy storage
Energy Technology Data Exchange (ETDEWEB)
Petersen, Tage [Danish Technological Institute, Aarhus (Denmark); Elmegaard, B. [Technical Univ. of Denmark. DTU Mechanical Engineering, Kgs. Lyngby (Denmark); Schroeder Pedersen, A. [Technical Univ. of Denmark. DTU Energy Conversion, Risoe Campus, Roskilde (Denmark)
2013-01-15
This project investigates the potential of a Compressed Air Energy Storage system (CAES system). CAES systems are used to store mechanical energy in the form of compressed air. The systems use electricity to drive the compressor at times of low electricity demand with the purpose of converting the mechanical energy into electricity at times of high electricity demand. Two such systems are currently in operation; one in Germany (Huntorf) and one in the USA (Macintosh, Alabama). In both cases, an underground cavern is used as a pressure vessel for the storage of the compressed air. Both systems are in the range of 100 MW electrical power output with several hours of production stored as compressed air. In this range, enormous volumes are required, which make underground caverns the only economical way to design the pressure vessel. Both systems use axial turbine compressors to compress air when charging the system. The compression leads to a significant increase in temperature, and the heat generated is dumped into the ambient. This energy loss results in a low efficiency of the system, and when expanding the air, the expansion leads to a temperature drop reducing the mechanical output of the expansion turbines. To overcome this, fuel is burned to heat up the air prior to expansion. The fuel consumption causes a significant cost for the storage. Several suggestions have been made to store compression heat for later use during expansion and thereby avoid the use of fuel (so called Adiabatic CAES units), but no such units are in operation at present. The CAES system investigated in this project uses a different approach to avoid compression heat loss. The system uses a pre-compressed pressure vessel full of air. A liquid is pumped into the bottom of the vessel when charging and the same liquid is withdrawn through a turbine when discharging. In this case, the liquid works effectively as a piston compressing the gas in the vessel, hence the name ''Adiabatic
Semiclassical Monte Carlo: A first principles approach to non-adiabatic molecular dynamics
International Nuclear Information System (INIS)
White, Alexander J.; Gorshkov, Vyacheslav N.; Wang, Ruixi; Tretiak, Sergei; Mozyrsky, Dmitry
2014-01-01
Modeling the dynamics of photophysical and (photo)chemical reactions in extended molecular systems is a new frontier for quantum chemistry. Many dynamical phenomena, such as intersystem crossing, non-radiative relaxation, and charge and energy transfer, require a non-adiabatic description which incorporate transitions between electronic states. Additionally, these dynamics are often highly sensitive to quantum coherences and interference effects. Several methods exist to simulate non-adiabatic dynamics; however, they are typically either too expensive to be applied to large molecular systems (10's-100's of atoms), or they are based on ad hoc schemes which may include severe approximations due to inconsistencies in classical and quantum mechanics. We present, in detail, an algorithm based on Monte Carlo sampling of the semiclassical time-dependent wavefunction that involves running simple surface hopping dynamics, followed by a post-processing step which adds little cost. The method requires only a few quantities from quantum chemistry calculations, can systematically be improved, and provides excellent agreement with exact quantum mechanical results. Here we show excellent agreement with exact solutions for scattering results of standard test problems. Additionally, we find that convergence of the wavefunction is controlled by complex valued phase factors, the size of the non-adiabatic coupling region, and the choice of sampling function. These results help in determining the range of applicability of the method, and provide a starting point for further improvement
Spatial non-adiabatic passage using geometric phases
Energy Technology Data Exchange (ETDEWEB)
Benseny, Albert; Busch, Thomas [Okinawa Institute of Science and Technology Graduate University, Quantum Systems Unit, Okinawa (Japan); Kiely, Anthony; Ruschhaupt, Andreas [University College Cork, Department of Physics, Cork (Ireland); Zhang, Yongping [Okinawa Institute of Science and Technology Graduate University, Quantum Systems Unit, Okinawa (Japan); Shanghai University, Department of Physics, Shanghai (China)
2017-12-15
Quantum technologies based on adiabatic techniques can be highly effective, but often at the cost of being very slow. Here we introduce a set of experimentally realistic, non-adiabatic protocols for spatial state preparation, which yield the same fidelity as their adiabatic counterparts, but on fast timescales. In particular, we consider a charged particle in a system of three tunnel-coupled quantum wells, where the presence of a magnetic field can induce a geometric phase during the tunnelling processes. We show that this leads to the appearance of complex tunnelling amplitudes and allows for the implementation of spatial non-adiabatic passage. We demonstrate the ability of such a system to transport a particle between two different wells and to generate a delocalised superposition between the three traps with high fidelity in short times. (orig.)
On the adiabatic theorem in quantum statistical mechanics
International Nuclear Information System (INIS)
Narnhofer, H.; Thirring, W.
1982-01-01
We show that with suitable assumptions the equilibrium states are exactly the states invariant under adiabatic local perturbations. The relevance of this fact to the problem of ergodicity is discussed. (Author)
Diffusion Monte Carlo approach versus adiabatic computation for local Hamiltonians
Bringewatt, Jacob; Dorland, William; Jordan, Stephen P.; Mink, Alan
2018-02-01
Most research regarding quantum adiabatic optimization has focused on stoquastic Hamiltonians, whose ground states can be expressed with only real non-negative amplitudes and thus for whom destructive interference is not manifest. This raises the question of whether classical Monte Carlo algorithms can efficiently simulate quantum adiabatic optimization with stoquastic Hamiltonians. Recent results have given counterexamples in which path-integral and diffusion Monte Carlo fail to do so. However, most adiabatic optimization algorithms, such as for solving MAX-k -SAT problems, use k -local Hamiltonians, whereas our previous counterexample for diffusion Monte Carlo involved n -body interactions. Here we present a 6-local counterexample which demonstrates that even for these local Hamiltonians there are cases where diffusion Monte Carlo cannot efficiently simulate quantum adiabatic optimization. Furthermore, we perform empirical testing of diffusion Monte Carlo on a standard well-studied class of permutation-symmetric tunneling problems and similarly find large advantages for quantum optimization over diffusion Monte Carlo.
Adiabatic rotation, quantum search, and preparation of superposition states
International Nuclear Information System (INIS)
Siu, M. Stewart
2007-01-01
We introduce the idea of using adiabatic rotation to generate superpositions of a large class of quantum states. For quantum computing this is an interesting alternative to the well-studied 'straight line' adiabatic evolution. In ways that complement recent results, we show how to efficiently prepare three types of states: Kitaev's toric code state, the cluster state of the measurement-based computation model, and the history state used in the adiabatic simulation of a quantum circuit. We also show that the method, when adapted for quantum search, provides quadratic speedup as other optimal methods do with the advantages that the problem Hamiltonian is time independent and that the energy gap above the ground state is strictly nondecreasing with time. Likewise the method can be used for optimization as an alternative to the standard adiabatic algorithm
Convergence of hyperspherical adiabatic expansion for helium-like systems
International Nuclear Information System (INIS)
Abrashkevich, A.G.; Abrashkevich, D.G.; Pojda, V.Yu.; Vinitskij, S.I.; Kaschiev, M.S.; Puzynin, I.V.
1988-01-01
The convergence of hyperspherical adiabatic expansion has been studied numerically. The spectral problems arising after separation of variables are solved by the finite-difference and finite element methods. The energies of the ground and some doubly excited staes of a hydrogen ion are calculated in the six-channel approximation within the 10 -4 a.u. accuracy. Obtained results demonstrate a rapid convergence of the hyperspherical adiabatic expansion. 14 refs.; 5 tabs
On Adiabatic Processes at the Elementary Particle Level
A, Michaud
2016-01-01
Analysis of adiabatic processes at the elementary particle level and of the manner in which they correlate with the principle of conservation of energy, the principle of least action and entropy. Analysis of the initial and irreversible adiabatic acceleration sequence of newly created elementary particles and its relation to these principles. Exploration of the consequences if this first initial acceleration sequence is not subject to the principle of conservation.
Adiabatic analysis of collisions. III. Remarks on the spin model
International Nuclear Information System (INIS)
Fano, U.
1979-01-01
Analysis of a spin-rotation model illustrates how transitions between adiabatic channel states stem from the second, rather than from the first, rate of change of these states, provided that appropriate identification of channels and scaling of the independent variable are used. These remarks, like the earlier development of a post-adiabatic approach, aim at elucidating the surprising success of approximate separation of variables in the treatment of complex mechanical systems
Adiabatic compression of elongated field-reversed configurations
Energy Technology Data Exchange (ETDEWEB)
Spencer, R.L.; Tuszewski, M.; Linford, R.K.
1983-06-01
The adiabatic compression of an elongated field-reversed configuration (FRC) is computed by using a one-dimensional approximation. The one-dimensional results are checked against a two-dimensional equilibrium code. For ratios of FRC separatrix length to separatrix radius greater than about ten, the one-dimensional results are accurate within 10%. To this accuracy, the adiabatic compression of FRC's can be described by simple analytic formulas.
Adiabatic compression of elongated field-reversed configurations
International Nuclear Information System (INIS)
Spencer, R.L.; Tuszewski, M.; Linford, R.K.
1983-01-01
The adiabatic compression of an elongated field-reversed configuration (FRC) is computed by using a one-dimensional approximation. The one-dimensional results are checked against a two-dimensional equilibrium code. For ratios of FRC separatrix length to separatrix radius greater than about ten, the one-dimensional results are accurate within 10%. To this accuracy, the adiabatic compression of FRC's can be described by simple analytic formulas
Non-adiabatic generator-coordinate calculation of H2+
International Nuclear Information System (INIS)
Tostes, J.G.R.; Para Univ., Belem; Toledo Piza, A.F.R. de
1982-10-01
A non-adiabatic calculation of the few lowest J=O states in the H 2+ molecule done within the framework of the Generator Coordinate Method is reported. Substantial accuracy is achivied with the diagonalization of matrices of very modest dimensions. The resulting wavefunctions are strongly dominated by just a few basis states. The computational scheme is set up so as to take the best advantage of good analytical approximations to existing adiabatic molecular wavefunctions. (Author) [pt
A note on the geometric phase in adiabatic approximation
International Nuclear Information System (INIS)
Tong, D.M.; Singh, K.; Kwek, L.C.; Fan, X.J.; Oh, C.H.
2005-01-01
The adiabatic theorem shows that the instantaneous eigenstate is a good approximation of the exact solution for a quantum system in adiabatic evolution. One may therefore expect that the geometric phase calculated by using the eigenstate should be also a good approximation of exact geometric phase. However, we find that the former phase may differ appreciably from the latter if the evolution time is large enough
Multiturn extraction and injection by means of adiabatic capture in stable islands of phase space
Directory of Open Access Journals (Sweden)
R. Cappi
2004-02-01
Full Text Available Recently a novel approach has been proposed for performing multiturn extraction from a circular machine. Such a technique consists of splitting the beam by means of stable islands created in transverse phase space by magnetic elements creating nonlinear fields, such as sextupoles and octupoles. Provided a slow time variation of the linear tune is applied, adiabatic with respect to the betatron motion, the islands can be moved in phase space and eventually charged particles may be trapped inside the stable structures. This generates a certain number of well-separated beamlets. Originally, this principle was successfully tested using a fourth-order resonance. In this paper the approach is generalized by considering other types of resonances as well as the possibility of performing multiple multiturn extractions. The results of numerical simulations are presented and described in detail. Of course, by time reversal, the proposed approach could be used also for multiturn injection.
A Controlled-Phase Gate via Adiabatic Rydberg Dressing of Neutral Atoms
Keating, Tyler; Deutsch, Ivan; Cook, Robert; Biederman, Grant; Jau, Yuan-Yu
2014-05-01
The dipole blockade effect between Rydberg atoms is a promising tool for quantum information processing in neutral atoms. So far, most efforts to perform a quantum logic gate with this effect have used resonant laser pulses to excite the atoms, which makes the system particularly susceptible to decoherence through thermal motional effects. We explore an alternative scheme in which the atomic ground states are adiabatically ``dressed'' by turning on an off-resonant laser. We analyze the implementation of a CPHASE gate using this mechanism and find that fidelities of >99% should be possible with current technology, owing primarily to the suppression of motional errors. We also discuss how such a scheme could be generalized to perform more complicated, multi-qubit gates; in particular, a simple generalization would allow us to perform a Toffoli gate in a single step.
Dynamical constraints and adiabatic invariants in chemical reactions.
Lorquet, J C
2007-08-23
For long-range electrostatic potentials and, more generally, when the topography of the potential energy surface is locally simple, the reaction path coordinate is adiabatically separable from the perpendicular degrees of freedom. For the ion-permanent dipole and ion-quadrupole interactions, the Poisson bracket of the adiabatic invariant decreases with the interfragment distance more rapidly than the electrostatic potential. The smaller the translational momentum, the moment of inertia of the neutral fragment, and the dipole or quadrupole moments are, the more reliable the adiabatic approximation is, as expected from the usual argumentation. Closed-form expressions for an effective one-dimensional potential in an adiabatic Hamiltonian are given. Connection with a model where the decoupling is exact is obtained in the limit of an infinitely heavy dipole. The dynamics is also constrained by adiabatic invariance for a harmonic valley about a curved reaction path, as shown by the reaction path Hamiltonian method. The maximum entropy method reveals that, as a result of the invariance properties of the entropy, constraints whose validity has been demonstrated locally only subsist in all parts of phase space. However, their form varies continuously, and they are not necessarily expressed in simple terms as they are in the asymptotic region. Therefore, although the influence of adiabatic invariance has been demonstrated at asymptotically large values of the reaction coordinate only, it persists in more interesting ranges.
Marante, Carlos; Klinker, Markus; Kjellsson, Tor; Lindroth, Eva; González-Vázquez, Jesús; Argenti, Luca; Martín, Fernando
2017-08-01
The XCHEM approach interfaces well established quantum chemistry packages with scattering numerical methods in order to describe single-ionization processes in atoms and molecules. This should allow one to describe electron correlation in the continuum at the same level of accuracy as quantum chemistry methods do for bound states. Here we have applied this method to study multichannel photoionization of Ne in the vicinity of the autoionizing states lying between the 2 s22 p5 and 2 s 2 p6 ionization thresholds. The calculated total photoionization cross sections are in very good agreement with the absolute measurement of Samson et al. [J. Electron Spectrosc. Relat. Phenom. 123, 265 (2002), 10.1016/S0368-2048(02)00026-9], and with independent benchmark calculations performed at the same level of theory. From these cross sections, we have extracted resonance positions, total autoionization widths, Fano profile parameters, and correlation parameters for the lowest three autoionizing states. The values of these parameters are in good agreement with those reported in earlier theoretical and experimental work. We have also evaluated β asymmetry parameter and partial photoionization cross sections and, from the latter, partial autoionization widths and Starace parameters for the same resonances, not yet available in the literature. Resonant features in the calculated β parameter are in good agreement with the experimental observations. We have found that the three lowest resonances preferentially decay into the 2 p-1ɛ d continuum rather than into the 2 p-1ɛ s one [Phys. Rev. A 89, 043415 (2014), 10.1103/PhysRevA.89.043415], in agreement with previous expectations, and that in the vicinity of the resonances the partial 2 p-1ɛ s cross section can be larger than the 2 p-1ɛ d one, in contrast with the accepted idea that the latter should amply dominate in the whole energy range. These results show the potential of the XCHEM approach to describe highly correlated process
Electron capture cross sections by O+ from atomic He
International Nuclear Information System (INIS)
Joseph, Dwayne C; Saha, Bidhan C
2009-01-01
The adiabatic representation is used in both the quantal and semi classical molecular orbital close coupling methods (MOCC) to evaluate charge exchange cross sections. Our results show good agreement with experimental cross sections
Electron capture cross sections by O+ from atomic He
Joseph, Dwayne C.; Saha, Bidhan C.
2009-11-01
The adiabatic representation is used in both the quantal and semi classical molecular orbital close coupling methods (MOCC) to evaluate charge exchange cross sections. Our results show good agreement with experimental cross sections
The analysis of the elastic scattering of 11Be and 6Li by adiabatic approximation
International Nuclear Information System (INIS)
Takagi, S.
2000-01-01
The unstable nuclei, particularly, the neutron halo nuclei which exist near by the neutron dripline, are recently one of the interesting topics in the nuclear physics. By the adiabatic approximation, R. C. Jhonson et al. have reproduced the experimental differential cross-section of the elastic scattering of the neutron halo nucleus 11 Be (+ l2 C) [1]. We have applied their method to the elastic scattering of another nucleus 6 Li which is not a halo nucleus but has the cluster structure as 11 Be. But it couldn't reproduce the experimental data, so that the method of Johnson et al. is poor in the case of 6 Li. (author)
Perturbation to Unified Symmetry and Adiabatic Invariants for Relativistic Hamilton Systems
International Nuclear Information System (INIS)
Zhang Mingjiang; Fang Jianhui; Lu Kai; Pang Ting; Lin Peng
2009-01-01
Based on the concept of adiabatic invariant, the perturbation to unified symmetry and adiabatic invariants for relativistic Hamilton systems are studied. The definition of the perturbation to unified symmetry for the system is presented, and the criterion of the perturbation to unified symmetry is given. Meanwhile, the Noether adiabatic invariants, the generalized Hojman adiabatic invariants, and the Mei adiabatic invariants for the perturbed system are obtained. (general)
Fast-forward of quantum adiabatic dynamics in electro-magnetic field
Masuda, Shumpei; Nakamura, Katsuhiro
2010-01-01
We show a method to accelerate quantum adiabatic dynamics of wavefunctions under electro-magnetic field by developing the previous theory (Masuda & Nakamura 2008 and 2010). Firstly we investigate the orbital dynamics of a charged particle. We derive the driving field which accelerates quantum adiabatic dynamics in order to obtain the final adiabatic states except for the spatially uniform phase such as the adiabatic phase in any desired short time. Fast-forward of adiabatic squeezing and tran...
International Nuclear Information System (INIS)
Winters, R.R.
1977-10-01
The analysis of the neutron capture cross section data for 51 V + n has now been completed up to 215 keV. Using a few neutron widths and spin and parity assignments from the literature, the capture data has yielded estimates of radiative widths for 45 s-wave resonances and capture areas for 139 resonances. Of particular interest is the very large s-wave radiative widths for this reaction and the rather broad distribution of radiative widths. A paper describing these results is included with this report. The analysis of the neutron capture cross sections for the reaction 205 Tl(n,γ) is presently being extended to incident neutron energy 115 keV. The study of the scattered-beam sensitivity of the total energy detectors at the ORELA capture facility continues. This small but troublesome effect has now been parameterized, but the errors to be assigned to the parameterization are not yet well defined. However, in obtaining additional data for the parameterization, a series of 208 Pb(n,γ) cross section measurements were made. The analysis of these data led to results important in understanding stellar nucleosynthesis and are reported in a paper included with this report. the analysis of the Te(n,γ) data proceeds methodically but slowly
Directory of Open Access Journals (Sweden)
Carbone D.
2016-01-01
Full Text Available The 13C(18O,16O15C reaction has been studied at 84 MeV incident energy. The ejectiles have been momentum analized by the MAGNEX spectrometer and 15C excitation energy spectra have been obtained up to about 20 MeV. In the region above the two-neutron separation energy, a bump has been observed at 13.7 MeV. The extracted cross section angular distribution for this structure, obtained by using different models for background, displays a clear oscillating pattern, typical of resonant state of the residual nucleus.
International Nuclear Information System (INIS)
Sinitsa, V.V.
