Sample records for ground state atoms

  1. Further Computations of the He Atom Ground State

    E-print Network

    Charles Schwartz

    2006-05-04

    Recently reported computations have been extended to give ten more decimals of accuracy in the ground state energy of the Schrodinger equation for the idealized Helium atom. With the F basis - Hylleraas coordinates with negative powers and a logarithm of s - carried to the fiftieth order (N = 24,099 terms) we find the eigenvalue E = -2.90372 43770 34119 59831 11592 45194 40444 66969 25309 ...

  2. Ground State and Excited State H-Atom Temperatures in a Microwave Plasma Diamond Deposition Reactor

    Microsoft Academic Search

    A. Gicquel; M. Chenevier; Y. Breton; M. Petiau; J. P. Booth; K. Hassouni

    1996-01-01

    Ground electronic state and excited state H-atom temperatures are measured in a microwave plasma diamond deposition reactor as a function of a low percentage of methane introduced in the feed gas and the averaged input microwave power density. Ground state H-atom temperatures (T_H) and temperature of the H-atom in the n=3 excited state (T_{Halpha}) are obtained from the measurements respectively

  3. Unraveling the chemical dynamics of bimolecular reactions of ground state boron atoms, B(2

    E-print Network

    Kaiser, Ralf I.

    Unraveling the chemical dynamics of bimolecular reactions of ground state boron atoms, B(2 PjArticle on the web 8th March 2004 The reaction dynamics of atomic boron, B(2 P), with acetylene, C2H2(X 1 Sg ž molecular beams technique. Only the atomic boron versus hydrogen atom exchange pathway was observed. Forward

  4. Interactions Between Ground-State Nitrogen Atoms and Molecules

    NASA Technical Reports Server (NTRS)

    Vanderslice, Joseph T.; Mason, Edward A.; Lippincott, Ellis R.

    1959-01-01

    Potential-energy curves for nitrogen atom (N-N) interactions corresponding to the X (1)Sigma(sup +, sub g), A (3)Sigma(sup +, sub u), (5)Sigma(sup +, sub g), (7)Sigma(sup +, sub u), B (3) Pi(sub g), C (3)(Pi(su u)and a (1)Pi(sub g) states of the nitrogen molecule N2 as well as curves for the atom-molecules (N-N2) and molecule-molecule (N2-N2) interactions have been calculated. All calculations have been based as nearly as possible on experimental data, including spectroscopically determined vibrational energy levels, scattering cross sections of atomic beams in gases, and measured vibrational relaxation times. In cases where experimental data were not available, approximate quantum-mechanical calculations have been made. Results obtained by these various methods are remarkably consistent with one another and are believed to have good accuracy.

  5. Ground-State Entanglement Properties of Helium Atom in a Finite Spherical Cavity

    NASA Astrophysics Data System (ADS)

    Ko?cik, Przemys?aw; Saha, Jayanta K.

    2015-05-01

    The effects of the spatial confinement on the ground-state entanglement properties of the helium atom have been studied. The finite oscillator potential is used to represent the confining potential. The transition to the free atom regime and the harmonic confinement regime are discussed in detail in dependence of the control parameters of the system.

  6. The role of correlation in the ground state energy of confined helium atom

    SciTech Connect

    Aquino, N. [Departamento de Fķsica, Universidad Autónoma Metropolitana-Iztapalapa, Apartado Postal 55-534, 09340 México Distrito Federal (Mexico)

    2014-01-14

    We analyze the ground state energy of helium atom confined by spherical impenetrable walls, and the role of the correlation energy in the total energy. The confinement of an atom in a cavity is one way in which we can model the effect of the external pressure on an atom. The calculations of energy of the system are carried out by the variational method. We find that the correlation energy remains almost constant for a range values of size of the boxes analyzed.

  7. Transport of ground-state hydrogen atoms in a plasma expansion.

    PubMed

    Mazouffre, S; Boogaarts, M G; Bakker, I S; Vankan, P; Engeln, R; Schram, D C

    2001-07-01

    The transport of ground-state atomic hydrogen in the expansion of a thermal plasma generated from an Ar-H2 mixture is studied by means of laser-based diagnostic techniques. The flow of hydrogen atoms is investigated by two-photon excitation laser-induced fluorescence (LIF), whereas Ar atoms are probed by LIF as well as by UV Rayleigh scattering. The transport of Ar atoms can be fully understood in terms of a free jet flow; H atoms on the contrary exhibit an anomalous behavior. In the course of the plasma expansion, hydrogen atoms decouple from the argon fluid by a diffusion process as a direct consequence of recombination of H atoms at the vessel walls. In this contribution it is shown, on the basis of experimental results, how plasma-surface interactions can strongly influence the flow pattern of an atomic radical fluid. PMID:11461414

  8. Ground state of the hydrogen atom via Dirac equation in a minimal-length scenario

    NASA Astrophysics Data System (ADS)

    Antonacci Oakes, T. L.; Francisco, R. O.; Fabris, J. C.; Nogueira, J. A.

    2013-07-01

    In this work we calculate the correction to the ground state energy of the hydrogen atom due to contributions arising from the presence of a minimal length. The minimal-length scenario is introduced by means of modifying the Dirac equation through a deformed Heisenberg algebra (Kempf algebra). With the introduction of the Coulomb potential in the new Dirac energy operator, we calculate the energy shift of the ground state of the hydrogen atom in first order of the parameter related to the minimal length via perturbation theory.

  9. Ground state cooling of an optomechanical resonator assisted by a ?-type atom.

    PubMed

    Zhang, Shuo; Zhang, Jian-Qi; Zhang, Jie; Wu, Chun-Wang; Wu, Wei; Chen, Ping-Xing

    2014-11-17

    We propose a ground state cooling scheme for an optomechanical resonator based on the system of one ?-type three-level atom trapped in an optomechanical cavity. This cooling scheme works in a single-photon coupling, and strong atom-cavity coupling regimes. By investigating the cooling dynamics, we find that there is an EIT-like quantum coherent effect in this system which can suppress the undesired transitions for heating. Moreover, our study shows that the final average phonon number of the optomechanical resonator can be smaller than the one based on the sideband cooling. Furthermore, the ground state cooling of the resonator can still be achieved after thermal fluctuations included. In addition, in comparison with previous cooling methods, there are fewer limitations on the decay rates of both the cavity and the atom in this scheme. As a result, this scheme is very suitable to realize the ground cooling of an optomechanical resonator in the experiment. PMID:25402052

  10. The ground state properties of spin-aligned atomic hydrogen, deuterium, and tritium

    NASA Technical Reports Server (NTRS)

    Etters, R. D.; Dugan, J. V., Jr.; Palmer, R. W.

    1975-01-01

    The internal energy, pressure, and compressibility of ground-state, spin-aligned atomic hydrogen, deuterium, and tritium are calculated assuming that all pair interactions occur via the atomic triplet (spin-aligned) potential. The conditions required to obtain atomic hydrogen and its isotopes in bulk are discussed; such a development would be of value in propulsion systems because of the light mass and energetic recombination of atomic hydrogen. Results show that atomic triplet hydrogen and deuterium remain gaseous at 0 K, and that tritium forms a liquid with a binding energy of approximately -0.75 K per atom at a molar volume of 130 cu cm per mole. The pair distribution function for these systems is calculated, and the predicted superfluid behavior of atomic triplet hydrogen and tritium is briefly discussed.

  11. Spin-exchange narrowing of the atomic ground-state resonances

    NASA Astrophysics Data System (ADS)

    Chalupczak, W.; Josephs-Franks, P.; Patton, B.; Pustelny, S.

    2014-10-01

    At the most fundamental level, the performance of atomic sensors is limited by quantum decoherence. The problem of decoherence has been addressed at low magnetic fields with atomic samples, where the limiting factor of the coherence lifetime arises from spin-exchange collisions. In this paper, we demonstrate the complex role of the collisions in the relaxation of quantum states of alkali-metal atoms. The detailed understanding of the collision role allows us to reduce the ground-state relaxation in stronger magnetic fields (tens ?T). Reduction of the relaxation rate enables improvement of the performance of atomic sensors. In particular, enhancement of the sensitivity of optical magnetometers in the detection of stronger magnetic fields may be obtained. Reduced transverse relaxation also enables increasing quantum-information storage time in atomic vapor.

  12. Simulation of the ground states of spin rings with cavity-assisted neutral atoms.

    PubMed

    Xue, Peng; Zhan, Xiang; Bian, Zhihao

    2015-01-01

    Quantum phase transitions occur when the ground state of a Hamiltonian undergoes qualitative changes with a control parameter changing. In this paper we consider a particular system--an Isng-type spin ring with competing many-body interactions. Depending on the relative strength interactions, the ground state of the system is either a product state or entangled state. We implement the system in a cavity-assisted neutral atomic simulator and study the non-locality and entanglement of the simulated ground state of an Ising-type three-spin ring with the control parameter changing. The simplicity of the setup and its robustness to noise give it a great practicality within the framework of current experimental technology. PMID:25557504

  13. Gas flow dependence of ground state atomic oxygen in plasma needle discharge at atmospheric pressure

    SciTech Connect

    Sakiyama, Yukinori; Graves, David B. [Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720 (United States); Knake, Nikolas; Schroeder, Daniel; Winter, Joerg; Schulz-von der Gathen, Volker [Institut fuer Experimentalphysik II, Ruhr-Universitaet Bochum, 44780 Bochum (Germany)

    2010-10-11

    We present clear evidence that ground state atomic oxygen shows two patterns near a surface in the helium plasma needle discharge. Two-photon absorption laser-induced fluorescence spectroscopy, combined with gas flow simulation, was employed to obtain spatially-resolved ground state atomic oxygen densities. When the feed gas flow rate is low, the radial density peaks along the axis of the needle. At high flow rate, a ring-shaped density distribution appears. The peak density is on the order of 10{sup 21} m{sup -3} in both cases. The results are consistent with a previous report of the flow-dependent bacterial killing pattern observed under similar conditions.

  14. An accurate few-parameter ground state wave function for the lithium atom

    NASA Astrophysics Data System (ADS)

    Guevara, Nicolais L.; Harris, Frank E.; Turbiner, Alexander V.

    A simple, seven-parameter trial function is proposed for a description of the ground state of the Lithium atom. It includes both spin functions. Inter-electronic distances appear in exponential form as well as in a pre-exponential factor, and the necessary energy matrix elements are evaluated by numerical integration in the space of the relative coordinates. Encouragingly accurate values of the energy and the cusp parameters as well as for some expectation values are obtained.

  15. Using uncertainty principle to find the ground-state energy of the helium and a helium-like Hookean atom

    Microsoft Academic Search

    Varun Harbola

    2011-01-01

    In this paper, we accurately estimate the ground-state energy and the atomic radius of the helium atom and a helium-like Hookean atom by employing the uncertainty principle in conjunction with the variational approach. We show that with the use of the uncertainty principle, electrons are found to be spread over a radial region, giving an electron cloud. Our calculation also

  16. The Hartree limit of Born's ensemble for the ground state of a bosonic atom or ion

    NASA Astrophysics Data System (ADS)

    Kiessling, Michael K.-H.

    2012-09-01

    The non-relativistic bosonic ground state is studied for quantum N-body systems with Coulomb interactions, modeling atoms or ions made of N "bosonic point electrons" bound to an atomic point nucleus of Z absolute "electron" charges, treated in Born-Oppenheimer approximation (the nuclear mass M = ?). By adapting an argument of Hogreve, it is shown that the (negative) {B}osonic ground state energy E_{{infty }}^{{B}}(Z,N) yields the monotone non-decreasing function Nmapsto E_{{infty }}^{{B}}(? N,N)/N^3 for any ? > 0. The main part of the paper furnishes a proof that whenever ? ? ?* ? 1/1.21, then the limit \\varepsilon (? ):=lim _{NrArr infty }E_{{infty }}^{{B}}(? N,N)/N^3 is governed by Hartree theory, and the rescaled bosonic ground state wave function factors into an infinite product of identical one-body wave functions determined by the Hartree equation. The proof resembles the construction of the thermodynamic mean-field limit of the classical ensembles with thermodynamically unstable interactions, except that here the ensemble is Born's, with |?|2 as ensemble probability density function on {R}^{3N}, with the Fisher information functional in the variational principle for Born's ensemble playing the role of the negative Gibbs entropy functional in the free-energy variational principle for the classical petit-canonical configurational ensemble.

  17. Ground-state atomic polarization relaxation-time measurement of Rb filled hypocycloidal core-shaped Kagome HC-PCF

    E-print Network

    Bradley, T D; McFerran, J J; Jouin, J; Debord, B; Alharbi, M; Thomas, P; Gerome, F; Benabid, F

    2015-01-01

    We report on the measurement of ground state atomic polarization relaxation tile of Rb vapor confined in five different hypocycloidal core shape Kagome hollow core photonic crystal fibers made with uncoated silica glass. We are able to distinguish between wall-collision and transit-time effects in optical waveguide and deduce the contribution of the atom's dwell time at the core wall surface. In contrast with convetional macroscopic atomic cell configuration, and in agreement with Monte Carlo simulations, the measured relaxation times were found to be at least one order of magnitude longer than the limit set by the atom-wall collisional relaxation from thermal atoms. This extended relaxation time is explained by the combination of a stronger contribution of the slow atoms in the atomic polarization build-up, and of the relatively significant contribution of dwell time to the relaxation process of the ground state polarization.

  18. Rubidium D1 and D2 atomic lines’ pressure broadened by ground-state helium atoms

    NASA Astrophysics Data System (ADS)

    Bouhadjar, F.; Alioua, K.; Bouazza, M. T.

    2014-09-01

    Full quantum calculations are performed to determine the spectral broadening of the rubidium D1 and D2 lines induced by collisions with helium perturbers. The potential curves of the low-lying RbHe molecular states, as well as the corresponding transition dipole moments, are generated theoretically with ab initio methods based on SA-CASSCF-MRCI calculations, including the spin-orbit effects. The absorption and emission coefficients at wavelengths lying between 650 and 950\\;nm and temperatures ranging from 100 to 3000 K are determined. The absorption profile reveals it is dominated by the free-free transitions, whereas the emission spectral shape arises from the free-free and bound-free transitions. The resulting red- and blue-wing profiles are compared with previous experimental and theoretical works.

  19. Electronic excitation of ground state atoms by collision with heavy gas particles

    NASA Technical Reports Server (NTRS)

    Hansen, C. Frederick

    1993-01-01

    Most of the important chemical reactions which occur in the very high temperature air produced around space vehicles as they enter the atmosphere were investigated both experimentally and theoretically, to some extent at least. One remaining reaction about which little is known, and which could be quite important at the extremely high temperatures that will be produced by the class of space vehicles now contemplated - such as the AOTV - is the excitation of bound electron states due to collisions between heavy gas particles. Rates of electronic excitation due to free electron collisions are known to be very rapid, but because these collisions quickly equilibrate the free and bound electron energy, the approach to full equilibrium with the heavy particle kinetic energy will depend primarily on the much slower process of bound electron excitation in heavy particle collisions and the subsequent rapid transfer to free electron energy. This may be the dominant mechanism leading to full equilibrium in the gas once the dissociation process has depleted the molecular states so the transfer between molecular vibrational energy and free electron energy is no longer available as a channel for equilibration of free electron and heavy particle kinetic energies. Two mechanisms seem probable in electronic excitation by heavy particle impact. One of these is the collision excitation and deexcitation of higher electronic states which are Rydberg like. A report, entitled 'Semi-Classical Theory of Electronic Excitation Rates', was submitted previously. This presented analytic expressions for the transition probabilities, assuming that the interaction potential is an exponential repulsion with a perturbation ripple due to the dipole-induced dipole effect in the case of neutral-neutral collisions, and to the ion-dipole interaction in the case of ion-neutral collisions. However the above may be, there is little doubt that excitation of ground state species by collision occurs at the point where the initial and final potentials cross, or at least come very close. Therefore, this mechanism would be applicable to the case where a gas is initially at very low temperature suddenly subjected to high energy heavy particle bombardment. This situation would model the measurement of excitation cross section by molecular beam techniques, for example. The purpose is to report values of cross sections and rate coefficients for collision excitation of ground state atoms estimated with the Landau-Zener transition theory and to compare results with measurement of excitation cross sections for a beam of Hydrogen atoms impacting Argon atom targets. Some very dubious approximations are used, and the comparison with measurement is found less than ideal, but results are at least consistent within order of magnitude. The same model is then applied to the case of N-N atom collisions, even though the approximations then become even more doubtful. Still the rate coefficients obtained are at least plausible in both magnitude and functional form, and as far as I am aware these are the only estimates available for such rate coefficients.

  20. ATOMIC AND MOLECULAR PHYSICS: Elastic Collisions Between two Ground-State P and D Atoms at Low and Ultralow Temperatures

    NASA Astrophysics Data System (ADS)

    Shi, De-Heng; Zhang, Jin-Ping; Sun, Jin-Feng; Ma, Heng; Liu, Yu-Fang; Zhu, Zun-Lue

    2010-02-01

    The PD(X3?-) interaction potential is constructed using the CCSD(T) theory and the basis set, aug-cc-pV5Z. Using this potential, the spectroscopic parameters are accurately determined. The present Do, De, Re, ?e, ?e?e, ?e, and Be are of 3.056 99 eV, 3.161 75 eV, 0.142 39 nm, 1701.558 cm-1, 23.6583 cm-1, 0.085 99 cm-1, and 4.3963 cm-1, respectively, which almost perfectly conform with the measurements. A total of 26 vibrational states is predicted when J = 0 by solving the radial Schrödinger equation of nuclear motion. The complete vibrational levels, classical turning points, initial rotation and centrifugal distortion constants when J = 0 are reported for the first time, which favorably agree with the experiments. The total and various partial-wave cross sections are calculated for the elastic impact between two ground-state P and D atoms at 1.0 × 10-12 - 1.0 × 10-4 a.u. when they approach each other along the PD(X3?-) potential. No shape resonances exist in the total elastic cross sections, though the peaks can be found for each partial wave until l = 6. The shape of the total elastic cross sections is dominated by the s partial wave at very low temperatures. Due to the weakness of the shape resonances of each partial wave, they are all passed into oblivion by the strong total elastic cross sections.

  1. Trends in Ground-State Entropies for Transition Metal Based Hydrogen Atom Transfer Reactions

    PubMed Central

    Mader, Elizabeth A.; Manner, Virginia W.; Markle, Todd F.; Wu, Adam; Franz, James A.; Mayer, James M.

    2009-01-01

    Reported herein are thermochemical studies of hydrogen atom transfer (HAT) reactions involving transition metal H-atom donors MIILH and oxyl radicals. [FeII(H2bip)3]2+, [FeII(H2bim)3]2+, [CoII(H2bim)3]2+ and RuII(acac)2(py-imH) [H2bip = 2,2’-bi-1,4,5,6-tetrahydropyrimidine, H2bim = 2,2’-bi-imidazoline, acac = 2,4-pentandionato, py-imH = 2-(2’-pyridyl)-imidazole)] each react with TEMPO (2,2,6,6-tetramethyl-1-piperidinoxyl) or tBu3PhO• (2,4,6-tri-tert-butylphenoxyl) to give the deprotonated, oxidized metal complex MIIIL, and TEMPOH or tBu3PhOH. Solution equilibrium measurements for the reaction of [CoII(H2bim)3]2+ with TEMPO show a large, negative ground-state entropy for hydrogen atom transfer, ?41 ± 2 cal mol?1 K?1. This is even more negative than the ?SoHAT = ?30 ± 2 cal mol?1 K?1 for the two iron complexes and the ?SoHAT for RuII(acac)2(py-imH) + TEMPO, 4.9 ± 1.1 cal mol?1 K?1, as reported earlier. Calorimetric measurements quantitatively confirm the enthalpy of reaction for [FeII(H2bip)3]2+ + TEMPO, thus also confirming ?SoHAT. Calorimetry on TEMPOH + tBu3PhO• gives ?HoHAT = ?11.2 ± 0.5 kcal mol?1 which matches the enthalpy predicted from the difference in literature solution BDEs. A brief evaluation of the literature thermochemistry of TEMPOH and tBu3PhOH supports the common assumption that ?SoHAT ? 0 for HAT reactions of organic and small gas-phase molecules. However, this assumption does not hold for transition metal based HAT reactions. The trend in magnitude of |?SoHAT| for reactions with TEMPO, RuII(acac)2(py-imH) << [FeII(H2bip)3]2+ = [FeII(H2bim)3]2+ < [CoII(H2bim)3]2+, is surprisingly well predicted by the trends for electron transfer half-reaction entropies, ?SoET, in aprotic solvents. This is because both ?SoET and ?SoHAT have substantial contributions from vibrational entropy, which varies significantly with the metal center involved. The close connection between ?SoHAT and ?SoET provides an important link between these two fields and provides a starting point from which to predict which HAT systems will have important ground-state entropy effects. PMID:19275235

  2. The space-time kinetics of the population of the copper atom ground state in a copper-vapor laser

    NASA Astrophysics Data System (ADS)

    Isaev, A. A.; Mikhkel'Soo, V. T.; Petrash, G. G.; Peet, V. E.; Ponomarev, I. V.

    1989-06-01

    A technique for measuring the population of the copper atom ground state in the medium of a self-heated copper-vapor laser is developed. The pulsed dye laser was used to sound the active medium (the temporal resolution was 5 ns and the spatial resolution was 2 mm). The kinetics of the ground state was studied in the excitation pulse and in the interpulse time interval over the whole temperature range of the stimulated emission (1360-1650 C) from a commercially produced laser.

  3. The Chemi-Ionization Processes in Slow Collisions of Rydberg Atoms with Ground State Atoms: Mechanism and Applications

    E-print Network

    Mihajlov, A A; Ignjatovic, Lj M; Klyucharev, A N; 10.1007/s10876-011-0438-7

    2012-01-01

    In this article the history and the current state of research of the chemiionization processes in atom-Rydberg atom collisions is presented. The principal assumptions of the model of such processes based on the dipole resonance mechanism, as well as the problems of stochastic ionization in atom-Rydberg atom collisions, are exposed. The properties of the collision kinetics in atom beams of various types used in contemporary experimentations are briefly described. Results of the calculation of the chemi-ionization rate coefficients are given and discussed for the range of the principal quantum number values 5 chemi-ionization processes in astrophysical and laboratory low-temperature plasmas, and the contemporary methods of their investigation are described. Also the directions of further research of chemi-ionization processes are discussed in this article.

  4. Thermalization of fast cesium 5D{sub 3sol2} atoms in collisions with ground-state cesium atoms

    Microsoft Academic Search

    A. Marks; A. P. Hickman; J. Huennekens; A. D. Streater

    2005-01-01

    We have investigated collisions involving fast, excited Cs atoms produced by photodissociating Csā molecules with a pulsed dye laser. The velocities of the atoms in the 5D state formed by the process Csā(X Ā¹Ļ{sub g}{sup +})+(ā\\/2Ļ)Ļ{sub pump}āCsā{sup *}āCs(5D)+Cs(6S) are much greater than typical thermal velocities associated with the cell temperature. Using a narrow-band cw probe laser to observe the increased

  5. Thermalization of fast cesium 5 D3\\/2 atoms in collisions with ground-state cesium atoms

    Microsoft Academic Search

    A. Marks; A. P. Hickman; A. D. Streater; J. Huennekens

    2005-01-01

    We have investigated collisions involving fast, excited Cs atoms produced by photodissociating Cs2 molecules with a pulsed dye laser. The velocities of the atoms in the 5D state formed by the process Cs2(XSigmag+1)+ℏomegapump-->Cs2*-->Cs(5D)+Cs(6S) are much greater than typical thermal velocities associated with the cell temperature. Using a narrow-band cw probe laser to observe the increased Doppler broadening of the 5D3\\/2-->5F5\\/2

  6. Large Ground-State Entropy Changes for Hydrogen Atom Transfer Reactions of Iron Complexes

    PubMed Central

    Mader, Elizabeth A.; Davidson, Ernest R.

    2008-01-01

    Reported herein are the hydrogen atom transfer (HAT) reactions of two closely related dicationic iron tris ?-diimine complexes. FeII(H2bip) (iron(II) tris[2,2?-bi-1,4,5,6-tetra-hydropyrimidine]diperchlorate) and FeII(H2bim) (iron(II) tris[2,2?-bi-2-imidazoline]diperchlorate) both transfer H• to TEMPO (2,2,6,6-tetramethyl-1-piperidinoxyl) to yield the hydroxylamine, TEMPO-H, and the respective deprotonated iron(III) species, FeIII(Hbip) or FeIII(Hbim). The ground-state thermodynamic parameters in MeCN were determined for both systems using both static and kinetic measurements. For FeII(H2bip) + TEMPO: ?G° = ?0.3 ± 0.2 kcal mol?1, ?H° =?9.4 ± 0.6 kcal mol?1, ?S° = ?30 ± 2 cal mol?1 K?1. For FeII(H2bim) + TEMPO: ?G° = 5.0 ± 0.2 kcal mol?1, ?H° = ?4.1 ± 0.9 kcal mol?1, ?S° = ?30 ± 3 cal mol?1 K?1. The large entropy changes for these reactions, |T?S°| = 9 kcal mol?1 at 298 K, are exceptions to the traditional assumption that ?S° ? 0 for simple HAT reactions. Various studies indicate that hydrogen-bonding, solvent effects, ion-pairing, and iron spin-equilibria do not make major contributions to the observed ?S°HAT. Instead, this effect arises primarily from changes in vibrational entropy upon oxidation of the iron center. Measurement of the electron transfer half-reaction entropy, |?S° Fe(H2bim)/ET| = 29 ± 3 cal mol?1 K?1, is consistent with a vibrational origin. This conclusion is supported by UHF/6-31G* calculations on the simplified reaction [FeII(H2N=CHCH=NH2)2(H2bim)]2+•••ONH2 ? [FeII(H2N=CHCH=NH2)2(Hbim)]2+•••HONH2. The discovery that ?S°HAT can deviate significantly from zero has important implications on the study of HAT and proton-coupled electron transfer (PCET) reactions. For instance, these results indicate that free energies, rather than enthalpies, should be used to estimate the driving force for HAT when transition metal centers are involved. PMID:17402735

  7. Experimental 4s and 3d Energies in Atomic Ground States

    Microsoft Academic Search

    James L. Bills

    1998-01-01

    Experimental ionization energies I4s and I3d are listed for K[Ar]4s1, K[Ar]3d1, and Ca to Cu in the lowest states of M[Ar]4s23dn and M[Ar]4s13dn+1. In a plot comparing -I4s(4s23dn) with -I3d(4s13dn+1), the lower one selects the ground state. Features of that plot are explained with a plot of the corresponding Hartree-Fock (HF) minus valence-exchange energies. A new definition is given for

  8. The Radiofrequency Spectra of Atoms Hyperfine Structure and Zeeman Effect in the Ground State of Li6, Li7, K39 and K41

    Microsoft Academic Search

    P. Kusch; S. Millman; I. I. Rabi

    1940-01-01

    The molecular beam magnetic resonance method previously used for the study of molecules has been extended to the study of atoms. Transitions between the members of hyperfine structure multiplets of the ground state of atoms have been observed directly. In this way the hyperfine structure intervals of the normal states of Li6, Li7, K39 and K41 have been measured. Since

  9. Ground state of the polar alkali-metal-atom-strontium molecules: Potential energy curve and permanent dipole moment

    SciTech Connect

    Guerout, R. [Laboratoire Kastler-Brossel, CNRS, ENS, Univ Pierre et Marie Curie case 74, Campus Jussieu, F-75252 Paris Cedex 05 (France); Aymar, M.; Dulieu, O. [Laboratoire Aime Cotton, CNRS, UPR3321, Bat. 505, Univ Paris-Sud, F-91405 Orsay Cedex (France)

    2010-10-15

    In this study, we investigate the structure of the polar alkali-metal-atom-strontium diatomic molecules as possible candidates for the realization of samples of ultracold polar molecular species not yet investigated experimentally. Using a quantum chemistry approach based on effective core potentials and core polarization potentials, we model these systems as effective three-valence-electron systems, allowing for calculation of electronic properties with full configuration interaction. The potential curve and the permanent dipole moment of the {sup 2}{Sigma}{sup +} ground state are determined as functions of the internuclear distance for LiSr, NaSr, KSr, RbSr, and CsSr molecules. These molecules are found to exhibit a significant permanent dipole moment, though smaller than those of the alkali-metal-atom-Rb molecules.

  10. Quantum Monte Carlo studies of the ground states of heavy atoms in neutron-star magnetic fields

    SciTech Connect

    Buecheler, Steffen; Engel, Dirk; Main, Joerg; Wunner, Guenter [Institut fuer Theoretische Physik 1, Universitaet Stuttgart, D-70550 Stuttgart (Germany)

    2007-09-15

    The 'released-phase' diffusion quantum Monte Carlo method is used to calculate the ground-state energies of atoms with nuclear charges from Z=2,3,4,...,26 for magnetic field strengths relevant for neutron stars. The feature of our study is the use of adiabatic approximation wave functions as guiding wave functions to initialize the quantum Monte Carlo procedure. Our calculations are motivated by the discovery of broad features in the thermal spectra of isolated neutron stars, which may be due to heavy atoms. Our results confirm previous results for nuclear charge numbers up to 10, and are the most accurate ones available in the literature to date for Z>10.

  11. PHYSICAL PROCESSES IN LASERS: Spatial-temporal kinetics of the ground state population of the copper atom in a copper vapor laser

    NASA Astrophysics Data System (ADS)

    Isaev, A. A.; Mikhkel'soo, V. T.; Petrash, G. G.; Peét, V. É.; Ponomarev, I. V.; Treshchalov, A. B.; Yurchenko, N. I.

    1989-06-01

    An analysis was made of a method of measuring the ground-state population of copper atoms in the medium of a self-heated copper vapor laser. The active medium was probed using radiation from a pulsed dye laser (temporal resolution 5 ns, spatial resolution 2 mm). An investigation was made of the ground-state kinetics during an excitation pulse and in an interpulse interval over the whole lasing temperature range of 1350-1650 °C in a commercial UL-101 laser. A deficit of copper atoms additional to the thermal one was revealed and studied using the radial distributions of the ground state population. The physical processes governing the radial distributions of copper atoms in the ground state are discussed.

  12. Forbidden transition properties in the ground-state configurations of singly ionized noble gas atoms for stellar and interstellar media

    NASA Astrophysics Data System (ADS)

    Nandy, D. K.; Sahoo, B. K.

    2015-06-01

    High-accuracy calculations of the forbidden transition amplitudes for the np 2P1/2 ? np 2P3/2 transitions with the ground-state principal quantum number n in singly charged inert gas atoms, which are of astrophysical interest, have been carried out using sophisticated relativistic many-body methods. Using these amplitudes, the line strengths, oscillator strengths and transition probabilities of the above transitions and lifetimes of the np 2P1/2 states are estimated precisely. Most of these transition wavelengths lie in the infrared region, while the corresponding Rn II line is the optical one, and they can be observed in the stellar and interstellar media, where the abundances of these ions have already been identified. The above forbidden transitions can also be very useful for astrophysical plasma diagnostics and can guide experiments to measure the lifetimes of the above np 2P1/2 states.

  13. Calculation of the ground-state energy and average distance between particles for the nonsymmetric muonic {sup 3}He atom

    SciTech Connect

    Eskandari, M.R. [Physics Department, Shiraz University, Shiraz 71454 (Iran, Islamic Republic of); Research Institute for Fundamental Sciences of Tabriz (Iran, Islamic Republic of); Rezaie, B. [Physics Department, Shiraz University, Shiraz 71454 (Iran, Islamic Republic of)

    2005-07-15

    A calculation of the ground-state energy and average distance between particles in the nonsymmetric muonic {sup 3}He atom is given. We have used a wave function with one free parameter, which satisfies boundary conditions such as the behavior of the wave function when two particles are close to each other or far away. In the proposed wave function, the electron-muon correlation function is also considered. It has a correct behavior for r{sub 12} tending to zero and infinity. The calculated values for the energy and expectation values of r{sup 2n} are compared with the multibox variational approach and the correlation function hyperspherical harmonic method. In addition, to show the importance and accuracy of approach used, the method is applied to evaluate the ground-state energy and average distance between the particles of nonsymmetric muonic {sup 4}He atom. Our obtained results are very close to the values calculated by the mentioned methods and giving strong indications that the proposed wave functions, in addition to being very simple, provide relatively accurate values for the energy and expectation values of r{sup 2n}, emphasizing the importance of the local properties of the wave function.

  14. Experimental 4s and 3d Energies in Atomic Ground States

    NASA Astrophysics Data System (ADS)

    Bills, James L.

    1998-05-01

    Experimental ionization energies I4s and I3d are listed for K[Ar]4s1, K[Ar]3d1, and Ca to Cu in the lowest states of M[Ar]4s23dn and M[Ar]4s13dn+1. In a plot comparing -I4s(4s23dn) with -I3d(4s13dn+1), the lower one selects the ground state. Features of that plot are explained with a plot of the corresponding Hartree-Fock (HF) minus valence-exchange energies. A new definition is given for the effective charge Zf. HF orbital energies. A new definition is given for the effective charge Zf. HF orbital energies e4s and e3d are used in concert with I4s and I3d to answer four questions: Why does the 4s sublevel fill before 3d? Why is ionization easier for 4s than 3d? When 4s23dn has e3d < e4s, why doesn't 4s23dn -> 4s13dn+1? Why are Cr and Cu each 4s13dn+1 instead of 4s23dn?

  15. Potential Energy Curves and Transport Properties for the Interaction of He with Other Ground-state Atoms

    NASA Technical Reports Server (NTRS)

    Partridge, Harry; Stallcop, James R.; Levin, Eugene; Arnold, Jim (Technical Monitor)

    2001-01-01

    The interactions of a He atom with a heavier atom are examined for 26 different elements, which are consecutive members selected from three rows (Li - Ne, Na - Ar, and K,Ca, Ga - Kr) and column 12 (Zn,Cd) of the periodic table. Interaction energies are determined wing high-quality ab initio calculations for the states of the molecule that would be formed from each pair of atoms in their ground states. Potential energies are tabulated for a broad range of Interatomic separation distances. The results show, for example, that the energy of an alkali interaction at small separations is nearly the same as that of a rare-gas interaction with the same electron configuration for the dosed shells. Furthermore, the repulsive-range parameter for this region is very short compared to its length for the repulsion dominated by the alkali-valence electron at large separations (beyond about 3-4 a(sub 0)). The potential energies in the region of the van der Waals minimum agree well with the most accurate results available. The ab initio energies are applied to calculate scattering cross sections and obtain the collision integrals that are needed to determine transport properties to second order. The theoretical values of Li-He total scattering cross sections and the rare-gas atom-He transport properties agree well (to within about 1%) with the corresponding measured data. Effective potential energies are constructed from the ab initio energies; the results have been shown to reproduce known transport data and can be readily applied to predict unknown transport properties for like-atom interactions.

  16. The state dependence of the interaction of metastable rare gas atoms Rg*(ms3 P 2,3 P 0) (Rg=Ne, Ar, Kr, Xe) with ground state sodium atoms

    Microsoft Academic Search

    S. Schohl; M. W. Müller; H. A. J. Meijer; M.-W. Ruf; H. Hotop; H. Morgner

    1990-01-01

    Using crossed beams of metastable rare gas atoms Rg*(ms3 P 2,3 P 0) (Rg=Ne, Ar, Kr, Xe) and ground state sodium atoms Na(3 s 2 S 1\\/2), we have measured the energy spectra of electrons released in the respective Penning ionization processes at thermal collision energies. For Rg*(3 P 2)+Na(3 s), the spectra are quite similar for the different rare

  17. Nonadiabatic couplings in low-energy collisions of hydrogen ground-state atoms

    SciTech Connect

    Wolniewicz, L. [Institute of Physics, Nicolaus Copernicus University, 87-100 Torun (Poland)

    2003-10-01

    The effect of nonadiabatic couplings on low-energy s-wave scattering of two hydrogen atoms is investigated. Coupling matrix elements are computed in a wide range of internuclear distances. The resulting scattering equations are numerically unstable and therefore are integrated only approximately. Computations are performed for H, D, and T atoms. The phase shifts in the zero velocity limit are inversely proportional to the nuclear reduced mass {delta}{sub 0}{approx_equal}0.392/{mu}. This leads to infinite scattering lengths.

  18. Trends in Ground-State Entropies for Transition Metal Based Hydrogen Atom Transfer Reactions

    Microsoft Academic Search

    Elizabeth A. Mader; Virginia W. Manner; Todd F. Markle; Adam Wu; James A. Franz; James M. Mayer

    2009-01-01

    Reported herein are thermochemical studies of hydrogen atom transfer (HAT) reactions involving transition metal H-atom donors MIILH and oxyl radicals. [FeII(H2bip)3]2+, [FeII(H2bim)3]2+, [CoII(H2bim)3]2+ and RuII(acac)2(py-imH) [H2bip = 2,2-bi-1,4,5,6-tetrahydro¬pyrimidine, H2bim = 2,2-bi-imidazoline, acac = 2,4-pentandionato, py-imH = 2-(2-pyridyl)¬imidazole)] each react with TEMPO (2,2,6,6-tetramethyl-1-piperidinoxyl) or tBu3PhO (2,4,6-tri-tert-butylphenoxyl) to give the deprotonated, oxidized metal complex MIIIL, and TEMPOH or tBu3PhOH. Solution equilibrium measurements

  19. Density-matrix theory for the ground state of spin-compensated harmonically confined two-electron model atoms with general interparticle repulsion

    E-print Network

    , while in 1 N-fermion systems were studied, within such an independent electron framework. There is nowDensity-matrix theory for the ground state of spin-compensated harmonically confined two-electron For model two-electron atoms with harmonic confinement, the correlated first-order density matrix can

  20. The state dependence of the interaction of metastable rare gas atoms Rg*(ms 3 P 2 , 3 P 0 ) (Rg=Ne, Ar, Kr, Xe) with ground state sodium atoms

    Microsoft Academic Search

    S. Schohl; M. W. Müller; H. A. J. Meijer; M-W Ruf; H. Hotop; H. Morgner

    1990-01-01

    Using crossed beams of metastable rare gas atoms Rg*(ms3P2,3P0) (Rg=Ne, Ar, Kr, Xe) and ground state sodium atoms Na(3s2S1\\/2), we have measured the energy spectra of electrons released in the respective Penning ionization processes at thermal collision energies. For Rg*(3P2)+Na(3s), the spectra are quite similar for the different rare gases, both in width and shape; they reflect attractive interactions in

  1. Ground State Spin Logic

    E-print Network

    J. D. Whitfield; M. Faccin; J. D. Biamonte

    2012-05-08

    Designing and optimizing cost functions and energy landscapes is a problem encountered in many fields of science and engineering. These landscapes and cost functions can be embedded and annealed in experimentally controllable spin Hamiltonians. Using an approach based on group theory and symmetries, we examine the embedding of Boolean logic gates into the ground state subspace of such spin systems. We describe parameterized families of diagonal Hamiltonians and symmetry operations which preserve the ground state subspace encoding the truth tables of Boolean formulas. The ground state embeddings of adder circuits are used to illustrate how gates are combined and simplified using symmetry. Our work is relevant for experimental demonstrations of ground state embeddings found in both classical optimization as well as adiabatic quantum optimization.

  2. Investigation of plasma excitation. volume i. electron impact studies of selected ground state and excited state rare gas atoms. Final report 7 Jun 77-20 Sep 80

    SciTech Connect

    Lake, M.L.

    1981-08-01

    Experiments were undertaken to determine electron impact cross sections of atoms in metastable states. One or two electron guns were used to first produce atoms in metastable states, then further excite these atoms to other levels. Limits on certain cross sections of helium atoms were obtained, but the detection limits of the apparatus prevented exhaustive study. Excitation functions and cross sections of xenon were obtained in the wavelength range from 3000 A to 9000 A.

  3. Stabilization and Manipulation of Electronically Phase-Separated Ground States in Defective Indium Atom Wires on Silicon

    NASA Astrophysics Data System (ADS)

    Zhang, Hui; Ming, Fangfei; Kim, Hyun-Jung; Zhu, Hongbin; Zhang, Qiang; Weitering, Hanno H.; Xiao, Xudong; Zeng, Changgan; Cho, Jun-Hyung; Zhang, Zhenyu

    2014-11-01

    Exploration and manipulation of electronic states in low-dimensional systems are of great importance in the fundamental and practical aspects of nanomaterial and nanotechnology. Here, we demonstrate that the incorporation of vacancy defects into monatomic indium wires on n -type Si(111) can stabilize electronically phase-separated ground states where the insulating 8 ×2 and metallic 4 ×1 phases coexist. Furthermore, the areal ratio of the two phases in the phase-separated states can be tuned reversibly by electric field or charge doping, and such tunabilities can be quantitatively captured by first principles-based modeling and simulations. The present results extend the realm of electronic phase separation from strongly correlated d -electron materials typically in bulk form to weakly interacting s p -electron systems in reduced dimensionality.

  4. Crystalline beam ground state

    SciTech Connect

    Wei, Jie [Brookhaven National Lab., Upton, NY (United States); Li, Xiao-Ping [Rutgers Univ., Piscataway, NJ (United States). Dept. of Physics; Sessler, A.M. [Lawrence Berkeley Lab., CA (United States)

    1993-06-11

    In order to employ molecular dynamics (MD) methods, commonly used in condensed matter physics, we have derived the equations of motion for a beam of charged particles in the rotating rest frame of the reference particle. We include in the formalism that the particles are confined by the guiding and focusing magnetic fields, and that they are confined in a conducting vacuum pipe while interacting with each other via a Coulomb force. Numerical simulations using MD methods has been performed to obtain the equilibrium crystalline beam structure. The effect of the shearing force, centrifugal force, and azimuthal variation of the focusing strength are investigated. It is found that a constant gradient storage ring can not give a crystalline beam, but that an alternating-gradient (AG) structure can. In such a machine the ground state is, except for one-dimensional (1-D) crystals, time dependent. The ground state is a zero entropy state, despite the time-dependent, periodic variation of the focusing force. The nature of the ground state, similar to that found by Schiffer et al. depends upon the density and the relative focusing strengths in the transverse directions. At low density, the crystal is 1-D. As the density increases, it transforms into various kinds of 2-D and 3-D crystals. If the energy of the beam is higher than the transition energy of the machine, the crystalline structure can not be formed for lack of radial focusing.

  5. Singlet and triplet potentials of the ground-state atom pair Rb + Cs studied by Fourier-transform spectroscopy

    SciTech Connect

    Docenko, O.; Tamanis, M.; Ferber, R.; Knoeckel, H.; Tiemann, E. [Laser Center, Department of Physics, University of Latvia, 19 Rainis boulevard, Riga LV-1586 (Latvia); Institute of Quantum Optics, Leibniz University Hannover, Welfengarten 1, D-30167 Hannover (Germany)

    2011-05-15

    A comprehensive study of the X {sup 1}{Sigma}{sup +} and a {sup 3}{Sigma}{sup +} electronic states of the Rb and Cs atom pair in RbCs is presented. Abundant spectroscopic data for the {sup 85}Rb{sup 133}Cs and {sup 87}Rb{sup 133}Cs isotopologues were obtained from Fourier-transform spectra of laser-induced fluorescence (LIF) from the B {sup 1}{Pi} and (4){sup 1}{Sigma}{sup +} states to the a {sup 3}{Sigma}{sup +} (4549 transitions) and X {sup 1}{Sigma}{sup +} (15 709 transitions) states. The X {sup 1}{Sigma}{sup +} state data were complemented by about 15 500 transitions obtained by Fellows et al.[J. Mol. Spectrosc. 197, 19 (1999)]. LIF progressions to the a {sup 3}{Sigma}{sup +} state range from v{sub a}=0 to 37, reaching an outer turning point at 15.97 A. For the X {sup 1}{Sigma}{sup +} state, by analyzing LIF from the shelflike (4){sup 1}{Sigma}{sup +}, the data are extended from v{sub x}=119 as observed in the above-cited paper to v{sub x}=129, extending the outer turning point from 10.7 to 17.55 A. From these data, potential energy curves were constructed simultaneously for both hyperfine coupled states X {sup 1}{Sigma}{sup +} and a {sup 3}{Sigma}{sup +} in a coupled-channels fitting routine. This allowed us to accurately model the potential close to the Rb(5s) + Cs(6s) atom-pair asymptote, which is required to simulate cold collision processes and to analyze the Feshbach resonances observed for {sup 87}Rb{sup 133}Cs by Pilch et al.[Phys. Rev. A 79, 042718 (2009)]. Dissociation energies were determined for the X {sup 1}{Sigma}{sup +} state as D{sub e}=3836.373(40) cm{sup -1} and for the a {sup 3}{Sigma}{sup +} state as D{sub e}=259.341(30) cm{sup -1}.

  6. PHYSICAL REVIEW A VOLUME 46, NUMBER 1 1 JULY 1992 Optically excited Zeeman coherences in atomic ground states: Nuclear-spin effects

    E-print Network

    Suter, Dieter

    sublevels of the electronic ground state can have a large effect on the overall behavior of the system=+ in Na, I =$ in Cs). The 46- J =+ electronic ground state consists then of two degen- erate substates ground states: Nuclear-spin effects Dieter Suter Instituteof

  7. Quantum Ground States as Equilibrium Particle-Vacuum Interaction States

    E-print Network

    Harold E. Puthoff

    2012-03-08

    A remarkable feature of atomic ground states is that they are observed to be radiationless in nature, despite (from a classical viewpoint) typically involving charged particles in accelerated motions. The simple hydrogen atom is a case in point. This universal groundstate characteristic is shown to derive from particle-vacuum interactions in which a dynamic equilibrium is established between radiation emission due to particle acceleration, and compensatory absorption from the zero-point fluctuations of the vacuum electromagnetic field. The result is a net radiationless ground state. This principle constitutes an overarching constraint that delineates an important feature of quantum ground states.

  8. Diffusion and reactivity of ground-state nitrogen atoms N(4S) between 3 and 15 K: application to the hydrogen abstraction reaction from methane under non-energetic conditions

    NASA Astrophysics Data System (ADS)

    Nourry, Sendres; Krim, Lahouari

    2015-07-01

    We have characterized the CH4 + N(4S) reaction in solid phase, at very low temperature, under non-energetic conditions and where the CH4 and N reactants are in their ground states. A microwave-driven atomic source has been used to generate ground-state nitrogen atoms N(4S), and experiments have been carried out at temperatures as low as 3 K to reduce the mobility of the trapped species in solid phase and hence to freeze the first step of the CH4 + N reaction pathway. Leaving the formed solid sample in the dark for a while allows all trapped reactants to relax to the ground state, specifically radicals and excited species streaming from the plasma discharge. Such a method could be the only possibility of proving that the CH4 + N reaction occurs between CH4 and N reactants in their ground states without any additional energy to initiate the chemical process. The appearance of the CH3 reaction product, just by inducing the mobility of N atoms between 3 and 11 K, translates that a hydrogen abstraction reaction from methane, under non-energetic conditions, will start occurring at very low temperature. The formation of methyl radical, under these experimental conditions, is due to recombination processes N(4S)-N(4S) of ground-state nitrogen atoms without any contribution of cosmic ray particles or high-energy photons.

  9. Experimental evidence of resonant energy collisional transfers between argon 1s and 2p states and ground state H atoms by laser collisional induced fluorescence

    NASA Astrophysics Data System (ADS)

    Carbone, Emile; van Dijk, Jan; Kroesen, Gerrit

    2015-04-01

    In this paper, laser collisional induced fluorescence (LCIF) is used to probe resonant excitation transfers in an argon/hydrogen plasma resulting from heavy particle collisions. Different radiative transitions between the 1s and 2p states (in Paschen's notation) of argon are optically pumped by a nanosecond laser pulse. The spontaneous fluorescence and collisional responses of the argon and hydrogen systems are monitored by optical emission spectroscopy. A surfatron plasma source is used to generate an argon plasma with a few per cent hydrogen addition at pressures between 0.65 and 20 mbar. The electron density is measured independently by means of Thomson scattering. The overall response of the plasma due to optical pumping of argon is briefly discussed and an overview of the known heteronuclear excitation transfers in an argon/hydrogen plasma is given. The propagation of the shortcut in the Ar(1s) to H(n = 2) excitation transfer due to the optical pumping of the Ar(1s) states is seen in the atomic hydrogen LCIF responses. For the first time, we give direct experimental evidence of the existence of an efficient excitation transfer: Additionally, measurements are performed in order to estimate the resonant energy transfer between the resonant argon 1s states and hydrogen atoms: for which no previously measured cross sections could be found in the literature. These are extra quenching channels of argon 1s and 2p states that should be included in collisional–radiative modeling of argon–hydrogen discharges. The high repetition rate of the dye laser allows us to obtain a high sensitivity in the measurements. LCIF is shown to be a powerful tool for unraveling electron and also heavy particle excitation channels in situ in the plasma phase. The technique was previously developed for measuring electron or species densities locally in the plasma, but we show that it can be advantageously used to probe collisional transfers between very short-lived species which exist simultaneously only in the plasma phase.

  10. Magnetic Field Measurement with Ground State Alignment

    NASA Astrophysics Data System (ADS)

    Yan, Huirong; Lazarian, A.

    Observational studies of magnetic fields are crucial. We introduce a process "ground state alignment" as a new way to determine the magnetic field direction in diffuse medium. The alignment is due to anisotropic radiation impinging on the atom/ion. The consequence of the process is the polarization of spectral lines resulting from scattering and absorption from aligned atomic/ionic species with fine or hyperfine structure. The magnetic field induces precession and realign the atom/ion and therefore the polarization of the emitted or absorbed radiation reflects the direction of the magnetic field. The atoms get aligned at their low levels and, as the life-time of the atoms/ions we deal with is long, the alignment induced by anisotropic radiation is susceptible to extremely weak magnetic fields (1 G ? B ? 10^{-15} G). In fact, the effects of atomic/ionic alignment were studied in the laboratory decades ago, mostly in relation to the maser research. Recently, the atomic effect has been already detected in observations from circumstellar medium and this is a harbinger of future extensive magnetic field studies. A unique feature of the atomic realignment is that they can reveal the 3D orientation of magnetic field. In this chapter, we shall review the basic physical processes involved in atomic realignment. We shall also discuss its applications to interplanetary, circumstellar and interstellar magnetic fields. In addition, our research reveals that the polarization of the radiation arising from the transitions between fine and hyperfine states of the ground level can provide a unique diagnostics of magnetic fields in the Epoch of Reionization.

  11. Nuclear Ground-State Masses and Deformations

    Microsoft Academic Search

    P. Moeller; J. R. Nix; W. D. Myers; W. J. Swiatecki

    1995-01-01

    We tabulate the atomic mass excesses and nuclear ground-state deformations of 8979 nuclei ranging from 16O to A = 339. The calculations are based on the finite-range droplet macroscopic model and the folded-Yukawa single-particle microscopic model. Relative to our 1981 mass table the current results are obtained with an improved macroscopic model, an improved pairing model with a new form

  12. Ground state energy at unitarity

    SciTech Connect

    Lee, Dean [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States)

    2008-08-15

    We consider two-component fermions on the lattice in the unitarity limit. This is an idealized limit of attractive fermions where the range of the interaction is zero and the scattering length is infinite. Using Euclidean time projection, we compute the ground state energy using four computationally different but physically identical auxiliary-field methods. The best performance is obtained using a bounded continuous auxiliary field and a nonlocal updating algorithm called the hybrid Monte Carlo. With this method, we calculate results for 10 and 14 fermions at lattice volumes 4{sup 3},5{sup 3},6{sup 3},7{sup 3},8{sup 3} and extrapolate to the continuum limit. For 10 fermions in a periodic cube, the ground state energy is 0.292(12) times the ground state energy for noninteracting fermions. For 14 fermions, the ratio is 0.329(5)

  13. Correlated Atomic Pair Functions by the e-?-Method. I. Ground State 11S and Lowest Excited States n1S (n > 1) and n3S of Helium

    NASA Astrophysics Data System (ADS)

    Seelig, F. F.; Becker, G. A.

    1999-12-01

    Some low n1S and n3S states of the helium atom are computed with the aid of the e-e method which formulates the electronic wave function of the 2 electrons ? = e-e F, where ?=Z(r1+r2)-½r12 and here Z = 2. Both the differential and the integral equation for F contain a pseudopotential ? instead of the true potential V that contrary to V is finite. For the ground state, F = 1 yields nearly the Hartree-Fock SCF accuracy, whereas a multinomial expansion in r1, r2 , r2 yields a relative error of about 10-7 . All integrals can be computed analytically and are derived from one single "parent" integral.

  14. Physics 139B Fall 2009 The Variational Computation of the Ground State Energy of Helium

    E-print Network

    California at Santa Cruz, University of

    Physics 139B Fall 2009 The Variational Computation of the Ground State Energy of Helium I. Introduction to the variational computation The Hamiltonian for the two­electron system of the helium atom is principle to compute the ground state energy of the helium atom. The ground state wave function

  15. Physics 139B Fall 2009 The Variational Computation of the Ground State Energy of Helium

    E-print Network

    California at Santa Cruz, University of

    Physics 139B Fall 2009 The Variational Computation of the Ground State Energy of Helium I. Introduction to the variational computation The Hamiltonian for the two-electron system of the helium atom is state energy of the helium atom. The ground state wave function of the helium atom is of the form: 1 2

  16. PHYSI CAI. 8 E VIE W A VOLUME 11, NUMBER JANUARY 1975 Variable dimensionality in atoms and its effect on the ground state of the helium

    E-print Network

    Stillinger, Frank

    effect on the ground state of the helium isoelectronic sequence David R. Herrick and Frank H. Stillinger energy of helium- like ions of arbitrary dimensionality. Dimension- ality here refers to the number) which contains some angular correlations through the interelectron separation R». %bile neither

  17. A theoretical study of the of DNA/RNA nucleobases interacting with noble metal atoms: the gold and silver cases. Part I: Ground state properties

    E-print Network

    Leal, Leonardo Andres Espinosa

    2014-01-01

    Interaction between DNA and Metalic NanoClusters (MNCs) in particular noble metals, have attracted attention in the last years due its unique and tunable optical characteristics. However despite the great experimental advances in this field, the theoretical explanation of its particular excited states remains unknown. In this work we present an exhaustive study of the stabilization and structural properties of the noble metal atoms: gold and silver in three charge states: anionic, neutral and cationic interacting with DNA/RNA by using a real-space DFT methodology. We have taken in account the effect of pairing between bases and the presence of the sugar backbone.

  18. Simulations of Ground and Space-Based Oxygen Atom Experiments

    NASA Technical Reports Server (NTRS)

    Minton, T. K.; Cline, J. A.; Braunstein, M.

    2002-01-01

    Fast, pulsed atomic oxygen sources are a key tool in ground-based investigations of spacecraft contamination and surface erosion effects. These technically challenging ground-based studies provide a before and after picture of materials under low-earth-orbit (LEO) conditions. It would be of great interest to track in real time the pulsed flux from the source to the surface sample target and beyond in order to characterize the population of atoms and molecules that actually impact the surface and those that make it downstream to any coincident detectors. We have performed simulations in order to provide such detailed descriptions of these ground-based measurements and to provide an assessment of their correspondence to the actual LEO environment. Where possible we also make comparisons to measured fluxes and erosion yields. To perform the calculations we use a detailed description of a measurement beam and surface geometry based on the W, pulsed apparatus at Montana State University. In this system, a short pulse (on the order of 10 microseconds) of an O/O2 beam impacts a flat sample about 40 cm downstream and slightly displaced &om the beam s central axis. Past this target, at the end of the beam axis is a quadrupole mass spectrometer that measures the relative in situ flux of 0102 to give an overall normalized erosion yield. In our simulations we use the Direct Simulation Monte Carlo (DSMC) method, and track individual atoms within the atomic oxygen pulse. DSMC techniques are typically used to model rarefied (few collision) gas-flows which occur at altitudes above approximately 110 kilometers. These techniques are well suited for the conditions here, and multi-collision effects that can only be treated by this or a similar technique are included. This simulation includes collisions with the surface and among gas atoms that have scattered from the surface. The simulation also includes descriptions of the velocity spread and spatial profiles of the O/O2 beam obtained from separate measurements. These computations use basic engineering models for the gas-gas and gas-surface scattering and focus on the influence of multi-collision effects. These simulations characterize many important quantities of interest including the actual flux of atoms that reach the surface, the energy distribution of this flux, as well as the direction of the velocity of the flux that strikes the surface. These quantities are important in characterizing the conditions which give rise to measured surface erosion. The calculations also yield time- snapshots of the pulse as it impacts and flows around the surface. These snapshots reveal the local environment of gas near the surface for the duration of the pulse. We are also able to compute the flux of molecules that travel downstream and reach the spectrometer, and we characterize their velocity distribution. The number of atoms that reach the spectrometer can in fact be influenced by the presence of the surface due to gas-gas collisions from atoms scattered h m the surface, and it will generally be less than that with the surface absent. This amounts to an overall normalization factor in computing erosion yields. We discuss these quantities and their relationship to the gas-surf$ce interaction parameters. We have also performed similar calculations corresponding to conditions (number densities, temperatures, and velocities) of low-earth orbit. The steady-state nature and lower overall flux of the actual space environment give rise to differences in the nature of the gas-impacts on the surface from those of the ground-based measurements using a pulsed source.

  19. Properties of the ground 3F2 state and the excited 3P0 state of atomic thorium in cold collisions with He3

    NASA Astrophysics Data System (ADS)

    Au, Yat Shan; Connolly, Colin B.; Ketterle, Wolfgang; Doyle, John M.

    2014-09-01

    Inelastic cross sections for collisions between thorium (Th) and helium (He3) are measured. For Th[3F2]-He3, we determine the ratio of momentum transfer to Zeeman relaxation cross sections to be ? ˜500 at 800 mK. For Th[3P0]-He3, we find no quenching of this metastable state during 106 collisions. We measure the radiative lifetime of Th[3P0] to be ? >130 ms. The observed stability of Th[3P0] opens up the possibility of trapping this metastable species.

  20. Ground state of hydrogen as a zero-point-fluctuation-determined state

    Microsoft Academic Search

    H. Puthoff

    1987-01-01

    We show here that, within the stochastic electrodynamic formulation and at the level of Bohr theory, the ground state of the hydrogen atom can be precisely defined as resulting from a dynamic equilibrium between radiation emitted due to acceleration of the electron in its ground-state orbit and radiation absorbed from zero-point fluctuations of the background vacuum electromagnetic field, thereby resolving

  1. Exact integral constraint requiring only the ground-state electron density as input on the exchange-correlation force - partial differential(V)(xc)(r)/partial differential(r) for spherical atoms.

    PubMed

    March, N H; Nagy, A

    2008-11-21

    Following some studies of integral(n)(r)inverted DeltaV(r)dr by earlier workers for the density functional theory (DFT) one-body potential V(r) generating the exact ground-state density, we consider here the special case of spherical atoms. The starting point is the differential virial theorem, which is used, as well as the Hiller-Sucher-Feinberg [Phys. Rev. A 18, 2399 (1978)] identity to show that the scalar quantity paralleling the above vector integral, namely, integral(n)(r) partial differential(V)(r)/partial differential(r)dr, is determined solely by the electron density n(0) at the nucleus for the s-like atoms He and Be. The force - partial differential(V)/ partial differential(r) is then related to the derivative of the exchange-correlation potential V(xc)(r) by terms involving only the external potential in addition to n(r). The resulting integral constraint should allow some test of the quality of currently used forms of V(xc)(r). The article concludes with results from the differential virial theorem and the Hiller-Sucher-Feinberg identity for the exact many-electron theory of spherical atoms, as well as for the DFT for atoms such as Ne with a closed p shell. PMID:19026052

  2. Chirped pulse excitation of two-atom Rydberg states

    NASA Astrophysics Data System (ADS)

    Kuznetsova, Elena

    2015-07-01

    We analyze the excitation of two ground state atoms to a double Rydberg state by a two-photon chirped optical pulse in the regime of adiabatic rapid passage (ARP). For intermediate Rydberg–Rydberg interaction strengths relevant for atoms separated by ?ten ?m, adiabatic excitation can be achieved at experimentally feasible Rabi frequencies and chirp rates of the pulses, resulting in high transfer efficiencies. We also study the adiabatic transfer between ground and Rydberg states as a means to realize a controlled phase gate between atomic qubits.

  3. State-selective all-optical detection of Rydberg atoms

    NASA Astrophysics Data System (ADS)

    Karlewski, Florian; Mack, Markus; Grimmel, Jens; Sįndor, Nóra; Fortįgh, József

    2015-04-01

    We present an all-optical protocol for detecting population in a selected Rydberg state of alkali-metal atoms. The detection scheme is based on the interaction of an ensemble of ultracold atoms with two laser pulses: one weak probe pulse which is resonant with the transition between the ground state and the first excited state, and a pulse with high intensity which couples the first excited state to the selected Rydberg state. We show that by monitoring the absorption signal of the probe laser over time, one can deduce the initial population of the Rydberg state. Furthermore, it is shown that—for suitable experimental conditions—the dynamical absorption curve contains information on the initial coherence between the ground state and the selected Rydberg state. We present the results of a proof-of-principle measurement performed on a cold gas of 87Rb atoms. The method is expected to find application in quantum computing protocols based on Rydberg atoms.

  4. Efficient scheme for atomic entangled states with cavity QED system

    E-print Network

    Pengbo Li

    2010-04-12

    A protocol is proposed to generate atomic entangled states in a cavity QED system. It utilizes Raman transitions or stimulated Raman adiabatic passages between two systems to entangle the ground states of two three-state $\\Lambda$-type atoms trapped in a single mode cavity. It does not need the measurements on cavity field nor atomic detection and can be implemented in a deterministic fashion. Since the present protocol is insensitive to both cavity decay and atomic spontaneous emission, the produced entangled states may have some interesting applications in quantum information processing.

  5. All-Optical Scheme to Produce Quantum Degenerate Dipolar Molecules in the Vibronic Ground State

    NASA Astrophysics Data System (ADS)

    Mackie, Matt; Debrosse, Catherine

    2010-03-01

    We consider two-color heteronuclear photoassociation of Bose-condensed atoms into dipolar molecules in the J=1 vibronic ground state, where a free-ground laser couples atoms directly to the ground state and a free-bound laser couples the atoms to an electronically-excited state. The addition of the excited state creates a second pathway for creating ground state molecules, leading to quantum interference between direct photoassociation and photoassociation via the excited molecular state, as well as a dispersive-like shift of the free-ground resonance position. Using LiNa as an example, these results are shown to depend on the detuning and intensity of the free-bound laser, as well as the semi-classical size of both molecular states. Despite strong enhancement, coherent conversion to the LiNa vibronic ground state is possible only in a limited regime near the free-bound resonance.

  6. Ground states of Fermions on lattices

    Microsoft Academic Search

    Taku Matsui; Minami Ohsawa

    1996-01-01

    We consider Fermion systems on integer lattices. We establish the existence of dynamics for a class of long range interactions.\\u000a The infinite volume ground states are considered. The equivalence of the variational principle and ground state conditions\\u000a is proved for long range interactions. We also prove that any pure translationally invariant ground state of the gauge invariant\\u000a algebra is extendible

  7. Unfrustrated qudit chains and their ground states

    SciTech Connect

    Movassagh, Ramis; Shor, Peter W. [Department of Mathematics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Farhi, Edward; Goldstone, Jeffrey [Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Nagaj, Daniel [Research Center for Quantum Information, Institute of Physics, Slovak Academy of Sciences, Bratislava (Slovakia); Osborne, Tobias J. [Institute for Advanced Study, Wissenschaftskolleg zu Berlin, Berlin (Germany)

    2010-07-15

    We investigate chains of d-dimensional quantum spins (qudits) on a line with generic nearest-neighbor interactions without translational invariance. We find the conditions under which these systems are not frustrated, that is, when the ground states are also the common ground states of all the local terms in the Hamiltonians. The states of a quantum spin chain are naturally represented in the matrix product states (MPS) framework. Using imaginary time evolution in the MPS ansatz, we numerically investigate the range of parameters in which we expect the ground states to be highly entangled and find them hard to approximate using our MPS method.

  8. Producing Squeezed Input States for an Atomic Clock Using an Optical Cavity

    E-print Network

    Vuletic, Vladan

    Producing Squeezed Input States for an Atomic Clock Using an Optical Cavity Ian D. Leroux, Monika H clock states (Figure 1c), such that the index of refraction of an atom in | |F = 2, mF = 0 blue: The field-insensitive states in the ground-state hyperfine manifold form an effective two-level atom (clock

  9. A facility to produce an energetic, ground state atomic oxygen beam for the simulation of the Low-Earth Orbit environment

    NASA Technical Reports Server (NTRS)

    Ketsdever, Andrew D.; Weaver, David P.; Muntz, E. P.

    1994-01-01

    Because of the continuing commitment to activity in low-Earth orbit (LEO), a facility is under development to produce energetic atmospheric species, particularly atomic oxygen, with energies ranging from 5 to 80 eV. This relatively high flux facility incorporates an ion engine to produce the corresponding specie ion which is charge exchanged to produce a neutral atomic beam. Ion fluxes of around 10(exp 15) sec(exp -1) with energies of 20-70 eV have been achieved. A geometrically augmented inertially tethered charge exchanger (GAITCE) was designed to provide a large column depth of charge exchange gas while reducing the gas load to the low pressure portion of the atomic beam facility. This is accomplished using opposed containment jets which act as collisional barriers to the escape of the dense gas region formed between the jets. Leak rate gains to the pumping system on the order of 10 were achieved for moderate jet mass flows. This system provides an attractive means for the charge exchange of atomic ions with a variety of gases to produce energetic atomic beams.

  10. Single State Atom Interferometry using Grating Echoes

    NASA Astrophysics Data System (ADS)

    Kumarakrishnan, A.

    2004-05-01

    Atom interferometers (AIs) have been recognized for their potential to make one of the most precise measurements of the atomic fine structure constant ?. We describe sensitive measurements of the atomic recoil frequency ?r = (h/2?)(? k)^2/2m_atom (which can be related to ?) using an AI that measures the momentum transfer ? k imparted to cold ^85Rb atoms in a single hyperfine ground state. Our measurements have been carried out both in the time domain and in the frequency domain. In the time domain, the excitation scheme is reminiscent of a photon echo experiment. Two off resonant standing wave pulses separated by t = T are used diffract and rephase a superposition of momentum states. This results in an atomic density grating in the vicinity of t = 2i^T, which is detected by measuring the amplitude of coherently back-scattered light from the sample. The amplitude of this echo signal is recorded as a function of T. Since the signal is modulated at ?_r, the precision is related to measuring the period over a long time scale. In the frequency domain, the excitation resembles a Ramsey fringe experiment in which the first excitation pulse consists of counter-propagating traveling wave pulses with optical frequencies ?1 and ?2 that differ by ?. The grating echo is detected near t=2^T by switching the k vectors for the second excitation pulse and measuring the amplitude and phase of the back-scattered light. Recoil spectra are obtained by varying ? and averaging over T and the precision is related to the width of the spectral components. Since we have been able to operate the AI on a time scale close to the transit time for cold atoms through the interferometer, it has become possible to investigate systematic effects at the level of 1ppm.

  11. Observation of Spin Exchange Between the Singly Ionized Xe+ Ground State and the Metastable State of Neutral Xenon

    Microsoft Academic Search

    Tetsuo Hadeishi; Chung-Heng Liu

    1966-01-01

    We have observed spin-exchange collisions between the singly ionized 2P32 ground state of Xe and the 3P2 metastable state of neutral Xe, both formed and aligned by electronic-impact excitation under space-charge neutralization. Extension to the rf spectroscopy of the ionized ground state of other noble-gas atoms seems promising.

  12. The ground state of dilute Tm, Pr, and U systems is degenerate

    Microsoft Academic Search

    M. Balińa; A. A. Aligia

    1991-01-01

    The ground state of the appropriate generalization of the impurity Anderson model for valence fluctuations between two realistic configurations, is obtained in the atomic, narrow-band limit, using the Lanczos method. This limit describes the strong-coupling fixed point of renormalization group treatments for intermediate valence and Kondo impurities. The resulting ground state of Tm is highly degenerate and contains states of

  13. Ground Water Contamination in the United States

    Microsoft Academic Search

    Veronica I. Pye; Ruth Patrick

    1983-01-01

    Ground water contamination is of increasing concern in the United States because about 50 percent of our drinking water comes from well water. The causes of contamination stem from both point sources and nonpoint sources. Since ground water moves slowly, the contaminant may affect only a small portion of an aquifer for a considerable period of time. Deleterious effects on

  14. Ground states of two-dimensional quasicrystals

    SciTech Connect

    Burkov, S.E. (Landau Institute for Theoretical Physics, GSP-1, 117940 Moscow V-334 (USSR) Brookhaven National Laboratory, Upton, NY (USA))

    1990-05-15

    Necessary conditions for a quasicrystal to be a ground state are found within the framework of a tiling model (thermal fluctuations are supposed to be irrelevant). It is proven that a generic quasicrystal cannot be a ground state. Only very special quasicrystals are shown to survive: They must possess high rotational symmetry or the frequencies defining quasiperiodic properties must satisfy numerous rational constraints. A quasicrystal may be a ground state only if hexagons flipping under the infinitesimal phason shift are not isolated from one another but form rows or nets. Necessary and sufficient conditions for a (2,3) quasicrystal to be a ground state are found. All (2,4) quasicrystals satisfying the necessary conditions are classified. Stability of a quasicrystalline phase is discussed.

  15. Variational calculation of ground-state energy of iron atoms and condensed matter in strong magnetic fields. [at neutron star surfaces

    NASA Technical Reports Server (NTRS)

    Flowers, E. G.; Ruderman, M. A.; Lee, J.-F.; Sutherland, P. G.; Hillebrandt, W.; Mueller, E.

    1977-01-01

    Variational calculations of the binding energies of iron atoms and condensed matter in strong magnetic fields (greater than 10 to the 12th gauss). These calculations include the electron exchange energy. The cohesive energy of the condensed matter, which is the difference between these two binding energies, is of interest in pulsar theories and in the description of the surfaces of neutron stars. It is found that the cohesive energy ranges from 2.6 keV to 8.0 keV.

  16. On the ground state of metallic hydrogen

    NASA Technical Reports Server (NTRS)

    Chakravarty, S.; Ashcroft, N. W.

    1978-01-01

    A proposed liquid ground state of metallic hydrogen at zero temperature is explored and a variational upper bound to the ground state energy is calculated. The possibility that the metallic hydrogen is a liquid around the metastable point (rs = 1.64) cannot be ruled out. This conclusion crucially hinges on the contribution to the energy arising from the third order in the electron-proton interaction which is shown here to be more significant in the liquid phase than in crystals.