1984-11-01
The author gives a scheme for the calculation of the self-shielding factors in the unresolved resonance region using the GRUCON applied program package. This package is especially created to be used in the conversion of evaluated neutron cross-section data, as available in existing data libraries, into multigroup microscopic constants. A detailed description of the formulae and algorithms used in the programs is given. Some typical examples of calculation are considered and the results are compared with those of other authors. The calculation accuracy is better than 2%
Quantum tunneling, adiabatic invariance and black hole spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Li, Guo-Ping; Zu, Xiao-Tao [University of Electronic Science and Technology of China, School of Physical Electronics, Chengdu (China); Pu, Jin [University of Electronic Science and Technology of China, School of Physical Electronics, Chengdu (China); China West Normal University, College of Physics and Space Science, Nanchong (China); Jiang, Qing-Quan [China West Normal University, College of Physics and Space Science, Nanchong (China)
2017-05-15
In the tunneling framework, one of us, Jiang, together with Han has studied the black hole spectroscopy via adiabatic invariance, where the adiabatic invariant quantity has been intriguingly obtained by investigating the oscillating velocity of the black hole horizon. In this paper, we attempt to improve Jiang-Han's proposal in two ways. Firstly, we once again examine the fact that, in different types (Schwarzschild and Painleve) of coordinates as well as in different gravity frames, the adiabatic invariant I{sub adia} = circular integral p{sub i}dq{sub i} introduced by Jiang and Han is canonically invariant. Secondly, we attempt to confirm Jiang-Han's proposal reasonably in more general gravity frames (including Einstein's gravity, EGB gravity and HL gravity). Concurrently, for improving this proposal, we interestingly find in more general gravity theories that the entropy of the black hole is an adiabatic invariant action variable, but the horizon area is only an adiabatic invariant. In this sense, we emphasize the concept that the quantum of the black hole entropy is more natural than that of the horizon area. (orig.)
Adiabatic cooling processes in frustrated magnetic systems with pyrochlore structure
Jurčišinová, E.; Jurčišin, M.
2017-11-01
We investigate in detail the process of adiabatic cooling in the framework of the exactly solvable antiferromagnetic spin-1/2 Ising model in the presence of the external magnetic field on an approximate lattice with pyrochlore structure. The behavior of the entropy of the model is studied and exact values of the residual entropies of all ground states are found. The temperature variation of the system under adiabatic (de)magnetization is investigated and the central role of the macroscopically degenerated ground states in cooling processes is explicitly demonstrated. It is shown that the model parameter space of the studied geometrically frustrated system is divided into five disjunct regions with qualitatively different processes of the adiabatic cooling. The effectiveness of the adiabatic (de)magnetization cooling in the studied model is compared to the corresponding processes in paramagnetic salts. It is shown that the processes of the adiabatic cooling in the antiferromagnetic frustrated systems are much more effective especially in nonzero external magnetic fields. It means that the frustrated magnetic materials with pyrochlore structure can be considered as very promising refrigerants mainly in the situations with nonzero final values of the magnetic field.
Quantum tunneling, adiabatic invariance and black hole spectroscopy
Li, Guo-Ping; Pu, Jin; Jiang, Qing-Quan; Zu, Xiao-Tao
2017-05-01
In the tunneling framework, one of us, Jiang, together with Han has studied the black hole spectroscopy via adiabatic invariance, where the adiabatic invariant quantity has been intriguingly obtained by investigating the oscillating velocity of the black hole horizon. In this paper, we attempt to improve Jiang-Han's proposal in two ways. Firstly, we once again examine the fact that, in different types (Schwarzschild and Painlevé) of coordinates as well as in different gravity frames, the adiabatic invariant I_adia = \\oint p_i dq_i introduced by Jiang and Han is canonically invariant. Secondly, we attempt to confirm Jiang-Han's proposal reasonably in more general gravity frames (including Einstein's gravity, EGB gravity and HL gravity). Concurrently, for improving this proposal, we interestingly find in more general gravity theories that the entropy of the black hole is an adiabatic invariant action variable, but the horizon area is only an adiabatic invariant. In this sense, we emphasize the concept that the quantum of the black hole entropy is more natural than that of the horizon area.
Adiabatic condition and the quantum hitting time of Markov chains
International Nuclear Information System (INIS)
Krovi, Hari; Ozols, Maris; Roland, Jeremie
2010-01-01
We present an adiabatic quantum algorithm for the abstract problem of searching marked vertices in a graph, or spatial search. Given a random walk (or Markov chain) P on a graph with a set of unknown marked vertices, one can define a related absorbing walk P ' where outgoing transitions from marked vertices are replaced by self-loops. We build a Hamiltonian H(s) from the interpolated Markov chain P(s)=(1-s)P+sP ' and use it in an adiabatic quantum algorithm to drive an initial superposition over all vertices to a superposition over marked vertices. The adiabatic condition implies that, for any reversible Markov chain and any set of marked vertices, the running time of the adiabatic algorithm is given by the square root of the classical hitting time. This algorithm therefore demonstrates a novel connection between the adiabatic condition and the classical notion of hitting time of a random walk. It also significantly extends the scope of previous quantum algorithms for this problem, which could only obtain a full quadratic speedup for state-transitive reversible Markov chains with a unique marked vertex.
Shortcuts to adiabaticity in cutting a spin chain
Energy Technology Data Exchange (ETDEWEB)
Ren, Feng-Hua [Department of Physics, Ocean University of China, Qingdao 266100 (China); School of Computer Engineering, Qingdao Technological University, Qingdao 266033 (China); Wang, Zhao-Ming, E-mail: mingmoon78@126.com [Department of Physics, Ocean University of China, Qingdao 266100 (China); Gu, Yong-Jian, E-mail: yjgu@ouc.edu.cn [Department of Physics, Ocean University of China, Qingdao 266100 (China)
2017-01-15
“Shortcuts to adiabaticity” represents a strategy for accelerating a quantum adiabatic process, is useful for preparing or manipulating a quantum state. In this paper, we investigate the adiabaticity in the dynamics of an XY spin chain. During the process of cutting one long chain into two short chains, a “shortcut” can be obtained by applying a sequence of external pulses. The fidelity which measures the adiabaticity can be dramatically enhanced by increasing the pulse strength or pulse duration time. This reliability can be kept for different types of pulses, such as random pulse time interval or random strength. The free choice of the pulse can be explained by the adiabatic representation of the Hamiltonian, and it shows that the control effects are determined by the integral of the control function in the time domain. - Highlights: • “Shortcuts to adiabaticity” is proposed by applying external pulses. • The adiabaticity can be accelerated by increasing pulse strength or duration time. • Control effects are determined by the integral of the control function with respect to time.
Calder, Alistair D; Hiorns, Melanie P; Abhyankar, Aruna; Mushtaq, Imran; Olsen, Oystein E
2007-04-01
Crossing renal vessels (CRV) are associated with ureteropelvic junction (UPJ) obstruction, particularly when presentation is beyond the neonatal period. Their presence may influence surgical management. To evaluate the accuracy of contrast-enhanced magnetic resonance angiography (CE-MRA) in the identification of CRV in children requiring surgical treatment of symptomatic UPJ obstruction, against a gold standard of laparoscopic or open surgical findings. We reviewed CE-MRA studies (3-D T2-weighted turbo spin-echo and multiphase 3-D spoiled gradient echo following intravenous gadolinium administration) of 14 children, age range 6-15 years, performed prior to surgery for suspected CRV-related UPJ obstruction. Consensus reviews of the CE-MRA studies were compared with surgical findings. CE-MRA demonstrated CRV at the level of the obstruction in nine and no crossing vessels in five children. These were all verified intraoperatively (chi2=14.0; Pchildren older than 6 years with symptomatic UPJ obstruction.
Quantitative dosing by nuclear magnetic resonance
International Nuclear Information System (INIS)
Solomon, I.
1958-01-01
The measurement of the absolute concentration of a heavy water reference containing approximately 99.8 per cent of D 2 O has been performed, by an original magnetic resonance method ('Adiabatic fast passage method') with a precision of 5.10 -5 on the D 2 O concentration. (author) [fr
Calculation of a hydrogen molecule in the adiabatic approximation
International Nuclear Information System (INIS)
Vukajlovich, F.R.; Mogilevskij, O.A.; Ponomarev, L.I.
1979-01-01
The adiabatic approximation js used for calculating the energy levels of a hydrogen molecule, i.e. of the simplest four-body system with a Coulomb interaction. The aim of this paper is the investigation of the possible use of the adiabatic method in the molecular problems. The most effective regions of its application are discussed. An infinite system of integro-differential equations is constructed, which describes the hydrogen molecule in the adiabatic approximation with the effective potentials taking into account the corrections to the nuclear motion. The energy of the first three vibrational states of the hydrogen molecule is calculated and compared with the experimental data. The convergence of the method is discussed
Adiabatic passage and ensemble control of quantum systems
International Nuclear Information System (INIS)
Leghtas, Z; Sarlette, A; Rouchon, P
2011-01-01
This paper considers population transfer between eigenstates of a finite quantum ladder controlled by a classical electric field. Using an appropriate change of variables, we show that this setting can be set in the framework of adiabatic passage, which is known to facilitate ensemble control of quantum systems. Building on this insight, we present a mathematical proof of robustness for a control protocol-chirped pulse-practised by experimentalists to drive an ensemble of quantum systems from the ground state to the most excited state. We then propose new adiabatic control protocols using a single chirped and amplitude-shaped pulse, to robustly perform any permutation of eigenstate populations, on an ensemble of systems with unknown coupling strengths. These adiabatic control protocols are illustrated by simulations on a four-level ladder.
Adiabatic Expansion of Electron Gas in a Magnetic Nozzle
Takahashi, Kazunori; Charles, Christine; Boswell, Rod; Ando, Akira
2018-01-01
A specially constructed experiment shows the near perfect adiabatic expansion of an ideal electron gas resulting in a polytropic index greater than 1.4, approaching the adiabatic value of 5 /3 , when removing electric fields from the system, while the polytropic index close to unity is observed when the electrons are trapped by the electric fields. The measurements were made on collisionless electrons in an argon plasma expanding in a magnetic nozzle. The collision lengths of all electron collision processes are greater than the scale length of the expansion, meaning the system cannot be in thermodynamic equilibrium, yet thermodynamic concepts can be used, with caution, in explaining the results. In particular, a Lorentz force, created by inhomogeneities in the radial plasma density, does work on the expanding magnetic field, reducing the internal energy of the electron gas that behaves as an adiabatically expanding ideal gas.
A design study of non-adiabatic electron guns
International Nuclear Information System (INIS)
Barroso, J.J.; Stellati, C.
1994-01-01
The design of a non-adiabatic gun capable of producing a 10 A, 50 KeV high-quality laminar electron beam is reported. In contrast to the magnetron injection gun with a conical cathode, where the beam is generated initially with a transverse velocity component, in the non-adiabatic gun electrons are extracted in a direction parallel to the axial guide magnetic field. The beam electrons acquire cyclotron motion as result of non-adiabatic processes in a strong non uniform electric field across the modulation anode. Such an extraction method gives rise to favourable features that are explored throughout the work. An extensive numerical simulation study has also been done to minimize velocity and energy spreads. (author). 3 refs, 5 figs, 1 tab
Dynamics of ionizing shock waves on adiabatic motions of gases
International Nuclear Information System (INIS)
Zorev, N.N.; Sklizkov, G.V.; Shikanov, A.S.
1982-01-01
Results are presented of an experimental investigation of free (adiabatic) motion of a spherical ionizing wave in deuterium produced by an expanding laser plasma. It is shown that the discrepancy between the free movement of shock waves (which lead to total ionization of the gas) and the Sedov-Taylor model of a spontaneous point explosion is not related to variations in the adiabat exponent γ and the motion occurs for a constant γ=5/3. The effect is ascribed to the influence of the shock wave front structure on the dynamics of its propagation. An analytic expression for the motion of symmetric ionizing shock waves is found which has an accuracy of better than 1%. As a result the adiabat exponent was determined experimentally. A method for determining the energy of a shock wave on the basis of its dynamics of motion is developed which has an accuracy of approximately 5% [ru
Alonso-Farré, J M; Gonzalo-Orden, M; Barreiro-Vázquez, J D; Barreiro-Lois, A; André, M; Morell, M; Llarena-Reino, M; Monreal-Pawlowsky, T; Degollada, E
2015-02-01
Computed tomography (CT) and low-field magnetic resonance imaging (MRI) were used to scan seven by-caught dolphin cadavers, belonging to two species: four common dolphins (Delphinus delphis) and three striped dolphins (Stenella coeruleoalba). CT and MRI were obtained with the animals in ventral recumbency. After the imaging procedures, six dolphins were frozen at -20°C and sliced in the same position they were examined. Not only CT and MRI scans, but also cross sections of the heads were obtained in three body planes: transverse (slices of 1 cm thickness) in three dolphins, sagittal (5 cm thickness) in two dolphins and dorsal (5 cm thickness) in two dolphins. Relevant anatomical structures were identified and labelled on each cross section, obtaining a comprehensive bi-dimensional topographical anatomy guide of the main features of the common and the striped dolphin head. Furthermore, the anatomical cross sections were compared with their corresponding CT and MRI images, allowing an imaging identification of most of the anatomical features. CT scans produced an excellent definition of the bony and air-filled structures, while MRI allowed us to successfully identify most of the soft tissue structures in the dolphin's head. This paper provides a detailed anatomical description of the head structures of common and striped dolphins and compares anatomical cross sections with CT and MRI scans, becoming a reference guide for the interpretation of imaging studies. © 2014 Blackwell Verlag GmbH.
Sarma, Manabendra; Adhikari, S; Mishra, Manoj K
2007-01-28
Vibrational excitation (nu(f), where psi(nu(i))(R,t) approximately =e(-iH(A(2))-(R)t/h phi(nu(i))(R) with time evolution under the influence of the resonance anionic Hamiltonian H(A(2) (-))(A(2) (-)=N(2)(-)/H(2) (-)) implemented using Lanczos and fast Fourier transforms. The target (A(2)) vibrational eigenfunctions phi(nu(i))(R) and phi(nu(f))(R) are calculated using Fourier grid Hamiltonian method applied to potential energy (PE) curves of the neutral target. Application of this simple systematization to calculate vibrational structure in e-N(2) and e-H(2) scattering cross-sections provides mechanistic insights into features underlying presence/absence of structure in e-N(2) and e-H(2) scattering cross-sections. The results obtained with approximate PE curves are in reasonable agreement with experimental/calculated cross-section profiles, and cross correlation functions provide a simple demarcation between the boomerang and impulse models.
International Nuclear Information System (INIS)
Matsubayashi, Yasutomo
1997-01-01
This study evaluated the usefulness of pre- and postoperative magnetic resonance imaging (MRI) of lumbar disc hernia with special attention to measurement of the cross-sectional area of the dural tube. Twenty-five patients (20 men and 5 women; 25 discs) who underwent posterior lumbar discectomy and 73 normal individuals (44 men and 29 women; 219 discs) of a similar age distribution were studied. Axial MRI was mainly used for the measurement of the dural tube. In the patient group, MRI examination was performed 1, 3, 6, and 12 months postoperatively. Assessment of the clinical symptoms was also included and used for comparison with the MRI evaluation. The cross-sectional area was significantly reduced to about 50% of the normal preoperatively. One month postoperatively, there was no significant increase in the size of the area, but after three months, the area increased significantly and progressed to the normal size within a year. One-month postoperatively, MRI examination was not considered useful because of postoperative hematoma and/or edema at the surgical site. The increase in the size of the cross-sectional area of the dural tube correlated well with the improvement in clinical symptoms. Three-months postoperatively, MRI evaluation of the lumbar disc seemed useful and measurement of the cross-sectional area of the dural tube appeared to serve as an indicator of the effectiveness of the surgery. (author)
Energy Technology Data Exchange (ETDEWEB)
Matsubayashi, Yasutomo [Juntendo Univ., Tokyo (Japan). School of Medicine
1997-07-01
This study evaluated the usefulness of pre- and postoperative magnetic resonance imaging (MRI) of lumbar disc hernia with special attention to measurement of the cross-sectional area of the dural tube. Twenty-five patients (20 men and 5 women; 25 discs) who underwent posterior lumbar discectomy and 73 normal individuals (44 men and 29 women; 219 discs) of a similar age distribution were studied. Axial MRI was mainly used for the measurement of the dural tube. In the patient group, MRI examination was performed 1, 3, 6, and 12 months postoperatively. Assessment of the clinical symptoms was also included and used for comparison with the MRI evaluation. The cross-sectional area was significantly reduced to about 50% of the normal preoperatively. One month postoperatively, there was no significant increase in the size of the area, but after three months, the area increased significantly and progressed to the normal size within a year. One-month postoperatively, MRI examination was not considered useful because of postoperative hematoma and/or edema at the surgical site. The increase in the size of the cross-sectional area of the dural tube correlated well with the improvement in clinical symptoms. Three-months postoperatively, MRI evaluation of the lumbar disc seemed useful and measurement of the cross-sectional area of the dural tube appeared to serve as an indicator of the effectiveness of the surgery. (author)
Hien, Nguyen Thi; Kim, Guinyun; Kim, Kwangsoo; Do, Nguyen Van; Khue, Pham Duc; Thanh, Kim Tien; Shin, Sung-Gyun; Cho, Moo-Hyun
2018-06-01
The thermal neutron capture cross-section (σ0) and resonance integral (I0) of the 108Pd(n,γ)109Pd reaction have been measured relative to that of the monitor reaction 197Au(n,γ)198Au. The measurements were carried out using the neutron activation with the cadmium ratio method. Both the samples and monitors were irradiated with and without cadmium cover of 0.5 mm thickness. The induced activities of the reaction products were measured with a well calibrated HPGe γ-ray detector. In order to improve the accuracy of the results, the necessary corrections for the counting losses were made. The thermal neutron capture cross-section and resonance integral of the 108Pd(n,γ)109Pd reaction were determined to be σ0,Pd = 8.68 ± 0.41 barn and I0,Pd = 245.6 ± 24.8 barn, respectively. The obtained results are compared with literature values and discussed.
Robust adiabatic approach to optical spin entangling in coupled quantum dots
International Nuclear Information System (INIS)
Gauger, Erik M; Benjamin, Simon C; Lovett, Brendon W; Nazir, Ahsan; Stace, Thomas M
2008-01-01
Excitonic transitions offer a possible route to ultrafast optical spin manipulation in coupled nanostructures. We perform here a detailed study of the three principal exciton-mediated decoherence channels for optically controlled electron spin qubits in coupled quantum dots: radiative decay of the excitonic state, exciton-phonon interactions, and Landau-Zener transitions between laser-dressed states. We consider a scheme for producing an entangling controlled-phase gate on a pair of coupled spins which, in its simplest dynamic form, renders the system subject to fast decoherence rates associated with exciton creation during the gating operation. In contrast, we show that an adiabatic approach employing off-resonant laser excitation allows us to suppress all sources of decoherence simultaneously, significantly increasing the fidelity of operations at only a relatively small gating time cost. We find that controlled-phase gates accurate to one part in 10 2 can realistically be achieved with the adiabatic approach, whereas the conventional dynamic approach does not appear to support a fidelity suitable for scalable quantum computation. Our predictions could be demonstrated experimentally in the near future
International Nuclear Information System (INIS)
Rinkleff, R.H.
1977-01-01
Using the method of optical double resonance, the 5s5p 3 P 1 level tensor polarizability of Cadmium has been measured. For this state, various authors have published different results, using different experimental methods. The experimental result presented here is in excellent agreement with the value of Happer, based on level crossing investigations, and agrees well with the theoretical result of Robinson based on a modified Sternheimer approximation, and so gives a reliable value for the tensor polarizability. Furthermore the tensor polarizability of the 6s6p 3 P 1 - level of the even Ytterbium isotopes and the odd Ytterbium 171 nucleus have been measured with the optical double resonance method, and the Stark constant has been calculated based on a given theory and oscillator strengths. Using the methods of optical double resonance and level crossing, the tensor polarizability of 5 excited levels of the Thulium configurations 4f 13 6s6p + 4f 12 5d6s 2 have been measured. From the experimental Stark constants and the angular coefficients of the eigenfunctions calculated by Camus, the radial integrals I(5d, 5p) and I(6p, 5d) are calculated for electric dipole transitions between levels of the configurations 4f 12 5d6s 2 + 4f 13 6s6p and levels of the 4f 12 6p6s 2 + 4f 13 6s5d configurations. The tensor polarizability calculated with these radial integrals show very good agreement with the experimental values. (orig./LH) [de
High beta lasing in micropillar cavities with adiabatic layer design
DEFF Research Database (Denmark)
Lermer, M.; Gregersen, Niels; Lorke, M.
2013-01-01
We report on lasing in optically pumped adiabatic micropillar cavities, based on the AlAs/GaAs material system. A detailed study of the threshold pump power and the spontaneous emission β factor in the lasing regime for different diameters dc is presented. We demonstrate a reduction of the thresh...... of the threshold pump power by over 2 orders of magnitude from dc = 2.25 μm down to 0.95 μm. Lasing with β factors exceeding 0.5 shows that adiabatic micropillars are operating deeply in the cavity quantum electrodynamics regime....