  17. Coherent Transfer of Photoassociated Molecules into the Rovibrational Ground State

    NASA Astrophysics Data System (ADS)

    Inouye, Shin

    2011-05-01

    Recently, there have been impressive advances in methods of creating ultracold molecules from ultracold atomic gases. One of the key technologies used there is Stimulated Raman Adiabatic Passage (STIRAP), which has been successfully used for transferring Feshbach molecules into the rovibrational ground state. Since STIRAP relies on quantum coherence, it is unclear if STIRAP is also useful for non-polarized sample, like photo-associated molecules in a magneto-optical trap. Here we report on the SITRAP transfer of weakly bound molecules produced by photoassociation (PA). Laser cooled 41 K and 87 Rb atoms were first photo-associated into loosely-bound molecules in the X 1 ? potential. Using v = 41, J = 1 level in the (3) 1 ? potential as an intermediate level, we succeeded in transferring molecules in the v = 91, J = 0 level into the absolute ground state (X 1 ? , v = 0, N = 0). High-resolution spectroscopy based on the coherent transfer revealed the hyperfine structure of both weakly-bound and tightly-bound molecules. Our results show that a pure sample of ultracold ground-state molecules is achieved via the all-optical association of laser-cooled atoms, opening possibilities to coherently manipulate a wide variety of molecules.In collaboration with Kiyotaka Aikawa, Kohei Oasa, University of Tokyo; Masahito Ueda, University of Tokyo, JST, ERATO; Jun Kobayashi, University of Tokyo; and Tetsuo Kishimoto, University of Electro-Communications.

  18. Optimal Control of Cold Ground-State Collisions by Shaped Laser Pulses

    NASA Astrophysics Data System (ADS)

    de Lima, Emanuel F.

    2015-07-01

    This works investigates the optimal laser control of the electronic ground-state collision of two cold atoms of distinct species. The control goal is to perform the photoassociation of the colliding pair of atoms along with the vibrational-rotational stabilization of the diatomic molecule taking advantage of the permanent dipole moment associated with the collision. Calculations are performed within a model system for the electronic ground state of Li+Cs. It is shown that an optimized laser pulse can induce the transition from the free state to the molecular rotational-vibrational ground state with high efficiency.

  19. On the atomic state densities of plasmas produced by the “torche ą injection axiale”

    Microsoft Academic Search

    J. Jonkers; H. P. C. Vos; Mullen van der JJAM; E. A. H. Timmermans

    1996-01-01

    The atomic state densities of helium and argon plasmas produced by the microwave driven plasma torch called the “torche ą injection axiale” are presented. They are obtained by absolute line intensity measurements of the excited states and by applying the ideal gas law to the ground state. It will be shown that the atomic state distribution function (ASDF) does not

  20. Sideband Cooling Micromechanical Motion to the Quantum Ground State

    E-print Network

    J. D. Teufel; T. Donner; Dale Li; J. H. Harlow; M. S. Allman; K. Cicak; A. J. Sirois; J. D. Whittaker; K. W. Lehnert; R. W. Simmonds

    2011-03-10

    The advent of laser cooling techniques revolutionized the study of many atomic-scale systems. This has fueled progress towards quantum computers by preparing trapped ions in their motional ground state, and generating new states of matter by achieving Bose-Einstein condensation of atomic vapors. Analogous cooling techniques provide a general and flexible method for preparing macroscopic objects in their motional ground state, bringing the powerful technology of micromechanics into the quantum regime. Cavity opto- or electro-mechanical systems achieve sideband cooling through the strong interaction between light and motion. However, entering the quantum regime, less than a single quantum of motion, has been elusive because sideband cooling has not sufficiently overwhelmed the coupling of mechanical systems to their hot environments. Here, we demonstrate sideband cooling of the motion of a micromechanical oscillator to the quantum ground state. Entering the quantum regime requires a large electromechanical interaction, which is achieved by embedding a micromechanical membrane into a superconducting microwave resonant circuit. In order to verify the cooling of the membrane motion into the quantum regime, we perform a near quantum-limited measurement of the microwave field, resolving this motion a factor of 5.1 from the Heisenberg limit. Furthermore, our device exhibits strong-coupling allowing coherent exchange of microwave photons and mechanical phonons. Simultaneously achieving strong coupling, ground state preparation and efficient measurement sets the stage for rapid advances in the control and detection of non-classical states of motion, possibly even testing quantum theory itself in the unexplored region of larger size and mass.

  1. Ground state of a dipolar crystal

    PubMed

    Gross; Wei

    2000-02-01

    We provide some of the strongest evidence to date that the ground state structure of an infinite collection of point dipoles with hardcore sphere interactions is body-centered tetragonal. The structure with the next highest binding energy is not face-centered cubic; a particular honeycomb structure has lower energy. PMID:11046504

  2. Product-state approximations to quantum ground states

    E-print Network

    Brandao, Fernando G.S.L.

    The local Hamiltonian problem consists of estimating the ground-state energy (given by the minimum eigenvalue) of a local quantum Hamiltonian. It can be considered as a quantum generalization of constraint satisfaction ...

  3. Simulation of the hydrogen ground state in Stochastic Electrodynamics

    E-print Network

    Theo M. Nieuwenhuizen; Matthew T. P. Liska

    2015-06-22

    Stochastic electrodynamics is a classical theory which assumes that the physical vacuum consists of classical stochastic fields with average energy $\\frac{1}{2}\\hbar \\omega$ in each mode, i.e., the zero-point Planck spectrum. While this classical theory explains many quantum phenomena related to harmonic oscillator problems, hard results on nonlinear systems are still lacking. In this work the hydrogen ground state is studied by numerically solving the Abraham -- Lorentz equation in the dipole approximation. First the stochastic Gaussian field is represented by a sum over Gaussian frequency components, next the dynamics is solved numerically using OpenCL. The approach improves on work by Cole and Zou 2003 by treating the full $3d$ problem and reaching longer simulation times. The results are compared with a conjecture for the ground state phase space density. Though short time results suggest a trend towards confirmation, in all attempted modelings the atom ionises at longer times.

  4. Ground state Zeeman coherence effects in an optically pumped cesium beam

    Microsoft Academic Search

    G. Théobald; N. Dimarcq; V. Giordano; P. Cérez

    1989-01-01

    The population trapping in a cesium beam induced at low magnetic field by sigma polarized light from a broadband laser diode has been investigated. The dip observed in the fluorescence is interpreted in terms of Zeeman coherences in the ground state which trap the atomic populations. A quantitative description is given through the analysis of the atom light interaction with

  5. Interactions Between Thermal Ground or Excited Atoms in the Vapor Phase: Many-Body Dipole–Dipole Effects, Molecular Dissociation, and Photoassociation Probed By Laser Spectroscopy

    Microsoft Academic Search

    J. G. Eden; B. J. Ricconi; Y. Xiao; F. Shen; A. A. Senin

    2008-01-01

    Atom–atom and atom–molecule interactions in the absence or presence of an optical radiation field are among the fundamental processes in atomic, molecular, and optical physics. This review addresses recent advances that provide insight into the dynamics of many-body fipole–dipole interactions between excited atoms at long range, and the production of a transient molecule from a pair of thermal, ground state

  6. Ground states of spin-2 condensates in an external magnetic field

    SciTech Connect

    Zheng, G.-P.; Tong, Y.-G.; Wang, F.-L. [Department of Physics, Henan Normal University, Xinxiang, Henan 453007 (China)

    2010-06-15

    The possible ground states of spin-2 Bose-Einstein condensates in an external magnetic field are obtained analytically and classified systematically according to the population of the condensed atoms at the hyperfine sublevels. It is shown that the atoms can populate simultaneously at four hyperfine sublevels in a weak magnetic field with only the linear Zeeman energy, in contrast to that in a stronger magnetic field with the quadratic Zeeman energy, where condensed atoms can at most populate at three hyperfine sublevels in the ground states. Any spin configuration we obtained will give a closed subspace in the order parameter space of the condensates.

  7. Ground state of the uranium ion in a metal with large j.j coupling

    Microsoft Academic Search

    A. C. Nunes

    1987-01-01

    A previous investigation into the ground state of a uranium ion fluctuating between two magnetic valence states in a free-electron sea is extended to take account of the effects of a large j.j coupling to the atomic electrons of the ion. We find, as in previous work, that the ground state is also a singlet with total angular momentum J=0.

  8. Sympathetic cooling of molecular ion motion to the ground state

    NASA Astrophysics Data System (ADS)

    Rugango, R.; Goeders, J. E.; Dixon, T. H.; Gray, J. M.; Khanyile, N. B.; Shu, G.; Clark, R. J.; Brown, K. R.

    2015-03-01

    We demonstrate sympathetic sideband cooling of a 40CaH+ molecular ion co-trapped with a 40Ca+ atomic ion in a linear Paul trap. Both axial modes of the two-ion chain are simultaneously cooled to near the ground state of motion. The center of mass mode is cooled to an average quanta of harmonic motion {{\\bar{n}}COM}=0.13+/- 0.03, corresponding to a temperature of 12.47+/- 0.03 ? K. The breathing mode is cooled to {{\\bar{n}}BM}=0.05+/- 0.02, corresponding to a temperature of 15.36+/- 0.01 ? K.

  9. Ground state energy of large polaron systems

    E-print Network

    Rafael D. Benguria; Rupert L. Frank; Elliott H. Lieb

    2014-09-18

    The last unsolved problem about the many-polaron system, in the Pekar-Tomasevich approximation, is the case of bosons with the electron-electron Coulomb repulsion of strength exactly 1 (the 'neutral case'). We prove that the ground state energy, for large $N$, goes exactly as $-N^{7/5}$, and we give upper and lower bounds on the asymptotic coefficient that agree to within a factor of $2^{2/5}$.

  10. Ground state properties of nuclear matter

    Microsoft Academic Search

    G. Wegmann

    1968-01-01

    The ground state properties of nuclear matter are calculated in the?11-approximation1. A nucleon-nucleon interaction of the Yamaguchi-type and thes-wave part ofTabakin's potential have been considered. In both cases too large values for the density of nuclear matter and the binding energy per nucleon are found. The momentum distribution turns out to be very small for momenta larger than the Fermi

  11. Ground state searches in fcc intermetallics

    SciTech Connect

    Wolverton, C.; de Fontaine, D. (Lawrence Berkeley Lab., CA (United States)); Ceder, G. (Massachusetts Inst. of Tech., Cambridge, MA (United States)); Dreysse, H. (Nancy-1 Univ., 54 (France). Lab. de Physique du Solide)

    1991-12-01

    A cluster expansion is used to predict the fcc ground states, i.e., the stable phases at zero Kelvin as a function of composition, for alloy systems. The intermetallic structures are not assumed, but derived regorously by minimizing the configurational energy subject to linear constraints. This ground state search includes pair and multiplet interactions which spatially extend to fourth nearest neighbor. A large number of these concentration-independent interactions are computed by the method of direct configurational averaging using a linearized-muffin-tin orbital Hamiltonian cast into tight binding form (TB-LMTO). The interactions, derived without the use of any adjustable or experimentally obtained parameters, are compared to those calculated via the generalized perturbation method extention of the coherent potential approximation within the context of a KKR Hamiltonian (KKR-CPA-GPM). Agreement with the KKR-CPA-GPM results is quite excellent, as is the comparison of the ground state results with the fcc-based portions of the experimentally-determined phase diagrams under consideration.

  12. Quantum state reconstruction on Atom-Chips

    E-print Network

    Cosimo Lovecchio; Shahid Cherukattil; Barbara Cilenti; Ivan Herrera; Francesco Saverio Cataliotti; Simone Montangero; Tommaso Calarco; Filippo Caruso

    2015-04-08

    We realize on an Atom-Chip a practical, experimentally undemanding, tomographic reconstruction algorithm relying on the time-resolved measurements of the atomic population distribution among atomic internal states. More specifically, we estimate both the state density matrix as well as the dephasing noise present in our system by assuming complete knowledge of the Hamiltonian evolution. The proposed scheme is based on routinely performed measurements and established experimental procedures, hence providing a simplified methodology for quantum technological applications.

  13. Weak value amplification of atomic cat states

    E-print Network

    Sumei Huang; Girish S. Agarwal

    2015-05-02

    We show the utility of the weak value measurement to observe the quantum interference between two close lying atomic coherent states in a post-selected atomic cat state, produced in a system of $N$ identical two-level atoms weakly interacting with a single photon field. Through the observation of the negative parts of the Wigner distribution of the post-selected atomic cat state, we find that the post-selected atomic cat state becomes more nonclassical when the post-selected polarization state of the single photon field tends toward becoming orthogonal to its pre-selected state. We show that the small phase shift in the post-selected atomic cat state can be amplified via measuring the peak shift of its phase distribution when the post-selected state of the single photon field is nearly orthogonal to its pre-selected state. We find that the amplification factor of of 15 [5] can be obtained for a sample of 10 [100] atoms. This effectively provides us with a method to discriminate two close lying states on the Bloch sphere. We discuss possible experimental implementation of the scheme, and conclude with a discussion of the Fisher information.

  14. Programmable solid state atom sources for nanofabrication.

    PubMed

    Han, Han; Imboden, Matthias; Stark, Thomas; Del Corro, Pablo G; Pardo, Flavio; Bolle, Cristian A; Lally, Richard W; Bishop, David J

    2015-06-28

    In this paper we discuss the development of a MEMS-based solid state atom source that can provide controllable atom deposition ranging over eight orders of magnitude, from ten atoms per square micron up to hundreds of atomic layers, on a target ?1 mm away. Using a micron-scale silicon plate as a thermal evaporation source we demonstrate the deposition of indium, silver, gold, copper, iron, aluminum, lead and tin. Because of their small sizes and rapid thermal response times, pulse width modulation techniques are a powerful way to control the atomic flux. Pulsing the source with precise voltages and timing provides control in terms of when and how many atoms get deposited. By arranging many of these devices into an array, one has a multi-material, programmable solid state evaporation source. These micro atom sources are a complementary technology that can enhance the capability of a variety of nano-fabrication techniques. PMID:26030007

  15. Conditional preparation of arbitrary atomic Dicke states

    E-print Network

    Karel Lemr; Jaromir Fiurasek

    2008-12-02

    We propose an experimentally accessible procedure for conditional preparation of highly non-classical states of collective spin of an atomic ensemble. The quantum state engineering is based on a combination of QND interaction between atoms and light previously prepared in a non-Gaussian state using photon subtraction from squeezed vacuum beam, homodyne detection on the output light beam, and a coherent displacement of atomic state. The procedure is capable of non-deterministic preparation of a wide class of superpositions of atomic Dicke states. We present several techniques to optimize the performance of the protocol and maximize the trade-off between fidelity of prepared state and success probability of the scheme.

  16. Analytic Solution of Ground State for Coulomb Plus Linear Potential

    E-print Network

    W. Q. Chao; C. S. Ju

    2001-11-26

    The newly developed single trajectory quadrature method is applied to solve the ground state quantum wave function for Coulomb plus linear potential. The general analytic expressions of the energy and wave function for the ground state are given. The convergence of the solution is also discussed. The method is applied to the ground state of the heavy quarkonium system.

  17. A ROUGHENING TRANSITION INDICATED BY THE BEHAVIOUR OF GROUND STATES

    E-print Network

    Paris-Sud XI, Université de

    A ROUGHENING TRANSITION INDICATED BY THE BEHAVIOUR OF GROUND STATES R. Koteck“y and S. Miracle in this contribution is to present some illustrations for the claim that already by looking at the ground states mean by ground states. We consider a finite spin model on a lattice L with configuration space = SL

  18. Ground-based investigations of atomic oxygen interactions with space station surfaces

    SciTech Connect

    Cross, J.B.; Cremers, D.A.; Tucker, D.F.

    1985-01-01

    High strength to weight ratio fiber organic epoxy materials are primary candidates as structural members for Space Station construction but preliminary STS exposure experiments have shown that many of these materials experience extensive etching by oxygen atoms present in low earth orbit (LEO). Oxygen atoms colliding with ram directed surfaces have energies of 5 eV (due to 8 km/s orbital velocity) and produce etching rates of 0.1 micron/orbit, i.e., 10% of the incoming O-atom flux reacts with organic based surfaces causing surface recession; while ram surface reflected O-atoms (thermal), react with rates 3 to 4 times lower. In order to investigate this problem ground-based simulation and testing facilities have been developed which include a high kinetic energy O-atom source, a sample exposure chamber and a high sensitivity molecular beam apparatus. The sample exposure chamber is suited for surveying materials for their O-atom reactivity through weight loss measurements. The high sensitivity molecular beam apparatus will be used for determining reaction mechanisms through measurements of reaction product identity, translational and internal state of products, and angular distribution of reaction products. The O-atom source, based on the use of a laser sustained discharge, has demonstrated O-atom translational temperatures of 8 to 9000 K and is presently operating with 50% oxygen in argon using 500 watts of CO/sub 2/ laser power which is expected to produce velocities of 4 to 5 km/s. One hour exposures of kapton, two types of fiber glass epoxy materials, and MgF/sub 2/ coated optics have been accomplished and preliminary results indicate that the coated aluminium optics have very low reaction rates while kapton has the highest rate.

  19. Best Possible Strategy for Finding Ground States

    SciTech Connect

    Franz, Astrid; Hoffmann, Karl Heinz; Salamon, Peter

    2001-06-04

    Finding the ground state of a system with a complex energy landscape is important for many physical problems including protein folding, spin glasses, chemical clusters, and neural networks. Such problems are usually solved by heuristic search methods whose efficacy is judged by empirical performance on selected examples. We present a proof that, within the large class of algorithms that simulate a random walk on the landscape, threshold accepting is the best possible strategy. In particular, it can perform better than simulated annealing and Tsallis statistics. Our proof is the first example of a provably optimal strategy in this area.

  20. Vlasov calculations of nuclear ground states

    E-print Network

    Aldo Bonasera; Toshiki Maruyama; Massimo Papa; Satoshi Chiba

    2001-10-26

    We describe some properties of nuclear ground states using a microscopic Vlasov approach. We propose a new method to find the energy minimum of the system enforcing the fermionic nature of the system. Calculations are performed for two different parametrization of the mean field: a simple momentum independent Skyrme potential and a momentum dependent one as proposed by Gale, Bertsch and Das Gupta. We show that the binding energies and radii of nuclei from $^{16}$O to $^{208}$Pb are reasonably reproduced by opportunely tuning the surface term. We also made some calculations for neutron rich/poor nuclei.

  1. Characterizing the atomic mass surface beyond the proton drip line via a-decay measurements of the s1/2 ground state of 165Re and the h11/2 isomer in 161Ta

    E-print Network

    D. O'Donnell; R. D. Page; C. Scholey; L. Bianco; L. Capponi; R. J. Carroll; I. G. Darby; L. Donosa; M. Drummond; F. Ertugral; P. T. Greenlees; T. Grahn; K. Hauschild; A. Herzan; U. Jakobsson; P. Jones; D. T. Joss; R. Julin; S. Juutinen; S. Ketelhut; M. Labiche; M. Leino; A. Lopez-Martens; K. Mullholland; P. Nieminen; P. Peura; P. Rahkila; S. Rinta-Antila; P. Ruotsalainen; M. Sandzelius; J. Saren; B. Saygi; J. Simpson; J. Sorri; A. Thornthwaite; J. Uusitalo

    2012-12-19

    The a-decay chains originating from the s1/2 and h11/2 states in 173Au have been investigated following fusion-evaporation reactions. Four generations of a radioactivities have been correlated with 173Aum leading to a measurement of the a decay of 161Tam. It has been found that the known a decay of 161Ta, which was previously associated with the decay of the ground state, is in fact the decay of an isomeric state. This work also reports on the first observation of prompt g rays feeding the ground state of 173Au. This prompt radiation was used to aid the study of the a-decay chain originating from the s1/2 state in 173Au. Three generations of a decays have been correlated with this state leading to the observation of a previously unreported activity which is assigned as the decay of 165Reg. This work also reports the excitation energy of an a-decaying isomer in 161Ta and the Q-value of the decay of 161Tag.

  2. Preparation and determination of spin-polarized states in multi-Zeeman-sublevel atoms

    SciTech Connect

    Wang, Bo; Han, Yanxu; Xiao, Jintao; Yang, Xudong; Zhang, Chunhong; Wang, Hai; Peng, Kunchi [The State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006 (China); Xiao, Min [The State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006 (China); Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701 (United States)

    2007-05-15

    We demonstrate a simple, all-optical technique to prepare and determine the desired internal quantum states in multi-Zeeman-sublevel atoms. By choosing appropriate coupling and pumping laser beams, atoms can be easily prepared in a desired Zeeman sublevel with high purity or in any chosen ground-state population distributions (spin-polarized quantum-state engineering). The population distributions or state purities of such prepared atomic states can be determined by using a weak, circularly polarized probe beam due to differences in transition strengths among different Zeeman sublevels. This technique will have potential impact on quantum-information processing in multilevel atomic systems.

  3. Seeking the Ground State of String Theory

    NASA Astrophysics Data System (ADS)

    Dine, M.

    The greatest obstacle to developing a string phenomenology is ourlack of understanding of the ground state. We explain why the dynamics which determines this state is not likely to be accessible to any systematic approximation. We note that the racetrack scheme, often cited as a counterexample, suffers from similar difficulties. We stress that the weakness of the gauge couplings, the gauge hierarchy, and coupling unification suggest that it may be possible to extract some information in a systematic approximation. We review the ideas of Kahler stabilization, an attempt to reconcile these facts. We consider whether the system is likely to sit at extremes of the moduli space, as in recent proposals for a low string scale. Finally we discuss the idea of Maximally Enhanced Symmetry, a hypothesis which is technically natural, compatible with basic facts about cosmology, and potentially predictive.

  4. Spontaneous skyrmion ground states in magnetic metals.

    PubMed

    Rössler, U K; Bogdanov, A N; Pfleiderer, C

    2006-08-17

    Since the 1950s, Heisenberg and others have addressed the problem of how to explain the appearance of countable particles in continuous fields. Stable localized field configurations were searched for an ingredient for a general field theory of elementary particles, but the majority of nonlinear field models were unable to predict them. As an exception, Skyrme succeeded in describing nuclear particles as localized states, so-called 'skyrmions'. Skyrmions are a characteristic of nonlinear continuum models ranging from microscopic to cosmological scales. Skyrmionic states have been found under non-equilibrium conditions, or when stabilized by external fields or the proliferation of topological defects. Examples are Turing patterns in classical liquids, spin textures in quantum Hall magnets, or the blue phases in liquid crystals. However, it has generally been assumed that skyrmions cannot form spontaneous ground states, such as ferromagnetic or antiferromagnetic order, in magnetic materials. Here, we show theoretically that this assumption is wrong and that skyrmion textures may form spontaneously in condensed-matter systems with chiral interactions without the assistance of external fields or the proliferation of defects. We show this within a phenomenological continuum model based on a few material-specific parameters that can be determined experimentally. Our model has a condition not considered before: we allow for softened amplitude variations of the magnetization, characteristic of, for instance, metallic magnets. Our model implies that spontaneous skyrmion lattice ground states may exist generally in a large number of materials, notably at surfaces and in thin films, as well as in bulk compounds, where a lack of space inversion symmetry leads to chiral interactions. PMID:16915285

  5. Teleportation of an atomic momentum state 

    E-print Network

    Qamar, S.; Zhu, S. Y.; Zubairy, M. Suhail.

    2003-01-01

    In this paper, we propose a scheme for teleportating a superposition of atomic center-of-mass momentum states to a superposition of the cavity field using quantum controlled-NOT gate via atomic scattering in the Bragg regime and cavity quantum...

  6. Transition state in atomic physics

    Microsoft Academic Search

    Charles Jaffé; David Farrelly; T. Uzer

    1999-01-01

    The transition state is fundamental to modern theories of reaction dynamics: essentially, the transition state is a structure in phase space that all reactive trajectories must cross. While transition-state theory (TST) has been used mainly in chemical physics, it is possible to apply the theory to considerable advantage in any collision problem that involves some form of reaction. Of special

  7. Programmable solid state atom sources for nanofabrication

    NASA Astrophysics Data System (ADS)

    Han, Han; Imboden, Matthias; Stark, Thomas; Del Corro, Pablo G.; Pardo, Flavio; Bolle, Cristian A.; Lally, Richard W.; Bishop, David J.

    2015-06-01

    In this paper we discuss the development of a MEMS-based solid state atom source that can provide controllable atom deposition ranging over eight orders of magnitude, from ten atoms per square micron up to hundreds of atomic layers, on a target ~1 mm away. Using a micron-scale silicon plate as a thermal evaporation source we demonstrate the deposition of indium, silver, gold, copper, iron, aluminum, lead and tin. Because of their small sizes and rapid thermal response times, pulse width modulation techniques are a powerful way to control the atomic flux. Pulsing the source with precise voltages and timing provides control in terms of when and how many atoms get deposited. By arranging many of these devices into an array, one has a multi-material, programmable solid state evaporation source. These micro atom sources are a complementary technology that can enhance the capability of a variety of nano-fabrication techniques.In this paper we discuss the development of a MEMS-based solid state atom source that can provide controllable atom deposition ranging over eight orders of magnitude, from ten atoms per square micron up to hundreds of atomic layers, on a target ~1 mm away. Using a micron-scale silicon plate as a thermal evaporation source we demonstrate the deposition of indium, silver, gold, copper, iron, aluminum, lead and tin. Because of their small sizes and rapid thermal response times, pulse width modulation techniques are a powerful way to control the atomic flux. Pulsing the source with precise voltages and timing provides control in terms of when and how many atoms get deposited. By arranging many of these devices into an array, one has a multi-material, programmable solid state evaporation source. These micro atom sources are a complementary technology that can enhance the capability of a variety of nano-fabrication techniques. Electronic supplementary information (ESI) available: A document containing further information about device characterization, summary of the evaporation experiments, technical details and data analysis of the measurement is supplied as ESI. In addition, three video files are included. One illustrates the operation of the source array and the other two are SEM videos of the dynamic process of silver evaporating on the source plate. See DOI: 10.1039/c5nr01331c

  8. Link atom bond length effect in ONIOM excited state calculations

    NASA Astrophysics Data System (ADS)

    Caricato, Marco; Vreven, Thom; Trucks, Gary W.; Frisch, Michael J.

    2010-08-01

    We investigate how the choice of the link atom bond length affects an electronic transition energy calculation with the so-called our own N-layer integrated molecular orbital molecular mechanics (ONIOM) hybrid method. This follows our previous paper [M. Caricato et al., J. Chem. Phys. 131, 134105 (2009)], where we showed that ONIOM is able to accurately approximate electronic transition energies computed at a high level of theory such as the equation of motion coupled cluster singles and doubles (EOM-CCSD) method. In this study we show that the same guidelines used in ONIOM ground state calculations can also be followed in excited state calculations, and that the link atom bond length has little effect on the ONIOM energy when a sensible model system is chosen. We also suggest further guidelines for excited state calculations which can help in checking the effectiveness of the definition of the model system and controlling the noise in the calculation.

  9. Time-dependent localized Hartree-Fock density-functional linear response approach for photoionization of atomic excited states

    E-print Network

    Zhou, Zhongyuan; Chu, Shih-I

    2009-05-13

    electron orbitals and kernel functions, and thus can be used to study the photoionization from atomic excited states. We have applied the approach to the calculation of photoionization cross sections of Ne ground state. The results are in agreement...

  10. Heralded Generation of an Atomic NOON State

    SciTech Connect

    Chen Yuao; Bao Xiaohui; Yuan Zhensheng; Chen Shuai; Pan Jianwei [Physikalisches Institut, Ruprecht-Karls-Universitaet Heidelberg, Philosophenweg 12, 69120 Heidelberg (Germany); Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhao Bo [Physikalisches Institut, Ruprecht-Karls-Universitaet Heidelberg, Philosophenweg 12, 69120 Heidelberg (Germany)

    2010-01-29

    We report the heralded generation of an atomic NOON state by observation of phase super resolution in a motion-sensitive spin-wave (SW) interferometer. The SW interferometer is implemented by generating a superposition of two SWs and observing the interference between them, where the interference fringe is sensitive to the atomic collective motion. By heralded generation of a second order NOON state in the SW interferometer, we observe the interference pattern which provides strong evidence of phase super resolution. The demonstrated SW interferometer can in principle be scaled up to a highly entangled state, and thus is of fundamental importance, and might be used as an inertial sensor.

  11. The ground state of dilute Tm systems is degenerate

    Microsoft Academic Search

    M. Balińa; A. A. Aligia

    1990-01-01

    The ground state of the appropriate generalization of the impurity Anderson model for valence fluctuations between two realistic Tm+2 and Tm+3 configurations is obtained, in the narrowband limit, using the Lanczos' method. This limit describes the strong-coupling fixed point of renormalization group treatments for intermediate valence and Kondo impurities. The resulting ground state is highly degenerate and contains states of

  12. Ground state properties of multi-polaron systems

    E-print Network

    Rupert L. Frank; Elliott H. Lieb; Robert Seiringer; Lawrence E. Thomas

    2012-09-17

    We summarize our recent results on the ground state energy of multi-polaron systems. In particular, we discuss stability and existence of the thermodynamic limit, and we discuss the absence of binding in the case of large Coulomb repulsion and the corresponding binding-unbinding transition. We also consider the Pekar-Tomasevich approximation to the ground state energy and we study radial symmetry of the ground state density.

  13. Creating and probing coherent atomic states

    SciTech Connect

    Reinhold, C.O.; Burgdoerfer, J. [Oak Ridge National Lab., TN (United States). Physics Div.]|[Univ. of Tennessee, Knoxville, TN (United States). Dept. of Physics and Astronomy; Frey, M.T.; Dunning, F.B. [Rice Univ., Houston, TX (United States)

    1997-06-01

    The authors present a brief review of recent experimental and theoretical time resolved studies of the evolution of atomic wavepackets. In particular, wavepackets comprising a superposition of very-high-lying Rydberg states which are created either using a short half-cycle pulse (HCP) or by rapid application of a DC field. The properties of the wavepackets are probed using a second HCP that is applied following a variable time delay and ionizes a fraction of the atoms, much like a passing-by ion in atomic collisions.

  14. Recent progress in simulation of the ground state of many Boson systems

    NASA Astrophysics Data System (ADS)

    Galli, D. E.; Reatto, L.

    2003-01-01

    We present two recent advances in the simulation of 4He in the condensed phase at zero temperature. Within the variational theory of strongly interacting bosons we have studied a cluster of 4He atoms with one alkali ion K+. For the wave function we have used a new shadow wave function (SWF) in which the coupling between one 4He atom and its shadow variable depends on its distance from the ion. This substantially improves the energy. The first shell around the ion contains 14 atoms which are spatially ordered. However the atoms of the first shell are not completely localized and frequent exchanges with atoms which are further from the ion take place. This also suggests that at least for the ion K+ the atoms of the first shell participate in the superfluidity. We have also introduced a new extension of the path integral ground state (PIGS) method which is able to compute exact ground state expectation values without extrapolations and with a SWF as the trial variational wave function to project on the ground state. This is an important extension which opens up the possibility of studying disorder phenomena in the solid phase by an exact method at zero temperature. We have applied this technique to compute the energy of formation of a vacancy at different densities in the solid phase of 4He. This computation confirms the variational result that a vacancy is a delocalized defect in the low density helium solid.

  15. Pure superposition states of atoms generated by a bichromatic elliptically polarized filed

    E-print Network

    A. V. Taichenachev; V. I. Yudin; V. L. Velichansky; A. S. Zibrov

    2005-03-03

    We find specific polarizations of components of a bichromatic field, which allow one to prepare pure superposition states of atoms, using the coherent population trapping effect. These $m$$-$$m$ states are prepared in the system of Zeeman substates of the ground-state hyperfine levels with arbitrary angular momenta $F_1$ and $F_2$. It is established that, in general case $m\

  16. Lossless anomalous dispersion and an inversionless gain doublet via dressed interacting ground states

    SciTech Connect

    Weatherall, James Owen [Department of Physics and Engineering Physics, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, New Jersey 07030 (United States); Department of Mathematical Sciences, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, New Jersey 07030 (United States); Department of Logic and Philosophy of Science, University of California Irvine, 3151 Social Science Plaza A, Irvine, California 92697 (United States); Search, Christopher P. [Department of Physics and Engineering Physics, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, New Jersey 07030 (United States)

    2010-02-15

    Transparent media exhibiting anomalous dispersion have been of considerable interest since Wang, Kuzmich, and Dogariu [Nature 406, 277 (2000)] first observed light propagate with superluminal and negative group velocities without absorption. Here, we propose an atomic model exhibiting these properties, based on a generalization of amplification without inversion in a five-level dressed interacting ground-state system. The system consists of a {Lambda} atom prepared as in standard electromagnetically induced transparency (EIT), with two additional metastable ground states coupled to the {Lambda} atom ground states by two rf-microwave fields. We consider two configurations by which population is incoherently pumped into the ground states of the atom. Under appropriate circumstances, we predict a pair of new gain lines with tunable width, separation, and height. Between these lines, absorption vanishes but dispersion is large and anomalous. The system described here is a significant improvement over other proposals in the anomalous dispersion literature in that it permits additional coherent control over the spectral properties of the anomalous region, including a possible 10{sup 4}-fold increase over the group delay observed by Wang, Kuzmich, and Dogariu.

  17. Perspectives for coherent optical formation of strontium molecules in their electronic ground state

    E-print Network

    Koch, Christiane

    Perspectives for coherent optical formation of strontium molecules in their electronic ground state . The present study focuses on strontium and addresses the question of how to produce dimer molecules atomic resonance was observed for calcium 16 , strontium 17,18 , and ytterbium 19 . Near the narrow- line

  18. Calculation of ground- and excited-state potential energy curves for barium-rare gas complexes in a pseudopotential approach

    Microsoft Academic Search

    E. Czuchaj; F. Rebentrost; H. Stoll; H. Preuss

    1998-01-01

    .   Adiabatic potential curves for the ground state and several low-lying excited states of the barium atom interacting with\\u000a Ne, Ar, Kr and Xe have been obtained from valence ab initio configuration-interaction calculations. Atomic cores are replaced\\u000a by scalar-relativistic l-dependent pseudopotentials, while core-polarization potentials are used for describing correlation contributions of the rare-gas\\u000a atoms and the Ba2+ cores. Implications of

  19. Mixed-valent ground state of CeO2

    Microsoft Academic Search

    Atsushi Fujimori

    1983-01-01

    The electronic ground state, core-hole states, and valence-hole states of CeO2 are studied taking into account strong correlation among the 4f electrons. The ground state is considered as a mixture of two configurations, 4f0 and spin-singlet totally symmetric 4f1-O 2p-hole states. By an analysis of the core-level photoemission spectrum, the 4f occupancy is obtained to be about 0.6. The possibility

  20. Interaction of Helium Rydberg State Atoms with Superfluid Helium

    NASA Astrophysics Data System (ADS)

    Fiedler, Steven L.; Eloranta, Jussi

    2014-03-01

    The pair potentials between ground state helium and Rydberg He atoms are calculated by the full configuration interaction electronic structure method for both the electronic singlet and the triplet manifolds. The obtained pair potentials are validated against existing experimental molecular and atomic data. Most states show remarkable energy barriers at long distances ( Å), which can effectively stabilize He against the formation of He at low nuclear kinetic energies. Bosonic density functional theory calculations, based on the calculated pair potential data, indicate that the triplet ground state He reside in spherical bubbles in superfluid helium with a barycenter radius of 6.1 Å at the liquid saturated vapor pressure. The pressure dependency of the relative He absorption line blue shift in the liquid was obtained through both the statistical line broadening theory as well as the dynamic adiabatic following method. The pronounced difference between the results from the static and dynamic models is attributed to the dynamic Jahn-Teller effect that takes places in the electronically excited state within the dephasing time of 150 fs. Transient non-thermalized liquid surroundings near He may contribute to an artificial reduction in the absorption line blue shift by up to 30 cm.

  1. On the ground state of Yang-Mills theory

    SciTech Connect

    Bakry, Ahmed S., E-mail: abakry@physics.adelaide.edu.au [Special Research Center for the Subatomic Structure of Matter, Department of Physics, University of Adelaide, South Australia 5005 (Australia); Leinweber, Derek B.; Williams, Anthony G. [Special Research Center for the Subatomic Structure of Matter, Department of Physics, University of Adelaide, South Australia 5005 (Australia)

    2011-08-15

    Highlights: > The ground state overlap for sets of meson potential trial states is measured. > Non-uniform gluonic distributions are probed via Wilson loop operator. > The locally UV-regulated flux-tube operators can optimize the ground state overlap. - Abstract: We investigate the overlap of the ground state meson potential with sets of mesonic-trial wave functions corresponding to different gluonic distributions. We probe the transverse structure of the flux tube through the creation of non-uniform smearing profiles for the string of glue connecting two color sources in Wilson loop operator. The non-uniformly UV-regulated flux-tube operators are found to optimize the overlap with the ground state and display interesting features in the ground state overlap.

  2. Ground-state properties of ultracold trapped bosons with an immersed ionic impurity

    NASA Astrophysics Data System (ADS)

    Schurer, J. M.; Schmelcher, P.; Negretti, A.

    2014-09-01

    We consider a trapped atomic ensemble of interacting bosons in the presence of a single trapped ion in a quasi-one-dimensional geometry. Our study is carried out by means of the newly developed multilayer-multiconfiguration time-dependent Hartree method for bosons, a numerical exact approach to simulate quantum many-body dynamics. In particular, we are interested in the scenario by which the ion is so strongly trapped that its motion can be effectively neglected. This enables us to focus on the atomic ensemble only. With the development of a model potential for the atom-ion interaction, we are able to numerically obtain the exact many-body ground state of the atomic ensemble in the presence of an ion. We analyze the influence of the atom number and the atom-atom interaction on the ground-state properties. Interestingly, for weakly interacting atoms, we find that the ion impedes the transition from the ideal gas behavior to the Thomas-Fermi limit. Furthermore, we show that this effect can be exploited to infer the presence of the ion both in the momentum distribution of the atomic cloud and by observing the interference fringes occurring during an expansion of the quantum gas. In the strong interacting regime, the ion modifies the fragmentation process in dependence of the atom number parity which allows a clear identification of the latter in expansion experiments. Hence, we propose in both regimes experimentally viable strategies to assess the impact of the ion on the many-body state of the atomic gas. This study serves as the first building block for systematically investigating the many-body physics of such hybrid system.

  3. Ground states of the IRF model in two dimensions

    NASA Astrophysics Data System (ADS)

    Teubner, Max

    1996-08-01

    Some of the ground states of Baxter's IRF model in the square lattice are constructed. It is shown that the model has an infinite series of ground states which correspond to monodisperse close-packed triangles of fixed orientation and varying size.

  4. Theory of Ground State Factorization in Quantum Cooperative Systems

    Microsoft Academic Search

    Salvatore M. Giampaolo; Gerardo Adesso; Fabrizio Illuminati

    2008-01-01

    We introduce a general analytic approach to the study of factorization points and factorized ground states in quantum cooperative systems. The method allows us to determine rigorously the existence, location, and exact form of separable ground states in a large variety of, generally nonexactly solvable, spin models belonging to different universality classes. The theory applies to translationally invariant systems, irrespective

  5. GROUND STATES AND DYNAMICS OF SPIN-ORBIT-COUPLED ...

    E-print Network

    2014-11-07

    We study analytically and asymptotically as well as numerically ground states and ... system of quantum gas can be controlled with high precision in experiments. ..... We remark that our methods and results are still valid for ... In addition, the ground state ?g is a solution to the following nonlinear eigenvalue ..... is uniformly.

  6. Ground State Entanglement in One Dimensional Translationally Invariant Quantum Systems

    E-print Network

    Irani, Sandy

    Ground State Entanglement in One Dimensional Translationally Invariant Quantum Systems Sandy Irani {Hn} for the infinite chain. The spectral gap of Hn is (1/poly(n)). Moreover, for any state in the ground space of Hn and any m, there are regions of size m with entanglement entropy (min{m, n

  7. Partially autoionizing states of atomic oxygen

    NASA Technical Reports Server (NTRS)

    Samson, J. A. R.; Petrosky, V. E.

    1972-01-01

    The Rydberg states 3d' (3Po)2,1,0 and 3s'' (3Po)2,1,0 and the inner shell transition 2s 2p5 (3Po)2,1,0, which are forbidden to autoionize on the basis of LS coupling, were observed in emission spectroscopy and in autoionization spectra produced in the photoelectron spectrum of atomic oxygen.

  8. Atomic Schrödinger cat-like states

    NASA Astrophysics Data System (ADS)

    Enriquez-Flores, Marco; Rosas-Ortiz, Oscar

    2010-10-01

    After a short overview of the basic mathematical structure of quantum mechanics we analyze the Schrödinger's antinomic example of a living and dead cat mixed in equal parts. Superpositions of Glauber kets are shown to approximate such macroscopic states. Then, two-level atomic states are used to construct mesoscopic kittens as appropriate linear combinations of angular momentum eigenkets for j = 1/2. Some general comments close the present contribution.

  9. Optical pumping and population transfer of nuclear-spin states of caesium atoms in high magnetic fields

    Microsoft Academic Search

    Jun Luo; Xian-Ping Sun; Xi-Zhi Zeng; Ming-Sheng Zhan

    2007-01-01

    Nuclear-spin states of gaseous-state Cs atoms in the ground state are optically manipulated using a Ti:sapphire laser in a magnetic field of 1.516 T, in which optical coupling of the nuclear-spin states is achieved through hyperfine interactions between electrons and nuclei. The steady-state population distribution in the hyperfine Zeeman sublevels of the ground state is detected by using a tunable

  10. Mixed Valence and Spin States of the Two-Impurity System New Hartree-Fock Ground States

    Microsoft Academic Search

    Hiroyuki Kaga

    1981-01-01

    New Hartree-Fock ground states are shown to result in the two-impurity Anderson model when coupled to boson-like interactions. The new states are asymmetric in both charge and spin in the two sites and exhibit the two types corresponding to the different exchange mechanisms. This situation in which two identical atoms behave as two unbalanced centers may have a variety of

  11. Experimental evidence for an isotopic effect in the formation of ultracold ground-state rubidium dimers

    Microsoft Academic Search

    A. Fioretti; O. Dulieu; C. Gabbanini

    2007-01-01

    We perform a comparative study of the formation of ultracold rubidium dimers in their ground state with both 85Rb and 87Rb isotopes. Ultracold rubidium molecules are created through photoassociation of ultracold atoms into rovibrational levels of the 0+u(5S1\\/2 + 5P1\\/2) excited state, which interact through resonant coupling (Dion et al 2001 Phys. Rev. Lett. 86 2253) with rovibrational levels of

  12. Existence of ground states for negative ions at the binding threshold

    E-print Network

    Jacopo Bellazzini; Rupert L. Frank; Elliott H. Lieb; Robert Seiringer

    2013-01-23

    As the nuclear charge Z is continuously decreased an N-electron atom undergoes a binding-unbinding transition at some critical Z_c. We investigate whether the electrons remain bound when Z=Z_c and whether the radius of the system stays finite as Z_c is approached. Existence of a ground state at Z_c is shown under the condition Z_cground state energy.

  13. Dimerized ground state in the one-dimensional spin-1 boson Hubbard model

    SciTech Connect

    Apaja, Vesa; Syljuaasen, Olav F. [Institut fuer Theoretische Physik, Johannes-Kepler Universitaet, A-4040 Linz (Austria); Nordita, Blegdamsvej 17, DK-2100, Copenhagen O (Denmark)

    2006-09-15

    We have investigated the one-dimensional spin-1 boson Hubbard model with antiferromagnetic interactions using quantum Monte Carlo methods. We obtain the shapes of the two lowest Mott lobes and show that the ground state within the lowest Mott lobe is dimerized. The results presented here are relevant for optically trapped antiferromagnetic spin-1 bosons. An experimental signature of the dimerized ground state is modulated Bragg peaks in the noise distribution of the atomic cloud obtained after switching off the trap. These Bragg peaks are located at wave vectors corresponding to half-integer multiples of the reciprocal wave vector of the optical lattice.

  14. Measurements of ground-state properties for nuclear structure studies by precision mass and laser spectroscopy

    NASA Astrophysics Data System (ADS)

    Blaum, K.; Block, M.; Cakirli, R. B.; Eliseev, S.; Kowalska, M.; Kreim, S.; Litvinov, Y. A.; Nagy, Sz; Nörtershäuser, W.; Yordanov, D. T.

    2011-09-01

    Atomic physics techniques like Penning-trap and storage-ring mass spectrometry as well as laser spectroscopy have provided sensitive high-precision tools for detailed studies of nuclear ground-state properties far from the valley of ß-stability. Mass, moment and nuclear charge radius measurements in long isotopic and isotonic chains have allowed extraction of nuclear structure information such as halos, shell and subshell closures, the onset of deformation, and the coexistence of nuclear shapes at nearly degenerate energies. This review covers experimental precision techniques to study nuclear ground-state properties and some of the most recent results for nuclear structure studies.

  15. Interface Representations of Critical Ground States

    NASA Astrophysics Data System (ADS)

    Kondev, Jane

    1995-01-01

    We study the critical properties of the F model, the three-coloring model on the honeycomb lattice, and the four-coloring model on the square lattice, by mapping these models to models of rough interfaces. In particular, we construct operators in a systematic way, which is provided by the interface representation, and we show that their scaling dimensions can be related to the stiffness of the interface. Two types of operators are found, and they correspond to electric and magnetic charges in the Coulomb gas which is related to the interface model by the usual duality transformation. Furthermore, we find that the stiffness of the interface models, and therefore all the critical exponents, can be calculated exactly by considering the contour correlation function which measures the probability that two points on the interface belong to the same contour loop. The exact information about the stiffness also allows us to analyze in detail the conformal field theories (CFT) that represent the scaling limits of the interface models. We find that CFT's associated with the F model, the three -coloring model, and the four-coloring model, have chiral symmetry algebras given by the su(2)_{k=1 }, su(3)_{k=1}, and su(4) _{k=1} Kac-Moody algebras, respectively. The three-coloring and the four coloring-model are ground states of certain antiferromagnetic Potts models, and the behavior of these Potts models at small but finite temperatures is determined by topological defects that can be defined in the associated interface models. In this way we calculate the correlation length and the specific heat of the Potts models, and they are in good agreement with numerical simulations. We also present our Monte-Carlo results for the scaling dimensions of operators in the four-coloring model, and they are in excellent agreement with our analytical results. Finally, we define geometrical exponents for contour loops on self -affine interfaces and calculate their values as a function of the roughness exponent. The fractal dimension of contour loops on experimentally observed rough interfaces can be used to characterize their morphology.

  16. Multiple-time-scale perturbation theory: Radiative decay of coupled atomic states

    Microsoft Academic Search

    G. L. Brooks Jr.; L. M. Scarfone

    1982-01-01

    The spontaneous radiative decay to the ground state of an atomic system initially in the higher of two excited states, coupled in a radiationless fashion by an external field, is investigated by the method of multiple-time-scale perturbation theory. The coupled differential equations of motion for the probability amplitudes are solved to second order, while the usual secular behavior of conventional

  17. Electron impact ionization of metastable 2P-state hydrogen atoms in the coplanar geometry

    NASA Astrophysics Data System (ADS)

    Dhar, S.; Nahar, N.

    Triple differential cross sections (TDCS) for the ionization of metastable 2P-state hydrogen atoms by electrons are calculated for various kinematic conditions in the asymmetric coplanar geometry. In this calculation, the final state is described by a multiple-scattering theory for ionization of hydrogen atoms by electrons. Results show qualitative agreement with the available experimental data and those of other theoretical computational results for ionization of hydrogen atoms from ground state, and our first Born results. There is no available other theoretical results and experimental data for ionization of hydrogen atoms from the 2P state. The present study offers a wide scope for the experimental study for ionization of hydrogen atoms from the metastable 2P state.

  18. Gamow-Teller transitions from the 14N ground state to the 14C ground and excited states

    NASA Astrophysics Data System (ADS)

    Kanada-En'yo, Yoshiko; Suhara, Tadahiro

    2014-04-01

    Gamow-Teller transitions from the 14N ground state to the 14C ground and excited states were investigated, based on the model of antisymmetrized molecular dynamics. The calculated strengths for the allowed transitions to the 0+, 1+, and 2+ states of 14C were compared with the experimental data measured by high-resolution charge-exchange reactions. The calculated GT transition to the 21+ state is strong while those to the 02,3+ and 22,3+ states having dominant 2?? excited configurations are relatively weak. The present calculation cannot describe the anonymously long lifetime of 14C, though the strength of the 14C ground state is somewhat suppressed because of the cluster (many-body) correlation in the ground states of 14C and 14N.

  19. A resonant state and the ground state of positronium hydride

    NASA Technical Reports Server (NTRS)

    Ho, Y. K.

    1978-01-01

    The lowest-lying resonance occurring in S-wave positronium-hydrogen scattering is reinvestigated, using the complex-rotation method. By employing a generalized Hylleraas-type wave function that includes all six interparticle coordinates, a very accurate value of the resonance position is obtained, along with a good value of the width. The present result for the resonance position (-1.205 plus or minus 0.001 Ry) is lower than the previous result of Drachman and Houston, who omitted the interelectronic coordinate in their trial function. In addition, the lowest ground-state energy of positronium hydride is obtained by using 210 terms in the trial wave function. The effect of the interelectronic coordinate and others on both the resonant energy and the binding energy of PsH is discussed.

  20. Ground water contamination in the United States

    Microsoft Academic Search

    R. Patrick; E. Ford; J. Quarles

    1987-01-01

    This book demonstrates an exhaustive research effort into published reports and legal documents of which 344 are cited. From the literature, the authors selected 84 tables and 41 figures and maps, adding to the value of the collected body of information provided within the text. These summarize and graphically illustrate the 10 major ground water regions, population served by source

  1. Antifreeze acceptability for ground-coupled heat pump ground loops in the United States

    SciTech Connect

    Den Braven, K.R. [Univ. of Idaho, Moscow, ID (United States). Dept. of Mechanical Engineering

    1998-10-01

    When designing and installing closed-loop ground-coupled heat pumps systems, it is necessary to be aware of applicable environmental regulations. Within the United States, nearly half of the states have regulations specifying or restricting the use of particular antifreezes or other fluids within the ground loop of a ground-coupled heat pump system. A number of other states have regulations pending. While all of these regulations are based on the need to preserve groundwater and/or aquifer quality, the list of acceptable antifreezes varies among those states with specified fluids. Typical antifreezes in use include ethylene glycol, propylene glycol, brines, alcohols, and potassium acetate. Each of these has its benefits and drawbacks. The status of the regulations has been determined for all of the states. An overview of the regulations is presented in this paper, along with a summary of the states` concerns.

  2. Narrow chaotic compound autoionizing states in atomic spectra

    SciTech Connect

    Flambaum, V.V.; Gribakina, A.A.; Gribakin, G.F. [School of Physics, University of New South Wales, Sydney 2052 (Australia)] [School of Physics, University of New South Wales, Sydney 2052 (Australia)

    1996-09-01

    Simultaneous excitation of several valence electrons in atoms gives rise to a dense spectrum of compound autoionizing states (AIS). These states are almost chaotic superpositions of large numbers of many-electron basis states built of single-electron orbitals. The mean level spacing {ital D} between such states is very small (e.g., {ital D}{lt}0.01 eV for the numerical example of {ital J}{sup {pi}}=4{sup {minus}} states of Ce just above the ionization threshold). The autoionization widths of these states estimated by perturbations, {gamma}=2{pi}{vert_bar}{ital W}{vert_bar}{sup 2}, where {ital W} is the Coulomb matrix element coupling the AIS to the continuum, are also small, but comparable with {ital D} in magnitude: {gamma}{approximately}{ital D}. Hence the nonperturbative interaction of AIS with each other via the continuum is very essential. It suppresses greatly the widths of the autoionizing resonances ({Gamma}{approx_equal}{ital D}{sup 2}/3{gamma}{lt}{ital D}), and leads to the emergence of a {open_quote}{open_quote}collective{close_quote}{close_quote} doorway state which accumulates a large share of the total width. This state is in essence a modified single-particle continuum decoupled from the resonances due to its large width. Narrow compound AIS should be a common feature of atomic spectra at energies sufficient for excitation of several electrons above the ground-state configuration. The narrow resonances can be observed as peaks in the photoabsorption, or, in electron-ion scattering, as Fano-type profiles on the background provided by the wide doorway-state resonance. It is also shown that the statistics of electromagnetic and autoionization amplitudes involving compound states are close to Gaussian. {copyright} {ital 1996 The American Physical Society.}

  3. Ground-state energy of a polaron in n dimensions

    NASA Astrophysics Data System (ADS)

    Peeters, F. M.; Xiaoguang, Wu; Devreese, J. T.

    1986-03-01

    The Fröhlich Hamiltonian is generalized to the case of an electron moving in n space dimensions. For n=2 and n=3 the familiar Fröhlich Hamiltonian is reobtained. The polaron ground-state energy is calculated up to fourth order in perturbation theory. We found that within the Feynman two-particle polaron model approximation the polaron ground-state energy satisfies the scaling relation EnD(?)=(n/3)E3D(\\{?[ (n-1)/2]3 ?? /2n?(n/2)\\}?), where EnD is the Feynman polaron ground-state energy for the polaron in n dimensions and E3D the energy in three dimensions.

  4. Encoding universal computation in the ground states of Ising lattices.

    PubMed

    Gu, Mile; Perales, Įlvaro

    2012-07-01

    We characterize the set of ground states that can be synthesized by classical two-body Ising Hamiltonians. We then construct simple Ising planar blocks that simulate efficiently a universal set of logic gates and connections, and hence any Boolean function. We therefore provide a new method of encoding universal computation in the ground states of Ising lattices and a simpler alternative demonstration of the known fact that finding the ground state of a finite Ising spin glass model is NP complete. We relate this with our previous result about emergent properties in infinite lattices. PMID:23005377

  5. Entangled states of trapped atomic ions

    Microsoft Academic Search

    Rainer Blatt; David Wineland

    2008-01-01

    To process information using quantum-mechanical principles, the states of individual particles need to be entangled and manipulated. One way to do this is to use trapped, laser-cooled atomic ions. Attaining a general-purpose quantum computer is, however, a distant goal, but recent experiments show that just a few entangled trapped ions can be used to improve the precision of measurements. If

  6. GROUND-WATER POLLUTION PROBLEMS IN THE SOUTHEASTERN UNITED STATES

    EPA Science Inventory

    An evaluation of principal sources of ground-water contamination has been carried out in seven southeastern States--Alabama, Florida, Georgia, Mississippi, North Carolina, South Carolina, and Virginia. Natural ground-water quality is good to excellent, except for the presence of ...

  7. On the atomic state densities of plasmas produced by the ``torche ą injection axiale''

    NASA Astrophysics Data System (ADS)

    Jonkers, J.; Vos, H. P. C.; van der Mullen, J. A. M.; Timmermans, E. A. H.

    1996-04-01

    The atomic state densities of helium and argon plasmas produced by the microwave driven plasma torch called the "torche ą injection axiale" are presented. They are obtained by absolute line intensity measurements of the excited states and by applying the ideal gas law to the ground state. It will be shown that the atomic state distribution function (ASDF) does not obey the Saha-Boltzmann law: the ASDF cannot be described by one temperature. From the shape of the ASDF it can be concluded that the plasma is ionising. By extrapolating the measured state densities towards the ionisation limit, a minimum value of the electron density can be determined.

  8. Approximating the ground state of gapped quantum spin systems

    SciTech Connect

    Michalakis, Spyridon [Los Alamos National Laboratory; Hamza, Eman [NON LANL; Nachtergaele, Bruno [NON LANL; Sims, Robert [NON LANL

    2009-01-01

    We consider quantum spin systems defined on finite sets V equipped with a metric. In typical examples, V is a large, but finite subset of Z{sup d}. For finite range Hamiltonians with uniformly bounded interaction terms and a unique, gapped ground state, we demonstrate a locality property of the corresponding ground state projector. In such systems, this ground state projector can be approximated by the product of observables with quantifiable supports. In fact, given any subset {chi} {contained_in} V the ground state projector can be approximated by the product of two projections, one supported on {chi} and one supported on {chi}{sup c}, and a bounded observable supported on a boundary region in such a way that as the boundary region increases, the approximation becomes better. Such an approximation was useful in proving an area law in one dimension, and this result corresponds to a multi-dimensional analogue.

  9. Separability and ground state factorization in quantum spin systems

    E-print Network

    Giampaolo, S M; Illuminati, F

    2009-01-01

    We investigate the existence and the properties of fully separable (fully factorized) ground states in quantum spin systems. Exploiting techniques of quantum information and entanglement theory we extend a recently introduced method and construct a general, self-contained theory of ground state factorization in frustration-free quantum spin models defined on lattices in any spatial dimension and for interactions of arbitrary range. We show that, quite generally, non exactly solvable models in external field admit exact, fully factorized ground state solutions. Unentangled ground states occur at finite values of the Hamiltonian parameters satisfying well defined balancing conditions between external fields and interaction strengths. These conditions are analytically determined together with the type of magnetic orderings compatible with factorization and the corresponding values of the fundamental observables such as energy and magnetization. The method is applied to a series of examples of increasing complexi...

  10. The ground state well depth position Rm of Van der Waals molecules and the spectral line shapes

    Microsoft Academic Search

    G. D. Roston; M. S. Helmi

    2006-01-01

    As the ground state potential curve is strongly related to spectral line shapes, the minumum position of the ground state potential is obtained from the experiemental absorption profile k(Deltanu, T) at high density of the radiating atoms. The temperature dependence of the absorption processes of Hg and Cd lines 253.65 and 326.1 nm, respectively perturbed by inert gases (Xe, Kr,

  11. The ground state well depth position R m of Van der Waals molecules and the spectral line shapes

    Microsoft Academic Search

    G. D. Roston; M. S. Helmi

    2006-01-01

    As the ground state potential curve is strongly related to spectral line shapes, the minumum position of the ground state potential is obtained from the experiemental absorption profile k(??, T) at high density of the radiating atoms. The temperature dependence of the absorption processes of Hg and Cd lines 253.65 and 326.1nm, respectively perturbed by inert gases (Xe, Kr, Ar

  12. Theory of ground state factorization in quantum cooperative systems

    E-print Network

    S. M. Giampaolo; G. Adesso; F. Illuminati

    2008-04-01

    We introduce a general analytic approach to the study of factorization points and factorized ground states in quantum cooperative systems. The method allows to determine rigorously existence, location, and exact form of separable ground states in a large variety of, generally non-exactly solvable, spin models belonging to different universality classes. The theory applies to translationally invariant systems, irrespective of spatial dimensionality, and for spin-spin interactions of arbitrary range.

  13. Theory of ground state factorization in quantum cooperative systems

    E-print Network

    Giampaolo, S M; Illuminati, F

    2008-01-01

    We introduce a general analytic approach to the study of factorization points and factorized ground states in quantum cooperative systems. The method allows to determine rigorously existence, location, and exact form of separable ground states in a large variety of, generally non-exactly solvable, spin models belonging to different universality classes. The theory applies to translationally invariant systems, irrespective of spatial dimensionality, and for spin-spin interactions of arbitrary range.

  14. Ground state energy fluctuations in the nuclear shell model

    Microsoft Academic Search

    Vķctor Velįzquez; Jorge G. Hirsch; Alejandro Frank; José Barea; Andrés P. Zuker

    2005-01-01

    Statistical fluctuations of the nuclear ground state energies are estimated using shell model calculations in which particles in the valence shells interact through well-defined forces, and are coupled to an upper shell governed by random 2-body interactions. Induced ground-state energy fluctuations are found to be one order of magnitude smaller than those previously associated with chaotic components, in close agreement

  15. Theory of ground state factorization in quantum cooperative systems.

    PubMed

    Giampaolo, Salvatore M; Adesso, Gerardo; Illuminati, Fabrizio

    2008-05-16

    We introduce a general analytic approach to the study of factorization points and factorized ground states in quantum cooperative systems. The method allows us to determine rigorously the existence, location, and exact form of separable ground states in a large variety of, generally nonexactly solvable, spin models belonging to different universality classes. The theory applies to translationally invariant systems, irrespective of spatial dimensionality, and for spin-spin interactions of arbitrary range. PMID:18518481

  16. The structure and energetics of TPD ground and excited states

    Microsoft Academic Search

    Igor Vragovic; Eva M. Calzado; Marķa A. Dķaz Garcķa

    2007-01-01

    We analyse the optimized geometric structure and energies of N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine (TPD) neutral molecule in ground and excited states. Ab initio calculations are performed at the Hartree Fock (HF) or single-excitation (CIS) level with 6-31G basis set using Gaussian 98 program. We got a good qualitative agreement with the results for the neutral molecule in the ground state obtained by density

  17. Ground State of the H3+ Molecular Ion: Physics Behind

    NASA Astrophysics Data System (ADS)

    Turbiner, A. V.; Lopez Vieyra, J. C.

    2013-10-01

    Five physics mechanisms of interaction leading to the binding of the H3+ molecular ion are identified. They are realized in a form of variational trial functions, and their respective total energies are calculated. Each of them provides subsequently the most accurate approximation for the Born-Oppenheimer (BO) ground state energy among (two-three-seven)-parametric trial functions being, correspondingly, H2-molecule plus proton (two variational parameters), H2+-ion plus H-atom (three variational parameters), and generalized Guillemin-Zener (seven variational parameters). These trial functions are chosen following a criterion of physical adequacy. They include the electronic correlation in the exponential form, exp(-r12), where - is a variational parameter. Superpositions of two different mechanisms of binding are investigated, and a particular one, which is a generalized Guillemin-Zener plus H2-molecule plus proton (ten variational parameters), provides the total energy at the equilibrium of E = -1.3432 au. The superposition of three mechanisms, generalized Guillemin-Zener plus (H2-molecule plus proton) plus (H2+-ion plus H) (14 parameters) leads to the total energy, which deviates from the best known BO energy to -0.0004 au, it reproduces two-three significant digits in exact, non-BO total energy. In general, our variational energy agrees in two-three-four significant digits with the most accurate results available at present as well as major expectation values.

  18. All-optical scheme for strongly enhanced production of a Bose-Einstein condensate of dipolar molecules in the vibronic ground state

    NASA Astrophysics Data System (ADS)

    Mackie, Matt; Debrosse, Catherine

    2010-04-01

    We consider two-color heteronuclear photoassociation of a dual-species Bose-Einstein condensate into a Bose-Einstein condensate of dipolar molecules in the J=1 vibronic ground state, where a free-ground laser couples atoms directly to the ground state and a free-bound laser couples the atoms to an electronically excited state. This problem raises an interest because heteronuclear photoassociation from atoms to near-ground-state molecules is limited by the small size of the target state. Nevertheless, the addition of the electronically excited state creates a second pathway for creating molecules in the vibronic ground state, leading to quantum interference between direct photoassociation and photoassociation via the excited molecular state, as well as a dispersivelike shift of the free-ground resonance position. Using LiNa as an example, these results are shown to depend on the detuning and intensity of the free-bound laser, as well as the semiclassical size of both molecular states. Whereas strong enhancement enables saturation of the free-ground transition, coherent conversion from a two-species condensate of atoms to a condensate of dipolar molecules in the vibronic ground state is only possible for a limited range of free-bound detunings near resonance.

  19. Calculation of ground- and excited-state potential energy curves for the Cd-rare gas complexes

    Microsoft Academic Search

    E. Czuchaj; H. Stoll

    1999-01-01

    Adiabatic potential curves for the ground state and several low-lying excited states of the cadmium atom interacting with He, Ne, Ar, Kr and Xe have been obtained from valence ab-initio CASSCF\\/CASPT2 calculations. The Cd2+ and the rare-gas-atom RG8+ cores are replaced by scalar-relativistic energy-consistent pseudopotentials; in the former case, a core-polarization potential has been added in order to account for

  20. Protocol for Atomic Oxygen Testing of Materials in Ground-Based Facilities. No. 2

    NASA Technical Reports Server (NTRS)

    Minton, Timothy K.

    1995-01-01

    A second version of standard guidelines is proposed for improving materials testing in ground-based atomic oxygen environments for the purpose of predicting the durability of the tested materials in low Earth orbit (LEO). Accompanying these guidelines are background information and notes about testing. Both the guidelines and the additional information are intended to aid users who wish to evaluate the potential hazard of atomic oxygen in LEO to a candidate space component without actually flying the component in space, and to provide a framework for more consistent atomic oxygen testing in the future.

  1. Generalized Collective States and Their Role in a Collective State Atomic Interferometer and Atomic Clock

    E-print Network

    Sarkar, Resham; Fang, Renpeng; Tu, Yanfei; Shahriar, Selim M

    2014-01-01

    We investigate the behavior of an ensemble of N non-interacting, identical atoms, excited by a laser with a wavelength of $\\lambda$. In general, the i-th atom sees a Rabi frequency $\\Omega_i$, an initial position dependent laser phase $\\phi_i$, and a motion induced Doppler shift of $\\delta_i$. When $\\Omega_i=\\Omega$ and $\\delta_i=\\delta$ for all atoms, the system evolves into a superposition of (N+1) symmetric collective states (SCS), independent of the values of $\\phi_i$. If $\\phi_i=\\phi$ for all atoms, these states simplify to the well-known Dicke collective states. When $\\Omega_i$ or $\\delta_i$ is distinct for each atom, the system evolves into a superposition of SCS as well as asymmetric collective states (ACS). For large N, the number of ACS's $(2^N-N-1)$ is far greater than that of the SCS. We show how to formulate the properties of all the collective states under various non-idealities, and use this formulation to understand the dynamics thereof. For the case where $\\Omega_i=\\Omega$ and $\\delta_i=\\delt...

  2. Direct measurement of concurrence for atomic two-qubit pure states

    SciTech Connect

    Romero, G.; Lopez, C. E.; Lastra, F.; Retamal, J. C. [Departamento de Fisica, Universidad de Santiago de Chile, Casilla 307 Correo 2, Santiago (Chile); Solano, E. [Physics Department, ASC, and CeNS, Ludwig-Maximilians-Universitaet, Theresienstrasse 37, D-80333 Munich (Germany); Seccion Fisica, Departamento de Ciencias, Pontificia Universidad Catolica del Peru, Apartado 1761, Lima (Peru)

    2007-03-15

    We propose a general scheme to measure the concurrence of an arbitrary two-qubit pure state in atomic systems. The protocol is based on one- and two-qubit operations acting on two available copies of the bipartite system, and followed by a global qubit readout. We show that it is possible to encode the concurrence in the probability of finding all atomic qubits in the ground state. Two possible scenarios are considered: atoms crossing three-dimensional microwave cavities and trapped ion systems.

  3. Nonlinear Faraday rotation and detection of superposition states in cold atoms

    SciTech Connect

    Wojciechowski, Adam; Zachorowski, Jerzy; Gawlik, Wojciech [Institute of Physics, Jagiellonian University, Reymonta 4, PL-30-059 Krakow (Poland); Joint Krakow-Berkeley Atomic Physics and Photonics Laboratory, Reymonta 4, PL-30-059 Krakow (Poland); Corsini, Eric [Department of Physics, University of California, Berkeley, California 94720-7300 (United States); Joint Krakow-Berkeley Atomic Physics and Photonics Laboratory, Reymonta 4, PL-30-059 Krakow (Poland)

    2010-05-15

    We report on the observation of nonlinear Faraday rotation with cold atoms at a temperature of {approx}100 {mu}K. The observed nonlinear rotation of the light polarization plane is up to 0.1 rad over the 1-mm-size atomic cloud in approximately 10-mG magnetic field. The nonlinearity of rotation results from long-lived coherence of ground-state Zeeman sublevels created by a near-resonant light. The method allows for creation, detection, and control of atomic superposition states. It also allows applications for precision magnetometry with high spatial and temporal resolution.

  4. Continuous Measurement Quantum State Tomography of Atomic Ensembles

    E-print Network

    Carlos A. Riofrķo

    2011-11-23

    Quantum state tomography is a fundamental tool in quantum information processing. It allows us to estimate the state of a quantum system by measuring different observables on many identically prepared copies of the system. This is, in general, a very time-consuming task that requires a large number of measurements. There are, however, systems in which the data acquisition can be done more efficiently. In fact, an ensemble of quantum systems can be prepared and manipulated by external fields while being continuously and collectively probed, producing enough information to estimate its state. This provides a basis for continuous measurement quantum tomography. In this protocol, an ensemble of identically prepared systems is collectively probed and controlled in a time-dependent manner to create an informationally complete continuous measurement record. The measurement history is then inverted to determine the state at the initial time. We use two different estimation methods: maximum likelihood and compressed sensing. The general formalism is applied to the case of reconstruction of the quantum state encoded in the magnetic sub-levels of a large-spin alkali atom, ${}^{133}$Cs. We apply this protocol to the case of reconstruction of states in the full 16-dimensional electronic-ground subspace ($F=3 \\oplus F=4$), controlled by microwaves and radio-frequency magnetic fields. We present an experimental demonstration of continuous measurement quantum tomography in an ensemble of cold cesium atoms with full control of its 16-dimensional Hilbert space. We show the exquisite level of control achieved in the lab and the excellent agreement between the theory discussed in this dissertation and the experimental results. This allows us to achieve fidelities >95% for low complexity quantum states, and >92% for arbitrary random states, which is a formidable accomplishment for a space of this size.

  5. Heat of Mixing and Ground-State Energy of Liquid He3He4 Mixtures

    Microsoft Academic Search

    P. Seligmann; D. O. Edwards; R. E. Sarwinski; J. T. Tough

    1969-01-01

    The heat evolved when He3 is added to liquid He3-He4 mixtures at the saturated vapor pressure has been measured for temperatures in the region of 0.05° K. The starting concentrations varied between zero and six atomic percent of He3. Since the variation of the energy with temperature (the specific heat) is known, the experiments give the ground-state energy and the

  6. Concentration for unknown atomic entangled states via cavity decay

    SciTech Connect

    Cao Zhuoliang; Yang Ming [School of Physics and Material Science, Anhui University, Hefei, 230039 (China); Zhang Lihua [School of Physics and Material Science, Anhui University, Hefei, 230039 (China); Department of Physics, Anqing Teacher College, Anqing, 246011 (China)

    2006-01-15

    We present a physical scheme for entanglement concentration of unknown atomic entangled states via cavity decay. In the scheme, the atomic state is used as a stationary qubit and the photonic state as a flying qubit, and a close maximally entangled state can be obtained from pairs of partially entangled states probabilistically.

  7. Towards new states of matter with atoms and photons

    E-print Network

    Towards new states of matter with atoms and photons Jonas Larson Stockholm University and Universität zu Köln Aarhus "Cold atoms and beyond" 26/6-2014 #12;Motivation Optical lattices + control QED = coupling between few material (atomic) and few electromagnetic degrees of freedom. Cavity atom

  8. Graph states as ground states of two-body frustration-free Hamiltonians

    NASA Astrophysics Data System (ADS)

    Darmawan, Andrew S.; Bartlett, Stephen D.