Adiabatic theory of ionization of atoms by intense laser pulses
International Nuclear Information System (INIS)
Tolstikhin, Oleg I; Morishita, Toru; Watanabe, Shinichi
2009-01-01
As a first step towards the adiabatic theory of ionization of atoms by intense laser pulses, here we consider the simplest one-dimensional zero-range potential model. The asymptotic solution to the time-dependent Schroedinger equation in the adiabatic regime is obtained and the photoelectron spectrum is calculated. The factorization formula for the photoelectron spectrum in the back-rescattering region, first suggested by Morishita et al. [Phys. Rev. Lett. 100, 013903 (2008)] on the basis of ab initio calculations, is derived analytically.
On the adiabatic theorem when eigenvalues dive into the continuum
DEFF Research Database (Denmark)
Cornean, Decebal Horia; Jensen, Arne; Knörr, Hans Konrad
2018-01-01
We consider a reduced two-channel model of an atom consisting of a quantum dot coupled to an open scattering channel described by a three-dimensional Laplacian. We are interested in the survival probability of a bound state when the dot energy varies smoothly and adiabatically in time. The initial...... in the adiabatic limit. At the end of the paper, we present a short outlook on how our method may be extended to cover other classes of Hamiltonians; details will be given elsewhere....
Resonance controlled transport in phase space
Leoncini, Xavier; Vasiliev, Alexei; Artemyev, Anton
2018-02-01
We consider the mechanism of controlling particle transport in phase space by means of resonances in an adiabatic setting. Using a model problem describing nonlinear wave-particle interaction, we show that captures into resonances can be used to control transport in momentum space as well as in physical space. We design the model system to provide creation of a narrow peak in the distribution function, thus producing effective cooling of a sub-ensemble of the particles.
Quraan, Maher A.
Photonuclear reactions are excellent means for understanding final state interactions (FSI). The photon interacts only electromagnetically, allowing a clean separation of the strong interaction channels in the final state. The availability of high duty factor electron machines and large acceptance detectors in the past decade have allowed a further investigation of these effects covering wider regions of phase space. In this experiment, we have successfully measured the D(/gamma, pp/pi/sp-) reaction cross section at the Saskatchewan Accelerator Laboratory (SAL) utilizing the Saskatchewan- Alberta Large Acceptance Detector (SALAD). This is the first measurement of the /gamma D /to pp/pi/sp--cross section covering a wide range of phase space with an attempt to study the FSI's and the /Delta - N interaction that has successfully reproduced the normalizations. The cross section for this reaction is compared to the calculation of J. M. Laget. Laget's theory is quite successful in describing the shapes of the distributions. as well as the overall magnitude of the cross section. The different FSI's and the /Delta - N interaction have an overall effect of 10%-15% on the single differential cross section, with the calculation that includes /Delta - N interaction having the best normalization compared to the data.
International Nuclear Information System (INIS)
Abdolsalami, M.; Abdolsalami, F.; Gonzalez, H.R.
1994-01-01
We have implemented nonlocal exchange effects rigorously in the first-order nondegenerate adiabatic (FONDA) theory. This implementation requires solving integrodifferential equations that involve double integrals. Separable and model exchange approximations that simplify the inclusion of exchange in the scattering calculations have been previously implemented in the FONDA theory. The discrepancy between the exact exchange FONDA cross sections and the separable and model exchange results suggests that one needs to include exchange rigorously to obtain accurate results over a wide range of energies. Specifically, a difference of up to 30% is observed between the exact and separable exchange FONDA cross sections at near-threshold energies. At higher energies the FONDA results from the rigorous and model exchange implementations disagree by as much as 10%
International Nuclear Information System (INIS)
Kiryutin, Alexey S.; Yurkovskaya, Alexandra V.; Lukzen, Nikita N.; Ivanov, Konstantin L.; Vieth, Hans-Martin
2015-01-01
A method for precise manipulation of non-thermal nuclear spin polarization by switching a RF-field is presented. The method harnesses adiabatic correlation of spin states in the rotating frame. A detailed theory behind the technique is outlined; examples of two-spin and three-spin systems prepared in a non-equilibrium state by Para-Hydrogen Induced Polarization (PHIP) are considered. We demonstrate that the method is suitable for converting the initial multiplet polarization of spins into net polarization: compensation of positive and negative lines in nuclear magnetic resonance spectra, which is detrimental when the spectral resolution is low, is avoided. Such a conversion is performed for real two-spin and three-spin systems polarized by means of PHIP. Potential applications of the presented technique are discussed for manipulating PHIP and its recent modification termed signal amplification by reversible exchange as well as for preparing and observing long-lived spin states
International Nuclear Information System (INIS)
Mackie, Matt; Suominen, Kalle-Antti; Haerkoenen, Kari; Collin, Anssi; Javanainen, Juha
2004-01-01
We theoretically examine Raman photoassociation of a Bose-Einstein condensate, revisiting stimulated Raman adiabatic passage (STIRAP). Due to collisional mean-field shifts, efficient molecular conversion requires strong coupling and low density, either of which can bring about rogue photodissociation to noncondensate modes. We demonstrate explicitly that rogue transitions are negligible for low excited-state fractions and photodissociation that is slower than the STIRAP time scale. Moreover, we derive a reduced-parameter model of collisions, and thereby find that a gain in the molecular conversion efficiency can be obtained by adjusting the atom-atom scattering length with off-resonant magnetoassociation. This gain saturates when the atom-atom scattering length is tuned to a specific fraction of either the molecule-molecule or atom-molecule scattering length. We conclude that a fully optimized STIRAP scheme may offer the best chance for achieving coherent conversion from an atomic to a molecular condensate with photoassociation
Optimum conditions for producing Cs2 molecular condensates by stimulated Raman adiabatic passage
International Nuclear Information System (INIS)
Feng Zhifang; Li Weidong; Wang Lirong; Xiao Liantuan; Jia Suotang
2009-01-01
The optimum conditions for producing Cs 2 molecular condensates from Cs atomic condensates with high transfer efficiency by stimulated Raman adiabatic passage are presented. Under the extended 'two-photon' resonance condition, including the two-photon process, the mean-field correction, and the tunneling coupling between two upper excited molecular levels, a high and stable conversion efficiency is realized. The high conversion efficiency could be achieved by following two methods under experimentally less demanding conditions (relatively small effective Rabi frequency for pump laser pulse). One is adjusting the detuning difference between two laser pulses for same effective Rabi frequencies with up to 87.2% transfer efficiency. Another one is adjusting the effective Rabi frequency, the detuning of dump laser for given effective Rabi frequency, and the detuning of pump laser with up to 80.7% transfer efficiency.
A high-field adiabatic fast passage ultracold neutron spin flipper for the UCNA experiment
Energy Technology Data Exchange (ETDEWEB)
Holley, A. T.; Pattie, R. W.; Young, A. R. [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States); Broussard, L. J. [Department of Physics, Duke University, Durham, North Carolina 27708 (United States); Davis, J. L.; Ito, T. M.; Lyles, J. T. M.; Makela, M.; Morris, C. L.; Mortensen, R.; Saunders, A. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Hickerson, K.; Mendenhall, M. P. [W. K. Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, California 91125 (United States); Liu, C.-Y. [Department of Physics, Indiana University, Bloomington, Indiana 47405 (United States); Mammei, R. R. [Department of Physics, Virginia Tech, Blacksburg, Virginia 24061 (United States); Rios, R. [Department of Physics, Idaho State University, Pocatello, Idaho 83209 (United States)
2012-07-15
The UCNA collaboration is making a precision measurement of the {beta} asymmetry (A) in free neutron decay using polarized ultracold neutrons (UCN). A critical component of this experiment is an adiabatic fast passage neutron spin flipper capable of efficient operation in ambient magnetic fields on the order of 1 T. The requirement that it operate in a high field necessitated the construction of a free neutron spin flipper based, for the first time, on a birdcage resonator. The design, construction, and initial testing of this spin flipper prior to its use in the first measurement of A with UCN during the 2007 run cycle of the Los Alamos Neutron Science Center's 800 MeV proton accelerator is detailed. These studies determined the flipping efficiency of the device, averaged over the UCN spectrum present at the location of the spin flipper, to be {epsilon}=0.9985(4).
Optimum conditions for producing Cs2 molecular condensates by stimulated Raman adiabatic passage
Feng, Zhifang; Li, Weidong; Wang, Lirong; Xiao, Liantuan; Jia, Suotang
2009-10-01
The optimum conditions for producing Cs2 molecular condensates from Cs atomic condensates with high transfer efficiency by stimulated Raman adiabatic passage are presented. Under the extended “two-photon” resonance condition, including the two-photon process, the mean-field correction, and the tunneling coupling between two upper excited molecular levels, a high and stable conversion efficiency is realized. The high conversion efficiency could be achieved by following two methods under experimentally less demanding conditions (relatively small effective Rabi frequency for pump laser pulse). One is adjusting the detuning difference between two laser pulses for same effective Rabi frequencies with up to 87.2% transfer efficiency. Another one is adjusting the effective Rabi frequency, the detuning of dump laser for given effective Rabi frequency, and the detuning of pump laser with up to 80.7% transfer efficiency.
Adiabatic compression and radiative compression of magnetic fields
International Nuclear Information System (INIS)
Woods, C.H.
1980-01-01
Flux is conserved during mechanical compression of magnetic fields for both nonrelativistic and relativistic compressors. However, the relativistic compressor generates radiation, which can carry up to twice the energy content of the magnetic field compressed adiabatically. The radiation may be either confined or allowed to escape
Non - Adiabaticity and Novel Isotope Effect in the Doped Cuprates
International Nuclear Information System (INIS)
Kresin, V.; WOLF, S. A.
1995-01-01
This paper reports a novel isotope effect which is due to a strong non-adiabaticity that manifests itself in the dependence of the carrier concentration on the isotopic mass. The critical temperature in turn depends on the carrier concentration giving rise to a unique and non-phononic isotope shift. (author)
Failure of geometric electromagnetism in the adiabatic vector Kepler problem
International Nuclear Information System (INIS)
Anglin, J.R.; Schmiedmayer, J.
2004-01-01
The magnetic moment of a particle orbiting a straight current-carrying wire may precess rapidly enough in the wire's magnetic field to justify an adiabatic approximation, eliminating the rapid time dependence of the magnetic moment and leaving only the particle position as a slow degree of freedom. To zeroth order in the adiabatic expansion, the orbits of the particle in the plane perpendicular to the wire are Keplerian ellipses. Higher-order postadiabatic corrections make the orbits precess, but recent analysis of this 'vector Kepler problem' has shown that the effective Hamiltonian incorporating a postadiabatic scalar potential ('geometric electromagnetism') fails to predict the precession correctly, while a heuristic alternative succeeds. In this paper we resolve the apparent failure of the postadiabatic approximation, by pointing out that the correct second-order analysis produces a third Hamiltonian, in which geometric electromagnetism is supplemented by a tensor potential. The heuristic Hamiltonian of Schmiedmayer and Scrinzi is then shown to be a canonical transformation of the correct adiabatic Hamiltonian, to second order. The transformation has the important advantage of removing a 1/r 3 singularity which is an artifact of the adiabatic approximation
Non-adiabatic rotational excitation of dipolar molecule under the ...
Indian Academy of Sciences (India)
J. Chem. Sci. Vol. 125, No. 5, September 2013, pp. 1213–1221. c Indian Academy of Sciences. ... The rotational wave packets of LiCl molecule excited non-adiabatically by half cycle pulse. (HCP) is .... pared to the intensities required for the ionization of ..... out and with delayed ultrashort HCP at different initial pulse dura-.
Adiabatic and diabatic aerosol transport to the Jungfraujoch
Energy Technology Data Exchange (ETDEWEB)
Lugauer, M.; Baltensperger, U.; Furger, M.; Jost, D.T.; Schwikowski, M.; Gaeggeler, H.W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)
1997-09-01
Synoptic scale vertical motion, here detected by the geopotential height of the 500 hPa surface, mainly accounts for the aerosol transport to the Jungfraujoch in winter. In summer, diabatic convection provides the dominant vertical transport mechanism. Nevertheless, synoptic scale adiabatic motion still determines whether diabatic convection can develop. (author) 2 figs., 2 refs.
Monte Carlo Simulation of Adiabatic Cooling and Nuclear Magnetism
DEFF Research Database (Denmark)
Lindgård, Per-Anker; Viertiö, H. E.; Mouritsen, Ole G.
1988-01-01
in experimental studies of nuclear magnetism using adiabatic demagnetization methods. It is found that, although fluctuations reduce the transition temperatures by 40%, the isentropes are reduced by less than 10% relative to those calculated by mean-field theory. The dynamics of the ordering process following...
Probing Entanglement in Adiabatic Quantum Optimization with Trapped Ions
Directory of Open Access Journals (Sweden)
Philipp eHauke
2015-04-01
Full Text Available Adiabatic quantum optimization has been proposed as a route to solve NP-complete problems, with a possible quantum speedup compared to classical algorithms. However, the precise role of quantum effects, such as entanglement, in these optimization protocols is still unclear. We propose a setup of cold trapped ions that allows one to quantitatively characterize, in a controlled experiment, the interplay of entanglement, decoherence, and non-adiabaticity in adiabatic quantum optimization. We show that, in this way, a broad class of NP-complete problems becomes accessible for quantum simulations, including the knapsack problem, number partitioning, and instances of the max-cut problem. Moreover, a general theoretical study reveals correlations of the success probability with entanglement at the end of the protocol. From exact numerical simulations for small systems and linear ramps, however, we find no substantial correlations with the entanglement during the optimization. For the final state, we derive analytically a universal upper bound for the success probability as a function of entanglement, which can be measured in experiment. The proposed trapped-ion setups and the presented study of entanglement address pertinent questions of adiabatic quantum optimization, which may be of general interest across experimental platforms.
Building an adiabatic quantum computer simulation in the classroom
Rodríguez-Laguna, Javier; Santalla, Silvia N.
2018-05-01
We present a didactic introduction to adiabatic quantum computation (AQC) via the explicit construction of a classical simulator of quantum computers. This constitutes a suitable route to introduce several important concepts for advanced undergraduates in physics: quantum many-body systems, quantum phase transitions, disordered systems, spin-glasses, and computational complexity theory.
Analysis of adiabatic transfer in cavity quantum electrodynamics
Indian Academy of Sciences (India)
adiabatic transfer process through the 'dark state' by a slow variation of the control laser intensity. ... control field of Rabi frequency C(t) transfers one photon in the cavity mode to a long- .... It gives an approximate statistical description of the.
Adiabatic invariants of the extended KdV equation
Energy Technology Data Exchange (ETDEWEB)
Karczewska, Anna [Faculty of Mathematics, Computer Science and Econometrics, University of Zielona Góra, Szafrana 4a, 65-246 Zielona Góra (Poland); Rozmej, Piotr, E-mail: p.rozmej@if.uz.zgora.pl [Institute of Physics, Faculty of Physics and Astronomy, University of Zielona Góra, Szafrana 4a, 65-246 Zielona Góra (Poland); Infeld, Eryk [National Centre for Nuclear Research, Hoża 69, 00-681 Warszawa (Poland); Rowlands, George [Department of Physics, University of Warwick, Coventry, CV4 7A (United Kingdom)
2017-01-30
When the Euler equations for shallow water are taken to the next order, beyond KdV, momentum and energy are no longer exact invariants. (The only one is mass.) However, adiabatic invariants (AI) can be found. When the KdV expansion parameters are zero, exact invariants are recovered. Existence of adiabatic invariants results from general theory of near-identity transformations (NIT) which allow us to transform higher order nonintegrable equations to asymptotically equivalent (when small parameters tend to zero) integrable form. Here we present a direct method of calculations of adiabatic invariants. It does not need a transformation to a moving reference frame nor performing a near-identity transformation. Numerical tests show that deviations of AI from constant values are indeed small. - Highlights: • We suggest a new and simple method for calculating adiabatic invariants of second order wave equations. • It is easy to use and we hope that it will be useful if published. • Interesting numerics included.
Adiabatic CMB perturbations in pre-big bang string cosmology
DEFF Research Database (Denmark)
Enqvist, Kari; Sloth, Martin Snoager
2001-01-01
We consider the pre-big bang scenario with a massive axion field which starts to dominate energy density when oscillating in an instanton-induced potential and subsequently reheats the universe as it decays into photons, thus creating adiabatic CMB perturbations. We find that the fluctuations...
Digitized adiabatic quantum computing with a superconducting circuit.
Barends, R; Shabani, A; Lamata, L; Kelly, J; Mezzacapo, A; Las Heras, U; Babbush, R; Fowler, A G; Campbell, B; Chen, Yu; Chen, Z; Chiaro, B; Dunsworth, A; Jeffrey, E; Lucero, E; Megrant, A; Mutus, J Y; Neeley, M; Neill, C; O'Malley, P J J; Quintana, C; Roushan, P; Sank, D; Vainsencher, A; Wenner, J; White, T C; Solano, E; Neven, H; Martinis, John M
2016-06-09
Quantum mechanics can help to solve complex problems in physics and chemistry, provided they can be programmed in a physical device. In adiabatic quantum computing, a system is slowly evolved from the ground state of a simple initial Hamiltonian to a final Hamiltonian that encodes a computational problem. The appeal of this approach lies in the combination of simplicity and generality; in principle, any problem can be encoded. In practice, applications are restricted by limited connectivity, available interactions and noise. A complementary approach is digital quantum computing, which enables the construction of arbitrary interactions and is compatible with error correction, but uses quantum circuit algorithms that are problem-specific. Here we combine the advantages of both approaches by implementing digitized adiabatic quantum computing in a superconducting system. We tomographically probe the system during the digitized evolution and explore the scaling of errors with system size. We then let the full system find the solution to random instances of the one-dimensional Ising problem as well as problem Hamiltonians that involve more complex interactions. This digital quantum simulation of the adiabatic algorithm consists of up to nine qubits and up to 1,000 quantum logic gates. The demonstration of digitized adiabatic quantum computing in the solid state opens a path to synthesizing long-range correlations and solving complex computational problems. When combined with fault-tolerance, our approach becomes a general-purpose algorithm that is scalable.
Evolutions of Yang Phase Under Cyclic Condition and Adiabatic Condition
International Nuclear Information System (INIS)
Qian Shangwu; Gu Zhiyu
2005-01-01
There are three non-integrable phases in literatures: Berry phase, Aharonov-Anandan phase, and Yang phase. This article discusses the evolutions of Yang phase under the cyclic condition and the adiabatic condition for the general time-dependent harmonic oscillator, thus reveals the intimate relations between these three non-integrable phases.
International Nuclear Information System (INIS)
Aleshin, V.S.
1980-01-01
Presented are calculated dependences for adiabatic compressibility, isoentropy coefficient and thermodynamic sound velocity of a two-phase media with homogeneous disperse structure being in a state of equilibrium. The character of the change of the values mentioned for vapor water media at the change of vapor mass composition in the mixture from zero to 1 is shown. Comparison of the calculated data as to dependences obtained with the experimental ones for critical regimes of vapor-water flow outflow through short and long cylindrical channels with sharp entrance rims. The calculation error does not exceed approximately 12%. Analysis of the results obtained showed that at outflow through short channels of metastable vapor liquid flow the main characteristics, like at outflow through long channels, are determined by the pressure in the exit cross section, mass vapor content and specific volume of the mixture, which are calculated with account for real overheating of the liquid to the exit cross section. At critical regime of outflow through the very long channels, when one can not neglect hydraulic resistance in the channel and the process is not isoentropic, the pressure and mass vapor content in the exit cross section also unambiguously determine the value of adiabatic compressibility of two-phase media, sound velocity and isoentropy coefficient in the cross section. Conclusion is made that the dependences obtained can be used with sufficient for practical purposes accuracy when solving different engineering problems, as well as for the calculations of the mixture consumption at flow of the reactor contours NAI with WWR
Wang, Kang-Kang; Zong, De-Cai; Wang, Ya-Jun; Li, Sheng-Hong
2016-05-01
In this paper, the transition between the stable state of a big density and the extinction state and stochastic resonance (SR) for a time-delayed metapopulation system disturbed by colored cross-correlated noises are investigated. By applying the fast descent method, the small time-delay approximation and McNamara and Wiesenfeld's SR theory, we investigate the impacts of time-delay, the multiplicative, additive noises and colored cross-correlated noise on the SNR and the shift between the two states of the system. Numerical results show that the multiplicative, additive noises and time-delay can all speed up the transition from the stable state to the extinction state, while the correlation noise and its correlation time can slow down the extinction process of the population system. With respect to SNR, the multiplicative noise always weakens the SR effect, while noise correlation time plays a dual role in motivating the SR phenomenon. Meanwhile, time-delay mainly plays a negative role in stimulating the SR phenomenon. Conversely, it could motivate the SR effect to increase the strength of the cross-correlation noise in the SNR-β plot, while the increase of additive noise intensity will firstly excite SR, and then suppress the SR effect.