    2014-07-01

    The framework of measurement-based quantum computation (MBQC) allows us to view the ground states of local Hamiltonians as potential resources for universal quantum computation. A central goal in this field is to find models with ground states that are universal for MBQC and that are also natural in the sense that they involve only two-body interactions and have a small local Hilbert space dimension. Graph states are the original resource states for MBQC, and while it is not possible to obtain graph states as exact ground states of two-body Hamiltonians, here we construct two-body frustration-free Hamiltonians that have arbitrarily good approximations of graph states as unique ground states. The construction involves taking a two-body frustration-free model that has a ground state convertible to a graph state with stochastic local operations, then deforming the model such that its ground state is close to a graph state. Each graph state qubit resides in a subspace of a higher dimensional particle. This deformation can be applied to two-body frustration-free Affleck-Kennedy-Lieb-Tasaki (AKLT) models, yielding Hamiltonians that are exactly solvable with exact tensor network expressions for ground states. For the star-lattice AKLT model, the ground state of which is not expected to be a universal resource for MBQC, applying such a deformation appears to enhance the computational power of the ground state, promoting it to a universal resource for MBQC. Transitions in computational power, similar to percolation phase transitions, can be observed when Hamiltonians are deformed in this way. Improving the fidelity of the ground state comes at the cost of a shrinking gap. While analytically proving gap properties for these types of models is difficult in general, we provide a detailed analysis of the deformation of a spin-1 AKLT state to a linear graph state.

  9. Graph states as ground states of two-body frustration-free Hamiltonians

    E-print Network

    Andrew S. Darmawan; Stephen D. Bartlett

    2014-07-10

    The framework of measurement-based quantum computation (MBQC) allows us to view the ground states of local Hamiltonians as potential resources for universal quantum computation. A central goal in this field is to find models with ground states that are universal for MBQC and that are also natural in the sense that they involve only two-body interactions and have a small local Hilbert space dimension. Graph states are the original resource states for MBQC, and while it is not possible to obtain graph states as exact ground states of two-body Hamiltonians here we construct two-body frustration-free Hamiltonians that have arbitrarily good approximations of graph states as unique ground states. The construction involves taking a two-body frustration-free model that has a ground state convertible to a graph state with stochastic local operations, then deforming the model such that its ground state is close to a graph state. Each graph state qubit resides in a subspace of a higher dimensional particle. This deformation can be applied to two-body frustration-free Affleck-Kennedy-Lieb-Tasaki (AKLT) models, yielding Hamiltonians that are exactly solvable with exact tensor network expressions for ground states. For the star-lattice AKLT model, the ground state of which is not expected to be a universal resource for MBQC, applying such a deformation appears to enhance the computational power of the ground state, promoting it to a universal resource for MBQC. Transitions in computational power, similar to percolation phase transitions, can be observed when Hamiltonians are deformed in this way. Improving the fidelity of the ground state comes at the cost of a shrinking gap. While analytically proving gap properties for these types of models is difficult in general, we provide a detailed analysis of the deformation of a spin-1 AKLT state to a linear graph state.

  10. Spin of the sup 219 Ra ground state

    SciTech Connect

    Hackett, E.D.; Kuehner, J.A.; Waddington, J.C. (Tandem Accelerator Laboratory, McMaster University, Hamilton, Ontario, Canada L8S 4K1 (CA)); Jones, G.D. (Department of Physics, Oliver Lodge Laboratory, University of Liverpool, Liverpool L69 3BX, United Kingdom)

    1989-09-01

    The {sup 208}Pb({sup 18}O,3{ital n}){sup 223}Th reaction at 83 MeV bombarding energy was used to populate the alpha-radioactive nucleus {sup 223}Th. Out-of-beam alpha-gamma coincidences were recorded at correlation angles of 90{degree} and 180{degree}. The {ital a}{sub 2} angular correlation coefficient was extracted for an alpha-gamma cascade to the {sup 215}Rn ground state via the 0.316 MeV excited state. This limited the assignment of the ground-state spin of {sup 219}Ra to ((7/2, 11) / 2 ){sup +}. .AE

  11. Ensemble Theory for Stealthy Hyperuniform Disordered Ground States

    NASA Astrophysics Data System (ADS)

    Torquato, S.; Zhang, G.; Stillinger, F. H.

    2015-04-01

    It has been shown numerically that systems of particles interacting with isotropic "stealthy" bounded long-ranged pair potentials (similar to Friedel oscillations) have classical ground states that are (counterintuitively) disordered, hyperuniform, and highly degenerate. Disordered hyperuniform systems have received attention recently because they are distinguishable exotic states of matter poised between a crystal and liquid that are endowed with novel thermodynamic and physical properties. The task of formulating an ensemble theory that yields analytical predictions for the structural characteristics and other properties of stealthy degenerate ground states in d -dimensional Euclidean space Rd is highly nontrivial because the dimensionality of the configuration space depends on the number density ? and there is a multitude of ways of sampling the ground-state manifold, each with its own probability measure for finding a particular ground-state configuration. The purpose of this paper is to take some initial steps in this direction. Specifically, we derive general exact relations for thermodynamic properties (energy, pressure, and isothermal compressibility) that apply to any ground-state ensemble as a function of ? in any d , and we show how disordered degenerate ground states arise as part of the ground-state manifold. We also derive exact integral conditions that both the pair correlation function g2(r ) and structure factor S (k ) must obey for any d . We then specialize our results to the canonical ensemble (in the zero-temperature limit) by exploiting an ansatz that stealthy states behave remarkably like "pseudo"-equilibrium hard-sphere systems in Fourier space. Our theoretical predictions for g2(r ) and S (k ) are in excellent agreement with computer simulations across the first three space dimensions. These results are used to obtain order metrics, local number variance, and nearest-neighbor functions across dimensions. We also derive accurate analytical formulas for the structure factor and thermal expansion coefficient for the excited states at sufficiently small temperatures for any d . The development of this theory provides new insights regarding our fundamental understanding of the nature and formation of low-temperature states of amorphous matter. Our work also offers challenges to experimentalists to synthesize stealthy ground states at the molecular level.

  12. Photoionization of ground and excited states of Ti I

    NASA Astrophysics Data System (ADS)

    Nahar, Sultana N.

    2015-07-01

    Detailed photoionization of ground and many excited states with autoionizing resonances of neutral Ti are presented. Ti I with 22 electrons forms a large number of bound states, the present work finds a total of 908 bound states with n ? 10 and l ? 8 . Photoionization cross sections (?PI) for all these bound states have been obtained. Calculations were carried out in the close-coupling R-matrix method using a wave function expansion that included 36 states of core ion Ti II. It is found that the resonances enhance the low energy region of photoionization of the ground and low lying excited states. The resonant features will increase the opacity, as expected of astrophysical observation, and hence play important role in determination of abundances in the elements in the astronomical objects. The excited states also show prominent structures of Seaton or photo-excitation-of-core resonances.

  13. Discontinuity in the Polaron Ground State

    Microsoft Academic Search

    Atsuko Sumi; Yutaka Toyozawa

    1973-01-01

    With Feynman's path integral method applied to an electron interacting with acoustic as well as with optical modes of lattice vibrations, it is shown that the abrupt change, as coupling increases, of the polaron state from nearly free type to self-trapping type is caused by the short range interaction (deformation potential due to acoustic vibrations) but not by the long

  14. Generating atomic multi-dimensional entangled states under large atom-cavity detuning

    E-print Network

    Peng Shi; Li-Bo Chen; Wen-Dong Li; Chun-Nian Ren; Chun-Hong Zheng; Yong-Jian Gu

    2012-09-25

    We propose a scheme to deterministically generate atomic two-dimensional and three-dimensional entangled states by passing two 87Rb atoms through a high-Q bi-mode cavity alternately. The scheme is insensitive to atomic spontaneous decay because of large atom-cavity detuning, the influence of cavity decay is also discussed. Our strictly numerical simulation shows our proposal is good enough to demonstrate the generation of atomic entanglement with high fidelity and within the current experimental technologies.

  15. Coherent States for the Hydrogen Atom John R. Klauder

    E-print Network

    Coherent States for the Hydrogen Atom by John R. Klauder Departments of Physics and Mathematics University of Florida, Gainesville, FL 32611 Abstract The long­standing problem of finding coherent states for the (bound state portion of the) hydrogen atom is positively resolved. The states in question: (i

  16. Optical emission spectroscopy of metal-halide lamps: Radially resolved atomic state distribution functions of Dy and Hg

    NASA Astrophysics Data System (ADS)

    Nimalasuriya, T.; Flikweert, A. J.; Stoffels, W. W.; Haverlag, M.; van der Mullen, J. J. A. M.; Pupat, N. B. M.

    2006-03-01

    Absolute line intensity measurements are performed on a metal-halide lamp. Several transitions of atomic and ionic Dy and atomic Hg are measured at different radial positions from which we obtain absolute atomic and ionic Dy intensity profiles. From these profiles we construct the radially resolved atomic state distribution function (ASDF) of the atomic and ionic Dy and the atomic Hg. From these ASDFs several quantities are determined as functions of radial position, such as the (excitation) temperature, the ion ratio Hg+/Dy+, the electron density, the ground state, and the total density of Dy atoms and ions. Moreover, these ASDFs give us insight about the departure from equilibrium. The measurements show a hollow density profile for the atoms and the ionization of atoms in the center. In the outer parts of the lamp molecules dominate.

  17. Optical emission spectroscopy of metal-halide lamps: Radially resolved atomic state distribution functions of Dy and Hg

    SciTech Connect

    Nimalasuriya, T.; Flikweert, A.J.; Stoffels, W.W.; Haverlag, M.; Mullen, J.J.A.M. van der; Pupat, N.B.M. [Department of Applied Physics, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Ecole Nationale Superieure de Chimie de Paris, 11 Rue Pierre et Marie Curie, 75005 Paris (France)

    2006-03-01

    Absolute line intensity measurements are performed on a metal-halide lamp. Several transitions of atomic and ionic Dy and atomic Hg are measured at different radial positions from which we obtain absolute atomic and ionic Dy intensity profiles. From these profiles we construct the radially resolved atomic state distribution function (ASDF) of the atomic and ionic Dy and the atomic Hg. From these ASDFs several quantities are determined as functions of radial position, such as the (excitation) temperature, the ion ratio Hg{sup +}/Dy{sup +}, the electron density, the ground state, and the total density of Dy atoms and ions. Moreover, these ASDFs give us insight about the departure from equilibrium. The measurements show a hollow density profile for the atoms and the ionization of atoms in the center. In the outer parts of the lamp molecules dominate.

  18. Ground-State Electromagnetic Moments of Calcium Isotopes

    E-print Network

    Ruiz, R F Garcia; Blaum, K; Frommgen, N; Hammen, M; Holt, J D; Kowalska, M; Kreim, K; Menendez, J; Neugart, R; Neyens, G; Nortershauser, W; Nowacki, F; Papuga, J; Poves, A; Schwenk, A; Simonis, J; Yordanov, D T

    2015-01-01

    High-resolution bunched-beam collinear laser spectroscopy was used to measure the optical hyperfine spectra of the $^{43-51}$Ca isotopes. The ground state magnetic moments of $^{49,51}$Ca and quadrupole moments of $^{47,49,51}$Ca were measured for the first time, and the $^{51}$Ca ground state spin $I=3/2$ was determined in a model-independent way. Our results provide a critical test of modern nuclear theories based on shell-model calculations using phenomenological as well as microscopic interactions. The results for the neutron-rich isotopes are in excellent agreement with predictions using interactions derived from chiral effective field theory including three-nucleon forces, while lighter isotopes illustrate the presence of particle-hole excitations of the $^{40}$Ca core in their ground state.

  19. Ground-State Electromagnetic Moments of Calcium Isotopes

    E-print Network

    R. F. Garcia Ruiz; M. L. Bissell; K. Blaum; N. Frommgen; M. Hammen; J. D. Holt; M. Kowalska; K. Kreim; J. Menendez; R. Neugart; G. Neyens; W. Nortershauser; F. Nowacki; J. Papuga; A. Poves; A. Schwenk; J. Simonis; D. T. Yordanov

    2015-04-17

    High-resolution bunched-beam collinear laser spectroscopy was used to measure the optical hyperfine spectra of the $^{43-51}$Ca isotopes. The ground state magnetic moments of $^{49,51}$Ca and quadrupole moments of $^{47,49,51}$Ca were measured for the first time, and the $^{51}$Ca ground state spin $I=3/2$ was determined in a model-independent way. Our results provide a critical test of modern nuclear theories based on shell-model calculations using phenomenological as well as microscopic interactions. The results for the neutron-rich isotopes are in excellent agreement with predictions using interactions derived from chiral effective field theory including three-nucleon forces, while lighter isotopes illustrate the presence of particle-hole excitations of the $^{40}$Ca core in their ground state.

  20. Probing Quantum Frustrated Systems via Factorization of the Ground State

    E-print Network

    Salvatore M. Giampaolo; Gerardo Adesso; Fabrizio Illuminati

    2010-05-20

    The existence of definite orders in frustrated quantum systems is related rigorously to the occurrence of fully factorized ground states below a threshold value of the frustration. Ground-state separability thus provides a natural measure of frustration: strongly frustrated systems are those that cannot accommodate for classical-like solutions. The exact form of the factorized ground states and the critical frustration are determined for various classes of nonexactly solvable spin models with different spatial ranges of the interactions. For weak frustration, the existence of disentangling transitions determines the range of applicability of mean-field descriptions in biological and physical problems such as stochastic gene expression and the stability of long-period modulated structures.

  1. Probing quantum frustrated systems via factorization of the ground state.

    PubMed

    Giampaolo, Salvatore M; Adesso, Gerardo; Illuminati, Fabrizio

    2010-05-21

    The existence of definite orders in frustrated quantum systems is related rigorously to the occurrence of fully factorized ground states below a threshold value of the frustration. Ground-state separability thus provides a natural measure of frustration: strongly frustrated systems are those that cannot accommodate for classical-like solutions. The exact form of the factorized ground states and the critical frustration are determined for various classes of nonexactly solvable spin models with different spatial ranges of the interactions. For weak frustration, the existence of disentangling transitions determines the range of applicability of mean-field descriptions in biological and physical problems such as stochastic gene expression and the stability of long-period modulated structures. PMID:20867055

  2. Improved fair sampling of ground states in Ising spin glasses

    NASA Astrophysics Data System (ADS)

    Katzgraber, Helmut G.; Zhu, Zheng; Ochoa, Andrew J.

    2015-03-01

    Verifying that an optimization approach can sample all solutions that minimize a Hamiltonian is a stringent test for any newly-developed algorithm. While most solvers easily compute the minimum of a cost function for small to moderate input sizes, equiprobable sampling of all ground-state configurations (within Poissonian fluctuations) is much harder to obtain. Most notably, methods such as transverse-field quantum annealing fail in passing this test for certain highly-degenerate problems. Here we present an attempt to sample ground states for Ising spin glasses based on a combination of low-temperature parallel tempering Monte Carlo combined with the cluster algorithm by Houdayer. Because the latter is rejection free and obeys details balance, the ground-state manifold is efficiently sampled. We illustrate the approach for Ising spin glasses on the D-Wave Two quantum annealer topology, known as the Chimera graph, as well as two-dimensional Ising spin glasses.

  3. Relativistic ground state of the heavy helium-like ions

    NASA Astrophysics Data System (ADS)

    Pruß-Hunzinger, S.; Mattes, M.; Sorg, M.

    2004-03-01

    The ground state of the two electrons in the Coulomb field of the highly charged ions ( Z ? 32) is analyzed within the context of Relativistic Schrödinger Theory (RST). Exploiting here the isotropic geometry of the ground state, the corresponding RST-Maxwell-Dirac eigenvalue system can be written down as a coupled system of ordinary differential equations for two radial ansatz functions R ±(r). The solutions of this coupled system are determined by numerical integration which admits to calculate the relativistic ground-state energy as the value of the RST energy functional upon these solutions. It is found that the RST predictions are of similar precision (relative to the experimental data) as the other theoretical approaches available in the literature. However it is also demonstrated that further progress can be made only by extending the RST formalism to take into account the self-energy effects.

  4. Chaotic compound states and resonances in many-electron atoms

    NASA Astrophysics Data System (ADS)

    Gribakina, Anna

    A realistic model of a quantum chaotic system, Ce atom, is analyzed. Using the relativistic CI method the spectra and the wave functions of odd and even levels of Ce with J=4 are calculated. It is shown that the structure of the excited states at excitation energies above 1 eV becomes similar to that of the compound states in heavy nuclei. The localization of the eigenstates on the energy scale is characterized by the spread width ?~ND, where D is the mean level spacing. The emergence of chaos in the spectrum, and the dependence of the N and ? on the excitation energy is studied. The structure of the real interaction matrix is compared with that assumed in the Band Random Matrix models. A formula expressing the mean squared values of matrix elements between the eigenstates is derived, and its applicability is checked. The hypothesis of a Gaussian distribution of the eigenstates' components and matrix elements has been checked. The existence of the dynamical enhancement of weak perturbations in systems with dense spectra is demonstrated. Simultaneous excitation of several valence electrons in atoms gives rise to a dense spectrum of compound autoionizing states (AIS). The autoionization widths of these states estimated by perturbations, /gamma=2/pi[ W]2, where W is the Coulomb matrix element coupling the AIS to the continuum, are small, but comparable with D in magnitude: ?~D. Hence, the interaction of AIS with each other via the continuum is very essential. It suppresses greatly the widths of the autoionizing resonances (/Gamma? D2/3/gamma/ll D), and leads to the emergence of a 'collective' doorway state which accumulates a large share of the total width. Narrow compound AIS should be a common feature of atomic spectra at energies sufficient for excitation of several electrons above the ground state. The narrow resonances can be observed as peaks in the photoabsorption, or, in electron-ion scattering, as Fano-type profiles on the background provided by the wide doorway-state resonance. The mixing between the Rydberg and compound states as a function of the residual interaction strength is studied in the general form. The Rydberg series are strongly perturbed for n~

  5. Glueballs and mesons: The ground states

    SciTech Connect

    Ganbold, G. [Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Institute of Physics and Technology, 210651 Ulaanbaatar (Mongolia)

    2009-02-01

    We provide a new, independent, and analytic estimate of the lowest glueball mass, and we found it at 1661 MeV within a relativistic quantum-field model based on analytic confinement. The conventional mesons and the weak decay constants are described to extend the consideration. For the spectra of two-gluon and two-quark bound states we solve the ladder Bethe-Salpeter equation. By using a minimal set of model parameters (the quark masses, the coupling constant, and the confinement scale) we obtain numerical results which are in reasonable agreement with experimental evidence in the wide range of energy scale. The model serves a reasonable framework to describe simultaneously different sectors in low-energy particle physics.

  6. Ground-state energy of a polaron in n dimensions

    Microsoft Academic Search

    F. M. Peeters; Wu Xiaoguang; J. T. Devreese

    1986-01-01

    The Fröhlich Hamiltonian is generalized to the case of an electron moving in n space dimensions. For n=2 and n=3 the familiar Fröhlich Hamiltonian is reobtained. The polaron ground-state energy is calculated up to fourth order in perturbation theory. We found that within the Feynman two-particle polaron model approximation the polaron ground-state energy satisfies the scaling relation EnD(alpha)=(n\\/3)E3D(\\\\{Gamma[ (n-1)\\/2]3 &surd;pi

  7. Topological invariants and the ground state wavefunction of topological insulators

    NASA Astrophysics Data System (ADS)

    Wang, Zhong; Zhang, Shou-Cheng

    2014-03-01

    We will talk about precise topological invariants defined in terms of the ground state wavefuntion. The Hall coefficients in even spatial dimensions and the magnetoelectric theta terms in odd spatial dimensions are expressed in terms of the ground state wavefunctions under generalized twisted-boundary conditions. This formulation is valid in the presence of arbitrary interaction and disorder, in particular, it is applicable to both integer and fractional topological insulators. (arXiv:1308.4900) Supported by Tsinghua University Initiative Scientific Research Program (No. 20121087986).

  8. From local to global ground states in Ising spin glasses

    E-print Network

    Ilia Zintchenko; Matthew B. Hastings; Matthias Troyer

    2015-01-09

    We consider whether it is possible to find ground states of frustrated spin systems by solving them locally. Using spin glass physics and Imry-Ma arguments in addition to numerical benchmarks we quantify the power of such local solution methods and show that for the average low-dimensional spin glass problem outside the spin- glass phase the exact ground state can be found in polynomial time. In the second part we present a heuristic, general-purpose hierarchical approach which for spin glasses on chimera graphs and lattices in two and three dimensions outperforms, to our knowledge, any other solver currently around, with significantly better scaling performance than simulated annealing.

  9. Ground-state rotational constants of 12CH 3D

    NASA Astrophysics Data System (ADS)

    Chackerian, C.; Guelachvili, G.

    1980-12-01

    An analysis of ground-state combination differences in the ?2( A1) fundamental band of 12CH 3D ( ?0 = 2200.03896 cm -1) has been made to yield values for the rotational constants B0, D0J, D0JK, H0JJJ, H0JJK, H0JKK, LJJJJ, L0JJJK, and order of magnitude values for L0JJKK and L0JKKK. These constants should be useful in assisting radio searches for this molecule in astrophysical sources. In addition, splittings of A1A2 levels ( J ? 17, K = 3) have been measured in both the ground and excited vibrational states of this band.

  10. On the triplet ground state of tetrahedral X4 clusters (X = Li, Na, K, Cu)

    NASA Astrophysics Data System (ADS)

    Verdicchio, Marco; Evangelisti, Stefano; Leininger, Thierry; Monari, Antonio

    2012-03-01

    The lowest electronic state of distorted tetrahedral X4 clusters (with X = Li, Na, K, Cu) is studied at coupled-cluster level using high-quality atomic basis sets. The ground state is found to have a triplet spin symmetry for this kind of geometry and for all the considered atomic species. The equilibrium geometries correspond to Jahn-Teller-distorted oblate tetrahedra having D2d symmetry, and tetrahedric structures are local minima on the potential-energy surfaces for the triplet states. Their energies lie between 0.2 eV (for the K4 cluster) and 0.9 eV (for Cu4) above the absolute minimum of the corresponding systems, which is a spin singlet having a rhombus geometry.

  11. On the triplet ground state of tetrahedral X4 clusters (X = Li, Na, K, Cu).

    PubMed

    Verdicchio, Marco; Evangelisti, Stefano; Leininger, Thierry; Monari, Antonio

    2012-03-01

    The lowest electronic state of distorted tetrahedral X(4) clusters (with X = Li, Na, K, Cu) is studied at coupled-cluster level using high-quality atomic basis sets. The ground state is found to have a triplet spin symmetry for this kind of geometry and for all the considered atomic species. The equilibrium geometries correspond to Jahn-Teller-distorted oblate tetrahedra having D(2d) symmetry, and tetrahedric structures are local minima on the potential-energy surfaces for the triplet states. Their energies lie between 0.2 eV (for the K(4) cluster) and 0.9 eV (for Cu(4)) above the absolute minimum of the corresponding systems, which is a spin singlet having a rhombus geometry. PMID:22401434

  12. Measurement-based quantum computer in the gapped ground state of a two-body Hamiltonian.

    PubMed

    Brennen, Gavin K; Miyake, Akimasa

    2008-07-01

    We propose a scheme for a ground-code measurement-based quantum computer, which enjoys two major advantages. First, every logical qubit is encoded in the gapped degenerate ground subspace of a spin-1 chain with nearest-neighbor two-body interactions, so that it equips built-in robustness against noise. Second, computation is processed by single-spin measurements along multiple chains dynamically coupled on demand, so as to keep teleporting only logical information into a gap-protected ground state of the residual chains after the interactions with spins to be measured are turned off. We describe implementations using trapped atoms or polar molecules in an optical lattice, where the gap is expected to be as large as 0.2 or 4.8 kHz, respectively. PMID:18764096

  13. Uncovering the hidden ground state of green fluorescent protein

    PubMed Central

    Kennis, John T. M.; Larsen, Delmar S.; van Stokkum, Ivo H. M.; Vengris, Mikas; van Thor, Jasper J.; van Grondelle, Rienk

    2004-01-01

    The fluorescence properties of GFP are strongly influenced by the protonation states of its chromophore and nearby amino acid side chains. In the ground state, the GFP chromophore is neutral and absorbs in the near UV. Upon excitation, the chromophore is deprotonated, and the resulting anionic chromophore emits its green fluorescence. So far, only excited-state intermediates have been observed in the GFP photocycle. We have used ultrafast multipulse control spectroscopy to prepare and directly observe GFP's hidden anionic ground-state intermediates as an integral part of the photocycle. Combined with dispersed multichannel detection and advanced global analysis techniques, the existence of two distinct anionic ground-state intermediates, I1 and I2, has been unveiled. I1 and I2 absorb at 500 and 497 nm, respectively, and interconvert on a picosecond timescale. The I2 intermediate has a lifetime of 400 ps, corresponding to a proton back-transfer process that regenerates the neutral ground state. Hydrogen/deuterium exchange of the protein leads to a significant increase of the I1 and I2 lifetimes, indicating that proton motion underlies their dynamics. We thus have assessed the complete chain of reaction intermediates and associated timescales that constitute the photocycle of GFP. Many elementary processes in biology rely on proton transfers that are limited by slow diffusional events, which seriously precludes their characterization. We have resolved the true reaction rate of a proton transfer in the molecular ground state of GFP, and our results may thus aid in the development of a generic understanding of proton transfer in biology. PMID:15608070

  14. Ground-state electromagnetic moments of calcium isotopes

    NASA Astrophysics Data System (ADS)

    Ruiz, R. F. Garcia; Bissell, M. L.; Blaum, K.; Frömmgen, N.; Hammen, M.; Holt, J. D.; Kowalska, M.; Kreim, K.; Menéndez, J.; Neugart, R.; Neyens, G.; Nörtershäuser, W.; Nowacki, F.; Papuga, J.; Poves, A.; Schwenk, A.; Simonis, J.; Yordanov, D. T.

    2015-04-01

    Background: The neutron-rich calcium isotopes have gained particular interest as evidence of closed-shell structures has recently been found in two exotic nuclei, at N =32 and N =34 . Additionally, the study of such neutron-rich systems has revealed new aspects of nuclear forces, in particular regarding the role of three-nucleon forces. Purpose: We study the electromagnetic properties of Ca isotopes around the neutron number N =32 . Methods: High-resolution bunched-beam collinear laser spectroscopy was used to measure the optical hyperfine spectra of the Ca-5143 isotopes. Results: The ground-state magnetic moments of Ca,5149 and quadrupole moments of Ca 47 ,49 ,51 were measured for the first time, and the 51Ca ground-state spin I = 3 /2 was determined in a model-independent way. Our experimental results are compared with state-of-the-art shell-model calculations using both phenomenological interactions and microscopic interactions derived from chiral effective field theory. Conclusions: The results for the ground-state moments of neutron-rich isotopes are in excellent agreement with predictions of interactions derived from chiral effective field theory including three-nucleon forces. Lighter isotopes illustrate the presence of particle-hole excitations of the 40Ca core in their ground state. Our results provide a critical test of modern nuclear theories, and give direct answer to the evolution of ground-state electromagnetic properties in the Ca isotopic chain across three doubly closed-shell configurations at N =20 , 28, 32 of this unique system.

  15. Asymptotics of Ground State Degeneracies in Quiver Quantum Mechanics

    E-print Network

    Clay Cordova; Shu-Heng Shao

    2015-03-11

    We study the growth of the ground state degeneracy in the Kronecker model of quiver quantum mechanics. This is the simplest quiver with two gauge groups and bifundamental matter fields, and appears universally in the context of BPS state counting in four-dimensional N=2 systems. For large ranks, the ground state degeneracy is exponential with slope a modular function that we are able to compute at integral values of its argument. We also observe that the exponential of the slope is an algebraic number and determine its associated algebraic equation explicitly in several examples. The speed of growth of the degeneracies, together with various physical features of the bound states, suggests a dual string interpretation.

  16. Bethe ansatz for the Toda lattice: Ground state and excitations

    Microsoft Academic Search

    Franz G. Mertens

    1984-01-01

    For a one-dimensional chain with exponential plus linear interactions the asymptotic wave functions are constructed by Bethe's ansatz using the exact two-body phase shift. Ground state energy and excitations are obtained by Lieb's method for two different boundary conditions. In the strongly anharmonic (weak coupling) regime the system behaves effectively like a gas of hard spheres with constant attraction, where

  17. Ground states of the massless Derezinski-Gerard model

    SciTech Connect

    Ohkubo, Atsushi [Graduate School of Informatics, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan)

    2009-11-15

    We consider the massless Derezinski-Gerard model introduced by Derezinski and Gerard in 1999. We give a sufficient condition for the existence of a ground state of the massless Derezinski-Gerard model without the assumption that the Hamiltonian of particles has compact resolvent.

  18. Ground-State Energy and Effective Mass of the Polaron

    Microsoft Academic Search

    Elliott H. Lieb; Kazuo Yamazaki

    1958-01-01

    The polaron Hamiltonian would be easily soluble were it not for the quartic term appearing therein. It is proposed to substitute for the quartic term a quadratic term having roughly the same properties, and in such a way that the ground-state energy of the new Hamiltonian is rigorously a lower bound for the true energy. With a very small amount

  19. Ground states for mean field models with a transverse component

    E-print Network

    Dmitry Ioffe; Anna Levit

    2012-10-09

    We investigate global logarithmic asymptotics of ground states for a family of quantum mean field models. Our approach is based on a stochastic representation and a combination of large deviation and weak KAM techniques. The spin- 1/2 case is worked out in more detail.

  20. VOLUME PROPERTIES OF GROUND-STATE NUCLEAR MATTER

    Microsoft Academic Search

    John Reynolds; Robert Puff

    1963-01-01

    An approximation for treating macroscopic bound systems in the ground ; state is applied to a homogeneous system of nuclear matter using a simple ; separable potential. More extensive numerical results are given for the density, ; energy density, chemical potential, effective potential, momentum distribution, ; pressure, and density correlation function. In addition, an ambiguity in the ; calculation of

  1. Disorder-induced neutral solitons in degenerate ground state polymers

    Microsoft Academic Search

    Marc Thilo Figge; Maxim V. Mostovoy; Jasper Knoester

    1998-01-01

    In this letter, we study the effects of weak off-diagonal disorder on conjugated polymers with a doubly degenerate ground-state. We find that disorder induces a finite density of neutral solitons in the lattice dimerization of a polymer chain. Interchain interactions result in a linear potential between the solitons and, if sufficiently strong, bind them into pairs resulting in an exponential

  2. Disorder-induced neutral solitons in degenerate ground state polymers

    Microsoft Academic Search

    Marc Thilo Figge; Maxim V. Mostovoy; Jasper Knoester

    1999-01-01

    We study the effects of weak off-diagonal disorder on ?-conjugated polymers with a doubly degenerate ground-state. We find that disorder induces a finite density of neutral solitons in the lattice dimerization of a polymer chain. Interchain interactions result in a linear potential between the solitons and, if sufficiently strong, bind them into pairs resulting in an exponential suppression of the

  3. Revised molecular constants for the ground state of CO

    Microsoft Academic Search

    André Le Floch

    1991-01-01

    The Dunham parameters of the ground state of the CO molecule are determined by a least squares fit of recent high-quality microwave and heterodyne frequency measurements. It is shown that these new parameters are more accurate than others obtained recently. Revised equilibrium molecular constants have been deduced from these new Dunham parameters and the mass-scaling coefficients determined by Guelachvili et

  4. Ground State Quantum Coherences: from Quantum Beats to Strong Control

    E-print Network

    Andres D. Cimmarusti; Burkley D. Patterson; Luis A. Orozco; Wanderson M. Pimenta; Pablo Barberis-Blostein; Howard J. Carmichael

    2014-01-14

    Second order correlations reveal quantum beats from a coherent ground-state superposition on the undriven mode of a two-mode cavity QED system. Continuous drive induces decoherence due to Rayleigh scattering. We control this with feedback and explore postselection techniques to extract specific behavior.

  5. Rydberg States of Atoms and Molecules

    NASA Astrophysics Data System (ADS)

    Stebbings, R. F.; Dunning, F. B.

    2011-03-01

    List of contributors; Preface; 1. Rydberg atoms in astrophysics A. Dalgarno; 2. Theoretical studies of hydrogen Rydberg atoms in electric fields R. J. Damburg and V. V. Kolosov; 3. Rydberg atoms in strong fields D. Kleppner, Michael G. Littman and Myron L. Zimmerman; 4. Spectroscopy of one- and two-electron Rydberg atoms C. Fabre and S. Haroche; 5. Interaction of Rydberg atoms with blackbody radiation T. F. Gallagher; 6. Theoretical approaches to low-energy collisions of Rydberg atoms with atoms and ions A. P. Hickman, R. E. Olson and J. Pascale; 7. Experimental studies of the interaction of Rydberg atoms with atomic species at thermal energies F. Gounand and J. Berlande; 8. Theoretical studies of collisions of Rydberg atoms with molecules Michio Matsuzawa; 9. Experimental studies of thermal-energy collisions of Rydberg atoms with molecules F. B. Dunning and R. F. Stebbings; 10. High-Rydberg molecules Robert S. Freund; 11. Theory of Rydberg collisions with electrons, ions and neutrals M. R. Flannery; 12. Experimental studies of the interactions of Rydberg atoms with charged particles J. -F. Delpech; 13. Rydberg studies using fast beams Peter M. Koch; Index.

  6. Spectral Aspects of the Microwave Ionization of Atomic Rydberg States

    E-print Network

    Delande, Dominique

    "coordinate" is the energy of the atomic electron in the microwave field. Even if we restrict the atomicSpectral Aspects of the Microwave Ionization of Atomic Rydberg States Andreas Buchleitner and Fractals, 5, 1125 (1995) Abstract We perform a numerical study of the microwave ionization of a Rydberg

  7. Speed of Markovian relaxation toward the ground state

    SciTech Connect

    Vogl, Malte; Schaller, Gernot; Brandes, Tobias [Institut fuer Theoretische Physik, Technische Universitaet Berlin, Hardenbergstr. 36, D-10623 Berlin (Germany)

    2010-01-15

    For sufficiently low reservoir temperatures, it is known that open quantum systems subject to decoherent interactions with the reservoir relax toward their ground state in the weak coupling limit. Within the framework of quantum master equations, this is formalized by the Born-Markov-secular (BMS) approximation, where one obtains the system Gibbs state with the reservoir temperature as a stationary state. When the solution to some problem is encoded in the (isolated) ground state of a system Hamiltonian, decoherence can therefore be exploited for computation. The computational complexity is then given by the scaling of the relaxation time with the system size n. We study the relaxation behavior for local and nonlocal Hamiltonians that are coupled dissipatively with local and nonlocal operators to a bosonic bath in thermal equilibrium. We find that relaxation is generally more efficient when coherences of the density matrix in the system energy eigenbasis are taken into account. In addition, the relaxation speed strongly depends on the matrix elements of the coupling operators between initial state and ground state. We show that Dicke superradiance is a special case of our relaxation models and can thus be understood as a coherence-assisted relaxation speedup.

  8. Quantum Splitting an Arbitrary Two-Atom State with a Six-Atom Entangled State in Cavity QED

    NASA Astrophysics Data System (ADS)

    Zhou, Lin; Liu, Zhong-min

    2015-07-01

    We demonstrate that a genuine six-atom entangled state can be used to realize the deterministic quantum information splitting of an arbitrary two-atom state in cavity QED. The scheme does not involve Bell-state measurement and is insensitive to both the cavity decay and the thermal field.

  9. Generation of nonground-state Bose-Einstein condensates by modulating atomic interactions

    NASA Astrophysics Data System (ADS)

    Ramos, E. R. F.; Henn, E. A. L.; Seman, J. A.; Caracanhas, M. A.; Magalhćes, K. M. F.; Helmerson, K.; Yukalov, V. I.; Bagnato, V. S.

    2008-12-01

    A technique is proposed for creating nonground-state Bose-Einstein condensates in a trapping potential by means of the temporal modulation of atomic interactions. Applying a time-dependent spatially homogeneous magnetic field modifies the atomic scattering length. A modulation of the scattering length excites the condensate, which, under special conditions, can be transferred to an excited nonlinear coherent mode. It is shown that a phase-transition-like behavior occurs in the time-averaged population imbalance between the ground and excited states. The application of the technique is analyzed and it is shown that the considered effect can be realized for experimentally available condensates.

  10. Use of multiwavelength emission from hollow cathode lamp for measurement of state resolved atom density of metal vapor produced by electron beam evaporation

    SciTech Connect

    Majumder, A.; Dikshit, B.; Bhatia, M. S.; Mago, V. K. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2008-09-15

    State resolved atom population of metal vapor having low-lying metastable states departs from equilibrium value. It needs to be experimentally investigated. This paper reports the use of hollow cathode lamp based atomic absorption spectroscopy technique to measure online the state resolved atom density (ground and metastable) of metal vapor in an atomic beam produced by a high power electron gun. In particular, the advantage of availability of multiwavelength emission in hollow cathode lamp is used to determine the atom density in different states. Here, several transitions pertaining to a given state have also been invoked to obtain the mean value of atom density thereby providing an opportunity for in situ averaging. It is observed that at higher source temperatures the atoms from metastable state relax to the ground state. This is ascribed to competing processes of atom-atom and electron-atom collisions. The formation of collision induced virtual source is inferred from measurement of atom density distribution profile along the width of the atomic beam. The total line-of-sight average atom density measured by absorption technique using hollow cathode lamp is compared to that measured by atomic vapor deposition method. The presence of collisions is further supported by determination of beaming exponent by numerically fitting the data.

  11. Use of multiwavelength emission from hollow cathode lamp for measurement of state resolved atom density of metal vapor produced by electron beam evaporation.

    PubMed

    Majumder, A; Dikshit, B; Bhatia, M S; Mago, V K

    2008-09-01

    State resolved atom population of metal vapor having low-lying metastable states departs from equilibrium value. It needs to be experimentally investigated. This paper reports the use of hollow cathode lamp based atomic absorption spectroscopy technique to measure online the state resolved atom density (ground and metastable) of metal vapor in an atomic beam produced by a high power electron gun. In particular, the advantage of availability of multiwavelength emission in hollow cathode lamp is used to determine the atom density in different states. Here, several transitions pertaining to a given state have also been invoked to obtain the mean value of atom density thereby providing an opportunity for in situ averaging. It is observed that at higher source temperatures the atoms from metastable state relax to the ground state. This is ascribed to competing processes of atom-atom and electron-atom collisions. The formation of collision induced virtual source is inferred from measurement of atom density distribution profile along the width of the atomic beam. The total line-of-sight average atom density measured by absorption technique using hollow cathode lamp is compared to that measured by atomic vapor deposition method. The presence of collisions is further supported by determination of beaming exponent by numerically fitting the data. PMID:19044405

  12. Ground Tests of Einstein's Equivalence Principle: From Lab-based to 10-m Atomic Fountains

    E-print Network

    D. Schlippert; H. Albers; L. L. Richardson; D. Nath; H. Heine; C. Meiners; É. Wodey; A. Billon; J. Hartwig; C. Schubert; N. Gaaloul; W. Ertmer; E. M. Rasel

    2015-07-21

    To date, no framework combining quantum field theory and general relativity and hence unifying all four fundamental interactions, exists. Violations of the Einstein's equivalence principle (EEP), being the foundation of general relativity, may hold the key to a theory of quantum gravity. The universality of free fall (UFF), which is one of the three pillars of the EEP, has been extensively tested with classical bodies. Quantum tests of the UFF, e.g. by exploiting matter wave interferometry, allow for complementary sets of test masses, orders of magnitude larger test mass coherence lengths and investigation of spin-gravity coupling. We review our recent work towards highly sensitive matter wave tests of the UFF on ground. In this scope, the first quantum test of the UFF utilizing two different chemical elements, Rb-87 and K-39, yielding an E\\"otv\\"os ratio $\\eta_{\\,\\text{Rb,K}}=(0.3\\pm 5.4)\\times 10^{-7}$ has been performed. We assess systematic effects currently limiting the measurement at a level of parts in $10^8$ and finally present our strategies to improve the current state-of-the-art with a test comparing the free fall of rubidium and ytterbium in a very long baseline atom interferometry setup. Here, a 10 m baseline combined with a precise control of systematic effects will enable a determination of the E\\"otv\\"os ratio at a level of parts in $10^{13}$ and beyond, thus reaching and overcoming the performance limit of the best classical tests.

  13. Producing translationally cold, ground-state CO molecules.

    PubMed

    Blokland, Janneke H; Riedel, Jens; Putzke, Stephan; Sartakov, Boris G; Groenenboom, Gerrit C; Meijer, Gerard

    2011-09-21

    Carbon monoxide molecules in their electronic, vibrational, and rotational ground state are highly attractive for trapping experiments. The optical or ac electric traps that can be envisioned for these molecules will be very shallow, however, with depths in the sub-milliKelvin range. Here, we outline that the required samples of translationally cold CO (X(1)?(+), v'' = 0, N'' = 0) molecules can be produced after Stark deceleration of a beam of laser-prepared metastable CO (a(3)?(1)) molecules followed by optical transfer of the metastable species to the ground state via perturbed levels in the A(1)? state. The optical transfer scheme is experimentally demonstrated and the radiative lifetimes and the electric dipole moments of the intermediate levels are determined. PMID:21950855

  14. Producing translationally cold, ground-state CO molecules

    NASA Astrophysics Data System (ADS)

    Blokland, Janneke H.; Riedel, Jens; Putzke, Stephan; Sartakov, Boris G.; Groenenboom, Gerrit C.; Meijer, Gerard

    2011-09-01

    Carbon monoxide molecules in their electronic, vibrational, and rotational ground state are highly attractive for trapping experiments. The optical or ac electric traps that can be envisioned for these molecules will be very shallow, however, with depths in the sub-milliKelvin range. Here, we outline that the required samples of translationally cold CO (X1?+, v'' = 0, N'' = 0) molecules can be produced after Stark deceleration of a beam of laser-prepared metastable CO (a3?1) molecules followed by optical transfer of the metastable species to the ground state via perturbed levels in the A1? state. The optical transfer scheme is experimentally demonstrated and the radiative lifetimes and the electric dipole moments of the intermediate levels are determined.

  15. Nonmagnetic ground state of PuO2

    NASA Astrophysics Data System (ADS)

    Shick, A. B.; Koloren?, J.; Havela, L.; Gouder, T.; Caciuffo, R.

    2014-01-01

    The correlated band theory implemented as a combination of the local density approximation with the exact diagonalization of the Anderson impurity model is applied to PuO2. We obtain an insulating electronic structure consistent with the experimental photoemission spectra. The calculations yield a band gap of 1.8 eV and a nonmagnetic singlet ground state that is characterized by a noninteger filling of the plutonium f shell (nf?4.5). Due to sizable hybridization of the f shell with the p states of oxygen, the ground state is more complex than the four-electron Russell-Saunders 5I4 manifold split by the crystal field. The inclusion of hybridization improves the agreement between the theory and experiment for the magnetic susceptibility.

  16. Heralded atomic-ensemble quantum memory for photon polarization states

    E-print Network

    Tanji, Haruka

    We describe the mapping of quantum states between single photons and an atomic ensemble. In particular, we demonstrate a heralded quantum memory based on the mapping of a photon polarization state onto a single collective-spin ...

  17. Experimental Investigation of Excited-State Lifetimes in Atomic Ytterbium

    SciTech Connect

    Bowers, C.J.; Budker, D.; Commins, E.D.; DeMille, D.; Freedman, S.J.; Nguyen, A.-T.; Shang, S.-Q.; /UC, Berkeley; Zolotorev, M.; /SLAC

    2011-11-15

    Lifetimes of 21 excited states in atomic Yb were measured using time-resolved fluorescence detection following pulsed laser excitation. The lifetime of the 4f{sup 14}5d6s {sup 3}D{sub 1} state, which is of particular importance for a proposed study of parity nonconservation in atoms, was measured to be 380(30) ns.

  18. Mixed configuration ground state in iron(II) phthalocyanine

    NASA Astrophysics Data System (ADS)

    Fernįndez-Rodrķguez, Javier; Toby, Brian; van Veenendaal, Michel

    2015-06-01

    We calculate the angular dependence of the x-ray linear and circular dichroism at the L2 ,3 edges of ? -Fe(II) Phthalocyanine (FePc) thin films using a ligand-field model with full configuration interaction. We find the best agreement with the experimental spectra for a mixed ground state of 3Eg(a1g 2eg3b2g 1) and 3B2 g(a1g 1eg4b2g 1) with the two configurations coupled by the spin-orbit interaction. The 3Eg(b ) and 3B2 g states have easy-axis and easy-plane anisotropies, respectively. Our model accounts for an easy-plane magnetic anisotropy and the measured magnitudes of the in-plane orbital and spin moments. The proximity in energy of the two configurations allows a switching of the magnetic anisotropy from easy plane to easy axis with a small change in the crystal field, as recently observed for FePc adsorbed on an oxidized Cu surface. We also discuss the possibility of a quintet ground state (5A1 g is 250 meV above the ground state) with planar anisotropy by manipulation of the Fe-C bond length by depositing the complex on a substrate that is subjected to a mechanical strain.

  19. Guidelines for ground motion definition for the eastern United States

    SciTech Connect

    Gwaltney, R.C.; Aramayo, G.A.; Williams, R.T.

    1985-06-01

    Guidelines for the determination of earthquake ground motion definition for the eastern United States are established here. Both far-field and near-field guidelines are given. The guidelines were based on an extensive review of the current procedures for specifying ground motion in the United States. Both empirical and theoretical procedures were used in establishing the guidelines because of the low seismicity in the eastern United States. Only a few large- to great-sized earthquakes (M/sub s/ > 7.5) have occurred in this region, no evidence of tectonic surface ruptures related to historic or Holocene earthquakes has been found, and no currently active plate boundaries of any kind are known in this region. Very little instrumented data have been gathered in the East. Theoretical procedures are proposed so that in regions of almost no data, a reasonable level of seismic ground motion activity can be assumed. The guidelines are to be used to develop the safe shutdown earthquake (SSE). A new procedure for establishing the operating basis earthquake (OBE) is proposed, in particular for the eastern United States. The OBE would be developed using a probabilistic assessment of the geological conditions and the recurrence of seismic events at a site. These guidelines should be useful in development of seismic design requirements for future reactors. 17 refs., figs., tabs.

  20. Incommensurate helical spin ground states on the hollandite lattice

    NASA Astrophysics Data System (ADS)

    Mandal, S.; Andreanov, A.; Crespo, Y.; Seriani, N.

    2014-09-01

    We present a model of classical Heisenberg spins on a hollandite lattice, which has been developed to describe the magnetic properties of ?-MnO2 and similar compounds. The model has only nearest-neighbor interacting spins, however, the strength and the sign of spin-spin interactions is anisotropic and depends on the nature of the bonds. Our analysis shows that the hollandite lattice supports four different incommensurate and helical magnetic ground states depending on the relative strengths and signs of spin-spin interactions. We show that the incommensurate helical ground states appear due to the geometrical frustration present in the model. We demonstrate that each of the four helical incommensurate magnetic phases are continuously connected to four different collinear antiferromagnetic ground states as the strength of spin-spin interaction along some bonds is increased. The present results give support to the presence of helical states that have been previously suggested experimentally for hollandite compounds. We provide an in-depth analysis of the magnetic form factors for each helical phase and describe how it could be used to identify each of these phases in neutron diffraction experiments.

  1. Zero Energy Ground State in the Three-Body System

    E-print Network

    Dmitry K. Gridnev

    2010-01-22

    We consider a 3--body system in $\\mathbb{R}^3$ with non--positive potentials and non--negative essential spectrum. Under certain requirements on the fall off of pair potentials it is proved that if at least one pair of particles has a zero energy resonance then a square integrable zero energy ground state of three particles does not exist. This complements the analysis in \\cite{1}, where it was demonstrated that square integrable zero energy ground states are possible given that in all two--body subsystems there is no negative energy bound states and no zero energy resonances. As a corollary it is proved that one can tune the coupling constants of pair potentials so that for any given $R, \\epsilon >0$: (a) the bottom of the essential spectrum is at zero; (b) there is a negative energy ground state $\\psi(\\xi)$, where $\\int |\\psi(\\xi)|^2 = 1$; (c) $\\int_{|\\xi| \\leq R} |\\psi(\\xi)|^2 < \\epsilon$.

  2. Ground state and dynamics of the biased dissipative two-state system: Beyond variational polaron theory

    E-print Network

    Ahsan Nazir; Dara P. S. McCutcheon; Alex W. Chin

    2012-06-12

    We propose a ground-state ansatz for the Ohmic spin-boson model that improves upon the variational treatment of Silbey and Harris for biased systems in the scaling limit. In particular, it correctly captures the smooth crossover behaviour expected for the ground-state magnetisation when moving between the delocalised and localised regimes of the model, a feature that the variational treatment is unable to properly reproduce, while it also provides a lower ground-state energy estimate in the crossover region. We further demonstrate the validity of our intuitive ground-state by showing that it leads to predictions in excellent agreement with those derived from a non-perturbative Bethe-ansatz technique. Finally, recasting our ansatz in the form of a generalised polaron transformation, we are able to explore the dissipative two-state dynamics beyond weak system-environment coupling within an efficient time-local master equation formalism.

  3. Ground state and dynamics of the biased dissipative two-state system: Beyond variational polaron theory

    E-print Network

    Nazir, Ahsan; Chin, Alex W

    2012-01-01

    We propose a ground-state ansatz for the Ohmic spin-boson model that improves upon the variational treatment of Silbey and Harris for biased systems in the scaling limit. In particular, it correctly captures the smooth crossover behaviour expected for the ground-state magnetisation when moving between the delocalised and localised regimes of the model, a feature that the variational treatment is unable to properly reproduce, while it also provides a lower ground-state energy estimate in the crossover region. We further demonstrate the validity of our intuitive ground-state by showing that it leads to predictions in excellent agreement with those derived from a non-perturbative Bethe-ansatz technique. Finally, recasting our ansatz in the form of a generalised polaron transformation, we are able to explore the dissipative two-state dynamics beyond weak system-environment coupling within an efficient time-local master equation formalism.

  4. Topological Entanglement Entropy, Ground State Degeneracy and Holography

    E-print Network

    Parnachev, Andrei

    2015-01-01

    Topological entanglement entropy, a measure of the long-ranged entanglement, is related to the degeneracy of the ground state on a higher genus surface. The exact relation depends on the details of the topological theory. We consider a class of holographic models where such relation might be similar to the one exhibited by Chern-Simons theory in a certain large N limit. Both the non-vanishing topological entanglement entropy and the ground state degeneracy in these holographic models are consequences of the topological Gauss-Bonnet term in the dual gravitational description. A soft wall holographic model of confinement is used to generate finite correlation length but keep the disk topology of the entangling surface in the bulk, necessary for nonvanishing topological entanglement entropy.

  5. Room temperature skyrmion ground state stabilized through interlayer exchange coupling

    NASA Astrophysics Data System (ADS)

    Chen, Gong; Mascaraque, Arantzazu; N'Diaye, Alpha T.; Schmid, Andreas K.

    2015-06-01

    Possible magnetic skyrmion device applications motivate the search for structures that extend the stability of skyrmion spin textures to ambient temperature. Here, we demonstrate an experimental approach to stabilize a room temperature skyrmion ground state in chiral magnetic films via exchange coupling across non-magnetic spacer layers. Using spin polarized low-energy electron microscopy to measure all three Cartesian components of the magnetization vector, we image the spin textures in Fe/Ni films. We show how tuning the thickness of a copper spacer layer between chiral Fe/Ni films and perpendicularly magnetized Ni layers permits stabilization of a chiral stripe phase, a skyrmion phase, and a single domain phase. This strategy to stabilize skyrmion ground states can be extended to other magnetic thin film systems and may be useful for designing skyrmion based spintronics devices.

  6. Universality in Ground State Energy Distributions of Random Elastic Manifolds

    Microsoft Academic Search

    Eira T. Seppälä; Kalle P. Kytölä; Mikko J. Alava

    2002-01-01

    The distribution of ground state energies of elastic manifolds with random-bond disorder is studied numerically in (1+1), (1+2), (1+3), and (2+1) dimensions. (1+1) -dimensional manifolds, or directed polymers, are known to have in a ``single valley'' an energy distribution which is Gaussian close to the mean, and has stretched exponential low and high energy tails with the stretching exponents eta-

  7. Ground-State Energy of a Many-Fermion System

    Microsoft Academic Search

    W. Kohn; J. M. Luttinger

    1960-01-01

    This paper contains a critique of the Brueckner-Goldstone perturbation series for the ground-state energy of an interacting gas of fermions. We have calculated this energy by first constructing the grand partition function at finite temperature, and then carefully taking the limit as T-->0. In general this leads to a series which differs from that of Brueckner and Goldstone. An exception

  8. Exact Ground State Energy of the Strong-Coupling Polaron

    Microsoft Academic Search

    Elliott H. Lieb; Lawrence E. Thomas

    1997-01-01

    :   The polaron has been of interest in condensed matter theory and field theory for about half a century, especially the limit\\u000a of large coupling constant, ?. It was not until 1983, however, that a proof of the asymptotic formula for the ground state\\u000a energy was finally given by using difficult arguments involving the large deviation theory of path integrals.

  9. Ground State Electronic Destabilization via Hyperconjugation in Aspartate Aminotransferase

    PubMed Central

    Griswold, Wait R.; Castro, Joan Nieto; Fisher, Andrew J.; Toney, Michael D.

    2012-01-01

    Binding isotope effects for L-aspartate reacting with the inactive K258A mutant of PLP-dependent aspartate aminotransferase to give a stable external aldimine intermediate are reported. They provide direct evidence for electronic ground state destabilization via hyperconjugation. The smaller equilibrium isotope effect with deazaPLP-reconstituted K258A indicates that the pyridine nitrogen plays an important role in labilizing the C?-H bond. PMID:22551424

  10. Calculated frequencies for the CO ground state transitions

    Microsoft Academic Search

    A. Le Floch

    1991-01-01

    Dunham parameters from microwave and heterodyne frequency measurements are used to compute the ground-state transitions of CO and the corresponding error. The data are selected from four sequences of delta-V = 0-3 which fall within a polygon that reflects the J and V ranges of the experimental measurements. A table is given for each sequence, and the frequencies for most

  11. Ground state solutions of asymptotically linear fractional Schrödinger equations

    NASA Astrophysics Data System (ADS)

    Chang, Xiaojun

    2013-06-01

    This paper is devoted to a time-independent fractional Schrödinger equation of the form (-? )^s u+V(x)u=f(x,u) in {R}N, where N ? 2, s ? (0, 1), (-?)s stands for the fractional Laplacian. We apply the variational methods to obtain the existence of ground state solutions when f(x, u) is asymptotically linear with respect to u at infinity.

  12. Ground states and concentration phenomena for the fractional Schrödinger equation

    NASA Astrophysics Data System (ADS)

    Moustapha Fall, Mouhamed; Mahmoudi, Fethi; Valdinoci, Enrico

    2015-06-01

    We consider here solutions of the nonlinear fractional Schrödinger equation We show that concentration points must be critical points for V. We also prove that if the potential V is coercive and has a unique global minimum, then ground states concentrate suitably at such a minimal point as ? tends to zero. In addition, if the potential V is radial and radially decreasing, then the minimizer is unique provided ? is small.

  13. Asymmetric Little model and its ground state energies

    E-print Network

    Mihailo Stojnic

    2013-06-17

    In this paper we look at a class of random optimization problems that arise in the forms typically known in statistical physics as Little models. In \\cite{BruParRit92} the Little models were studied by means of the well known tool from the statistical physics called the replica theory. A careful consideration produced a physically sound conclusion that the behavior of almost all important features of the Little models essentially resembles the behavior of the corresponding ones of appropriately scaled Sherrington-Kirkpatrick (SK) model. In this paper we revisit the Little models and consider their ground state energies as one of their main features. We then rigorously show that they indeed can be lower-bounded by the corresponding ones related to the SK model. We also provide a mathematically rigorous way to show that the replica symmetric estimate of the ground state energy is in fact a rigorous upper-bound of the ground state energy. Moreover, we then recall on a set of powerful mechanisms we recently designed for a study of the Hopfield models in \\cite{StojnicHopBnds10,StojnicMoreSophHopBnds10} and show how one can utilize them to substantially lower the upper-bound that the replica symmetry theory provides.

  14. Ground States and Folding Dynamics of Colloidal Clusters

    NASA Astrophysics Data System (ADS)

    Klein, Ellen; Rogers, W. Benjamin; Manoharan, Vinothan N.

    2015-03-01

    We experimentally study colloidal clusters consisting of N<100 spherical particles with short range, isotropic interactions. These clusters are a model system for understanding colloidal self-assembly and dynamics, since the positions and motion of the particles can be observed in real space. For N <= 10 the ground states are degenerate; previous work The Free-Energy Landscape of Clusters of Attractive Hard Spheres, has shown that the probabilities of observing specific clusters depend primarily on their rotational entropy, which is determined by symmetry. Thus, less symmetric structures are more frequently observed. However, for large N the ground state should be a highly symmetric close-packed lattice. We seek to understand how this transition occurs as a function of N . To do this, we coat colloidal particles with complementary DNA strands that induce a short-range, temperature dependent interparticle attraction. We then assemble and anneal an ensemble of clusters with N >= 10. We characterize the number of apparent ground states, their symmetries, and their probabilities as a function of N. We also observe how these clusters fold into minimal-energy configurations by subjecting them to an electric field that we then relax.

  15. Microwave spectrum of s-cis-glyoxal in the ground and excited vibrational states

    Microsoft Academic Search

    A. Kh. Mamleev; R. G. Latypova; L. N. Gunderova; V. I. Tyulin; N. M. Pozdeev

    1980-01-01

    The microwave spectrum of s-cis-glyoxal in the ground and two excited vibrational states has been studied. The rotational constants A, B, C and tim inertia defects of the molecule in the ground vibrational state and the first excited state of the torsional vibration have been determined. The quartie centrifugal stretching constants of the ground vibrational state have been found. The

  16. Coupled Cluster Calculations of Ground and Excited States of Nuclei

    NASA Astrophysics Data System (ADS)

    Kowalski, K.; Dean, D. J.; Hjorth-Jensen, M.; Papenbrock, T.; Piecuch, P.

    2004-04-01

    The standard and renormalized coupled cluster methods with singles, doubles, and noniterative triples and their generalizations to excited states, based on the equation of motion coupled cluster approach, are applied to the 4He and 16O nuclei. A comparison of coupled cluster results with the results of the exact diagonalization of the Hamiltonian in the same model space shows that the quantum chemistry inspired coupled cluster approximations provide an excellent description of ground and excited states of nuclei. The bulk of the correlation effects is obtained at the coupled cluster singles and doubles level. Triples, treated noniteratively, provide the virtually exact description.

  17. Coupled cluster calculations of ground and excited states of nuclei.

    PubMed

    Kowalski, K; Dean, D J; Hjorth-Jensen, M; Papenbrock, T; Piecuch, P

    2004-04-01

    The standard and renormalized coupled cluster methods with singles, doubles, and noniterative triples and their generalizations to excited states, based on the equation of motion coupled cluster approach, are applied to the 4He and 16O nuclei. A comparison of coupled cluster results with the results of the exact diagonalization of the Hamiltonian in the same model space shows that the quantum chemistry inspired coupled cluster approximations provide an excellent description of ground and excited states of nuclei. The bulk of the correlation effects is obtained at the coupled cluster singles and doubles level. Triples, treated noniteratively, provide the virtually exact description. PMID:15089597

  18. Aurora Borealis: stochastic cellular automata simulations of the excited-state dynamics of oxygen atoms.

    NASA Astrophysics Data System (ADS)

    Seybold, P. G.; Kier, L. B.; Cheng, C.-K.

    1999-12-01

    Emissions from the 1S and 1D excited states of atomic oxygen play a prominent role in creating the dramatic light displays (aurora borealis) seen in the skies over polar regions of the Northern Hemisphere. A probabilistic asynchronous cellular automaton model described previously has been applied to the excited-state dynamics of atomic oxygen. The model simulates the time-dependent variations in ground (3P) and excited-state populations that occur under user-defined probabilistic transition rules for both pulse and steady-state conditions. Although each trial simulation is itself an independent "experiment", deterministic values for the excited-state emission lifetimes and quantum yields emerge as limiting cases for large numbers of cells or large numbers of trials. Stochastic variations in the lifetimes and emission yields can be estimated from repeated trials.

  19. Quantum state manipulation of single-Cesium-atom qubit in a micro-optical trap

    NASA Astrophysics Data System (ADS)

    Wang, Zhi-Hui; Li, Gang; Tian, Ya-Li; Zhang, Tian-Cai

    2014-10-01

    Based on single Cesium atoms trapped in a 1064 nm microscopic optical trap we have exhibited a single qubit encoded in the Cesium "clock states". The single qubit initialization, detection and the fast state rotation with high efficiencies are demonstrated and this state manipulation is crucial for quantum information processing. The ground states Rabi flopping rate of 229.0 ± 0.6 kHz is realized by a two-photon Raman process. A clock states dephasing time of 3.0±0.7 ms is measured, while an irreversible homogeneous dephasing time of 124±17 ms is achieved by using the spin-echo technique. This well-controlled single atom provides an idea quantum qubit and quantum node for quantum information processing.

  20. Ground state blind quantum computation on AKLT state

    Microsoft Academic Search

    Tomoyuki Morimae; Vedran Dunjko; Elham Kashefi

    2010-01-01

    The blind quantum computing protocols (BQC) enable a classical client with limited quantum technology to delegate a computation to the quantum server(s) in such a way that the privacy of the computation is preserved. Here we present a new scheme for BQC that uses the concept of the measurement based quantum computing with the novel resource state of Affleck-Kennedy-Lieb-Tasaki (AKLT)

  1. Experimental Proposal to Detect Topological Ground State Degeneracy

    NASA Astrophysics Data System (ADS)

    Barkeshli, Maissam; Oreg, Yuval; Qi, Xiao-Liang

    2014-03-01

    One of the most profound features of topologically ordered states of matter, such as the fractional quantum Hall (FQH) states, is that they possess topology-dependent ground state degeneracies that are robust to all local perturbations. Here we present the first proposal to directly detect these topological degeneracies in an experimentally accessible setup. The detection scheme uses nonlinear electrical conductance measurements in a double layer FQH system, with appropriately patterned top and bottom gates. We propose two experimental platforms; in the first, the detection of topo- logically degenerate states coincides with the detection of ZN parafermion zero modes. We map the relevant physics to a single-channel ZN quantum impurity model, providing a novel generalization of the Kondo model. Our proposal can also be adapted to detect the ZN parafermion zero modes recently discovered in FQH line junctions proximitized with superconductivity.

  2. An atom diode

    E-print Network

    A. Ruschhaupt; J. G. Muga

    2004-08-20

    An atom diode, i.e., a device that lets the ground state atom pass in one direction but not in the opposite direction in a velocity range is devised. It is based on the adiabatic transfer achieved with two lasers and a third laser potential that reflects the ground state.

  3. ELECTRONIC STRUCTURE FOR THE GROUND STATE OF T1H FROM RELATIVISTIC MULTICONFIGURATION SCF CALCULATIONS

    SciTech Connect

    Christiansen, P.A.; Pitzer, K.S.

    1980-07-01

    The dissociation curve for the ground state of TlH was computed using a relativistic {omega}-{omega} coupling formalism. The relativistic effects represented by the Dirac equation were introduced using effective potentials generated from atomic Dirac-Fock wave functions using a generalization of the improved effective potential formulation of Christiansen, Lee, and Pitzer. The multiconfiguration SCF treatment used is a generalization of the two-component molecular spinor formalism of Lee, Ermler, and Pitzer. Using a five configuration wave function we were able to obtain approximately 85% of the experimental dissociation energy. Our computations indicate that the bond is principally sigma in form, despite the large spin-orbit splitting in atomic thallium. Furthermore the bond appears to be slightly ionic (Tl{sup +}H{sup -}) with about 0.3 extra electron charge on the hydrogen.

  4. Hartree-Fock Study on Magnetic Ground State of Uranium 5f Orbital in Ferromagnetic US

    NASA Astrophysics Data System (ADS)

    Shishidou, T.; Oguchi, T.; Jo, T.

    1997-03-01

    We study the magnetic ground state of the uranium 5f orbital of ferromagnetic US on the basis of a realistic multi-band tight-binding Hartree-Fock (HF) model, in which uranium 5f, 6d and 7s and sulfur 3s and 3p orbitals and full degeneracy of each orbital are considered. The multipole 5f-5f Coulomb interaction on the uranium site is treated within HF approximation and the spin-orbit interaction of the uranium 5f electron is explicitly included. The magnetic moment of US is widely believed to be dominated by its orbital component M_l, which is about twice as large as the spin counterpart Ms with the opposite sign, indicating that the magnetic ground state is not close to the atomic limit. Our HF model can describe well the magnetic ground state of US ( M_total ~= 1.8?B and Ml / Ms ~= -2), while an LSDA band-structure calculation underestimates the orbital moment considerably (T. Kraft et al.), Phys. Rev. B52, 3561 (1995). Calculations of the XMCD spectrum at uranium M_4,5 edge (S. P. Collins et al.), J. Phys.: Condens. Matter 7, 9325 (1995) are presented and the validity of our model for US is discussed. This work is supported by JSPS Research Fellowships for Young Scientists.

  5. Atomic oxygen interaction with spacecraft materials: Relationship between orbital and ground-based testing for materials certification

    NASA Technical Reports Server (NTRS)

    Cross, Jon B.; Koontz, Steven L.; Lan, Esther H.

    1993-01-01

    The effects of atomic oxygen on boron nitride (BN), silicon nitride (Si3N4), Intelsat 6 solar cell interconnects, organic polymers, and MoS2 and WS2 dry lubricant, were studied in Low Earth Orbit (LEO) flight experiments and in a ground based simulation facility. Both the inflight and ground based experiments employed in situ electrical resistance measurements to detect penetration of atomic oxygen through materials and Electron Spectroscopy for Chemical Analysis (ESCA) analysis to measure chemical composition changes. Results are given. The ground based results on the materials studied to date show good qualitative correlation with the LEO flight results, thus validating the simulation fidelity of the ground based facility in terms of reproducing LEO flight results. In addition it was demonstrated that ground based simulation is capable of performing more detailed experiments than orbital exposures can presently perform. This allows the development of a fundamental understanding of the mechanisms involved in the LEO environment degradation of materials.

  6. Coulomb breakup of 37Mg and its ground state structure

    NASA Astrophysics Data System (ADS)

    Shubhchintak; Neelam; Chatterjee, R.; Shyam, R.; Tsushima, K.

    2015-07-01

    We calculate Coulomb breakup of the neutron rich nucleus 37Mg on a Pb target at the beam energy of 244 MeV /nucleon within the framework of a finite range distorted wave Born approximation theory that is extended to include the effects of projectile deformation. In this theory, the breakup amplitude involves the full wave function of the projectile ground state. Calculations have been carried out for the total one-neutron removal cross section (?-1n), the neutron-core relative energy spectrum, the parallel momentum distribution of the core fragment, the valence neutron angular, and energy-angular distributions. The calculated ?-1n has been compared with the recently measured data to put constraints on the spin parity, and the one-neutron separation energy (Sn) of the 37Mg ground state (37Mggs). The dependence of ?-1n on the deformation of this state has also been investigated. While a spin parity assignment of 7 /2- for the 37Mggs is ruled out by our study, neither of the 3 /2- and 1 /2+ assignments can be clearly excluded. Using the spectroscopic factor of one for both the 3 /2- and 1 /2+ configurations and ignoring the projectile deformation effects, the Sn values of 0.35 ± 0.06 MeV and 0.50 ± 0.07 MeV, respectively, are extracted for the two configurations. However, the extracted Sn is strongly dependent on the spectroscopic factor and the deformation effects of the respective configuration. The narrow parallel momentum distribution of the core fragment and the strong forward peaking of the valence neutron angular distribution suggest a one-neutron halo configuration in either of the 2p3/2 and 2s1/2 configurations of the 37Mg ground state.

  7. Preparing a Seven-Atom Entangled State in Cavity QED

    NASA Astrophysics Data System (ADS)

    Li, Yuan-hua; Nie, Li-ping; Li, Xiao-lan

    2015-07-01

    We propose a scheme for preparing a seven-atom maximally entangled state (Zha et al., J. Phys. A: Math. Theor. 45, 255, 2012) in cavity QED, where the atoms interact simultaneously with the highly detuned single-mode cavity and the strong classical driving field. Thus our scheme is insensitive to both the cavity decay and thermal field.

  8. Generation of macroscopic singlet states in a cold atomic ensemble.

    PubMed

    Behbood, N; Martin Ciurana, F; Colangelo, G; Napolitano, M; Tóth, Géza; Sewell, R J; Mitchell, M W

    2014-08-29

    We report the generation of a macroscopic singlet state in a cold atomic sample via quantum nondemolition measurement-induced spin squeezing. We observe 3 dB of spin squeezing and detect entanglement with 5? statistical significance using a generalized spin-squeezing inequality. The degree of squeezing implies at least 50% of the atoms have formed singlets. PMID:25215981

  9. Coherence and entanglement in the ground-state of a bosonic Josephson junction:from macroscopic Schrödinger cats to separable Fock states

    E-print Network

    Giovanni Mazzarella; Luca Salasnich; Alberto Parola; Flavio Toigo

    2011-04-12

    We consider a bosonic Josephson junction made of $N$ ultracold and dilute atoms confined by a quasi one-dimensional double-well potential within the two-site Bose-Hubbard model framework. The behaviour of the system is investigated at zero temperature by varying the inter-atomic interaction from the strongly attractive regime to the repulsive one. We show that the ground-state exhibits a crossover from a macroscopic Schr\\"odinger-cat state to a separable Fock state through an atomic coherent regime. By diagonalizing the Bose-Hubbard Hamiltonian we characterize the emergence of the mascroscopic cat states by calculating the Fisher information $F$, the coherence by means of the visibility $\\alpha$ of the interference fringes in the momentum distribution, and the quantum correlations by using the entanglement entropy $S$. Both Fisher information and visibility are shown to be related to the ground state energy by employing the Hellmann-Feynman theorem. This result, together with a perturbative calculation of the ground-state energy, makes possible to obtain simple analytical formulas for $F$ and $\\alpha$ over a range of interactions, in excellent agreement with the exact diagonalization of the Bose-Hubbard Hamiltonian. In the attractive regime the entanglement entropy attains values very close to its upper limit for a specific interaction strength lying in the region where coherence is lost and self trapping sets in.

  10. Optical pumping and readout of bismuth hyperfine states in silicon for atomic clock applications.

    PubMed

    Saeedi, K; Szech, M; Dluhy, P; Salvail, J Z; Morse, K J; Riemann, H; Abrosimov, N V; Nötzel, N; Litvinenko, K L; Murdin, B N; Thewalt, M L W

    2015-01-01

    The push for a semiconductor-based quantum information technology has renewed interest in the spin states and optical transitions of shallow donors in silicon, including the donor bound exciton transitions in the near-infrared and the Rydberg, or hydrogenic, transitions in the mid-infrared. The deepest group V donor in silicon, bismuth, has a large zero-field ground state hyperfine splitting, comparable to that of rubidium, upon which the now-ubiquitous rubidium atomic clock time standard is based. Here we show that the ground state hyperfine populations of bismuth can be read out using the mid-infrared Rydberg transitions, analogous to the optical readout of the rubidium ground state populations upon which rubidium clock technology is based. We further use these transitions to demonstrate strong population pumping by resonant excitation of the bound exciton transitions, suggesting several possible approaches to a solid-state atomic clock using bismuth in silicon, or eventually in enriched (28)Si. PMID:25990870

  11. Optical pumping and readout of bismuth hyperfine states in silicon for atomic clock applications

    PubMed Central

    Saeedi, K.; Szech, M.; Dluhy, P.; Salvail, J.Z.; Morse, K.J.; Riemann, H.; Abrosimov, N.V.; Nötzel, N.; Litvinenko, K.L.; Murdin, B.N.; Thewalt, M.L.W.