Energy Technology Data Exchange (ETDEWEB)
Zawadzka-Kazimierczuk, Anna; Kozminski, Wiktor [University of Warsaw, Faculty of Chemistry (Poland); Billeter, Martin, E-mail: martin.billeter@chem.gu.se [University of Gothenburg, Biophysics Group, Department of Chemistry and Molecular Biology (Sweden)
2012-09-15
While NMR studies of proteins typically aim at structure, dynamics or interactions, resonance assignments represent in almost all cases the initial step of the analysis. With increasing complexity of the NMR spectra, for example due to decreasing extent of ordered structure, this task often becomes both difficult and time-consuming, and the recording of high-dimensional data with high-resolution may be essential. Random sampling of the evolution time space, combined with sparse multidimensional Fourier transform (SMFT), allows for efficient recording of very high dimensional spectra ({>=}4 dimensions) while maintaining high resolution. However, the nature of this data demands for automation of the assignment process. Here we present the program TSAR (Tool for SMFT-based Assignment of Resonances), which exploits all advantages of SMFT input. Moreover, its flexibility allows to process data from any type of experiments that provide sequential connectivities. The algorithm was tested on several protein samples, including a disordered 81-residue fragment of the {delta} subunit of RNA polymerase from Bacillus subtilis containing various repetitive sequences. For our test examples, TSAR achieves a high percentage of assigned residues without any erroneous assignments.
International Nuclear Information System (INIS)
Froehner, F.H.; Larson, Duane C.; Tagesen, Siegfried; Petrizzi, Luigi; Hasegawa, Akira; Nakagawa, Tsuneo; Hogenbirk, Alfred; Weigmann, H.
1995-01-01
A Working Party on International Evaluation Co-operation was established under the sponsorship of the OECD/NEA Nuclear Science Committee (NSC) to promote the exchange of information on nuclear data evaluations, validation, and related topics. Its aim is also to provide a framework for co-operative activities between members of the major nuclear data evaluation projects. This includes the possible exchange of scientists in order to encourage co-operation. Requirements for experimental data resulting from this activity are compiled. The Working Party determines common criteria for evaluated nuclear data files with a view to assessing and improving the quality and completeness of evaluated data. The Parties to the project are: ENDF (United States), JEFF/EFF (NEA Data Bank Member countries), and JENDL (Japan). Co-operation with evaluation projects of non-OECD countries are organised through the Nuclear Data Section of the International Atomic Energy Agency (IAEA). NEA/NSC Subgroup 15 has had the task to assess self-shielding effects in the unresolved resonance range of structural materials, in particular their importance at various energies, and possible ways to deal with them in shielding and activation work. The principal results achieved are summarised briefly, in particular: - New data base consisting of high-resolution transmission data measured at Oak Ridge and Geel; - Improved theoretical understanding of cross-section fluctuations, including their prediction, that has been derived from the Hauser-Feshbach theory; - Benchmark results on the importance of self-shielding in iron at various energies; - Consequences for information storage in evaluated nuclear data files; - Practical utilisation of self-shielding information from evaluated files. Benchmark results as well as the Hauser-Feshbach theory show that self-shielding effects are important up to a 4-or 5-MeV neutron energy. Fluctuation factors extracted from high-resolution total cross-section data can be
Carey, Ralph; Lucchese, Robert R.; Gianturco, F. A.
2013-05-01
We present scattering calculations of electron collisions with the platinum-containing compound cis-diamminedichloroplatinum (CDDP), commonly known as cisplatin, between 0.5 eV and 6 eV, and the corresponding isolated Pt atom from 0.1 eV to 10 eV. We find evidence of resonances in e--CDDP scattering, using an ab initio description of the target. We computed scattering matrix elements from equations incorporating exchange and polarization effects through the use of the static-exchange plus density functional correlation potential. Additionally, we made use of a purely local adiabatic model potential that allows Siegert eigenstates to be calculated, thereby allowing inspection of the possible resonant scattering wave functions. The total cross section for electron scattering from (5d10) 1S Pt displays a large magnitude, monotonic decay from the initial collision energies, with no apparent resonance scattering features in any scattering symmetry. By contrast, the e--CDDP scattering cross section shows a small feature near 3.8 eV, which results from a narrow, well localized resonance of b2 symmetry. These findings are then related to the possible electron-mediated mechanism of the action of CDDP on DNA replication as suggested by recent experiments.
Ober, C P; Freeman, L E
2010-06-01
The purpose of this study was to provide a detailed description of cross-sectional anatomic structures of the manus of a black bear cadaver and correlate anatomic findings with corresponding features in computed tomographic (CT) and magnetic resonance (MR) images. CT, MR imaging, and transverse sectioning were performed on the thoracic limb of a cadaver female black bear which had no evidence of lameness or thoracic limb abnormality prior to death. Features in CT and MR images corresponding to clinically important anatomic structures in anatomic sections were identified. Most of the structures identified in transverse anatomic sections were also identified using CT and MR imaging. Bones, muscles and tendons were generally easily identified with both imaging modalities, although divisions between adjacent muscles were rarely visible with CT and only visible sometimes with MR imaging. Vascular structures could not be identified with either imaging modality.
Gibbons, L E; Latikka, P; Videman, T; Manninen, H; Battié, M C
1997-10-01
The relationship between trunk muscle morphology as measured on transverse magnetic resonance images and isokinetic lifting, psychophysical lifting, and static back muscle endurance testing was examined in 110 men, ages 35-67 years (mean, 48 years), who had been chosen based on their exposure to a wide variety of occupational and leisure-time physical activities. The computed T2-relaxation times and the T2-weighted and proton density-weighted signal intensities of the erector spinae, quadratus lumborum, and psoas major muscles had almost no association with any of the strength tests. The cross-sectional areas of the muscles had good correlations with isokinetic lifting strength (r = 0.46-0.53). They did not correlate well with psychophysical lifting and static back muscle endurance. Other characteristics or neurological or psychological factors may have more influence on those tests.
Stomp, Wouter; Krabben, Annemarie; van der Heijde, Désirée; Huizinga, Tom W J; Bloem, Johan L; van der Helm-van Mil, Annette H M; Reijnierse, Monique
2014-08-01
Magnetic resonance imaging (MRI) is increasingly used in rheumatoid arthritis (RA) research. A European League Against Rheumatism (EULAR) task force recently suggested that MRI can improve the certainty of RA diagnosis. Because this recommendation may reflect a tendency to use MRI in daily practice, thorough studies on the value of MRI are required. Thus far no large studies have evaluated the accuracy of MRI to differentiate early RA from other patients with early arthritis. We performed a large cross-sectional study to determine whether patients who are clinically classified with RA differ in MRI features compared to patients with other diagnoses. In our study, 179 patients presenting with early arthritis (median symptom duration 15.4 weeks) underwent 1.5T extremity MRI of unilateral wrist, metacarpophalangeal, and metatarsophalangeal joints according to our arthritis protocol, the foot without contrast. Images were scored according to OMERACT Rheumatoid Arthritis Magnetic Resonance Imaging Scoring (RAMRIS) by 2 independent readers. Tenosynovitis was also assessed. The main outcome was fulfilling the 1987 American College of Rheumatology (ACR) criteria for RA. Test characteristics and areas under the receiver-operator-characteristic curves (AUC) were evaluated. In subanalyses, the 2010 ACR/EULAR criteria were used as outcome, and analyses were stratified for anticitrullinated protein antibodies (ACPA). The ACR 1987 criteria were fulfilled in 43 patients (24.0%). Patients with RA had higher scores for synovitis, tenosynovitis, and bone marrow edema (BME) than patients without RA (p arthritis patients.
International Nuclear Information System (INIS)
Soliman, N.F.
2012-01-01
In k 0 - Neutron Activation Analysis (k 0 -NAA), the conversion from the tabulated Q 0 (ratio of the resonance integral to thermal neutron cross-section)to Q 0 (α) (α is the shape factor of the epithermal neutron flux, indicating the deviation of the epithermal neutron spectrum from the ideal 1/E shape) are calculated using a FORTRAN program. The calculations are done for most elements that can be detected by neutron activation using different values of the parameter (α) ranging from -0.1≤α≤+0.1. The obtained data are used to study the dependence of the values (α) on the irradiation position factor in (k 0 -NAA)equation for some selected isotopes differ in their resonance energy and its Q 0 values. The results show that, the irradiation factor is affective mainly for low thermal tro epithermal flux ratio f especially for Q 0 value greater than 50. so consequently determining the irradiation parameters α value is not needed for irradiation positions that rich with thermal neutron. But for high f values the irradiation position factor should be taken into account. On the other hand the constructed FORTRAN program can be used to calculate the value Q 0 (α) directly for different value of α
International Nuclear Information System (INIS)
Chou Chau, Yuan-Fong; Lim, Chee Ming; Kumara, N. T. R. N.; Yoong, Voo Nyuk; Lee, Chuanyo; Huang, Hung Ji; Lin, Chun-Ting; Chiang, Hai-Pang
2016-01-01
Tunable surface plasmon resonance (SPR) and dipole cavity plasmon modes of the scattering cross section (SCS) spectra on the single solid-gold/gold-shell nanorod have been numerically investigated by using the finite element method. Various effects, such as the influence of SCS spectra under x- and y-polarizations on the surface of the single solid-gold/gold-shell nanorod, are discussed in detail. With the single gold-shell nanorod, one can independently tune the relative SCS spectrum width by controlling the rod length and rod diameter, and the surface scattering by varying the shell thickness and polarization direction, as well as the dipole peak energy. These behaviors are consistent with the properties of localized SPRs and offer a way to optically control and produce selected emission wavelengths from the single solid-gold/gold-shell nanorod. The electric field and magnetic distributions provide us a qualitative idea of the geometrical properties of the single solid-gold/gold-shell nanorod on plasmon resonance.
Role of giant resonance excitation in heavy ion collisions
International Nuclear Information System (INIS)
Catara, F.; Chomaz, Ph.
1987-01-01
In this paper we discuss several aspects of heavy ion collisions involving collective vibrational modes. In our approach the relative motion is treated in a semiclassical approximation, while the intrinsic degrees of freedom are described microscopically within the RPA. The differences with respect to macroscopic models are analyzed in the appendix. First we present some results on the inelastic scattering cross section and we show that the structures observed experimentally can be explained in terms of multiple excitation of the Giant Quadrupole Resonance. After we calculate an adiabatic polarization potential describing the coupling to the collective vibrational modes and show that it produces a strong enhancement of the subbarrier fusion cross section. This enhancement is found to be enough to reproduce the experimental data for symmetric systems, while for asymmetric reactions the coupling to other degrees of freedom, like transfer, is needed. Finally we report some preliminary results on a dynamical calculation of the real and imaginary parts of the polarization potential. We show that at high incident energies (E/A > 20MeV) the role of the Giant Quadrupole Resonance becomes dominant
International Nuclear Information System (INIS)
Vinitskii, S.I.; Puzynin, I.V.; Puzynina, T.P.
1992-01-01
An effective adiabatic approach is given for the analysis of three-particle interactions that makes it possible, even in the simple two-level approximation, to reflect all the qualitative characteristics of mesic-atom resonance reactions and to obtain good qualitative agreement with various time-consuming calculations. 6 figs
Energy Technology Data Exchange (ETDEWEB)
Avakyan, R.O.; Avetisyan, A.; Bagdasaryan, A.S.; Vartapetyan, G.A.; Danagulyan, S.S.; Eganov, V.S.; Karapetyan, A.P.; Kosakov, I.K.; Marukyan, G.O.; Matevosyan, M.
1983-11-01
The energy dependence of the asymmetry in the cross section for the ..gamma..p..-->..p..pi../sup 0/ reaction induced by a polarized photon beam is measured in the energy region 0.75--1.3 GeV at the neutral-pion emission angle theta(0 = 70/sup 0/ in the c.m. system. The experimental data are compared with various theoretical predictions. A prediction based on the use of fixed-t dispersion relations is in satisfactory agreement with the experimental results.
International Nuclear Information System (INIS)
Timokhov, V.M.; Bokhovko, M.V.; Kazakov, L.E.; Kononov, V.N.; Manturov, G.N.; Poletaev, E.D.
1988-01-01
Results of measurements of neutron radiative capture cross sections in the energy range of 20-450 keV and of neutron transmission in the energy range of 20-1400 keV for 112,114,115,116,117,118,119,120,122 ,124S n isotopes and natural mixture of tin are presented. Analysis of the experimental data in the framework of nuclear reactions statistical theory is carried out, as a result of which data on neutron and radiation strength functions, potential scattering radii for S- and P-neutrons, as well as nuclear levels density parameters, are obtained
Mughabghab, Said
2018-01-01
Atlas of Neutron Resonances: Resonance Properties and Thermal Cross Sections Z= 1-60, Sixth Edition, contains an extensive list of detailed individual neutron resonance parameters for Z=1-60, as well as thermal cross sections, capture resonance integrals, average resonance parameters and a short survey of the physics of thermal and resonance neutrons. The long introduction contains: nuclear physics formulas aimed at neutron physicists; topics of special interest such as valence neutron capture, nuclear level density parameters, and s-, p-, and d-wave neutron strength functions; and various comparisons of measured quantities with the predictions of nuclear models, such as the optical model. As in the last edition, additional features have been added to appeal to a wider spectrum of users. These include: spin-dependent scattering lengths that are of interest to solid-state physicists, nuclear physicists and neutron evaluators; calculated and measured Maxwellian average 5-keV and 30-keV capture cross sections o...
Electron capture cross sections by O{sup +} from atomic He
Energy Technology Data Exchange (ETDEWEB)
Joseph, Dwayne C; Saha, Bidhan C [Department of Physics, Florida A and M University, Tallahassee, FL-32307 (United States)
2009-11-01
The adiabatic representation is used in both the quantal and semi classical molecular orbital close coupling methods (MOCC) to evaluate charge exchange cross sections. Our results show good agreement with experimental cross sections
Directory of Open Access Journals (Sweden)
Tracey A Willis
Full Text Available We conducted a prospective multinational study of muscle pathology using magnetic resonance imaging (MRI in patients with limb-girdle muscular dystrophy 2I (LGMD2I. Thirty eight adult ambulant LGMD2I patients (19 male; 19 female with genetically identical mutations (c.826C>A in the fukutin-related protein (FKRP gene were recruited. In each patient, T1-weighted (T1w imaging was assessed by qualitative grading for 15 individual lower limb muscles and quantitative Dixon imaging was analysed on 14 individual lower limb muscles by region of interest analysis. We described the pattern and appearance of muscle pathology and gender differences, not previously reported for LGMD2I. Diffuse fat infiltration of the gastrocnemii muscles was demonstrated in females, whereas in males fat infiltration was more prominent in the medial than the lateral gastrocnemius (p = 0.05. In the anterior thigh of males, in contrast to females, median fat infiltration in the vastus medialis muscle (45.7% exceeded that in the vastus lateralis muscle (11.2% (p<0.005. MRI is non-invasive, objective and does not rely on patient effort compared to clinical and physical measures that are currently employed. We demonstrated (i that the quantitative Dixon technique is an objective quantitative marker of disease and (ii new observations of gender specific patterns of muscle involvement in LGMD2I.
Energy Technology Data Exchange (ETDEWEB)
Calder, Alistair D.; Hiorns, Melanie P.; Olsen, Oystein E. [Hospital for Children NHS Trust, Department of Radiology, London (United Kingdom); Abhyankar, Aruna; Mushtaq, Imran [Hospital for Children NHS Trust, Department of Urology, London (United Kingdom)
2007-04-15
Crossing renal vessels (CRV) are associated with ureteropelvic junction (UPJ) obstruction, particularly when presentation is beyond the neonatal period. Their presence may influence surgical management. To evaluate the accuracy of contrast-enhanced magnetic resonance angiography (CE-MRA) in the identification of CRV in children requiring surgical treatment of symptomatic UPJ obstruction, against a gold standard of laparoscopic or open surgical findings. We reviewed CE-MRA studies (3-D T2-weighted turbo spin-echo and multiphase 3-D spoiled gradient echo following intravenous gadolinium administration) of 14 children, age range 6-15 years, performed prior to surgery for suspected CRV-related UPJ obstruction. Consensus reviews of the CE-MRA studies were compared with surgical findings. CE-MRA demonstrated CRV at the level of the obstruction in nine and no crossing vessels in five children. These were all verified intraoperatively ({chi}{sup 2} = 14.0; P < 0.001). In eight of the nine patients with CRV there was no evidence of intrinsic obstruction at surgery. In the remaining patient there was fibrosis of the upper ureter. CE-MRA is an accurate means of identifying CRV in children older than 6 years with symptomatic UPJ obstruction. (orig.)
International Nuclear Information System (INIS)
Calder, Alistair D.; Hiorns, Melanie P.; Olsen, Oystein E.; Abhyankar, Aruna; Mushtaq, Imran
2007-01-01
Crossing renal vessels (CRV) are associated with ureteropelvic junction (UPJ) obstruction, particularly when presentation is beyond the neonatal period. Their presence may influence surgical management. To evaluate the accuracy of contrast-enhanced magnetic resonance angiography (CE-MRA) in the identification of CRV in children requiring surgical treatment of symptomatic UPJ obstruction, against a gold standard of laparoscopic or open surgical findings. We reviewed CE-MRA studies (3-D T2-weighted turbo spin-echo and multiphase 3-D spoiled gradient echo following intravenous gadolinium administration) of 14 children, age range 6-15 years, performed prior to surgery for suspected CRV-related UPJ obstruction. Consensus reviews of the CE-MRA studies were compared with surgical findings. CE-MRA demonstrated CRV at the level of the obstruction in nine and no crossing vessels in five children. These were all verified intraoperatively (χ 2 = 14.0; P < 0.001). In eight of the nine patients with CRV there was no evidence of intrinsic obstruction at surgery. In the remaining patient there was fibrosis of the upper ureter. CE-MRA is an accurate means of identifying CRV in children older than 6 years with symptomatic UPJ obstruction. (orig.)
Adiabatic theorem for the time-dependent wave operator
International Nuclear Information System (INIS)
Viennot, David; Jolicard, Georges; Killingbeck, John P.; Perrin, Marie-Yvonne
2005-01-01
The application of time-dependent wave operator theory to the development of a quantum adiabatic perturbation theory is treated both theoretically and numerically, with emphasis on the description of field-matter interactions which involve short laser pulses. It is first shown that the adiabatic limit of the time-dependent wave operator corresponds to a succession of instantaneous static Bloch wave operators. Wave operator theory is then shown to be compatible with the two-time Floquet theory of light-matter interaction, thus allowing the application of Floquet theory to cases which require the use of a degenerate active space. A numerical study of some problems shows that the perturbation strength associated with nonadiabatic processes can be reduced by using multidimensional active spaces and illustrates the capacity of the wave operator approach to produce a quasiadiabatic treatment of a nominally nonadiabatic Floquet dynamical system
Adiabatic instability in coupled dark energy/dark matter models
International Nuclear Information System (INIS)
Bean, Rachel; Flanagan, Eanna E.; Trodden, Mark
2008-01-01
We consider theories in which there exists a nontrivial coupling between the dark matter sector and the sector responsible for the acceleration of the Universe. Such theories can possess an adiabatic regime in which the quintessence field always sits at the minimum of its effective potential, which is set by the local dark matter density. We show that if the coupling strength is much larger than gravitational, then the adiabatic regime is always subject to an instability. The instability, which can also be thought of as a type of Jeans instability, is characterized by a negative sound speed squared of an effective coupled dark matter/dark energy fluid, and results in the exponential growth of small scale modes. We discuss the role of the instability in specific coupled cold dark matter and mass varying neutrino models of dark energy and clarify for these theories the regimes in which the instability can be evaded due to nonadiabaticity or weak coupling.
An adiabatic matching device for the Orsay linear positron accelerator
International Nuclear Information System (INIS)
Chehab, R.; Le Meur, G.; Mouton, B.; Renard, M.
1983-03-01
An adiabatically tapered solenoidal magnetic field is used to match positron beam source emittance to accelerating section acceptance. Such a matching system improves the accepted energy band which has been accurately computed and compared with analytical determination. The tapered field is provided by stacked pancakes and solenoids of various radii; total lens length is about 0.75m. The adiabatic matching system took place of a quarter wave transformer system and has been in operation for two years. Positron conversion ratio is 3.3% for a 1 GeV incident beam and presents a factor of nearly two of improvement for the positron yield. Energy bandwidth of positron beam has also been increased by a factor of nearly 2.5; the output positron beam energy is of 1.2 GeV
Adiabatic pair creation in heavy-ion and laser fields
International Nuclear Information System (INIS)
Pickl, P.; Durr, D.
2008-01-01
The planned generation of lasers and heavy-ion colliders renews the hope to see electron-positron pair creation in strong classical fields. This old prediction is usually referred to as spontaneous pair creation. We observe that both heavy-ion collisions and pair creation in strong laser fields, are instances of the theory of adiabatic pair creation. We shall present the theory, thereby correcting earlier results. We give the momentum distribution of created pairs in overcritical fields. We discuss carefully the proposed experimental verifications and conclude that pure laser-based experiments are highly questionable. We propose a new experiment, joining laser fields and heavy ions, which may be feasible with present-day technology and which may indeed verify the theoretical prediction of adiabatic pair creation. Our presentation relies on recent rigorous works in mathematical physics. (authors)
Adiabatic compression of elongated field-reversed configurations
Energy Technology Data Exchange (ETDEWEB)
Spencer, R.L.; Tuszewski, M.; Linford, R.K.
1982-01-01
The simplest model of plasma dynamics is the adiabatic model. In this model the plasma is assumed to be in MHD equilibrium at each instant of time. The equilibria are connected by the requirement that they all have the same entropy per unit flux, i.e., the equilibria form a sequence generated by adiabatic changes. The standard way of computing such a sequence of equilibria was developed by Grad, but its practical use requires a fairly complicated code. It would be helpful if approximately the same results could be gotten either with a much simpler code or by analytical techniques. In Sec. II a one-dimensional equilibrium code is described and its results are checked against a two-dimensional equilibrium code; in Sec. III an even simpler analytic calculation is presented.
Adiabatic translation factors in slow ion-atom collisions
International Nuclear Information System (INIS)
Vaaben, J.; Taulbjerg, K.
1981-01-01
The general properties of translation factors in slow atomic collisions are discussed. It is emphasised that an acceptable form of translation factors must be conceptually consistent with the basic underlying assumption of the molecular model; i.e. translation factors must relax adiabatically at intermediate and small internuclear separations. A simple physical argument is applied to derive a general parameter-free expression for the translation factor pertinent to an electron in a two-centre Coulomb field. Within the present approach the adiabatic translation factor is considered to be a property of the two-centre field independently of the molecular state under consideration. The generalisation to many-electron systems is therefore readily made. (author)
Adiabatic tapered optical fiber fabrication in two step etching
Chenari, Z.; Latifi, H.; Ghamari, S.; Hashemi, R. S.; Doroodmand, F.
2016-01-01
A two-step etching method using HF acid and Buffered HF is proposed to fabricate adiabatic biconical optical fiber tapers. Due to the fact that the etching rate in second step is almost 3 times slower than the previous droplet etching method, terminating the fabrication process is controllable enough to achieve a desirable fiber diameter. By monitoring transmitted spectrum, final diameter and adiabaticity of tapers are deduced. Tapers with losses about 0.3 dB in air and 4.2 dB in water are produced. The biconical fiber taper fabricated using this method is used to excite whispering gallery modes (WGMs) on a microsphere surface in an aquatic environment. So that they are suitable to be used in applications like WGM biosensors.
Adiabatic pipelining: a key to ternary computing with quantum dots
Pečar, P.; Ramšak, A.; Zimic, N.; Mraz, M.; Lebar Bajec, I.
2008-12-01
The quantum-dot cellular automaton (QCA), a processing platform based on interacting quantum dots, was introduced by Lent in the mid-1990s. What followed was an exhilarating period with the development of the line, the functionally complete set of logic functions, as well as more complex processing structures, however all in the realm of binary logic. Regardless of these achievements, it has to be acknowledged that the use of binary logic is in computing systems mainly the end result of the technological limitations, which the designers had to cope with in the early days of their design. The first advancement of QCAs to multi-valued (ternary) processing was performed by Lebar Bajec et al, with the argument that processing platforms of the future should not disregard the clear advantages of multi-valued logic. Some of the elementary ternary QCAs, necessary for the construction of more complex processing entities, however, lead to a remarkable increase in size when compared to their binary counterparts. This somewhat negates the advantages gained by entering the ternary computing domain. As it turned out, even the binary QCA had its initial hiccups, which have been solved by the introduction of adiabatic switching and the application of adiabatic pipeline approaches. We present here a study that introduces adiabatic switching into the ternary QCA and employs the adiabatic pipeline approach to successfully solve the issues of elementary ternary QCAs. What is more, the ternary QCAs presented here are sizewise comparable to binary QCAs. This in our view might serve towards their faster adoption.
Adiabaticity and gravity theory independent conservation laws for cosmological perturbations
Romano, Antonio Enea; Mooij, Sander; Sasaki, Misao
2016-04-01
We carefully study the implications of adiabaticity for the behavior of cosmological perturbations. There are essentially three similar but different definitions of non-adiabaticity: one is appropriate for a thermodynamic fluid δPnad, another is for a general matter field δPc,nad, and the last one is valid only on superhorizon scales. The first two definitions coincide if cs2 = cw2 where cs is the propagation speed of the perturbation, while cw2 = P ˙ / ρ ˙ . Assuming the adiabaticity in the general sense, δPc,nad = 0, we derive a relation between the lapse function in the comoving slicing Ac and δPnad valid for arbitrary matter field in any theory of gravity, by using only momentum conservation. The relation implies that as long as cs ≠cw, the uniform density, comoving and the proper-time slicings coincide approximately for any gravity theory and for any matter field if δPnad = 0 approximately. In the case of general relativity this gives the equivalence between the comoving curvature perturbation Rc and the uniform density curvature perturbation ζ on superhorizon scales, and their conservation. This is realized on superhorizon scales in standard slow-roll inflation. We then consider an example in which cw =cs, where δPnad = δPc,nad = 0 exactly, but the equivalence between Rc and ζ no longer holds. Namely we consider the so-called ultra slow-roll inflation. In this case both Rc and ζ are not conserved. In particular, as for ζ, we find that it is crucial to take into account the next-to-leading order term in ζ's spatial gradient expansion to show its non-conservation, even on superhorizon scales. This is an example of the fact that adiabaticity (in the thermodynamic sense) is not always enough to ensure the conservation of Rc or ζ.
Adiabatic pipelining: a key to ternary computing with quantum dots
International Nuclear Information System (INIS)
Pecar, P; Zimic, N; Mraz, M; Lebar Bajec, I; Ramsak, A
2008-01-01
The quantum-dot cellular automaton (QCA), a processing platform based on interacting quantum dots, was introduced by Lent in the mid-1990s. What followed was an exhilarating period with the development of the line, the functionally complete set of logic functions, as well as more complex processing structures, however all in the realm of binary logic. Regardless of these achievements, it has to be acknowledged that the use of binary logic is in computing systems mainly the end result of the technological limitations, which the designers had to cope with in the early days of their design. The first advancement of QCAs to multi-valued (ternary) processing was performed by Lebar Bajec et al, with the argument that processing platforms of the future should not disregard the clear advantages of multi-valued logic. Some of the elementary ternary QCAs, necessary for the construction of more complex processing entities, however, lead to a remarkable increase in size when compared to their binary counterparts. This somewhat negates the advantages gained by entering the ternary computing domain. As it turned out, even the binary QCA had its initial hiccups, which have been solved by the introduction of adiabatic switching and the application of adiabatic pipeline approaches. We present here a study that introduces adiabatic switching into the ternary QCA and employs the adiabatic pipeline approach to successfully solve the issues of elementary ternary QCAs. What is more, the ternary QCAs presented here are sizewise comparable to binary QCAs. This in our view might serve towards their faster adoption.
Adiabatic pipelining: a key to ternary computing with quantum dots.
Pečar, P; Ramšak, A; Zimic, N; Mraz, M; Lebar Bajec, I
2008-12-10
The quantum-dot cellular automaton (QCA), a processing platform based on interacting quantum dots, was introduced by Lent in the mid-1990s. What followed was an exhilarating period with the development of the line, the functionally complete set of logic functions, as well as more complex processing structures, however all in the realm of binary logic. Regardless of these achievements, it has to be acknowledged that the use of binary logic is in computing systems mainly the end result of the technological limitations, which the designers had to cope with in the early days of their design. The first advancement of QCAs to multi-valued (ternary) processing was performed by Lebar Bajec et al, with the argument that processing platforms of the future should not disregard the clear advantages of multi-valued logic. Some of the elementary ternary QCAs, necessary for the construction of more complex processing entities, however, lead to a remarkable increase in size when compared to their binary counterparts. This somewhat negates the advantages gained by entering the ternary computing domain. As it turned out, even the binary QCA had its initial hiccups, which have been solved by the introduction of adiabatic switching and the application of adiabatic pipeline approaches. We present here a study that introduces adiabatic switching into the ternary QCA and employs the adiabatic pipeline approach to successfully solve the issues of elementary ternary QCAs. What is more, the ternary QCAs presented here are sizewise comparable to binary QCAs. This in our view might serve towards their faster adoption.
Ion motion in the current sheet with sheared magnetic field – Part 2: Non-adiabatic effects
Directory of Open Access Journals (Sweden)
A. V. Artemyev
2013-10-01
Full Text Available We investigate dynamics of charged particles in current sheets with the sheared magnetic field. In our previouspaper (Artemyev et al., 2013 we studied the particle motion in such magnetic field configurations on the basis of the quasi-adiabatic theory and conservation of the quasi-adiabatic invariant. In this paper we concentrate on violation of the adiabaticity due to jumps of this invariant and the corresponding effects of stochastization of a particle motion. We compare effects of geometrical and dynamical jumps, which occur due to the presence of the separatrix in the phase plane of charged particle motion. We show that due to the presence of the magnetic field shear, the average value of dynamical jumps is not equal to zero. This effect results in the decrease of the time interval necessary for stochastization of trapped particle motion. We investigate also the effect of the magnetic field shear on transient trajectories, which cross the current sheet boundaries. Presence of the magnetic field shear leads to the asymmetry of reflection and transition of particles in the current sheet. We discuss the possible influence of single-particle effects revealed in this paper on the current sheet structure and dynamics.
Fast fracture: an adiabatic restriction on thermally activated crack propagation
Energy Technology Data Exchange (ETDEWEB)
Burns, S.J.
1978-01-01
Slow, isothermal, crack propagation is widely suspected to be rate controlled by thermally activated plastic deformation in the crack tip region. Adiabatic conditions are generally established in the fracture modified material at the tip of a crack during fast fracture. The temperature of this material is not the temperature of the specimen and is generally not measured during fast fracture. Thus, a complete thermodynamic description of adiabatic crack propagation data can not be made. When the slow, isothermal, crack propagation mechanisms are assumed to be operative during adiabatic crack propagation then certain predictions can be made. For example: the changes in the driving force due to temperature and rate are always in the opposite sense; there is no minimum in the driving force versus crack velocity without a change in mechanism; the temperature rise in the crack tip fracture modified material is determined mainly by the activation enthalpy for crack propagation; the interpretation of fast fracture structural steel data from simple plastic models is suspect since these materials have dissimilar isothermal temperature dependencies.
Non-Adiabatic Molecular Dynamics Methods for Materials Discovery
Energy Technology Data Exchange (ETDEWEB)
Furche, Filipp [Univ. of California, Irvine, CA (United States); Parker, Shane M. [Univ. of California, Irvine, CA (United States); Muuronen, Mikko J. [Univ. of California, Irvine, CA (United States); Roy, Saswata [Univ. of California, Irvine, CA (United States)
2017-04-04
The flow of radiative energy in light-driven materials such as photosensitizer dyes or photocatalysts is governed by non-adiabatic transitions between electronic states and cannot be described within the Born-Oppenheimer approximation commonly used in electronic structure theory. The non-adiabatic molecular dynamics (NAMD) methods based on Tully surface hopping and time-dependent density functional theory developed in this project have greatly extended the range of molecular materials that can be tackled by NAMD simulations. New algorithms to compute molecular excited state and response properties efficiently were developed. Fundamental limitations of common non-linear response methods were discovered and characterized. Methods for accurate computations of vibronic spectra of materials such as black absorbers were developed and applied. It was shown that open-shell TDDFT methods capture bond breaking in NAMD simulations, a longstanding challenge for single-reference molecular dynamics simulations. The methods developed in this project were applied to study the photodissociation of acetaldehyde and revealed that non-adiabatic effects are experimentally observable in fragment kinetic energy distributions. Finally, the project enabled the first detailed NAMD simulations of photocatalytic water oxidation by titania nanoclusters, uncovering the mechanism of this fundamentally important reaction for fuel generation and storage.
Thermal reservoir sizing for adiabatic compressed air energy storage
Energy Technology Data Exchange (ETDEWEB)
Kere, Amelie; Goetz, Vincent; Py, Xavier; Olives, Regis; Sadiki, Najim [Perpignan Univ. (France). PROMES CNRS UPR 8521; Mercier-Allart, Eric [EDF R et D, Chatou (France)
2012-07-01
Despite the operation of the two existing industrial facilities to McIntosh (Alabama), and for more than thirty years, Huntorf (Germany), electricity storage in the form of compressed air in underground cavern (CAES) has not seen the development that was expected in the 80s. The efficiency of this form of storage was with the first generation CAES, less than 50%. The evolving context technique can significantly alter this situation. The new generation so-called Adiabatic CAES (A-CAES) is to retrieve the heat produced by the compression via thermal storage, thus eliminating the necessity of gas to burn and would allow consideration efficiency overall energy of the order of 70%. To date, there is no existing installation of A-CAES. Many studies describe the principal and the general working mode of storage systems by adiabatic compression of air. So, efficiencies of different configurations of adiabatic compression process were analyzed. The aim of this paper is to simulate and analyze the performances of a thermal storage reservoir integrated in the system and adapted to the working conditions of a CAES.
Narrow-line laser cooling by adiabatic transfer
Norcia, Matthew A.; Cline, Julia R. K.; Bartolotta, John P.; Holland, Murray J.; Thompson, James K.
2018-02-01
We propose and demonstrate a novel laser cooling mechanism applicable to particles with narrow-linewidth optical transitions. By sweeping the frequency of counter-propagating laser beams in a sawtooth manner, we cause adiabatic transfer back and forth between the ground state and a long-lived optically excited state. The time-ordering of these adiabatic transfers is determined by Doppler shifts, which ensures that the associated photon recoils are in the opposite direction to the particle’s motion. This ultimately leads to a robust cooling mechanism capable of exerting large forces via a weak transition and with reduced reliance on spontaneous emission. We present a simple intuitive model for the resulting frictional force, and directly demonstrate its efficacy for increasing the total phase-space density of an atomic ensemble. We rely on both simulation and experimental studies using the 7.5 kHz linewidth 1S0 to 3P1 transition in 88Sr. The reduced reliance on spontaneous emission may allow this adiabatic sweep method to be a useful tool for cooling particles that lack closed cycling transitions, such as molecules.
Quantum trajectories for time-dependent adiabatic master equations
Yip, Ka Wa; Albash, Tameem; Lidar, Daniel A.
2018-02-01
We describe a quantum trajectories technique for the unraveling of the quantum adiabatic master equation in Lindblad form. By evolving a complex state vector of dimension N instead of a complex density matrix of dimension N2, simulations of larger system sizes become feasible. The cost of running many trajectories, which is required to recover the master equation evolution, can be minimized by running the trajectories in parallel, making this method suitable for high performance computing clusters. In general, the trajectories method can provide up to a factor N advantage over directly solving the master equation. In special cases where only the expectation values of certain observables are desired, an advantage of up to a factor N2 is possible. We test the method by demonstrating agreement with direct solution of the quantum adiabatic master equation for 8-qubit quantum annealing examples. We also apply the quantum trajectories method to a 16-qubit example originally introduced to demonstrate the role of tunneling in quantum annealing, which is significantly more time consuming to solve directly using the master equation. The quantum trajectories method provides insight into individual quantum jump trajectories and their statistics, thus shedding light on open system quantum adiabatic evolution beyond the master equation.
International Nuclear Information System (INIS)
Takatoshi, Ichikawa; Kouichi, Hagino; Akira, Iwamoto
2011-01-01
We propose a novel extension of the standard coupled-channel (CC) model in order to account for the steep falloff of fusion cross sections at deep-subbarrier incident energies. We introduce a damping factor in the coupling potential in the CC model, simulating smooth transitions from sudden to adiabatic states in deep- subbarrier fusion reactions. The CC model extended with the damping factor can reproduce well not only the steep falloff of the fusion cross section but also the saturation of the logarithmic derivatives for the fusion cross sections at deep-subbarrier energies for the 16 O+ 208 Pb, 64 Ni+ 64 Ni, and 58 Ni+ 58 Ni reactions at the deep-subbarrier energies. The important point in our model is that the transition takes place at different places for each Eigen channel. We conclude that the smooth transition from the two-body to the adiabatic one-body potential is responsible for the steep falloff of the fusion cross section
International Nuclear Information System (INIS)
Kadyk, J.A.; Abrams, G.S.; Briggs, D.D.
1975-01-01
An analysis of data at the psi(3.7) resonance gives a partial width to electrons, MMA ub e/ = 2.2 +- 0.5 keV, and limits on total width 200 keV + π - is observed with a branching ratio 0.31 +- 0.04, and psi(3.7) → psi(3.1) + anything has a branching ratio of 0.54 +- 0.08. The psi resonances appear to have the same G-parity. An enhancement occurs in the total hadronic cross section at a c.m. energy of about 4.1 GeV, rising to about 32 nb from a level of 18 nb adjacent to peak, which is about 300 MeV wide. The integrated cross section for the peak is about 5.5 nb-GeV, comparable to that for the psi(3.7) and psi(3.1) resonances. (U.S.)
International Nuclear Information System (INIS)
Abrams, G.S.; Briggs, D.D.; Chinowsky, W.; Friedberg, C.E.; Goldhaber, G.; Hollebeek, R.J.; Litke, A.; Lulu, B.A.; Pierre, F.; Sadoulet, B.; Trilling, G.H.; Whitaker, J.S.; Wiss, J.E.; Zipse, J.E.
1975-01-01
An analysis of data at the psi(3.7) resonance gives a partial width to electrons GAMMA(e)=2.2+-0.5keV, and limits on total width 200keV + π - is observed with a branching ratio 0.31+-0.04, and psi(3.7)→psi(3.1) + anything has a branching ratio of 0.54+-0.08. The psi resonances appear to have the same G-parity. An enhancement occurs in the total hadronic cross section at a c.m. energy of about 4.1GeV, rising to about 32nb from a level of 18nb adjacent to peak, which is about 300MeV wide. The integrated cross section for the peak is about 5.5nb-GeV, comparable to that for the psi(3.7) and psi(3.1) resonances
Adiabatic pressure dependence of the 2.7 and 1.9 micron water vapor bands
Mathai, C. V.; Walls, W. L.; Broersma, S.
1977-01-01
An acoustic excitation technique is used to determine the adiabatic pressure derivative of the spectral absorptance of the 2.7 and 1.9 micron water vapor bands, and the 3.5 micron HCl band. The dependence of this derivative on thermodynamic parameters such as temperature, concentration, and pressure is evaluated. A cross-flow water vapor system is used to measure spectral absorptance. Taking F as the ratio of nonrigid to rotor line strengths, it is found that an F factor correction is needed for the 2.7 micron band. The F factor for the 1.9 micron band is also determined. In the wings of each band a wavelength can be found where the concentration dependence is predominant. Farther out in the wings a local maximum occurs for the temperature derivative. It is suggested that the pressure derivative is significant in the core of the band.