    2015-01-01

    The push for a semiconductor-based quantum information technology has renewed interest in the spin states and optical transitions of shallow donors in silicon, including the donor bound exciton transitions in the near-infrared and the Rydberg, or hydrogenic, transitions in the mid-infrared. The deepest group V donor in silicon, bismuth, has a large zero-field ground state hyperfine splitting, comparable to that of rubidium, upon which the now-ubiquitous rubidium atomic clock time standard is based. Here we show that the ground state hyperfine populations of bismuth can be read out using the mid-infrared Rydberg transitions, analogous to the optical readout of the rubidium ground state populations upon which rubidium clock technology is based. We further use these transitions to demonstrate strong population pumping by resonant excitation of the bound exciton transitions, suggesting several possible approaches to a solid-state atomic clock using bismuth in silicon, or eventually in enriched 28Si. PMID:25990870

  12. Ground-State Hyperfine Structure of Heavy Hydrogen-Like Ions

    NASA Astrophysics Data System (ADS)

    Kühl, T.; Borneis, S.; Dax, A.; Engel, T.; Faber, S.; Gerlach, M.; Holbrow, C.; Huber, G.; Marx, D.; Merz, P.; Quint, W.; Schmitt, F.; Seelig, P.; Tomaselli, M.; Winter, H.; Wuertz, M.; Beckert, K.; Franzke, B.; Nolden, F.; Reich, H.; Steck, M.

    Contributions of quantum electrodynamics (QED) to the combined electric and magnetic interaction between the electron and the nucleus can be studied by optical spectroscopy in high-Z hydrogen-like heavy ions. The transition studied is the ground-state hyperfine structure transition, well known from the 21 cm line in atomic hydrogen. The hyperfine splitting of the is ground state of hydrogen-like systems constitutes the simplest and most basic magnetic interaction in atomic physics. The Z3-increase leads to a transition energy in the UV-region of the optical spectrum for the case of Bi82+. At the same time, the QED correction rises to nearly 1 fraction of higher order contributions. This situation is particularly useful for a comparison with non-perturbative QED calculations. The combination of exceptionally intense electric and magnetic fields electric and magnetic fields is unique. This transition has become accessible to precision laser spectroscopy at the high-energy heavy-ion storage ring at GSI-Darmstadt in the hydrogen-like 209Bi82+ and 207Pb81+. In the meantime, 165Ho66+ and 185,187Re74+ were also studied with reduced resolution by conventional optical spectroscopy at the SuperEBIT ion trap at Lawrence Livermore National Laboratory.

  13. Symmetry Breakdown in Ground State Dissociation of HD{sup +}

    SciTech Connect

    Ben-Itzhak, I. [James R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506 (United States)] [James R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506 (United States); Wells, E. [James R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506 (United States)] [James R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506 (United States); Carnes, K. D. [James R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506 (United States)] [James R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506 (United States); Krishnamurthi, Vidhya [James R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506 (United States)] [James R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506 (United States); Weaver, O. L. [James R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506 (United States)] [James R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506 (United States); Esry, B. D. [Institute for Theoretical Atomic and Molecular Physics, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138 (United States)] [Institute for Theoretical Atomic and Molecular Physics, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138 (United States)

    2000-07-03

    Experimental studies of the dissociation of the electronic ground state of HD{sup +} following ionization of HD by fast proton impact indicate that the H{sup +}+D 1s dissociation channel is more likely than the H1s+D {sup +} dissociation channel by about 7% . This isotopic symmetry breakdown is due to the finite nuclear mass correction to the Born-Oppenheimer approximation which makes the 1s{sigma} state 3.7 meV lower than the 2p{sigma} state at the dissociation limit. The measured fractions of the two dissociation channels are in agreement with coupled-channels calculations of 1s{sigma} to 2p{sigma} transitions. (c) 2000 The American Physical Society.

  14. Improved estimates of the total correlation energy in the ground state of the water molecule

    E-print Network

    Anderson, James B.

    Improved estimates of the total correlation energy in the ground state of the water molecule Arne calculations of the electronic energy of the ground state of the water molecule yield energies lower than those for the electronic energy of the ground state of the water molecule. The energy given by a fixed-node quantum Monte

  15. Complete population transfer in degenerate n-state atoms

    E-print Network

    J. H. McGuire; Kh. Kh. Shakov; Kh. Yu. Rakhimov

    2003-06-11

    We find a set of conditions to achieve complete population transfer, via coherent population trapping, from an initial state to a designated final state at a designated time in a degenerate n-state atom, where the transitions are caused by an external interaction.

  16. Determination of Ground-Laboratory to In-Space Effective Atomic Oxygen Fluence for DC 93?500 Silicone

    NASA Technical Reports Server (NTRS)

    deGroh, Kim K.; Banks, Bruce A.; Ma, David

    2004-01-01

    The objective of this research was to calibrate the ground-to-space effective atomic oxygen fluence for DC 93-500 silicone in a thermal energy electron cyclotron resonance (ECR) oxygen plasma facility. Silicones, commonly used spacecraft materials, do not chemically erode with atomic oxygen attack like other organic materials but form an oxidized hardened silicate surface layer. Therefore, the effective atomic oxygen fluence in a ground test facility should not be determined based on mass loss measurements, as they are with organic polymers. A technique has been developed at the Glenn Research Center to determine the equivalent amount of atomic oxygen exposure in an ECR ground test facility to produce the same degree of atomic oxygen damage as in space. The approach used was to compare changes in the surface hardness of ground test (ECR) exposed DC 93-500 silicone with DC 93-500 exposed to low Earth orbit (LEO) atomic oxygen as part of a shuttle flight experiment. The ground to in-space effective atomic oxygen fluence correlation was determined based on the fluence in the ECR source that produced the same hardness for the fluence in-space. Nanomechanical hardness versus contact depth measurements were obtained for five ECR exposed DC 93-500 samples (ECR exposed for 18 to 40 hrs, corresponding to Kapton effective fluences of 4.2 x 10(exp 20) to 9.4 x 10(exp 20) atoms/sq cm, respectively) and for space exposed DC 93-500 from the Evaluation of Oxygen Interactions with Materials III (EOIM III) shuttle flight experiment, exposed to LEO atomic oxygen for 2.3 x 10(exp 20) atoms/sq cm. Pristine controls were also evaluated. A ground-to-space correlation value was determined based on correlation values for four contact depths (150, 200, 250, and 300 nm), which represent the near surface depth data. The results indicate that the Kapton effective atomic oxygen fluence in the ECR facility needs to be 2.64 times higher than in LEO to replicate equivalent exposure damage in the ground test silicone as occurred in the space exposed silicone.

  17. The ground state of germylidene (H2C=Ge)

    Microsoft Academic Search

    David A. Hostutler; Dennis J. Clouthier; Steven W. Pauls

    2002-01-01

    Single vibronic level emission spectra have been obtained by pumping individual vibronic bands in the B~1B2-X~1A1 electronic transitions of jet-cooled H2CGe and D2CGe. Analysis of the spectra gave for the first time the frequencies of the following ground state fundamentals: for H2CGe, nu2=1238 cm-1, nu3=782 cm-1, nu4=673 cm-1, nu6=351 cm-1, and for D2CGe, nu1=2089 cm-1, nu2=1000 cm-1, nu3=694 cm-1, nu4=520

  18. First observation of ground state dineutron decay: 16Be.

    PubMed

    Spyrou, A; Kohley, Z; Baumann, T; Bazin, D; Brown, B A; Christian, G; DeYoung, P A; Finck, J E; Frank, N; Lunderberg, E; Mosby, S; Peters, W A; Schiller, A; Smith, J K; Snyder, J; Strongman, M J; Thoennessen, M; Volya, A

    2012-03-01

    We report on the first observation of dineutron emission in the decay of 16Be. A single-proton knockout reaction from a 53??MeV/u 17B beam was used to populate the ground state of 16Be. 16Be is bound with respect to the emission of one neutron and unbound to two-neutron emission. The dineutron character of the decay is evidenced by a small emission angle between the two neutrons. The two-neutron separation energy of 16Be was measured to be 1.35(10) MeV, in good agreement with shell model calculations, using standard interactions for this mass region. PMID:22463404

  19. Disorder-induced neutral solitons in degenerate ground state polymers

    E-print Network

    Marc Thilo Figge; Maxim V. Mostovoy; Jasper Knoester

    1998-11-17

    In this letter, we study the effects of weak off-diagonal disorder on conjugated polymers with a doubly degenerate ground-state. We find that disorder induces a finite density of neutral solitons in the lattice dimerization of a polymer chain. Interchain interactions result in a linear potential between the solitons and, if sufficiently strong, bind them into pairs resulting in an exponential suppression of the soliton density. As neutral solitons carry spin 1/2, they contribute to the polymer's magnetic properties. We calculate the magnetic susceptibility and suggest measurements of the magnetic susceptibility in {\\it trans}-polyacetylene at low temperatures.

  20. Evidence for the ground-state resonance of 26O

    E-print Network

    Lunderberg, E; Kohley, Z; Attanayake, H; Baumann, T; Bazin, D; Christian, G; Divaratne, D; Grimes, S M; Haagsma, A; Finck, J E; Frank, N; Luther, B; Mosby, S; Nagy, T; Peaslee, G F; Schiller, A; Snyder, J; Spyrou, A; Strongman, M J; Thoennessen, M

    2012-01-01

    Evidence for the ground state of the neutron-unbound nucleus 26O was observed for the first time in the single proton-knockout reaction from a 82 MeV/u 27F beam. Neutrons were measured in coincidence with 24O fragments. 26O was determined to be unbound by 150+50-150 keV from the observation of low-energy neutrons. This result agrees with recent shell model calculations based on microscopic two- and three-nucleon forces.

  1. Ground-Laboratory to In-Space Effective Atomic-Oxygen Fluence Determined for DC 93-500 Silicone

    NASA Technical Reports Server (NTRS)

    deGroh, Kim K.; Banks, Bruce A.; Ma, David

    2005-01-01

    Surfaces on the leading edge of spacecraft in low Earth orbit (e.g., surface facing the velocity direction), such as on the International Space Station, are subject to atomic oxygen attack, and certain materials are susceptible to erosion. Therefore, ground-based laboratory testing of the atomic oxygen durability of spacecraft materials is necessary for durability assessment when flight data are not available. For accurate space simulation, the facility is commonly calibrated on the basis of the mass loss of Kapton (DuPont, Wilmington, DE) as a control sample for effective fluence determination. This is because Kapton has a well-characterized atomic oxygen erosion yield (E(sub y), in cubic centimeters per atom) in the low Earth orbit (LEO) environment. Silicones, a family of commonly used spacecraft materials, do not chemically erode away with atomic oxygen attack like other organic materials that have volatile oxidation products. Instead, silicones react with atomic oxygen and form an oxidized hardened silicate surface layer. Often the loss of methyl groups causes shrinkage of the surface skin and "mud-tile" crazing degradation. But silicones often do not lose mass, and some silicones actually gain mass during atomic oxygen exposure. Therefore, the effective atomic oxygen fluence for silicones in a ground-test facility should not be determined on the basis of traditional mass-loss measurements, as it is with polymers that erode. Another method for determining effective fluence needs to be employed for silicones. A new technique has been developed at the NASA Glenn Research Center for determining the effective atomic oxygen fluence for silicones in ground-test facilities. This technique determines the equivalent amount of atomic oxygen oxidation on the basis of changes in the surface-oxide hardness. The specific approach developed was to compare changes in the surface hardness of ground-laboratory-exposed DC93-500 silicone with DC93-500 exposed to LEO atomic oxygen as part of a shuttle flight experiment. The on-the-ground to in-space effective atomic oxygen fluence was determined on the basis of the Kapton effective fluence in the ground-laboratory facility that produced the same hardness for the fluence in space.

  2. The perfect atom: Bound states of supersymmetric quantum electrodynamics

    NASA Astrophysics Data System (ADS)

    Herzog, Christopher P.; Klose, Thomas

    2010-11-01

    We study hydrogen-like atoms in N=1 supersymmetric quantum electrodynamics with an electronic and a muonic family. These atoms are bound states of an anti-muon and an electron or their superpartners. The exchange of a photino converts different bound states into each other. We determine the energy eigenstates and calculate the spectrum to fourth order in the fine structure constant. A difference between these perfect atoms and non-supersymmetric ones is the absence of hyperfine structure. We organize the eigenstates into supermultiplets of the underlying symmetry algebra.

  3. Face-dependent Auger neutralization and ground-state energy shift for He in front of Al surfaces

    SciTech Connect

    Wethekam, S.; Winter, H. [Institut fuer Physik, Humboldt-Universitaet zu Berlin, Brook-Taylor-Strasse 6, D-12489 Berlin (Germany); Valdes, Diego; Monreal, R. C. [Departamento de Fisica Teorica de la Materia Condendada C-V, Universidad Autonoma de Madrid, E-28049 Madrid (Spain)

    2008-08-15

    He atoms and ions with keV energies are scattered under grazing angles of incidence from Al(111), Al(100), and Al(110) surfaces. Fractions of surviving ions and normal energy gains of He{sup +} ions prior to neutralization, derived from shifts of angular distributions for incident atoms and ions, are compared to results from three-dimensional Monte Carlo simulations based on theoretically calculated Auger neutralization rates and He ground-state energy shifts. From the good agreement of experimental data with simulations, we conclude a detailed microscopic understanding for a model system of ion-surface interactions. Our work provides further evidence for the recently reported surface Miller index dependence for the neutralization of He{sup +} ions at metal surfaces. The study is extended to the face dependence of the He ground-state energy shift.

  4. Ground States and Excited States in a Tunable Graphene Quantum Dot

    Microsoft Academic Search

    Lin-Jun Wang; Gang Cao; Tao Tu; Hai-Ou Li; Cheng Zhou; Xiao-Jie Hao; Guang-Can Guo; Guo-Ping Guo

    2011-01-01

    We prepare an etched gate tunable quantum dot in single-layer graphene and present transport measurement in this system. We extract the information of the ground states and excited states of the graphene quantum dot, as denoted by the presence of characteristic Coulomb blockade diamond diagrams. The results demonstrate that the quantum dot in single-layer graphene bodes well for future quantum

  5. Combined quantum-state preparation and laser cooling of a continuous beam of cold atoms

    SciTech Connect

    Di Domenico, Gianni; Devenoges, Laurent; Dumas, Claire; Thomann, Pierre [Laboratoire Temps-Frequence, Universite de Neuchatel, Avenue de Bellevaux 51, CH-2009 Neuchatel (Switzerland)

    2010-11-15

    We use two-laser optical pumping on a continuous atomic fountain in order to prepare cold cesium atoms in the same quantum ground state. A first laser excites the F=4 ground state to pump the atoms toward F=3 while a second {pi}-polarized laser excites the F=3{yields}F{sup '}=3 transition of the D{sub 2} line to produce Zeeman pumping toward m=0. To avoid trap states, we implement the first laser in a two-dimensional optical lattice geometry, thereby creating polarization gradients. This configuration has the advantage of simultaneously producing Sisyphus cooling when the optical lattice laser is tuned between the F=4{yields}F{sup '}=4 and F=4{yields}F{sup '}=5 transitions of the D{sub 2} line, which is important to remove the heat produced by optical pumping. Detuning the frequency of the second {pi}-polarized laser reveals the action of a mechanism improving both laser cooling and state-preparation efficiency. A physical interpretation of this mechanism is discussed.

  6. Realizing a Kondo-correlated state with ultracold atoms.

    PubMed

    Bauer, Johannes; Salomon, Christophe; Demler, Eugene

    2013-11-22

    We propose a novel realization of Kondo physics with ultracold atomic gases. It is based on a Fermi sea of two different hyperfine states of one atom species forming bound states with a different species, which is spatially confined in a trapping potential. We show that different situations displaying Kondo physics can be realized when Feshbach resonances between the species are tuned by a magnetic field and the trapping frequency is varied. We illustrate that a mixture of 40K and 23Na atoms can be used to generate a Kondo-correlated state and that momentum resolved radio frequency spectroscopy can provide unambiguous signatures of the formation of Kondo resonances at the Fermi energy. We discuss how tools of atomic physics can be used to investigate open questions for Kondo physics, such as the extension of the Kondo screening cloud. PMID:24313499

  7. Microwave-dressed state-selective potentials for atom interferometry

    E-print Network

    Guarrera, V; Reichel, J; Rosenbusch, P

    2015-01-01

    We propose a novel and robust technique to realize a beam splitter for trapped Bose-Einstein condensates (BECs). The scheme relies on the possibility of producing different potentials simultaneously for two internal atomic states. The atoms are coherently transferred, via a Rabi coupling between the two long-lived internal states, from a single well potential to a double-well. We present numerical simulations supporting our proposal and confirming excellent efficiency and fidelity of the transfer process with realistic numbers for a BEC of $^{87}$Rb. We discuss the experimental implementation by suggesting state-selective microwave potentials as an ideal tool to be exploited for magnetically trapped atoms. The working principles of this technique are tested on our atom chip device which features an integrated coplanar micro-wave guide. In particular, the first realization of a double-well potential by using a microwave dressing field is reported. Experimental results are presented together with numerical simu...

  8. Cloning and variation of ground state intestinal stem cells.

    PubMed

    Wang, Xia; Yamamoto, Yusuke; Wilson, Lane H; Zhang, Ting; Howitt, Brooke E; Farrow, Melissa A; Kern, Florian; Ning, Gang; Hong, Yue; Khor, Chiea Chuen; Chevalier, Benoit; Bertrand, Denis; Wu, Lingyan; Nagarajan, Niranjan; Sylvester, Francisco A; Hyams, Jeffrey S; Devers, Thomas; Bronson, Roderick; Lacy, D Borden; Ho, Khek Yu; Crum, Christopher P; McKeon, Frank; Xian, Wa

    2015-06-11

    Stem cells of the gastrointestinal tract, pancreas, liver and other columnar epithelia collectively resist cloning in their elemental states. Here we demonstrate the cloning and propagation of highly clonogenic, 'ground state' stem cells of the human intestine and colon. We show that derived stem-cell pedigrees sustain limited copy number and sequence variation despite extensive serial passaging and display exquisitely precise, cell-autonomous commitment to epithelial differentiation consistent with their origins along the intestinal tract. This developmentally patterned and epigenetically maintained commitment of stem cells is likely to enforce the functional specificity of the adult intestinal tract. Using clonally derived colonic epithelia, we show that toxins A or B of the enteric pathogen Clostridium difficile recapitulate the salient features of pseudomembranous colitis. The stability of the epigenetic commitment programs of these stem cells, coupled with their unlimited replicative expansion and maintained clonogenicity, suggests certain advantages for their use in disease modelling and regenerative medicine. PMID:26040716

  9. Magnetic ground state of semiconducting transition metal trichalcogenide monolayers

    SciTech Connect

    Sivadas, Mr. Nikhil [Carnegie Mellon University (CMU); Daniels, Matthew W. [Carnegie Mellon University (CMU); Swendsen, Robert H. [Carnegie Mellon University (CMU); Okamoto, Satoshi [ORNL; Xiao, Di [Carnegie Mellon University (CMU)

    2015-01-01

    Layered transition-metal trichalcogenides with the chemical formula ABX3 have attracted recent interest as potential candidates for two-dimensional magnets. Using first-principles calculations within density functional theory, we investigate the magnetic ground states of monolayers of Mn- and Cr-based semiconducting trichalcogenides.We show that the second and third nearest-neighbor exchange interactions (J2 and J3) between magnetic ions, which have been largely overlooked in previous theoretical studies, are crucial in determining the magnetic ground state. Specifically, we find that monolayer CrSiTe3 is an antiferromagnet with a zigzag spin texture due to significant contribution from J3, whereas CrGeTe3 is a ferromagnet with a Curie temperature of 106 K. Monolayers of Mn compounds (MnPS3 and MnPSe3) always show antiferromagnetic N eel order. We identify the physical origin of various exchange interactions, and demonstrate that strain can be an effective knob for tuning the magnetic properties. Possible magnetic ordering in the bulk is also discussed. Our study suggests that ABX3 can be a promising platform to explore two-dimensional magnetic phenomena.

  10. On the nature of the oligoacene ground state

    NASA Astrophysics Data System (ADS)

    Hachmann, Johannes; Dorando, Jonathan; Aviles, Michael; Kin-Lic Chan, Garnet

    2007-03-01

    The nature of the oligoacene ground state - its spin, singlet-triplet gap, and diradical character as a function of chain-length - is a question of ongoing theoretical and experimental interest with notable technological implications. Previous computational studies have given inconclusive answers to this challenging electronic structure problem (see e.g. [1]). In the present study we exploit the capabilities of the local ab initio Density Matrix Renormalization Group (DMRG) [2], which allows the numerically exact (FCI) solution of the Schr"odinger equation in a chosen 1-particle basis and active space for quasi-one-dimensional systems. We compute the singlet-triplet gap from first principles as a function of system length ranging from naphthalene to tetradecacene, correlating the full ?-space (i.e. up to 58 electrons in 58 orbitals) and converging the results to a few ?Eh accuracy [3]. In order to study the diradical nature of the oligoacene ground state we calculate expectation values over different diradical occupation and pair-correlation operators. Furthermore we study the natural orbitals and their occupation. [1] Bendikov, Duong, Starkey, Houk, Carter, Wudl, JACS 126 (2004), 7416. [2] Hachmann, Cardoen, Chan, JCP 125 (2006), 144101. [3] Hachmann, Dorando, Avil'es, Chan, in preparation.

  11. Magnetic ground state of semiconducting transition-metal trichalcogenide monolayers

    NASA Astrophysics Data System (ADS)

    Sivadas, Nikhil; Daniels, Matthew W.; Swendsen, Robert H.; Okamoto, Satoshi; Xiao, Di

    2015-06-01

    Layered transition-metal trichalcogenides with the chemical formula A B X3 have attracted recent interest as potential candidates for two-dimensional magnets. Using first-principles calculations within density functional theory, we investigate the magnetic ground states of monolayers of Mn- and Cr-based semiconducting trichalcogenides. We show that the second and third nearest-neighbor exchange interactions (J2 and J3) between magnetic ions, which have been largely overlooked in previous theoretical studies, are crucial in determining the magnetic ground state. Specifically, we find that monolayer CrSiTe3 is an antiferromagnet with a zigzag spin texture due to significant contribution from J3, whereas CrGeTe3 is a ferromagnet with a Curie temperature of 106 K. Monolayers of Mn compounds (MnPS3 and MnPSe3) always show antiferromagnetic Néel order. We identify the physical origin of various exchange interactions, and demonstrate that strain can be an effective knob for tuning the magnetic properties. Possible magnetic ordering in the bulk is also discussed. Our study suggests that A B X3 can be a promising platform to explore two-dimensional magnetic phenomena.

  12. Generation of decoherence-free displaced squeezed states of radiation fields and a squeezed reservoir for atoms in cavity QED

    E-print Network

    T. Werlang; R. Guzman; F. O. Prado; C. J. Villas-Boas

    2008-06-17

    We present a way to engineer an effective anti-Jaynes-Cumming and a Jaynes-Cumming interaction between an atomic system and a single cavity mode and show how to employ it in reservoir engineering processes. To construct the effective Hamiltonian, we analyse considered the interaction of an atomic system in a \\{Lambda} configuration, driven by classical fields, with a single cavity mode. With this interaction, we firstly show how to generate a decoherence-free displaced squeezed state for the cavity field. In our scheme, an atomic beam works as a reservoir for the radiation field trapped inside the cavity, as employed recently by S. Pielawa et al. [Phys. Rev. Lett. 98, 240401 (2007)] to generate an Einstein-Podolsky-Rosen entangled radiation state in high-Q resonators. In our scheme, all the atoms have to be prepared in the ground state and, as in the cited article, neither atomic detection nor precise interaction times between the atoms and the cavity mode are required. From this same interaction, we can also generate an ideal squeezed reservoir for atomic systems. For this purpose we have to assume, besides the engineered atom-field interaction, a strong decay of the cavity field (i.e., the cavity decay must be much stronger than the effective atom-field coupling). With this scheme, some interesting effects in the dynamics of an atom in a squeezed reservoir could be tested.

  13. Revisiting "Quantum State Sharing of an Arbitrary Two-Atom State by Using a Six-Atom Cluster State in Cavity QED"

    NASA Astrophysics Data System (ADS)

    Zhang, Zi-yun; Xiong, Kuang-wei; Zuo, Xue-qin; Zhang, Wen

    2013-08-01

    In Nie et al. (Int. J. Theor. Phys. 50: 2526, 2011), authors put forward a cavity QED scheme for deterministic quantum state sharing (QSTS) of an arbitrary two-atom state. They claimed that, the quantum channel of the QSTS scheme is a six-atom cluster state. After simple calculation, one can see that the quantum channel they used is a direct product of two three-atom GHZ states. In this paper, we propose a cavity QED scheme for QSTS of an arbitrary two-atom state via a six-atom cluster state channel. In our scheme, two two-atom Bell state measurements are transformed into the discrimination of single-atom product states. Moreover, the two-atom unitary operation is changed to single-qubit unitary operations. Our scheme is insensitive to the cavity decay. The necessary time for the scheme is much shorter than the Rydberg-atom lifespan, therefore atom decays do not need to be considered.

  14. Relativistic many-body perturbation theory for general open-shell multiplet states of atoms

    NASA Astrophysics Data System (ADS)

    Ishikawa, Yasuyuki; Koc, Konrad

    1996-06-01

    A relativistic many-body perturbation theory, which accounts for relativistic and electron-correlation effects for general open-shell multiplet states of atoms and molecules, is developed and implemented with analytic basis sets of Gaussian spinors. The theory retains the essential aspects of Mo/ller-Plesset perturbation theory by employing the relativistic single-Fock-operator method of Koc and Ishikawa [Phys. Rev. A 49, 794 (1994)] for general open-shell systems. Open-shell Dirac-Fock and relativistic many-body perturbation calculations are reported for the ground and low-lying excited states of Li, B2+, Ne7+, and Ca11+.

  15. Determination of atomic hydrogen densities in the MLT and thermospheric regions from coincident ground-based and satellite airglow data

    Microsoft Academic Search

    E. J. Mierkiewicz; J. Bishop; F. L. Roesler; S. M. Nossal; J. F. Gomez; G. J. Madsen

    2003-01-01

    Coincident ground- and satellite-based geocoronal hydrogen emission data are presented, along with forward-modeling analysis results. Atomic hydrogen plays several unique roles in the terrestrial atmosphere. For example, as a daughter of the important mesospheric minor species H2O and CH4, knowledge of the MLT atomic hydrogen density distribution and associated vertical flux may prove to be valuable in understanding the chemistry

  16. Transmission-line decelerators for atoms in high Rydberg states

    NASA Astrophysics Data System (ADS)

    Lancuba, P.; Hogan, S. D.

    2014-11-01

    Beams of helium atoms in Rydberg states with principal quantum number n =52 , and traveling with an initial speed of 1950 m/s, have been accelerated, decelerated, and guided while confined in moving electric traps generated above a curved, surface-based electrical transmission line with a segmented center conductor. Experiments have been performed with atoms guided at constant speed, and with accelerations exceeding 107 m /s 2. In each case, the manipulated atoms were detected by spatially resolved, pulsed electric field ionization. The effects of tangential and centripetal accelerations on the effective trapping potentials experienced by the atoms in the decelerator have been studied, with the resulting observations highlighting contributions from the density of excited Rydberg atoms to the acceleration, deceleration, and guiding efficiencies in the experiments.

  17. Symmetry adapted coherent states for three-level atoms interacting with one-mode radiation

    NASA Astrophysics Data System (ADS)

    López-Peńa, R.; Cordero, S.; Nahmad-Achar, E.; Castańos, O.

    2015-06-01

    We introduce a combination of coherent states as variational test functions for the atomic and radiation sectors to describe a system of Na three-level atoms interacting with a one-mode quantised electromagnetic field, with and without the rotating wave approximation, which preserves the symmetry presented by the Hamiltonian. These provide us with the possibility of finding analytical solutions for the ground and first excited states. We study the properties of these solutions for the V-configuration in the double resonance condition, and calculate the expectation values of the number of photons, the atomic populations, the total number of excitations, and their corresponding fluctuations. We also calculate the photon number distribution and the linear entropy of the reduced density matrix to estimate the entanglement between matter and radiation. For the first time, we exhibit analytical expressions for all of these quantities, as well as an analytical description for the phase diagram in parameter space, which distinguishes the normal and collective regions, and which gives us all the quantum phase transitions of the ground state from one region to the other as we vary the interaction parameters (the matter-field coupling constants) of the model, in functional form.

  18. Thermodynamic ground state of MgB{sub 6} predicted from first principles structure search methods

    SciTech Connect

    Wang, Hui [State Key Lab of Superhard Materials, Jilin University, Changchun 130012 (China) [State Key Lab of Superhard Materials, Jilin University, Changchun 130012 (China); Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2 (Canada); LeBlanc, K. A. [Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2 (Canada)] [Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2 (Canada); Gao, Bo [State Key Lab of Superhard Materials, Jilin University, Changchun 130012 (China)] [State Key Lab of Superhard Materials, Jilin University, Changchun 130012 (China); Yao, Yansun, E-mail: yansun.yao@usask.ca [Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2 (Canada) [Department of Physics and Engineering Physics, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E2 (Canada); Canadian Light Source, Saskatoon, Saskatchewan S7N 0X4 (Canada)

    2014-01-28

    Crystalline structures of magnesium hexaboride, MgB{sub 6}, were investigated using unbiased structure searching methods combined with first principles density functional calculations. An orthorhombic Cmcm structure was predicted as the thermodynamic ground state of MgB{sub 6}. The energy of the Cmcm structure is significantly lower than the theoretical MgB{sub 6} models previously considered based on a primitive cubic arrangement of boron octahedra. The Cmcm structure is stable against the decomposition to elemental magnesium and boron solids at atmospheric pressure and high pressures up to 18.3 GPa. A unique feature of the predicted Cmcm structure is that the boron atoms are clustered into two forms: localized B{sub 6} octahedra and extended B{sub ?} ribbons. Within the boron ribbons, the electrons are delocalized and this leads to a metallic ground state with vanished electric dipoles. The present prediction is in contrast to the previous proposal that the crystalline MgB{sub 6} maintains a semiconducting state with permanent dipole moments. MgB{sub 6} is estimated to have much weaker electron-phonon coupling compared with that of MgB{sub 2}, and therefore it is not expected to be able to sustain superconductivity at high temperatures.

  19. Theoretical study of the ground-state structures and properties of niobium hydrides under pressure

    NASA Astrophysics Data System (ADS)

    Gao, Guoying; Hoffmann, Roald; Ashcroft, N. W.; Liu, Hanyu; Bergara, Aitor; Ma, Yanming

    2013-11-01

    As part of a search for enhanced superconductivity, we explore theoretically the ground-state structures and properties of some hydrides of niobium over a range of pressures and particularly those with significant hydrogen content. A primary motivation originates with the observation that under normal conditions niobium is the element with the highest superconducting transition temperature (Tc), and moreover some of its compounds are metals again with very high Tc's. Accordingly, combinations of niobium with hydrogen, with its high dynamic energy scale, are also of considerable interest. This is reinforced further by the suggestion that close to its insulator-metal transition, hydrogen may be induced to enter the metallic state somewhat prematurely by the addition of a relatively small concentration of a suitable transition metal. Here, the methods used correctly reproduce some ground-state structures of niobium hydrides at even higher concentrations of niobium. Interestingly, the particular stoichiometries represented by NbH4 and NbH6 are stabilized at fairly low pressures when proton zero-point energies are included. While no paired H2 units are found in any of the hydrides we have studied up to 400 GPa, we do find complex and interesting networks of hydrogens around the niobiums in high-pressure NbH6. The Nb-Nb separations in NbHn are consistently larger than those found in Nb metal at the respective pressures. The structures found in the ground states of the high hydrides, many of them metallic, suggest that the coordination number of hydrogens around each niobium atom grows approximately as 4n in NbHn (n = 1-4), and is as high as 20 in NbH6. NbH4 is found to be a plausible candidate to become a superconductor at high pressure, with an estimated Tc ˜ 38 K at 300 GPa.

  20. Stability of quantum-dot excited-state laser emission under simultaneous ground-state perturbation

    NASA Astrophysics Data System (ADS)

    Kaptan, Y.; Röhm, A.; Herzog, B.; Lingnau, B.; Schmeckebier, H.; Arsenijevi?, D.; Mikhelashvili, V.; Schöps, O.; Kolarczik, M.; Eisenstein, G.; Bimberg, D.; Woggon, U.; Owschimikow, N.; Lüdge, K.

    2014-11-01

    The impact of ground state amplification on the laser emission of In(Ga)As quantum dot excited state lasers is studied in time-resolved experiments. We find that a depopulation of the quantum dot ground state is followed by a drop in excited state lasing intensity. The magnitude of the drop is strongly dependent on the wavelength of the depletion pulse and the applied injection current. Numerical simulations based on laser rate equations reproduce the experimental results and explain the wavelength dependence by the different dynamics in lasing and non-lasing sub-ensembles within the inhomogeneously broadened quantum dots. At high injection levels, the observed response even upon perturbation of the lasing sub-ensemble is small and followed by a fast recovery, thus supporting the capacity of fast modulation in dual-state devices.

  1. Dephasing model for spatially extended atomic states in cyclotronlike resonances

    Microsoft Academic Search

    R. E. Wagner; S. Radovich; J. Gillespie; Q. Su; R. Grobe

    2002-01-01

    In recent work, the formation of ring-shaped electron distributions for hydrogen atoms in resonant static magnetic-laser fields has exclusively been associated with the impact of relativity. In this note we will generalize this statement and show that the nonlinearity associated with the nuclear binding force can trigger similarly shaped steady-state charge clouds in atoms under suitable conditions. The dephasing model,

  2. Ground-Laboratory to In-Space Atomic Oxygen Correlation for the Polymer Erosion and Contamination Experiment (PEACE) Polymers

    NASA Technical Reports Server (NTRS)

    Stambler, Arielle H.; Inoshita, Karen E.; Roberts, Lily M.; Barbagallo, Claire E.; deGroh, Kim K.; Banks, Bruce A.

    2011-01-01

    The Materials International Space Station Experiment 2 (MISSE 2) Polymer Erosion and Contamination Experiment (PEACE) polymers were exposed to the environment of low Earth orbit (LEO) for 3.95 years from 2001 to 2005. There were 41 different PEACE polymers, which were flown on the exterior of the International Space Station (ISS) in order to determine their atomic oxygen erosion yields. In LEO, atomic oxygen is an environmental durability threat, particularly for long duration mission exposures. Although spaceflight experiments, such as the MISSE 2 PEACE experiment, are ideal for determining LEO environmental durability of spacecraft materials, ground-laboratory testing is often relied upon for durability evaluation and prediction. Unfortunately, significant differences exist between LEO atomic oxygen exposure and atomic oxygen exposure in ground-laboratory facilities. These differences include variations in species, energies, thermal exposures and radiation exposures, all of which may result in different reactions and erosion rates. In an effort to improve the accuracy of ground-based durability testing, ground-laboratory to in-space atomic oxygen correlation experiments have been conducted. In these tests, the atomic oxygen erosion yields of the PEACE polymers were determined relative to Kapton H using a radio-frequency (RF) plasma asher (operated on air). The asher erosion yields were compared to the MISSE 2 PEACE erosion yields to determine the correlation between erosion rates in the two environments. This paper provides a summary of the MISSE 2 PEACE experiment; it reviews the specific polymers tested as well as the techniques used to determine erosion yield in the asher, and it provides a correlation between the space and ground laboratory erosion yield values. Using the PEACE polymers asher to in-space erosion yield ratios will allow more accurate in-space materials performance predictions to be made based on plasma asher durability evaluation.