Parametric Resonance in a Time-Dependent Harmonic Oscillator
Directory of Open Access Journals (Sweden)
P. N. Nesterov
2013-01-01
Full Text Available In this paper, we study the phenomenon of appearance of new resonances in a timedependent harmonic oscillator under an oscillatory decreasing force. The studied equation belongs to the class of adiabatic oscillators and arises in connection with the spectral problem for the one-dimensional Schr¨odinger equation with Wigner–von Neumann type potential. We use a specially developed method for asymptotic integration of linear systems of differential equations with oscillatory decreasing coefficients. This method uses the ideas of the averaging method to simplify the initial system. Then we apply Levinson’s fundamental theorem to get the asymptotics for its solutions. Finally, we analyze the features of a parametric resonance phenomenon. The resonant frequencies of perturbation are found and the pointwise type of the parametric resonance phenomenon is established. In conclusion, we construct an example of a time-dependent harmonic oscillator (adiabatic oscillator in which the parametric resonances, mentioned in the paper, may occur.
Revisiting the theory of the evolution of pick-up ion distributions: magnetic or adiabatic cooling?
Directory of Open Access Journals (Sweden)
H. J. Fahr
2007-01-01
Full Text Available We study the phasespace behaviour of heliospheric pick-up ions after the time of their injection as newly created ions into the solar wind bulk flow from either charge exchange or photoionization of interplanetary neutral atoms. As interaction with the ambient MHD wave fields we allow for rapid pitch angle diffusion, but for the beginning of this paper we shall neglect the effect of quasilinear or nonlinear energy diffusion (Fermi-2 acceleration induced by counterflowing ambient waves. In the up-to-now literature connected with the convection of pick-up ions by the solar wind only adiabatic cooling of these ions is considered which in the solar wind frame takes care of filling the gap between the injection energy and energies of the thermal bulk of solar wind ions. Here we reinvestigate the basics of the theory behind this assumption of adiabatic pick-up ion reactions and correlated predictions derived from it. We then compare it with the new assumption of a pure magnetic cooling of pick-up ions simply resulting from their being convected in an interplanetary magnetic field which decreases in magnitude with increase of solar distance. We compare the results for pick-up ion distribution functions derived along both ways and can point out essential differences of observational and diagnostic relevance. Furthermore we then include stochastic acceleration processes by wave-particle interactions. As we can show, magnetic cooling in conjunction with diffusive acceleration by wave-particle interaction allows for an unbroken power law with the unique power index γ=−5 beginning from lowest velocities up to highest energy particles of about 100 KeV which just marginally can be in resonance with magnetoacoustic turbulences. Consequences for the resulting pick-up ion pressures are also analysed.
Revisiting the theory of the evolution of pick-up ion distributions: magnetic or adiabatic cooling?
Directory of Open Access Journals (Sweden)
H. J. Fahr
2008-01-01
Full Text Available We study the phasespace behaviour of heliospheric pick-up ions after the time of their injection as newly created ions into the solar wind bulk flow from either charge exchange or photoionization of interplanetary neutral atoms. As interaction with the ambient MHD wave fields we allow for rapid pitch angle diffusion, but for the beginning of this paper we shall neglect the effect of quasilinear or nonlinear energy diffusion (Fermi-2 acceleration induced by counterflowing ambient waves. In the up-to-now literature connected with the convection of pick-up ions by the solar wind only adiabatic cooling of these ions is considered which in the solar wind frame takes care of filling the gap between the injection energy and energies of the thermal bulk of solar wind ions. Here we reinvestigate the basics of the theory behind this assumption of adiabatic pick-up ion reactions and correlated predictions derived from it. We then compare it with the new assumption of a pure magnetic cooling of pick-up ions simply resulting from their being convected in an interplanetary magnetic field which decreases in magnitude with increase of solar distance. We compare the results for pick-up ion distribution functions derived along both ways and can point out essential differences of observational and diagnostic relevance. Furthermore we then include stochastic acceleration processes by wave-particle interactions. As we can show, magnetic cooling in conjunction with diffusive acceleration by wave-particle interaction allows for an unbroken power law with the unique power index γ=−5 beginning from lowest velocities up to highest energy particles of about 100 KeV which just marginally can be in resonance with magnetoacoustic turbulences. Consequences for the resulting pick-up ion pressures are also analysed.
Implementation of quantum logic gates via Stark-tuned Förster resonance in Rydberg atoms
Huang, Xi-Rong; Hu, Chang-Sheng; Shen, Li-Tuo; Yang, Zhen-Biao; Wu, Huai-Zhi
2018-02-01
We present a scheme for implementation of controlled-Z and controlled-NOT gates via rapid adiabatic passage and Stark-tuned Förster resonance. By sweeping the Förster resonance once without passing through it and adiabatically tuning the angle-dependent Rydberg-Rydberg interaction of the dipolar nature, the system can be effectively described by a two-level system with the adiabatic theorem. The single adiabatic passage leads to a gate fidelity as high as 0.999 and a greatly reduced gate operation time. We investigate the scheme by considering an actual atomic level configuration with rubidium atoms, where the fidelity of the controlled-Z gate is still higher than 0.99 under the influence of the Zeeman effect.
Energy Technology Data Exchange (ETDEWEB)
Katoh, Toshio; Nakamura, Shoji; Harada, Hideo [Power Reactor and Nuclear Fuel Development Corp., Tokyo (Japan); Hatsukawa, Yuichi; Shinohara, Nobuo; Hata, Kentaro; Kobayashi, Katsutoshi; Motoishi, Shoji; Tanase, Masakazu
1997-03-01
The thermal neutron(2,200 m/s neutron) capture cross section({sigma}{sub 0}) and the resonance integral(I{sub 0}) of the reaction {sup 135}Cs(n,{gamma}){sup 136}Cs were measured by an activation method. Targets of radioactive cesium, which include {sup 135}Cs, {sup 137}Cs and stable {sup 133}Cs, were irradiated with reactor neutrons within or without a Cd shield case. The ratio of the number of nuclei of {sup 135}Cs to that of {sup 137}Cs was measured with a quadrupole mass spectrometer. This ratio and the ratio of activity of {sup 136}Cs to that of {sup 137}Cs were used for deduction of the {sigma}{sub 0} and the I{sub 0} of {sup 135}Cs. The {sigma}{sub 0} and the I{sub 0} of the reaction {sup 135}Cs(n,{sigma}){sup 136}Cs were 8.3 {+-} 0.3 barn and 38.1 {+-} 2.6 barn, respectively. (author)
Energy Technology Data Exchange (ETDEWEB)
Tintera, Jaroslav; Porod, Vaclav; Rolencova, Eva; Fendrych, Pavel [Institute for Clinical and Experimental Medicine, Department of Radiology, Prague 4 (Czech Republic); Cihak, Robert; Mlcochova, Hanka; Kautzner, Josef [Institute for Clinical and Experimental Medicine, Department of Cardiology, Prague 4 (Czech Republic)
2006-12-15
One of the recognised complications of catheter ablation is pulmonary venous stenosis. The aim of this study was to compare two methods of evaluation of pulmonary venous diameter for follow-up assessment of the above complication: (1) a linear approach evaluating two main diameters of the vein, (2) semiautomatically measured cross-sectional area (CSA). The study population consists of 29 patients. All subjects underwent contrast-enhanced magnetic resonance angiography (CeMRA) of the pulmonary veins (PVs) before and after the ablation; 14 patients were also scanned 3 months later. PV diameter was evaluated from two-dimensional multiplanar reconstructions by measuring either the linear diameter or CSA. A comparison between pulmonary venous CSA and linear measurements revealed a systematic difference in absolute values. This difference was not significant when comparing the relative change CSA and quadratic approximation using linear extents (linear approach). However, a trend towards over-estimation of calibre reduction was documented for the linear approach. Using CSA assessment, significant PV stenosis was found in ten PVs (8%) shortly after ablation. Less significant PV stenosis, ranging from 20 to 50% was documented in other 18 PVs (15%). CeMRA with CSA assessment of the PVs is suitable method for evaluation of PV diameters. (orig.)
Directory of Open Access Journals (Sweden)
Allansdotter-Johnsson Ase
2009-01-01
Full Text Available Abstract Background Knowledge about age-specific normal values for left ventricular mass (LVM, end-diastolic volume (EDV, end-systolic volume (ESV, stroke volume (SV and ejection fraction (EF by cardiac magnetic resonance imaging (CMR is of importance to differentiate between health and disease and to assess the severity of disease. The aims of the study were to determine age and gender specific normal reference values and to explore the normal physiological variation of these parameters from adolescence to late adulthood, in a cross sectional study. Methods Gradient echo CMR was performed at 1.5 T in 96 healthy volunteers (11–81 years, 50 male. Gender-specific analysis of parameters was undertaken in both absolute values and adjusted for body surface area (BSA. Results Age and gender specific normal ranges for LV volumes, mass and function are presented from the second through the eighth decade of life. LVM, ESV and EDV rose during adolescence and declined in adulthood. SV and EF decreased with age. Compared to adult females, adult males had higher BSA-adjusted values of EDV (p = 0.006 and ESV (p Conclusion LV volumes, mass and function vary over a broad age range in healthy individuals. LV volumes and mass both rise in adolescence and decline with age. EF showed a rapid decline in adolescence compared to changes throughout adulthood. These findings demonstrate the need for age and gender specific normal ranges for clinical use.
International Nuclear Information System (INIS)
Tintera, Jaroslav; Porod, Vaclav; Rolencova, Eva; Fendrych, Pavel; Cihak, Robert; Mlcochova, Hanka; Kautzner, Josef
2006-01-01
One of the recognised complications of catheter ablation is pulmonary venous stenosis. The aim of this study was to compare two methods of evaluation of pulmonary venous diameter for follow-up assessment of the above complication: (1) a linear approach evaluating two main diameters of the vein, (2) semiautomatically measured cross-sectional area (CSA). The study population consists of 29 patients. All subjects underwent contrast-enhanced magnetic resonance angiography (CeMRA) of the pulmonary veins (PVs) before and after the ablation; 14 patients were also scanned 3 months later. PV diameter was evaluated from two-dimensional multiplanar reconstructions by measuring either the linear diameter or CSA. A comparison between pulmonary venous CSA and linear measurements revealed a systematic difference in absolute values. This difference was not significant when comparing the relative change CSA and quadratic approximation using linear extents (linear approach). However, a trend towards over-estimation of calibre reduction was documented for the linear approach. Using CSA assessment, significant PV stenosis was found in ten PVs (8%) shortly after ablation. Less significant PV stenosis, ranging from 20 to 50% was documented in other 18 PVs (15%). CeMRA with CSA assessment of the PVs is suitable method for evaluation of PV diameters. (orig.)
Simulating a topological transition in a superconducting phase qubit by fast adiabatic trajectories
Wang, Tenghui; Zhang, Zhenxing; Xiang, Liang; Gong, Zhihao; Wu, Jianlan; Yin, Yi
2018-04-01
The significance of topological phases has been widely recognized in the community of condensed matter physics. The well controllable quantum systems provide an artificial platform to probe and engineer various topological phases. The adiabatic trajectory of a quantum state describes the change of the bulk Bloch eigenstates with the momentum, and this adiabatic simulation method is however practically limited due to quantum dissipation. Here we apply the "shortcut to adiabaticity" (STA) protocol to realize fast adiabatic evolutions in the system of a superconducting phase qubit. The resulting fast adiabatic trajectories illustrate the change of the bulk Bloch eigenstates in the Su-Schrieffer-Heeger (SSH) model. A sharp transition is experimentally determined for the topological invariant of a winding number. Our experiment helps identify the topological Chern number of a two-dimensional toy model, suggesting the applicability of the fast adiabatic simulation method for topological systems.
13C, 15N Resonance Assignment of Parts of the HET-s Prion Protein in its Amyloid Form
International Nuclear Information System (INIS)
Siemer, Ansgar B.; Ritter, Christiane; Steinmetz, Michel O.; Ernst, Matthias; Riek, Roland; Meier, Beat H.
2006-01-01
The partial 15 N and 13 C solid-state NMR resonance assignment of the HET-s prion protein fragment 218-289 in its amyloid form is presented. It is based on experiments measured at MAS frequencies in the range of 20-40 kHz using exclusively adiabatic polarization-transfer schemes. The resonance assignment within each residue is based on two-dimensional 13 C-- 13 C correlation spectra utilizing the DREAM mixing scheme. The sequential linking of the assigned residues used a set of two- and three-dimensional 15 N-- 13 C correlation experiments. Almost all cross peaks visible in the spectra are assigned, but only resonances from 43 of the 78 amino-acid residues could be detected. The missing residues are thought to be highly disordered and/or highly dynamic giving rise to broad resonance lines that escaped detection in the experiments applied. The line widths of the observed resonances are narrow and comparable to line widths observed in micro-crystalline samples. The 43 assigned residues are located in two fragments of about 20 residues
Adiabatic quantum computation and quantum annealing theory and practice
McGeoch, Catherine C
2014-01-01
Adiabatic quantum computation (AQC) is an alternative to the better-known gate model of quantum computation. The two models are polynomially equivalent, but otherwise quite dissimilar: one property that distinguishes AQC from the gate model is its analog nature. Quantum annealing (QA) describes a type of heuristic search algorithm that can be implemented to run in the ``native instruction set'''' of an AQC platform. D-Wave Systems Inc. manufactures {quantum annealing processor chips} that exploit quantum properties to realize QA computations in hardware. The chips form the centerpiece of a nov
η Condensate of Fermionic Atom Pairs via Adiabatic State Preparation
International Nuclear Information System (INIS)
Kantian, A.; Daley, A. J.; Zoller, P.
2010-01-01
We discuss how an η condensate, corresponding to an exact excited eigenstate of the Fermi-Hubbard model, can be produced with cold atoms in an optical lattice. Using time-dependent density matrix renormalization group methods, we analyze a state preparation scheme beginning from a band insulator state in an optical superlattice. This state can act as an important test case, both for adiabatic preparation methods and the implementation of the many-body Hamiltonian, and measurements on the final state can be used to help detect associated errors.
Stimulated Raman adiabatic passage in Tm3+:YAG
International Nuclear Information System (INIS)
Alexander, A. L.; Lauro, R.; Louchet, A.; Chaneliere, T.; Le Goueet, J. L.
2008-01-01
We report on the experimental demonstration of stimulated Raman adiabatic passage in a Tm 3+ :YAG crystal. Tm 3+ :YAG is a promising material for use in quantum information processing applications, but as yet there are few experimental investigations of coherent Raman processes in this material. We investigate the effect of inhomogeneous broadening and Rabi frequency on the transfer efficiency and the width of the two-photon spectrum. Simulations of the complete Tm 3+ :YAG system are presented along with the corresponding experimental results
Non-adiabatic pumping in an oscillating-piston model
Chuchem, Maya; Dittrich, Thomas; Cohen, Doron
2012-05-01
We consider the prototypical "piston pump" operating on a ring, where a circulating current is induced by means of an AC driving. This can be regarded as a generalized Fermi-Ulam model, incorporating a finite-height moving wall (piston) and non-trivial topology (ring). The amount of particles transported per cycle is determined by a layered structure of phase space. Each layer is characterized by a different drift velocity. We discuss the differences compared with the adiabatic and Boltzmann pictures, and highlight the significance of the "diabatic" contribution that might lead to a counter-stirring effect.
Adiabatic invariants in stellar dynamics. 2: Gravitational shocking
Weinberg, Martin D.
1994-01-01
A new theory of gravitational shocking based on time-dependent perturbation theory shows that the changes in energy and angular momentum due to a slowly varying disturbance are not exponentially small for stellar dynamical systems in general. It predicts significant shock heating by slowly varying perturbations previously thought to be negligible according to the adiabatic criterion. The theory extends the scenarios traditionally computed only with the impulse approximation and is applicable to a wide class of disturbances. The approach is applied specifically to the problem of disk shocking of star clusters.
Non-adiabatic study of the Kepler subgiant KIC 6442183
Directory of Open Access Journals (Sweden)
Grosjean M.
2015-01-01
Full Text Available Thanks to the precision of Kepler observations, [3] were able to measure the linewidth and amplitude of individual modes (including mixed modes in several subgiant power spectra. We perform a forward modelling of a Kepler subgiant based on surface properties and observed frequencies. Non-adiabatic computations including a time- dependent treatment of convection give the lifetimes of radial and non-radial modes. Next, combining the lifetimes and inertias with a stochastic excitation model gives the amplitudes of the modes. We can now directly compare theoretical and observed linewidths and amplitudes of mixed-modes to obtain new constraints on our theoretical models.
Quasi-adiabatic Switching for Metal-Island Quantum-dot Cellular Automata
Toth, Geza; Lent, Craig S.
2000-01-01
Recent experiments have demonstrated a working cell suitable for implementing the Quantum-dot Cellular Automata (QCA) paradigm. These experiments have been performed using metal island clusters. The most promising approach to QCA operation involves quasi-adiabatically switching the cells. This has been analyzed extensively in gated semiconductor cells. Here we present a metal island cell structure that makes quasi-adiabatic switching possible. We show how this permits quasi-adiabatic clocking...
Three-particle decays of light-nuclei resonances
DEFF Research Database (Denmark)
Álvarez-Rodríguez, R.; Jensen, A.S.; Garrido, E.
2012-01-01
We have studied the three-particle decay of 12C, 9Be and 6Be resonances. These nuclei have been described as three-body systems by means of the complex scaled hyperspherical adiabatic expansion method. The short-distance part of the wave function is responsible for the energies, whereas the infor...
Energy Technology Data Exchange (ETDEWEB)
Panikkath, Priyada; Mohanakrishnan, P. [Manipal University, Manipal Centre for Natural Sciences, Karnataka (India)
2017-03-15
Thermal neutron capture cross-sections and resonance integrals of {sup 139}La(n, γ){sup 140}La and {sup 140}Ce (n, γ){sup 141}Ce are measured with respect to reference reactions {sup 197}Au(n, γ){sup 198}Au and {sup 55}Mn(n, γ){sup 56}Mn using the neutron activation technique. Measurements are carried out using neutrons from an Am-Be source located inside a concrete bunker. Two different methods are used for determining self-shielding factors of activation foils as well as for finding the epithermal neutron spectrum shape factor. For {sup 139}La with reference to {sup 197}Au and {sup 55}Mn the measured thermal cross sections are 9.24 ± 0.25 b and 9.28 ± 0.37 b, respectively, while the measured resonance integrals are 12.18 ± 0.67 b and 11.81 ± 0.94 b, respectively. For {sup 140}Ce with reference to {sup 197}Au and {sup 55}Mn the measured thermal cross sections are 0.44 ± 0.01 b and 0.44 ± 0.02 b, respectively, while the measured resonance integrals are 0.55 ± 0.03 b and 0.54 ± 0.04 b, respectively. The present measurements are compared with earlier measurements and evaluations. Presently estimated values confirm the established {sup 139}La(n, γ){sup 140}La cross-sections. The presently measured thermal capture cross-section {sup 140}Ce(n, γ){sup 141}Ce, though lower than the evaluated data, is having higher accuracy compared to previous measurements with large uncertainties. The resonance integral measured is higher (like most previous measurements) than most evaluations requiring a revision of the evaluated data. (orig.)
Dynamic and Thermodynamic Properties of a CA Engine with Non-Instantaneous Adiabats
Directory of Open Access Journals (Sweden)
Ricardo T. Paéz-Hernández
2017-11-01
Full Text Available This paper presents an analysis of a Curzon and Alhborn thermal engine model where both internal irreversibilities and non-instantaneous adiabatic branches are considered, operating with maximum ecological function and maximum power output regimes. Its thermodynamic properties are shown, and an analysis of its local dynamic stability is performed. The results derived are compared throughout the work with the results obtained previously for a case in which the adiabatic branches were assumed as instantaneous. The results indicate a better performance for thermodynamic properties in the model with instantaneous adiabatic branches, whereas there is an improvement in robustness in the case where non-instantaneous adiabatic branches are considered.
Non-adiabatic effect on Laughlin's argument of the quantum Hall effect
International Nuclear Information System (INIS)
Maruyama, I; Hatsugai, Y
2009-01-01
We have numerically studied a non-adiabatic charge transport in the quantum Hall system pumped by a magnetic flux, as one of the simplest theoretical realizations of non-adiabatic Thouless pumping. In the adiabatic limit, a pumped charge is quantized, known as Laughlin's argument in a cylindrical lattice. In a uniform electric field, we obtained a formula connecting quantized pumping in the adiabatic limit and no-pumping in the sudden limit. The intermediate region between the two limits is determined by the Landau gap. A randomness or impurity effect is also discussed.
Estimation of the adiabatic energy limit versus beta in Baseball II
International Nuclear Information System (INIS)
Foote, J.H.
1976-01-01
Several estimates of the adiabatic energy limit versus beta in Baseball II are summarized, and the calculational methods used to obtain them are described. Some estimates are based on analytic expressions; for others, particle orbits are calculated, magnetic-moment jumps are inspected, and adiabatic limits then derived. The results are sensitive to the assumed variation of the combined vacuum-plus-plasma magnetic field. The calculated adiabatic energy limit falls rapidly with beta, even for a gradual magnetic-field variation. If we assume a sharp depression in the axial profile of the combined magnetic field for a finite-beta plasma, the adiabatic limit can be further markedly reduced
Optimization using quantum mechanics: quantum annealing through adiabatic evolution
International Nuclear Information System (INIS)
Santoro, Giuseppe E; Tosatti, Erio
2006-01-01
We review here some recent work in the field of quantum annealing, alias adiabatic quantum computation. The idea of quantum annealing is to perform optimization by a quantum adiabatic evolution which tracks the ground state of a suitable time-dependent Hamiltonian, where 'ℎ' is slowly switched off. We illustrate several applications of quantum annealing strategies, starting from textbook toy-models-double-well potentials and other one-dimensional examples, with and without disorder. These examples display in a clear way the crucial differences between classical and quantum annealing. We then discuss applications of quantum annealing to challenging hard optimization problems, such as the random Ising model, the travelling salesman problem and Boolean satisfiability problems. The techniques used to implement quantum annealing are either deterministic Schroedinger's evolutions, for the toy models, or path-integral Monte Carlo and Green's function Monte Carlo approaches, for the hard optimization problems. The crucial role played by disorder and the associated non-trivial Landau-Zener tunnelling phenomena is discussed and emphasized. (topical review)
Adiabatic Processes Realized with a Trapped Brownian Particle
Martínez, Ignacio A.; Roldán, Édgar; Dinis, Luis; Petrov, Dmitri; Rica, Raúl A.
2015-03-01
The ability to implement adiabatic processes in the mesoscale is of key importance in the study of artificial or biological micro- and nanoengines. Microadiabatic processes have been elusive to experimental implementation due to the difficulty in isolating Brownian particles from their fluctuating environment. Here we report on the experimental realization of a microscopic quasistatic adiabatic process employing a trapped Brownian particle. We circumvent the complete isolation of the Brownian particle by designing a protocol where both characteristic volume and temperature of the system are changed in such a way that the entropy of the system is conserved along the process. We compare the protocols that follow from either the overdamped or underdamped descriptions, demonstrating that the latter is mandatory in order to obtain a vanishing average heat flux to the particle. We provide analytical expressions for the distributions of the fluctuating heat and entropy and verify them experimentally. Our protocols could serve to implement the first microscopic engine that is able to attain the fundamental limit for the efficiency set by Carnot.
FRW-type cosmologies with adiabatic matter creation
International Nuclear Information System (INIS)
Lima, J.A.; Germano, A.S.; Abramo, L.R.
1996-01-01
Some properties of cosmological models with matter creation are investigated in the framework of the Friedmann-Robertson-Walker line element. For adiabatic matter creation, as developed by Prigogine and co-workers, we derive a simple expression relating the particle number density n and energy density ρ which holds regardless of the matter creation rate. The conditions to generate inflation are discussed and by considering the natural phenomenological matter creation rate ψ=3βnH, where β is a pure number of the order of unity and H is the Hubble parameter, a minimally modified hot big-bang model is proposed. The dynamic properties of such models can be deduced from the standard ones simply by replacing the adiabatic index γ of the equation of state by an effective parameter γ * =γ(1-β). The thermodynamic behavior is determined and it is also shown that ages large enough to agree with observations are obtained even given the high values of H suggested by recent measurements. copyright 1996 The American Physical Society
International Nuclear Information System (INIS)
Leal, L.; Shibata, K.; Iwamoto, O.; Chiba, G.; Noguere, G.; Saint Jean, C. de; Sirakov, I.; Capote, R.; Sublet, J.C.; Coste-Delclaux, M.; Jouanne, C.; MacFarlane, R.E.; Kahler, A.C. Jr.; Lubitz, C.R.; Cullen, D.; Herman, M.; Ribon, P.
2011-01-01
This report summarises the work performed under WPEC Subgroup 32 (SG32) on issues pertinent to the methodology used in the unresolved resonance region (URR). The main purpose of SG32 was to verify the validity of the Single-level Breit-Wigner (SLBW) cross-section representation in the URR for self-shielding calculations. While SG32 work was under way, several other developments related to the URR on this subject came into play that had a direct impact on the results of calculations. The work described in this report focuses on: - testing of the SLBW formalism in the URR for fissile and fertile isotopes; - URR covariance representation; - interpolation issue with a URR resonance parameter for the infinitely dilute cross-section calculations; - ENDF URR parameter representation based on the LSSF = 0 or LSSF = 1 option
International Nuclear Information System (INIS)
Cain, Peter A; Ahl, Ragnhild; Hedstrom, Erik; Ugander, Martin; Allansdotter-Johnsson, Ase; Friberg, Peter; Arheden, Hakan
2009-01-01
Knowledge about age-specific normal values for left ventricular mass (LVM), end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV) and ejection fraction (EF) by cardiac magnetic resonance imaging (CMR) is of importance to differentiate between health and disease and to assess the severity of disease. The aims of the study were to determine age and gender specific normal reference values and to explore the normal physiological variation of these parameters from adolescence to late adulthood, in a cross sectional study. Gradient echo CMR was performed at 1.5 T in 96 healthy volunteers (11–81 years, 50 male). Gender-specific analysis of parameters was undertaken in both absolute values and adjusted for body surface area (BSA). Age and gender specific normal ranges for LV volumes, mass and function are presented from the second through the eighth decade of life. LVM, ESV and EDV rose during adolescence and declined in adulthood. SV and EF decreased with age. Compared to adult females, adult males had higher BSA-adjusted values of EDV (p = 0.006) and ESV (p < 0.001), similar SV (p = 0.51) and lower EF (p = 0.014). No gender differences were seen in the youngest, 11–15 year, age range. LV volumes, mass and function vary over a broad age range in healthy individuals. LV volumes and mass both rise in adolescence and decline with age. EF showed a rapid decline in adolescence compared to changes throughout adulthood. These findings demonstrate the need for age and gender specific normal ranges for clinical use
International Nuclear Information System (INIS)
Kubota, Mitsuaki; Kurosawa, Hisashi; Ikeda, Hiroshi; Takazawa, Yuji; Kawasaki, Takayuki; Ishijima, Muneaki; Kim, Song-Gon; Seto, Hiroaki
2009-01-01
Bone marrow abnormalities (BMAs) are frequently found in osteoarthritis (OA) of the knee with magnetic resonance imaging (MRI). Some reports have suggested BMA was correlated with the X-ray stage of OA and also with knee pain, but the reports depended on two-dimensional images without considering the spatial expansion of BMAs. To determine whether three-dimensional expansion of a BMA with MRI in patient with medial-type OA of the knee is correlated with the radiographic stage of OA and clinical findings using a semi-quantitative method. Cross-sectional study. This study enrolled 238 patients with medial-type OA. Radiography and MRI of the knee were taken in all participants. X-rays were graded using the Kellgren-Lawrence (K/L) grade (1-4). T2-weighted fat-suppressed MRI images were used to score the size of the BMA according to the whole-organ MRI score (WORMS). A new scoring system defined as the spatial BMA score (s-score), which specifically addressed the spatial expansion of BMAs, was examined to assess the size of the BMA. BMA frequency was examined in subdivisions of the articular surfaces of the knee according to the X-ray stages of the K/L grade and the correlation of the s-score to the clinical findings. BMA frequency in the medial femorotibial joint (MFTJ; 74%) was significantly higher than in the lateral femorotibial joint (LFTJ; 14%) and patellofemoral joint (PFJ; 14%; P<0.01). The s-score of the MFTJ was strongly correlated with the X-ray stage assessed by the K/L grade. The s-score of the MFTJ was also correlated with the clinical findings. The frequency and spatial expansion of BMAs in the MFTJ are strongly correlated with the X-ray stage of medial-type OA as well as the clinical findings. (author)
Nota, Nienke M; Burke, Sarah M; den Heijer, Martin; Soleman, Remi S; Lambalk, Cornelis B; Cohen-Kettenis, Peggy T; Veltman, Dick J; Kreukels, Baudewijntje P
2017-12-01
It is hypothesized that transpeople show sex-atypical differentiation of the brain. Various structural neuroimaging studies provide support for this notion, but little is known about the sexual differentiation of functional resting-state networks in transpeople. In this study we therefore aimed to determine whether brain functional connectivity (FC) patterns in transpeople are sex-typical or sex-atypical, before and after the start of cross-sex hormone therapy (CHT). We acquired resting-state functional magnetic resonance data in 36 transpeople (22 with female sex assigned at birth), first during gonadal suppression, and again four months after start of CHT, and in 37 cisgender people (20 females), both sessions without any hormonal intervention. We used independent component analysis to identify the default mode network (DMN), salience network (SN), and left and right working memory network (WMN). These spatial maps were used for group comparisons. Within the DMN, SN, and left WMN similar FC patterns were found across groups. However, within the right WMN, cisgender males showed significantly greater FC in the right caudate nucleus than cisgender females. There was no such sex difference in FC among the transgender groups and they did not differ significantly from either of the cisgender groups. CHT (in transgender participants) and circulating sex steroids (in cisgender participants) did not affect FC. Our findings may suggest that cisgender males and females experience a dissimilar (early) differentiation of the right WMN and that such differentiation is less pronounced in transpeople. Copyright © 2017 Elsevier Masson SAS. All rights reserved.
Margossian, Renee; Schwartz, Marcy L; Prakash, Ashwin; Wruck, Lisa; Colan, Steven D; Atz, Andrew M; Bradley, Timothy J; Fogel, Mark A; Hurwitz, Lynne M; Marcus, Edward; Powell, Andrew J; Printz, Beth F; Puchalski, Michael D; Rychik, Jack; Shirali, Girish; Williams, Richard; Yoo, Shi-Joon; Geva, Tal
2009-08-01
Assessment of the size and function of a functional single ventricle (FSV) is a key element in the management of patients after the Fontan procedure. Measurement variability of ventricular mass, volume, and ejection fraction (EF) among observers by echocardiography and cardiac magnetic resonance imaging (CMR) and their reproducibility among readers in these patients have not been described. From the 546 patients enrolled in the Pediatric Heart Network Fontan Cross-Sectional Study (mean age 11.9 +/- 3.4 years), 100 echocardiograms and 50 CMR studies were assessed for measurement reproducibility; 124 subjects with paired studies were selected for comparison between modalities. Interobserver agreement for qualitative grading of ventricular function by echocardiography was modest for left ventricular (LV) morphology (kappa = 0.42) and weak for right ventricular (RV) morphology (kappa = 0.12). For quantitative assessment, high intraclass correlation coefficients were found for echocardiographic interobserver agreement (LV 0.87 to 0.92, RV 0.82 to 0.85) of systolic and diastolic volumes, respectively. In contrast, intraclass correlation coefficients for LV and RV mass were moderate (LV 0.78, RV 0.72). The corresponding intraclass correlation coefficients by CMR were high (LV 0.96, RV 0.85). Volumes by echocardiography averaged 70% of CMR values. Interobserver reproducibility for the EF was similar for the 2 modalities. Although the absolute mean difference between modalities for the EF was small (<2%), 95% limits of agreement were wide. In conclusion, agreement between observers of qualitative FSV function by echocardiography is modest. Measurements of FSV volume by 2-dimensional echocardiography underestimate CMR measurements, but their reproducibility is high. Echocardiographic and CMR measurements of FSV EF demonstrate similar interobserver reproducibility, whereas measurements of FSV mass and LV diastolic volume are more reproducible by CMR.
Energy Technology Data Exchange (ETDEWEB)
Ganich, P P; Parlag, O A; Sikora, D I; Sychev, S I
1989-03-01
Relation between yields and cross sections of photofission and photoproduction is studied in order to use them in the methods for analysis of fissile nuclides. Total yield of delayed neutrons from the {sup 232}Th target and ratios of total yields from {sup 238}U and {sup 232}Th targets were measured in the M=300 microtron in 6-18 MeV energy range. Efficiency of the suggested method for refining the {sup 238}U photofission cross sections in the range of E1-giant resonance is shown.
Rabli, Djamal; McCarroll, Ronald
2018-02-01
This review surveys the different theoretical approaches, used to describe inelastic and rearrangement processes in collisions involving atoms and ions. For a range of energies from a few meV up to about 1 keV, the adiabatic representation is expected to be valid and under these conditions, inelastic and rearrangement processes take place via a network of avoided crossings of the potential energy curves of the collision system. In general, such avoided crossings are finite in number. The non-adiabatic coupling, due to the breakdown of the Born-Oppenheimer separation of the electronic and nuclear variables, depends on the ratio of the electron mass to the nuclear mass terms in the total Hamiltonian. By limiting terms in the total Hamiltonian correct to first order in the electron to nuclear mass ratio, a system of reaction coordinates is found which allows for a correct description of both inelastic channels. The connection between the use of reaction coordinates in the quantum description and the electron translation factors of the impact parameter approach is established. A major result is that only when reaction coordinates are used, is it possible to introduce the notion of a minimal basis set. Such a set must include all avoided crossings including both radial coupling and long range Coriolis coupling. But, only when reactive coordinates are used, can such a basis set be considered as complete. In particular when the centre of nuclear mass is used as centre of coordinates, rather than the correct reaction coordinates, it is shown that erroneous results are obtained. A few results to illustrate this important point are presented: one concerning a simple two-state Landau-Zener type avoided crossing, the other concerning a network of multiple crossings in a typical electron capture process involving a highly charged ion with a neutral atom.
Interaction of plasma vortices with resonant particles
DEFF Research Database (Denmark)
Jovanovic, D.; Pécseli, Hans; Juul Rasmussen, J.
1990-01-01
Kinetic effects associated with the electron motion along magnetic field lines in low‐beta plasmas are studied. Using the gyrokinetic description of electrons, a kinetic analog of the reduced magnetohydrodynamic equations is derived, and it is shown that in the strongly nonlinear regime...... particles. The evolution equations indicate the possibility of excitation of plasma vortices by electron beams....... they possess localized solutions in the form of dipolar vortices, which can efficiently interact with resonant electrons. In the adiabatic limit, evolution equations are derived for the vortex parameters, describing exchange of the energy, enstrophy, and of the Poynting vector between the vortex and resonant...
Dzyaloshinskii-Moriya interactions and adiabatic magnetization dynamics in molecular magnets
De Raedt, H; Miyashita, S; Michielsen, K; Machida, M
A microscopic model of the molecular magnet V-15 is used to study mechanisms for the adiabatic change of the magnetization in time-dependent magnetic fields. The effects of the Dzyaloshinskii-Moriya interaction, the most plausible source for the energy-level repulsions that lead to adiabatic changes
Properties of a two stage adiabatic demagnetization refrigerator
International Nuclear Information System (INIS)
Fukuda, H; Ueda, S; Arai, R; Numazawa, T; Li, J; Saito, A T; Nakagome, H
2015-01-01
Currently, many space missions using cryogenic temperatures are being planned. In particular, high resolution sensors such as Transition Edge Sensors need very low temperatures, below 100 mK. It is well known that the adiabatic demagnetization refrigerator (ADR) is one of most useful tools for producing ultra-low temperatures in space because it is gravity independent. We studied a continuous ADR system consisting of 4 stages and demonstrated it could provide continuous temperatures around 100 mK. However, there was some heat leakage from the power leads which resulted in reduced cooling power. Our efforts to upgrade our ADR system are presented. We show the effect of using the HTS power leads and discuss a cascaded Carnot cycle consisting of 2 ADR units. (paper)
Adiabatic quantum-flux-parametron cell library adopting minimalist design
Energy Technology Data Exchange (ETDEWEB)
Takeuchi, Naoki, E-mail: takeuchi-naoki-kx@ynu.jp [Institute of Advanced Sciences, Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama 240-8501 (Japan); Yamanashi, Yuki; Yoshikawa, Nobuyuki [Institute of Advanced Sciences, Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama 240-8501 (Japan); Department of Electrical and Computer Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama 240-8501 (Japan)
2015-05-07
We herein build an adiabatic quantum-flux-parametron (AQFP) cell library adopting minimalist design and a symmetric layout. In the proposed minimalist design, every logic cell is designed by arraying four types of building block cells: buffer, NOT, constant, and branch cells. Therefore, minimalist design enables us to effectively build and customize an AQFP cell library. The symmetric layout reduces unwanted parasitic magnetic coupling and ensures a large mutual inductance in an output transformer, which enables very long wiring between logic cells. We design and fabricate several logic circuits using the minimal AQFP cell library so as to test logic cells in the library. Moreover, we experimentally investigate the maximum wiring length between logic cells. Finally, we present an experimental demonstration of an 8-bit carry look-ahead adder designed using the minimal AQFP cell library and demonstrate that the proposed cell library is sufficiently robust to realize large-scale digital circuits.
Adiabatic photo-steering theory in topological insulators
Inoue, Jun-ichi
2014-12-01
Feasible external control of material properties is a crucial issue in condensed matter physics. A new approach to achieving this aim, named adiabatic photo-steering, is reviewed. The core principle of this scheme is that several material constants are effectively turned into externally tunable variables by irradiation of monochromatic laser light. Two-dimensional topological insulators are selected as the optimal systems that exhibit a prominent change in their properties following the application of this method. Two specific examples of photo-steered quantum phenomena, which reflect topological aspects of the electronic systems at hand, are presented. One is the integer quantum Hall effect described by the Haldane model, and the other is the quantum spin Hall effect described by the Kane-Mele model. The topological quantities associated with these phenomena are the conventional Chern number and spin Chern number, respectively. A recent interesting idea, time-reversal symmetry breaking via a temporary periodic external stimulation, is also discussed.
Adiabatic surface thermometer for improved production braze quality
International Nuclear Information System (INIS)
Dittbenner, G.R.
1975-01-01
An adiabatic surface thermometer was developed to control automatically the critical temperature-time cycle of a production vacuum-brazing process. Investigations revealed that optimum braze-joint strength required precise control of the brazing temperature. Spot-welded thermocouples could not be used because the spot welds cause surface damage. This thermometer touches the surface and uses a differential thermocouple and heater to measure surface temperature without heat flow, thereby eliminating large errors caused by conduction losses common to conventional spring-loaded thermocouples. Temperatures in air or vacuum are measured to 800 0 C with errors less than 5 0 C. This thermometer has minimized the rejection of production parts, resulting in a cost saving to the U. S. Energy Research and Development Administration
Novel latch for adiabatic quantum-flux-parametron logic
International Nuclear Information System (INIS)
Takeuchi, Naoki; Yamanashi, Yuki; Yoshikawa, Nobuyuki; Ortlepp, Thomas
2014-01-01
We herein propose the quantum-flux-latch (QFL) as a novel latch for adiabatic quantum-flux-parametron (AQFP) logic. A QFL is very compact and compatible with AQFP logic gates and can be read out in one clock cycle. Simulation results revealed that the QFL operates at 5 GHz with wide parameter margins of more than ±22%. The calculated energy dissipation was only ∼0.1 aJ/bit, which yields a small energy delay product of 20 aJ·ps. We also designed shift registers using QFLs to demonstrate more complex circuits with QFLs. Finally, we experimentally demonstrated correct operations of the QFL and a 1-bit shift register (a D flip-flop)
Adiabatic Hamiltonian deformation, linear response theory, and nonequilibrium molecular dynamics
International Nuclear Information System (INIS)
Hoover, W.G.
1980-01-01
Although Hamiltonians of various kinds have previously been used to derive Green-Kubo relations for the transport coefficients, the particular choice described is uniquely related to thermodynamics. This nonequilibrium Hamiltonian formulation of fluid flow provides pedagogically simple routes to nonequilibrium fluxes and distribution functions, to theoretical understanding of long-time effects, and to new numerical methods for simulating systems far from equilibrium. The same methods are now being applied to solid-phase problems. At the relatively high frequencies used in the viscous fluid calculations described, solids typically behave elastically. Lower frequencies lead to the formation of dislocations and other defects, making it possible to study plastic flow. A property of the nonequilibrium equations of motion which might be profitably explored is their effective irreversibility. Because only a few particles are necessary to generate irreversible behavior, simulations using adiabatic deformations of the kind described here could perhaps elucidate the instability in the equations of motion responsible for irreversibility
Diskoseismology: Probing accretion disks. I - Trapped adiabatic oscillations
Nowak, Michael A.; Wagoner, Robert V.
1991-01-01
The normal modes of acoustic oscillations within thin accretion disks which are terminated by an innermost stable orbit around a slowly rotating black hole or weakly magnetized compact neutron star are analyzed. The dominant relativistic effects which allow modes to be trapped within the inner region of the disk are approximated via a modified Newtonian potential. A general formalism is developed for investigating the adiabatic oscillations of arbitrary unperturbed disk models. The generic behavior is explored by way of an expansion of the Lagrangian displacement about the plane of symmetry and by assuming separable solutions with the same radial wavelength for the horizontal and vertical perturbations. The lowest eigenfrequencies and eigenfunctions of a particular set of radial and quadrupole modes which have minimum motion normal for the plane are obtained. These modes correspond to the standard dispersion relation of disk theory.
Hydroxylamine nitrate self-catalytic kinetics study with adiabatic calorimetry
Energy Technology Data Exchange (ETDEWEB)
Liu Lijun [Mary Kay O' Connor Process Safety Center, Artie McFerrin Department of Chemical Engineering, Texas A and M University System, College Station, TX 77843-3122 (United States); Wei Chunyang [BASF Corporation, Wyandotte, MI 48192 (United States); Guo Yuyan; Rogers, William J. [Mary Kay O' Connor Process Safety Center, Artie McFerrin Department of Chemical Engineering, Texas A and M University System, College Station, TX 77843-3122 (United States); Sam Mannan, M. [Mary Kay O' Connor Process Safety Center, Artie McFerrin Department of Chemical Engineering, Texas A and M University System, College Station, TX 77843-3122 (United States)], E-mail: mannan@tamu.edu
2009-03-15
Hydroxylamine nitrate (HAN) is an important member of the hydroxylamine compound family with applications that include equipment decontamination in the nuclear industry and aqueous or solid propellants. Due to its instability and autocatalytic behavior, HAN has been involved in several incidents at the Hanford and Savannah River Site (SRS) [Technical Report on Hydroxylamine Nitrate, US Department of Energy, 1998]. Much research has been conducted on HAN in different areas, such as combustion mechanism, decomposition mechanism, and runaway behavior. However, the autocatalytic decomposition behavior of HAN at runaway stage has not been fully addressed due to its highly exothermic and rapid decomposition behavior. This work is focused on extracting HAN autocatalytic kinetics and analyzing HAN critical behavior from adiabatic calorimetry measurements. A lumped autocatalytic kinetic model for HAN and associated model parameters are determined. Also the storage and handling critical conditions of diluted HAN solution without metal presence are quantified.
Adiabatic Cooling for Rovibrational Spectroscopy of Molecular Ions
DEFF Research Database (Denmark)
Fisher, Karin
2017-01-01
The field of cold molecular ions is a fast growing one, with applications in high resolution spectroscopy and metrology, the search for time variations of fundamental constants, cold chemistry and collisions, and quantum information processing, to name a few. The study of single molecular ions...... is attractive as it enables one to push the limits of spectroscopic accuracy. Non-destructive spectroscopic detection of molecular ions can be achieved by co-trapping with an easier to detect atomic ion. The ion chain has coupled motion, and transitions which change both the internal and motional states...... to the measured heating rates, almost perfectly fitting existing heating rate theory. Further, the same model successfully predicted the heating rates of the in-phase mode of a two-ion crystal, indicating that we can use it to predict the heating rates in experiments on molecule-atom chains. Adiabatic cooling...
Electron Correlation from the Adiabatic Connection for Multireference Wave Functions
Pernal, Katarzyna
2018-01-01
An adiabatic connection (AC) formula for the electron correlation energy is derived for a broad class of multireference wave functions. The AC expression recovers dynamic correlation energy and assures a balanced treatment of the correlation energy. Coupling the AC formalism with the extended random phase approximation allows one to find the correlation energy only from reference one- and two-electron reduced density matrices. If the generalized valence bond perfect pairing model is employed a simple closed-form expression for the approximate AC formula is obtained. This results in the overall M5 scaling of the computation cost making the method one of the most efficient multireference approaches accounting for dynamic electron correlation also for the strongly correlated systems.
Dynamic hysteresis of a uniaxial superparamagnet: Semi-adiabatic approximation
International Nuclear Information System (INIS)
Poperechny, I.S.; Raikher, Yu.L.; Stepanov, V.I.
2014-01-01
The semi-adiabatic theory of magnetic response of a uniaxial single-domain ferromagnetic particle is presented. The approach is developed in the context of the kinetic theory and allows for any orientation of the external field. Within this approximation, the dynamic magnetic hysteresis loops in an ac field are calculated. It is demonstrated that they very closely resemble those obtained by the full kinetic theory. The behavior of the effective coercive force is analyzed in detail, and for it a simple formula is proposed. This relation accounts not only for the temperature behavior of the coercive force, as the previous ones do, but also yields the dependence on the frequency and amplitude of the applied field
Hydrodynamics of adiabatic inverted annular flow: an experimental study
International Nuclear Information System (INIS)
De Jarlais, G.; Ishii, M.
1983-01-01
For low-quality film boiling in tubes or rod bundles, the flow pattern may consist of a liquid jet-like core surrounded by a vapor annulus, i.e., inverted annular flow. The stability, shape, and break-up mechanisms of this liquid core must be understood in order to model correctly this regime and to develop appropriate interfacial transfer correlations. This paper reports on a study in which inverted annular flow was simulated in an adiabatic system. Turbulent water jets, issuing downward from long-aspect nozzles were enclosed within cocurrent gas annuli. Jet-core diameter and velocity, and gas-annulus diameter, velocity, and species were varied, yielding liquid Reynolds numbers up to 33,000, void fractions from 0.29 to 0.95, and relative velocities from near zero to over 80 m/s. Jet-core break-up lengths and secondarily, core break-up mechanisms, were observed visually, using strobe lighting
Hydrodynamic stability of inverted annular flow in an adiabatic simulation
International Nuclear Information System (INIS)
De Jarlais, G.; Ishii, M.; Linehan, J.
1986-01-01
Inverted annular flow was simulated adiabatically with turbulent water jets, issuing downward from large aspect ratio nozzles, enclosed in gas annuli. Velocities, diameters, and gas species were varied, and core jet length, shape, breakup mode, and dispersed core droplet sizes were recorded at approximately 750 data points. Inverted annular flow destabilization led to inverted slug flow at low relative velocities, and to dispersed droplet flow, core breakup length correlations were developed by extending work on free liquid jets to include this coaxial, jet disintegration phenomenon. The results show length dependence upon D/sub J/, Re/sub J/, We/sub J/, α, and We/sub G/,rel. Correlations for core shape, breakup mechanisms, and dispersed core droplet size were also developed, by extending the results of free jet stability, roll wave entrainment, and churn turbulent droplet stability studies
Adiabatic invariants in stellar dynamics. 1: Basic concepts
Weinberg, Martin D.
1994-01-01
The adiabatic criterion, widely used in astronomical dynamics, is based on the harmonic oscillator. It asserts that the change in action under a slowly varying perturbation is exponentially small. Recent mathematical results that precisely define the conditions for invariance show that this model does not apply in general. In particular, a slowly varying perturbation may cause significant evolution stellar dynamical systems even if its time scale is longer than any internal orbital time scale. This additional 'heating' may have serious implications for the evolution of star clusters and dwarf galaxies which are subject to long-term environmental forces. The mathematical developments leading to these results are reviewed, and the conditions for applicability to and further implications for stellar systems are discussed. Companion papers present a computational method for a general time-dependent disturbance and detailed example.
Adiabatic effective action for vortices in neutral and charged superfluids
International Nuclear Information System (INIS)
Hatsuda, M.; Sato, M.; Yahikozawa, S.; Hatsuda, T.
1996-01-01
Adiabatic effective action for vortices in neutral and charged superfluids at zero temperature are calculated using the topological Landau-Ginzburg theory recently proposed by Hatsuda, Yahikozawa, Ao and Thouless, and vortex dynamics are examined. The Berry phase term arising in the effective action naturally yields the Magnus force in both neutral and charged superfluids. It is shown that in neutral superfluid there is only one degree of freedom, namely the center of vorticities, and the vortex energy is proportional to the sum of all vorticities so that it is finite only for the vanishing total vorticity of the system. On the other hand the effective mass and the vortex energy for a vortex in charged superfluids are defined individually as expected. The effects of the vortex core on these quantities are also estimated. The possible depinning scenario which is governed by the Magnus force and the inertial mass is also discussed
Adiabatic pumping solutions in global AdS
Energy Technology Data Exchange (ETDEWEB)
Carracedo, Pablo [Meteo-Galicia,Santiago de Compostela E-15782 (Spain); Mas, Javier; Musso, Daniele; Serantes, Alexandre [Departamento de Física de Partículas, Universidade de Santiago de Compostela,Santiago de Compostela E-15782 (Spain); Instituto Galego de Física de Altas Enerxías (IGFAE),Santiago de Compostela E-15782 (Spain)
2017-05-26
We construct a family of very simple stationary solutions to gravity coupled to a massless scalar field in global AdS. They involve a constantly rising source for the scalar field at the boundary and thereby we name them pumping solutions. We construct them numerically in D=4. They are regular and, generically, have negative mass. We perform a study of linear and nonlinear stability and find both stable and unstable branches. In the latter case, solutions belonging to different sub-branches can either decay to black holes or to limiting cycles. This observation motivates the search for non-stationary exactly time-periodic solutions which we actually construct. We clarify the role of pumping solutions in the context of quasistatic adiabatic quenches. In D=3 the pumping solutions can be related to other previously known solutions, like magnetic or translationally-breaking backgrounds. From this we derive an analytic expression.
Hydroxylamine nitrate self-catalytic kinetics study with adiabatic calorimetry
International Nuclear Information System (INIS)
Liu Lijun; Wei Chunyang; Guo Yuyan; Rogers, William J.; Sam Mannan, M.
2009-01-01
Hydroxylamine nitrate (HAN) is an important member of the hydroxylamine compound family with applications that include equipment decontamination in the nuclear industry and aqueous or solid propellants. Due to its instability and autocatalytic behavior, HAN has been involved in several incidents at the Hanford and Savannah River Site (SRS) [Technical Report on Hydroxylamine Nitrate, US Department of Energy, 1998]. Much research has been conducted on HAN in different areas, such as combustion mechanism, decomposition mechanism, and runaway behavior. However, the autocatalytic decomposition behavior of HAN at runaway stage has not been fully addressed due to its highly exothermic and rapid decomposition behavior. This work is focused on extracting HAN autocatalytic kinetics and analyzing HAN critical behavior from adiabatic calorimetry measurements. A lumped autocatalytic kinetic model for HAN and associated model parameters are determined. Also the storage and handling critical conditions of diluted HAN solution without metal presence are quantified
Standing shocks in adiabatic black hole accretion of rotating matter
International Nuclear Information System (INIS)
Abramowicz, M.A.; Chakrabarti, S.K.
1988-08-01
We present all the solutions for stationary, axially symmetric, transonic, adiabatic flows with polytropic, rotating fluid configurations of small transverse thickness, in an arbitrarily chosen potential. Special attention is paid to the formation of the standing shocks in the case of black hole accretion and winds. We point out the possibility of three types of shocks depending upon three extreme physical conditions at the shocks. These are: Rankine-Hugoniot shocks, isentropic compression waves, and isothermal shocks. We write down the shock conditions for these three cases and discuss briefly the physical situations under which these shocks may form. A complete discussion on the properties of these shocks will be presented elsewhere. (author). 21 refs, 4 figs
Adiabatic quantum-flux-parametron cell library adopting minimalist design
International Nuclear Information System (INIS)
Takeuchi, Naoki; Yamanashi, Yuki; Yoshikawa, Nobuyuki
2015-01-01
We herein build an adiabatic quantum-flux-parametron (AQFP) cell library adopting minimalist design and a symmetric layout. In the proposed minimalist design, every logic cell is designed by arraying four types of building block cells: buffer, NOT, constant, and branch cells. Therefore, minimalist design enables us to effectively build and customize an AQFP cell library. The symmetric layout reduces unwanted parasitic magnetic coupling and ensures a large mutual inductance in an output transformer, which enables very long wiring between logic cells. We design and fabricate several logic circuits using the minimal AQFP cell library so as to test logic cells in the library. Moreover, we experimentally investigate the maximum wiring length between logic cells. Finally, we present an experimental demonstration of an 8-bit carry look-ahead adder designed using the minimal AQFP cell library and demonstrate that the proposed cell library is sufficiently robust to realize large-scale digital circuits
Pritychenko, B.; Mughabghab, S. F.
2012-12-01
We present calculations of neutron thermal cross sections, Westcott factors, resonance integrals, Maxwellian-averaged cross sections and astrophysical reaction rates for 843 ENDF materials using data from the major evaluated nuclear libraries and European activation file. Extensive analysis of newly-evaluated neutron reaction cross sections, neutron covariances, and improvements in data processing techniques motivated us to calculate nuclear industry and neutron physics quantities, produce s-process Maxwellian-averaged cross sections and astrophysical reaction rates, systematically calculate uncertainties, and provide additional insights on currently available neutron-induced reaction data. Nuclear reaction calculations are discussed and new results are presented. Due to space limitations, the present paper contains only calculated Maxwellian-averaged cross sections and their uncertainties. The complete data sets for all results are published in the Brookhaven National Laboratory report.
Adiabatic approximation with exponential accuracy for many-body systems and quantum computation
International Nuclear Information System (INIS)
Lidar, Daniel A.; Rezakhani, Ali T.; Hamma, Alioscia
2009-01-01
We derive a version of the adiabatic theorem that is especially suited for applications in adiabatic quantum computation, where it is reasonable to assume that the adiabatic interpolation between the initial and final Hamiltonians is controllable. Assuming that the Hamiltonian is analytic in a finite strip around the real-time axis, that some number of its time derivatives vanish at the initial and final times, and that the target adiabatic eigenstate is nondegenerate and separated by a gap from the rest of the spectrum, we show that one can obtain an error between the final adiabatic eigenstate and the actual time-evolved state which is exponentially small in the evolution time, where this time itself scales as the square of the norm of the time derivative of the Hamiltonian divided by the cube of the minimal gap.
Adiabatic motion of charged dust grains in rotating magnetospheres
International Nuclear Information System (INIS)
Northrop, T.G.; Hill, J.R.
1983-01-01
Dust grains in the ring systems and rapidly rotating magnetospheres of the outer planets such as Jupiter and Saturn may be sufficiently charged that the magnetic and electric forces on them are comparable with the gravitational force. The adiabatic theory of charged particle motion has previously been applied to electrons and atomic size particles. But it is also applicable to these charged dust grains in the micrometer and smaller size range. We derive here the guiding center equation of motion, drift velocity, and parallel equation of motion for these grains in a rotating magnetosphere. The effects of periodic grain charge-discharge have not been treated previously and have been included in this analysis. Grain charge is affected by the surrounding plasma properties and by the grain plasma velocity (among other factors), both of which may vary over the gyrocircle. The resulting charge-discharge process at the gyrofrequency destroys the invariance of the magnetic moment and causes a grain to move radially. The magnetic moment may increase or decrease, depending on the gyrophase of the charge variation. If it decreases, the motion is always toward synchronous radius for an equatorial grain. But the orbit becomes circular before the grain reaches synchronous radius, a conclusion that follows from an exact constant of the motion. This circularization can be viewed as a consequence of the gradual reduction in the magnetic moment. This circularization also suggests that dust grains leaving Io could not reach the region of the Jovian ring, but several effects could change that conclusion. Excellent qualitative and quantitative agreement is obtained between adiabatic theory and detailed numerical orbit integrations
Observational tests of non-adiabatic Chaplygin gas
Energy Technology Data Exchange (ETDEWEB)
Carneiro, S.; Pigozzo, C., E-mail: saulo.carneiro@pq.cnpq.br, E-mail: cpigozzo@ufba.br [Instituto de Física, Universidade Federal da Bahia, Campus de Ondina, Salvador, BA 40210-340 (Brazil)
2014-10-01
In a previous paper [1] it was shown that any dark sector model can be mapped into a non-adiabatic fluid formed by two interacting components, one with zero pressure and the other with equation-of-state parameter ω = -1. It was also shown that the latter does not cluster and, hence, the former is identified as the observed clustering matter. This guarantees that the dark matter power spectrum does not suffer from oscillations or instabilities. It applies in particular to the generalised Chaplygin gas, which was shown to be equivalent to interacting models at both background and perturbation levels. In the present paper we test the non-adiabatic Chaplygin gas against the Hubble diagram of type Ia supernovae, the position of the first acoustic peak in the anisotropy spectrum of the cosmic microwave background and the linear power spectrum of large scale structures. We consider two different compilations of SNe Ia, namely the Constitution and SDSS samples, both calibrated with the MLCS2k2 fitter, and for the power spectrum we use the 2dFGRS catalogue. The model parameters to be adjusted are the present Hubble parameter, the present matter density and the Chaplygin gas parameter α. The joint analysis best fit gives α ≈ - 0.5, which corresponds to a constant-rate energy flux from dark energy to dark matter, with the dark energy density decaying linearly with the Hubble parameter. The ΛCDM model, equivalent to α = 0, stands outside the 3σ confidence interval.
Thermodynamic study of ibuprofen by adiabatic calorimetry and thermal analysis
International Nuclear Information System (INIS)
Xu Fen; Sun Lixian; Tan Zhicheng; Liang Jianguo; Li Ruilian
2004-01-01
Molar heat capacities of ibuprofen were precisely measured with a small sample precision automated adiabatic calorimeter over the temperature range from 80 to 400 K. The polynomial functions of C p,m (J K -1 mol -1 ) versus T were established on the heat capacity measurements by means of the least fitting square method. The functions are as follows: for solid ibuprofen, at the temperature range of 79.105 K≤T≤333.297 K, C p,m =144.27+77.046X+3.5171X 2 +10.925X 3 +11.224X 4 , where X=(T-206.201)/127.096; for liquid ibuprofen, at the temperature range of 353.406 K≤T≤378.785 K, C p,m =325.79+8.9696X-1.6073X 2 -1.5145X 3 , where X=(T-366.095)/12.690. A fusion transition at T=348.02 K was found from the C p -T curve. The molar enthalpy and entropy of the fusion transition were determined to be 26.65 kJ mol -1 and 76.58 J mol -1 K -1 , respectively. The thermodynamic functions on the base of the reference temperature of 298.15 K, (H T -H 298.15 ) and (S T -S 298.15 ), were derived. Thermal characteristic of ibuprofen was studied by thermo-gravimetric analysis (TG-DTG) and differential scanning calorimeter (DSC). The temperature of fusion, the molar enthalpy and entropy of fusion obtained by DSC were well consistent with those obtained by adiabatic calorimeter. The evaporation process of ibuprofen was investigated further by TG and DTG, and the activation energy of the evaporation process was determined to be 80.3±1.4 kJ mol -1
DEFF Research Database (Denmark)
Frimurer, Thomas M.; Günther, Peter H.; Sørensen, Morten Dahl
1999-01-01
adiabatic mapping, conformational change, essentialdynamics, free energy simulations, Kunitz type inhibitor *ga3(VI)......adiabatic mapping, conformational change, essentialdynamics, free energy simulations, Kunitz type inhibitor *ga3(VI)...