  3. 61 FR 33260 - Pesticides and Ground Water State Management Plan Regulation

    Federal Register 2010, 2011, 2012, 2013, 2014

    1996-06-26

    ...connected to surface waters. While a State's goal...articulate its ground- water protection philosophy...addresses both the ground waters to be [[Page 33269...health, environment, agriculture, and water agencies. The SMP...

  4. Tuning the magnetic ground state of a triangular lattice system

    SciTech Connect

    Garlea, Vasile O [ORNL; Savici, Andrei T [ORNL; Jin, Rongying [Louisiana State University

    2011-01-01

    The anisotropic triangular lattice of the crednerite system Cu(Mn$_{1-x}$Cu$_{x}$)O$_{2}$ is used as a basic model for studying the influence of spin disorder on the ground state properties of a two-dimensional frustrated antiferromagnet. Neutron diffraction measurements show that the undoped phase (x=0) undergoes a transition to antiferromagnetic long-range order that is stabilized by a frustration-relieving structural distortion. Small deviation from the stoichiometric composition alters the magnetoelastic characteristics and reduces the effective dimensionality of the magnetic lattice. Upon increasing the doping level, the interlayer coupling changes from antiferromagnetic to ferromagnetic, while the structural distortion is fully suppressed. Concomitantly, the long-range magnetic order is gradually transformed into a two-dimensional order.

  5. Unresolved question of the 10He ground state resonance.

    PubMed

    Kohley, Z; Snyder, J; Baumann, T; Christian, G; DeYoung, P A; Finck, J E; Haring-Kaye, R A; Jones, M; Lunderberg, E; Luther, B; Mosby, S; Simon, A; Smith, J K; Spyrou, A; Stephenson, S L; Thoennessen, M

    2012-12-01

    The ground state of (10)He was populated using a 2p2n-removal reaction from a 59 MeV/u (14)Be beam. The decay energy of the three-body system, (8)He+n+n, was measured and a resonance was observed at E=1.60(25) MeV with a 1.8(4) MeV width. This result is in agreement with previous invariant mass spectroscopy measurements, using the (11)Li(-p) reaction, but is inconsistent with recent transfer reaction results. The proposed explanation that the difference, about 500 keV, is due to the effect of the extended halo nature of (11)Li in the one-proton knockout reaction is no longer valid as the present work demonstrates that the discrepancy between the transfer reaction results persists despite using a very different reaction mechanism, (14)Be(-2p2n). PMID:23368186

  6. Unresolved Question of the He10 Ground State Resonance

    NASA Astrophysics Data System (ADS)

    Kohley, Z.; Snyder, J.; Baumann, T.; Christian, G.; DeYoung, P. A.; Finck, J. E.; Haring-Kaye, R. A.; Jones, M.; Lunderberg, E.; Luther, B.; Mosby, S.; Simon, A.; Smith, J. K.; Spyrou, A.; Stephenson, S. L.; Thoennessen, M.

    2012-12-01

    The ground state of He10 was populated using a 2p2n-removal reaction from a 59MeV/u Be14 beam. The decay energy of the three-body system, He8+n+n, was measured and a resonance was observed at E=1.60(25)MeV with a 1.8(4) MeV width. This result is in agreement with previous invariant mass spectroscopy measurements, using the Li11(-p) reaction, but is inconsistent with recent transfer reaction results. The proposed explanation that the difference, about 500 keV, is due to the effect of the extended halo nature of Li11 in the one-proton knockout reaction is no longer valid as the present work demonstrates that the discrepancy between the transfer reaction results persists despite using a very different reaction mechanism, Be14(-2p2n).

  7. a New Phenomenological Formula for Ground-State Binding Energies

    NASA Astrophysics Data System (ADS)

    Gangopadhyay, G.

    A phenomenological formula based on liquid drop model has been proposed for ground-state binding energies of nuclei. The effect due to bunching of single particle levels has been incorporated through a term resembling the one-body Hamiltonian. The effect of n-p interaction has been included through a function of valence nucleons. A total of 50 parameters has been used in the present calculation. The root mean square (r.m.s.) deviation for the binding energy values for 2140 nuclei comes out to be 0.376 MeV, and that for 1091 alpha decay energies is 0.284 MeV. The correspondence with the conventional liquid drop model is discussed.

  8. A new phenomenological formula for ground state binding energies

    E-print Network

    Gangopadhyay, G

    2010-01-01

    A phenomenological formula based on liquid drop model has been proposed for ground state binding energies of nuclei. The effect due to bunching of single particle levels has been incorporated through a term resembling the one-body Hamiltonian. The effect of n-p interaction has been included through a function of valence nucleons. A total of 50 parameters has been used in the present calculation. The r.m.s. deviation for the binding energy values for 2140 nuclei comes out to be 0.376 MeV, and that for 1091 alpha decay energies is 0.284 MeV. The correspondence with the conventional liquid drop model is discussed.

  9. Ground states for fractional Schrödinger equations with critical growth

    NASA Astrophysics Data System (ADS)

    Shang, Xudong; Zhang, Jihui

    2014-02-01

    In this paper we study the existence and multiplicity of solutions for the critical fractional Schrödinger equation \\begin{equation*} \\varepsilon^{2\\alpha}(-\\Delta)^{\\alpha}u + V(x)u= |u|^{2_{\\alpha}^{*}-2}u + \\lambda f(u), \\tqs x\\in{R}^{N}, \\end{equation*} where ? and ? are positive parameters, 0 < ? < 1, (-?)? denotes the fractional Laplacian of order ?, N > 2?, 2_{\\alpha}^{*} = \\frac{2N}{N- 2\\alpha} is the fractional critical exponent; V is a positive continuous potential satisfying some conditions and f is a continuous subcritical nonlinear term. We prove that the equation has a nonnegative ground state solution and investigate the relation between the number of solutions and the topology of the set where V attains its minimum, for all sufficiently large ? and small ?.

  10. Exact ground states of rotating Bose gases close to a Feshbach resonance.

    PubMed

    Cooper, N R

    2004-06-01

    We study the ground states of rotating Bose gases when interactions are affected by a nearby Feshbach resonance. We show that exact ground states at high angular momentum can be found analytically for a general model for the resonant interactions. We identify parameter regimes where the exact ground states are exotic fractional quantum Hall states, the excitations of which obey nonabelian exchange statistics. PMID:15245205

  11. Anisotropy of electronic interaction between atoms in arbitrary states

    NASA Astrophysics Data System (ADS)

    Krems, Roman; Groenenboom, Gerrit; Dalgarno, Alexander

    2004-05-01

    A general tensorial expansion for the interaction potential between two atoms in arbitrary states is derived and the relations between the expansion coefficients and the Born-Oppenheimer potentials of the diatomic molecule are obtained. The representation of the interaction potential is given in the laboratory coordinate system. It is demonstrated that a complete expansion of the interaction potential must employ tensors that are invariant under the inversion of the coordinate system and the expansion in terms of conventional spherical harmonics is not adequate for the case of two atoms in states with non-zero electronic orbital angular momenta. The concept of the interaction anisotropy between two open-shell atoms is introduced. The correctness of the formalism is demonstrated by the example of two atoms in P-states. The collision problem of two atoms in arbitrary states can be reformulated with the use of our expansion that is particularly convenient for the analysis of scattering in the presence of external magnetic or electric fields. The anisotropy of electronic interaction drives the Zeeman predissociation, collisionally induced Zeeman relaxation, spin-orbit transitions and the spin-orbit predissociation. Given the relations between the Born-Oppenheimer potentials and the tensorial expansion coefficients we obtained, it is possible to analyze the probabilities of these processes in different systems without specific scattering calculations.

  12. Ground state of an actinide impurity fluctuating between two magnetic valence states

    Microsoft Academic Search

    A. C. Nunes; J. W. Rasul; G. A. Gehring

    1985-01-01

    The authors consider, using a combination of variational and 1\\/N techniques, an actinide impurity whose lowest ionic configurations are f2 and f3 embedded in a free electron matrix. They show that the ground state is a singlet, in agreement with recent experiments on dilute uranium systems.

  13. Ground state of an ion fluctuating between two magnetic valence states

    Microsoft Academic Search

    Y. Yafet; C. M. Varma; B. Jones

    1985-01-01

    As a model for mixed-valence thulium which fluctuates between the configurations f13, S=(1\\/2), and f12, S=1, we consider an ion with orbital degeneracy embedded in a free-electron continuum. We construct variational states of different total-spin multiplicity, namely singlet, doublet, and triplet. We find that the ground state is a singlet, with the triplet and doublet lying higher in energy and

  14. Characterization of Coupled Ground State and Excited State Equilibria by Fluorescence Spectral Deconvolution

    Microsoft Academic Search

    Wouter Caarls; M. Soledad Celej; Alexander P. Demchenko; Thomas M. Jovin

    2010-01-01

    Fluorescence probes with multiparametric response based on the relative variation in the intensities of several emission bands\\u000a are of great general utility. An accurate interpretation of the system requires the determination of the number, positions\\u000a and intensities of the spectral components. We have developed a new algorithm for spectral deconvolution that is applicable\\u000a to fluorescence probes exhibiting a two-state ground-state

  15. Nonlinear ground-state pump-probe spectroscopy in an ultracold rubidium system

    NASA Astrophysics Data System (ADS)

    Mills, Arthur K.; Elliott, D. S.

    2012-12-01

    We present results of our experimental investigations of nonlinear ground-state pump-probe spectroscopy in ultracold 85Rb collected in a magneto-optical trap. These measurements represent an extension of a similar pump-probe spectroscopy in a two-level atomic system when strongly driven by a near-resonant pump beam. In the present three-level system, coherence-induced gain at the probe laser frequency can be observed at specific frequencies within the spectrum. The absorption or gain spectra that we observe resemble those of the two-level gain spectra, but different interference processes lead to features that are not present in the two-level case. We describe our measurements of this interaction in this work.

  16. Structural expansions for the ground state energy of a simple metal

    NASA Technical Reports Server (NTRS)

    Hammerberg, J.; Ashcroft, N. W.

    1973-01-01

    A structural expansion for the static ground state energy of a simple metal is derived. An approach based on single particle band structure which treats the electron gas as a non-linear dielectric is presented, along with a more general many particle analysis using finite temperature perturbation theory. The two methods are compared, and it is shown in detail how band-structure effects, Fermi surface distortions, and chemical potential shifts affect the total energy. These are of special interest in corrections to the total energy beyond third order in the electron ion interaction, and hence to systems where differences in energies for various crystal structures are exceptionally small. Preliminary calculations using these methods for the zero temperature thermodynamic functions of atomic hydrogen are reported.

  17. Few-parameter exponentially correlated wavefunctions for the ground state of lithium

    NASA Astrophysics Data System (ADS)

    Albert, Victor V.; Guevara, Nicolais L.; Sabin, John R.; Harris, Frank E.

    Compact, but relatively accurate wavefunctions for the ground state of the Li atom were obtained through the use of a limited basis of exponentially correlated functions with optimized nonlinear parameters. In contrast to our earlier work, the basis contains pre-exponential factors that improve the rate of convergence of the basis-set expansion. The matrix elements needed in the present work were evaluated analytically using recursive methods reported recently by one of us; a check on the programming was provided by comparison with numerical evaluations carried out by Turbiner and Guevara. The rate of convergence of the expansion is compared with those of Hylleraas-basis computations, and a comparison is also made with exponentially correlated studies of He-like systems.

  18. Excited-state intramolecular proton transfer to carbon atoms: nonadiabatic surface-hopping dynamics simulations.

    PubMed

    Xia, Shu-Hua; Xie, Bin-Bin; Fang, Qiu; Cui, Ganglong; Thiel, Walter

    2015-04-21

    Excited-state intramolecular proton transfer (ESIPT) between two highly electronegative atoms, for example, oxygen and nitrogen, has been intensely studied experimentally and computationally, whereas there has been much less theoretical work on ESIPT to other atoms such as carbon. We have employed CASSCF, MS-CASPT2, RI-ADC(2), OM2/MRCI, DFT, and TDDFT methods to study the mechanistic photochemistry of 2-phenylphenol, for which such an ESIPT has been observed experimentally. According to static electronic structure calculations, irradiation of 2-phenylphenol populates the bright S1 state, which has a rather flat potential in the Franck-Condon region (with a shallow enol minimum at the CASSCF level) and may undergo an essentially barrierless ESIPT to the more stable S1 keto species. There are two S1/S0 conical intersections that mediate relaxation to the ground state, one in the enol region and one in the keto region, with the latter one substantially lower in energy. After S1 ? S0 internal conversion, the transient keto species can return back to the S0 enol structure via reverse ground-state hydrogen transfer in a facile tautomerization. This mechanistic scenario is verified by OM2/MRCI-based fewest-switches surface-hopping simulations that provide detailed dynamic information. In these trajectories, ESIPT is complete within 118 fs; the corresponding S1 excited-state lifetime is computed to be 373 fs in vacuum. Most of the trajectories decay to the ground state via the S1/S0 conical intersection in the keto region (67%), and the remaining ones via the enol region (33%). The combination of static electronic structure computations and nonadiabatic dynamics simulations is expected to be generally useful for understanding the mechanistic photophysics and photochemistry of molecules with intramolecular hydrogen bonds. PMID:25711992

  19. Two-Dimensional Clusters of Colloidal Spheres: Ground States, Excited States, and Structural Rearrangements

    NASA Astrophysics Data System (ADS)

    Perry, Rebecca W.; Holmes-Cerfon, Miranda C.; Brenner, Michael P.; Manoharan, Vinothan N.

    2015-06-01

    We study experimentally what is arguably the simplest yet nontrivial colloidal system: two-dimensional clusters of six spherical particles bound by depletion interactions. These clusters have multiple, degenerate ground states whose equilibrium distribution is determined by entropic factors, principally the symmetry. We observe the equilibrium rearrangements between ground states as well as all of the low-lying excited states. In contrast to the ground states, the excited states have soft modes and low symmetry, and their occupation probabilities depend on the size of the configuration space reached through internal degrees of freedom, as well as a single "sticky parameter" encapsulating the depth and curvature of the potential. Using a geometrical model that accounts for the entropy of the soft modes and the diffusion rates along them, we accurately reproduce the measured rearrangement rates. The success of this model, which requires no fitting parameters or measurements of the potential, shows that the free-energy landscape of colloidal systems and the dynamics it governs can be understood geometrically.

  20. Bound-state beta decay of highly ionized atoms

    Microsoft Academic Search

    K. Takahashi; R. N. Boyd; G. J. Mathews; K. Yokoi

    1987-01-01

    Nuclear ..beta.. decays of highly ionized atoms under laboratory conditions are studied. Theoretical predictions of ..beta..-decay rates are given for a few cases in which bound-state ..beta.. decay produces particularly interesting effects. A possible storage-ring experiment is proposed for measuring bound-state ..beta..-decay rates, which will be most easily applied to the decay of Ā³H\\/sup +\\/. .AE

  1. Lamb Shift in the Metastable States of the Helium Atom

    Microsoft Academic Search

    Kiu S. Suh; M. H. Zaidi

    1966-01-01

    The radiative corrections of order alpha^3 rydbergs are evaluated for the ionization energy of the metastable states 21,3S, of the helium atom. In the calculation of the average excitation energy k_0, the main contribution comes from the transition to (ms, np) and (ms, ? p) states. The oscillator strengths for transitions to (1s, ? p), (2s, ? p) and (3s,

  2. Arsenic in Ground-Water Resources of the United States

    USGS Publications Warehouse

    Welch, Alan H.; Watkins, Sharon A.; Helsel, Dennis R.; Focazio, Michael J.

    2000-01-01

    Arsenic is a naturally occurring element in rocks, soils, and the waters in contact with them. Recognized as a toxic element for centuries, arsenic today also is a human health concern because it can contribute to skin, bladder, and other cancers (National Research Council, 1999). Recently, the National Research Council (1999) recommended lowering the current maximum contaminant level (MCL) allowed for arsenic in drinking water of 50 ?g/L (micrograms per liter), citing risks for developing bladder and other cancers. The U.S. Environmental Protection Agency (USEPA) will propose a new, and likely lower, arsenic MCL during 2000 (U.S. Environmental Protection Agency, 2000). This fact sheet provides information on where and to what extent natural concentrations of arsenic in ground water exceed possible new standards. The U.S. Geological Survey (USGS) has collected and analyzed arsenic in potable (drinkable) water from 18,850 wells in 595 counties across the United States during the past two decades. These wells are used for irrigation, industrial purposes, and research, as well as for public and private water supply. Arsenic concentrations in samples from these wells are similar to those found in nearby public supplies (see Focazio and others, 1999). The large number of samples, broad geographic coverage, and consistency of methods produce a more accurate and detailed picture of arsenic concentrations than provided by any previous studies.

  3. XUV frequency-comb metrology on the ground state of helium

    SciTech Connect

    Kandula, Dominik Z.; Gohle, Christoph; Pinkert, Tjeerd J.; Ubachs, Wim; Eikema, Kjeld S. E. [LaserLaB Amsterdam, VU University, De Boelelaan 1081, NL-1081HV Amsterdam (Netherlands)

    2011-12-15

    The operation of a frequency comb at extreme ultraviolet (xuv) wavelengths based on pairwise amplification and nonlinear upconversion to the 15th harmonic of pulses from a frequency-comb laser in the near-infrared range is reported. It is experimentally demonstrated that the resulting spectrum at 51 nm is fully phase coherent and can be applied to precision metrology. The pulses are used in a scheme of direct-frequency-comb excitation of helium atoms from the ground state to the 1s4p and 1s5p {sup 1} P{sub 1} states. Laser ionization by auxiliary 1064 nm pulses is used to detect the excited-state population, resulting in a cosine-like signal as a function of the repetition rate of the frequency comb with a modulation contrast of up to 55%. Analysis of the visibility of this comb structure, thereby using the helium atom as a precision phase ruler, yields an estimated timing jitter between the two upconverted-comb laser pulses of 50 attoseconds, which is equivalent to a phase jitter of 0.38 (6) cycles in the xuv at 51 nm. This sets a quantitative figure of merit for the operation of the xuv comb and indicates that extension to even shorter wavelengths should be feasible. The helium metrology investigation results in transition frequencies of 5 740 806 993 (10) and 5 814 248 672 (6) MHz for excitation of the 1s4p and 1s5p {sup 1} P{sub 1} states, respectively. This constitutes an important frequency measurement in the xuv, attaining high accuracy in this windowless part of the electromagnetic spectrum. From the measured transition frequencies an eight-fold-improved {sup 4}He ionization energy of 5 945 204 212 (6) MHz is derived. Also, a new value for the {sup 4}He ground-state Lamb shift is found of 41 247 (6) MHz. This experimental value is in agreement with recent theoretical calculations up to order m{alpha}{sup 6} and m{sup 2}/M{alpha}{sup 5}, but with a six-times-higher precision, therewith providing a stringent test of quantum electrodynamics in bound two-electron systems.

  4. Ground Water Quality Protection. State and Local Strategies.

    ERIC Educational Resources Information Center

    National Academy of Sciences - National Research Council, Washington, DC. Commission on Physical Sciences, Mathematics, and Resources.

    Using regional case studies, this document examines representative programs for dealing with ground water contamination. Section one describes the ground water protection strategy of the U.S. Environmental Protection Agency (EPA); (2) discusses the limited data available for determining the extent of contamination; (3) provides a listing of the…

  5. ATOMIC AND MOLECULAR PHYSICS: Generation of a Super Strong Attosecond Pulse from an Atomic Superposition State Irradiated by a Shape-Optimized Short Pulse

    NASA Astrophysics Data System (ADS)

    Guo, Fu-Ming; Yang, Yu-Jun; Jin, Ming-Xing; Ding, Da-Jun; Zhu, Qi-Ren

    2009-11-01

    Using a linearly polarized, phase-stabilized 3-fs driving pulse of 800 nm central wavelength shape-optimized on its ascending edge by its an amplitude-reduced pulse irradiating on a superposition state of the helium atom, we demonstrate theoretically the generation of a super strong isolated 176-attosecond pulse in the spectral region of 93-124 eV. The unusually high intensity of this attosecond pulse is marked by the Rabi-like oscillations emerging in the time-dependent populations of the ground state and the continuum during the occurrence of the electron recombination, which is for the first time observed in this work.

  6. Ground State Depleted (GSD) Solid State Lasers: Principles, Characteristics, And Scaling

    NASA Astrophysics Data System (ADS)

    Krupke, William F.; Chase, Lloyd L.

    1989-07-01

    A novel class of rare earth doped solid state lasers is described. The Ground State Depleted (GSD) laser is pumped by an intense (>tens kW/cm2) narrowband (75%), (3) a gain element that is optically thick at the pump wavelength, (4) a gain element that has a substantially uniform gain distribution due to a bleaching of the pump transition at the pump intensity utilized. These features enable efficient room temperature operation of rare earth ion laser transitions terminating on the ground manifold. The relationships between laser parameters (cross sections, saturation fluences and fluxes, bleaching wave velocities, etc.) are given and laser performance scaling relationships are presented and discussed.

  7. Ground beef consumption patterns in the United States, FoodNet, 2006 through 2007.

    PubMed

    Taylor, Ethel V; Holt, Kristin G; Mahon, Barbara E; Ayers, Tracy; Norton, Dawn; Gould, L Hannah

    2012-02-01

    Infection resulting from foodborne pathogens, including Escherichia coli O157:H7, is often associated with consumption of raw or undercooked ground beef. However, little is known about the frequency of ground beef consumption in the general population. The objective of this study was to describe patterns of self-reported ground beef and pink ground beef consumption using data from the 2006 through 2007 FoodNet Population Survey. From 1 July 2006 until 30 June 2007, residents of 10 FoodNet sites were contacted by telephone and asked about foods consumed within the previous week. The survey included questions regarding consumption of ground beef patties both inside and outside the home, the consumption of pink ground beef patties and other types of ground beef inside the home, and consumption of ground beef outside the home. Of 8,543 survey respondents, 75.3% reported consuming some type of ground beef in the home. Of respondents who ate ground beef patties in the home, 18.0% reported consuming pink ground beef. Consumption of ground beef was reported most frequently among men, persons with incomes from $40,000 to $75,000 per year, and persons with a high school or college education. Ground beef consumption was least often reported in adults ?65 years of age. Men and persons with a graduate level education most commonly reported eating pink ground beef in the home. Reported consumption of ground beef and pink ground beef did not differ by season. Ground beef is a frequently consumed food item in the United States, and rates of consumption of pink ground beef have changed little since previous studies. The high rate of consumption of beef that has not been cooked sufficiently to kill pathogens makes pasteurization of ground beef an important consideration, especially for those individuals at high risk of complications from foodborne illnesses such as hemolytic uremic syndrome. PMID:22289595

  8. The effect of the van der Waals interaction on the excited state for atom guiding in metal-coated, hollow-core optical fibers

    Microsoft Academic Search

    Herschel S. Pilloff

    2000-01-01

    The study of atom guiding in a metal-coated, hollow-core optical fiber has been extended to the case of moderate to strong coherent excitation. Significant populations of the upper level are produced and the effect of the increased van der Waals interaction of the excited state with the inner wall is represented as a multiplicative scaling factor of the ground state

  9. Construction of accurate Kohn-Sham potentials for the lowest states of the helium atom: Accurate test of the ionization-potential theorem

    E-print Network

    Lindgren, Ingvar

    Construction of accurate Kohn-Sham potentials for the lowest states of the helium atom: Accurate Kohn-Sham potentials have been constructed for the ground 1s2 1 S state and, in particular and the procedure of van Leeuwen and Baerends (Phys. Rev. A49, 2138 (1994)). The resulting Kohn-Sham orbitals

  10. Ground-state properties and magnetic excitations of the mixed valence state: Cerium-based alloys

    Microsoft Academic Search

    B. H. Grier; R. D. Parks; S. M. Shapiro; C. F. Majkrzak

    1981-01-01

    Both the static and dynamic magnetic behavior of the mixed valence system, Ce\\/sub 0.9-x\\/La\\/sub x\\/Th\\/sub 0.1\\/, have been studied through magnetic susceptibility and inelastic neutron scattering experiments. For small La concentrations (x< or approx. =0.09), the system exhibits a first-order valence transition to a strongly mixed valent ground state, whereas nearly integral valent, local moment behavior results for x> or

  11. Pair supersolid with atom-pair hopping on the state-dependent triangular lattice

    NASA Astrophysics Data System (ADS)

    Zhang, Wanzhou; Yin, Ruoxi; Wang, Yancheng

    2013-11-01

    We systematically study an extended Bose-Hubbard model with atom hopping and atom-pair hopping in the presence of a three-body constraint on the triangular lattice. By means of large-scale quantum Monte Carlo simulations, the ground-state phase diagram is studied. We find a first-order transition between the atomic superfluid phase and the pair superfluid phase when the ratio of the atomic hopping and the atom-pair hopping is adapted. The first-order transition remains unchanged under various conditions. We then focus on the interplay among the atom-pair hopping, the on-site repulsion, and the nearest-neighbor repulsion. With on-site repulsion present, we observe first-order transitions between the Mott insulators and pair superfluid driven by the pair hopping. With the nearest-neighbor repulsion turning on, three typical solid phases with 2/3, 1, and 4/3 filling emerge at small atom-pair hopping region. A stable pair supersolid phase is found at small on-site repulsion. This is due to the three-body constraint and the pair hopping, which essentially make the model a quasihardcore boson system. Thus the pair supersolid state emerges basing on the order-by-disorder mechanism, by which hardcore bosons avoid classical frustration on the triangular lattice. Without on-site repulsion, the transitions between the pair supersolid and the atom superfluid or pair superfluid are first order, except for the particle-hole symmetric point. With weak on-site repulsion and atom hopping turning on, the transition between the pair supersolid and pair superfluid phase becomes continuous. The transition between solid and pair supersolid is three-dimensional XY university, with dynamical exponent z=1 and correlation exponent ?=0.67155. The thermal melting of pair supersolid belongs to the two-dimensional Ising university. We check both energetic and mechanical balance of pair supersolid phase. Lowering the three-body constraint, no pair supersolid is found due to the absence of degeneracy of pair solids in classical limits. We describe the experimental realization of pair tunneling on state dependent lattice.

  12. Transition Properties of Low Lying States in Atomic Indium

    E-print Network

    Sahoo, B K

    2011-01-01

    We present here the results of our relativistic many-body calculations of various properties of the first six low-lying excited states of indium. The calculations were performed using the relativistic coupled-cluster method in the framework of the singles, doubles and partial triples approximation. We obtain a large lifetime ~10s for the [4p^6]5s^2 5p_{3/2} state, which had not been known earlier. Our precise results could be used to shed light on the reliability of the lifetime measurements of the excited states of atomic indium that we have considered in the present work.

  13. Ground state energy of the polaron in the relativistic quantum electrodynamics

    SciTech Connect

    Sasaki, Itaru [Department of Mathematics, Hokkaido University, Sapporo 060-0810 (Japan)

    2005-10-01

    We consider the polaron model in the relativistic quantum electrodynamics. We prove that the ground state energy of the model is finite for all values of the fine-structure constant and the ultraviolet cutoff {lambda}. Moreover we give an upper bound and a lower bound of the ground state energy.

  14. Ground State Energy of the Polaron in the Relativistic Quantum Electrodynamics

    E-print Network

    Ground State Energy of the Polaron in the Relativistic Quantum Electrodynamics Itaru Sasaki-sasaki@math.sci.hokudai.ac.jp July 30, 2005 Abstract We consider the polaron model in the relativistic quantum electrodynam- ics energy. Key words: relativistic QED; ground state energy, polaron model. 1 Introduction and Main Results

  15. Improved lower bounds on the ground-state entropy of the antiferromagnetic Potts model

    NASA Astrophysics Data System (ADS)

    Chang, Shu-Chiuan; Shrock, Robert

    2015-05-01

    We present generalized methods for calculating lower bounds on the ground-state entropy per site, S0, or equivalently, the ground-state degeneracy per site, W =eS0/kB , of the antiferromagnetic Potts model. We use these methods to derive improved lower bounds on W for several lattices.

  16. Novel Electronic Ground States and Phenomena in d- and f-electron Materials

    Microsoft Academic Search

    M. Brian Maple

    2000-01-01

    A rich variety of novel electronic ground states have been discovered in strongly correlated d- and f-electron materials during the past three decades. The competing interactions underlying these electronic ground states and their sensitivity to parameters such as temperature T, chemical composition x, pressure P, and magnetic field H, lead to extraordinary physical phenomena and complex phase diagrams in the

  17. Ground states and magnetic responses of model valence-fluctuation systems

    Microsoft Academic Search

    B. H. Brandow

    1979-01-01

    Variational ground state wavefunctions are presented and optimized for two model valence-fluctuation systems based on Anderson lattice Hamiltonians in the U approaches infinity limit. Although these wavefunctions are approximate, they are treated in an essentially exact manner. The response of the ground state to a magnetic field is discussed.

  18. PHYSICAL REVIEW B 84, 094502 (2011) Nondeterministic ultrafast ground-state cooling of a mechanical resonator

    E-print Network

    2011-01-01

    projective measurements on an auxiliary flux qubit which interacts with it. We find that ground-state cooling) is a small macroscopic mechanical object, which can behave as a single-mode harmonic oscillator with a high frequency and a high quality factor. The physical realization of its quantum ground state, usually coupled

  19. Finding Ground States of Sherrington-Kirkpatrick Spin Glasses with Hierarchical BOA and Genetic Algorithms

    E-print Network

    Kobe, Sigismund

    Finding Ground States of Sherrington-Kirkpatrick Spin Glasses with Hierarchical BOA and Genetic- erarchical Bayesian optimization algorithm (hBOA) to reli- ably identify ground states of SK instances. Performance of hBOA is compared to that of the genetic algorithm with two common crossover operators

  20. Interactions leading to disordered ground states and unusual low-temperature behavior Robert D. Batten,1

    E-print Network

    Torquato, Salvatore

    Bravais-lattice configurations. The shear elastic constant of ground-state Bravais- lattice configurations molecular-dynamics simulations, we observe negative thermal-expansion behavior at low temperatures, where have been derived for the ground-state energies and elastic constants of the Gaussian core model 15

  1. A fast algorithm for approximating the ground state energy on a quantum computer

    E-print Network

    Papageorgiou, Anargyros

    computers to solve eigenvalue problems in quantum chemistry with very encouraging results [8, 17]. See alsoA fast algorithm for approximating the ground state energy on a quantum computer A. Papageorgiou, I study a ground state eigenvalue problem and exhibit a quantum algorithm that achieves relative error

  2. Z dependence of atomic parameters for selected autoionizing states of two-electron ions

    SciTech Connect

    Karim, K.R.; Bhalla, C.P.

    1988-03-01

    X-ray and Auger transition rates from doubly excited 2p/sup 2/ /sup 1/D/sub 2/, 2s/sup 2/ /sup 1/S/sub 0/, 2p3p /sup 1/D/sub 2/, 2p/sup 2/ /sup 3/P/sub 2/, and 2p4d /sup 1/F/sub 3/ states of heliumlike ions are presented for Z = 10, 14, 18, 20, 22, 24, 26, and 28. Intensity factors of x-ray satellites originating from dielectronic recombination of ground-state hydrogenic ions via the above autoionizing states are also calculated. The calculations are performed in the intermediate-coupling scheme with the inclusion of configuration interaction using the Hartree-Fock-Slater atomic model.

  3. GROUND WATER MANAGEMENT IN THE SOUTHEASTERN UNITED STATES

    EPA Science Inventory

    This study characterizes current and potential ground-water resource problems in North and South Carolina, Georgia, Florida, Alabama, Mississippi, Tennessee, and Kentucky. It discusses those issues that could constrain development or adversely affect environmental quality or huma...

  4. Ground-State Cooling of a Trapped Ion Using Long-Wavelength Radiation

    NASA Astrophysics Data System (ADS)

    Weidt, S.; Randall, J.; Webster, S. C.; Standing, E. D.; Rodriguez, A.; Webb, A. E.; Lekitsch, B.; Hensinger, W. K.

    2015-07-01

    We demonstrate ground-state cooling of a trapped ion using radio-frequency (rf) radiation. This is a powerful tool for the implementation of quantum operations, where rf or microwave radiation instead of lasers is used for motional quantum state engineering. We measure a mean phonon number of n Æ=0.13 (4 ) after sideband cooling, corresponding to a ground-state occupation probability of 88(7)%. After preparing in the vibrational ground state, we demonstrate motional state engineering by driving Rabi oscillations between the |n =0 ? and |n =1 ? Fock states. We also use the ability to ground-state cool to accurately measure the motional heating rate and report a reduction by almost 2 orders of magnitude compared with our previously measured result, which we attribute to carefully eliminating sources of electrical noise in the system.

  5. Ground-state cooling of a trapped ion using long-wavelength radiation

    E-print Network

    S. Weidt; J. Randall; S. C. Webster; E. D. Standing; A. Rodriguez; A. E. Webb; B. Lekitsch; W. K. Hensinger

    2015-06-04

    We demonstrate ground-state cooling of a trapped ion using radio-frequency (RF) radiation. This is a powerful tool for the implementation of quantum operations, where RF or microwave radiation instead of lasers is used for motional quantum state engineering. We measure a mean phonon number of $\\overline{n} = 0.13(4)$ after sideband cooling, corresponding to a ground-state occupation probability of 88(7)\\%. After preparing in the vibrational ground state, we demonstrate motional state engineering by driving Rabi oscillations between the n=0 and n=1 Fock states. We also use the ability to ground-state cool to accurately measure the motional heating rate and report a reduction by almost two orders of magnitude compared to our previously measured result, which we attribute to carefully eliminating sources of electrical noise in the system.

  6. Analysis and Computation for Ground State Solutions of Bose ...

    E-print Network

    Cai, Y. and Wang, H.

    2013-03-26

    degenerate quantum Fermi gases, as fermions are the fundamental building ... the many effects of quantum statistics directly and may be used as an efficient tool ...... internal atomic Josephson junction, East Asia J. Appl. Math., 1 (2010), pp

  7. Stability and Symmetry-Breaking Bifurcation for the Ground States of a NLS with a ?' Interaction

    NASA Astrophysics Data System (ADS)

    Adami, Riccardo; Noja, Diego

    2013-02-01

    We determine and study the ground states of a focusing Schrödinger equation in dimension one with a power nonlinearity | ?|2 ? ? and a strong inhomogeneity represented by a singular point perturbation, the so-called (attractive) ?' interaction, located at the origin. The time-dependent problem turns out to be globally well posed in the subcritical regime, and locally well posed in the supercritical and critical regime in the appropriate energy space. The set of the (nonlinear) ground states is completely determined. For any value of the nonlinearity power, it exhibits a symmetry breaking bifurcation structure as a function of the frequency (i.e., the nonlinear eigenvalue) ?. More precisely, there exists a critical value ?* of the nonlinear eigenvalue ?, such that: if ?0 < ? < ?*, then there is a single ground state and it is an odd function; if ? > ?* then there exist two non-symmetric ground states. We prove that before bifurcation (i.e., for ? < ?*) and for any subcritical power, every ground state is orbitally stable. After bifurcation (? = ?* + 0), ground states are stable if ? does not exceed a value {?^star} that lies between 2 and 2.5, and become unstable for ? > ?*. Finally, for ? > 2 and {? ? ?^*}, all ground states are unstable. The branch of odd ground states for ? < ?* can be continued at any ? > ?*, obtaining a family of orbitally unstable stationary states. Existence of ground states is proved by variational techniques, and the stability properties of stationary states are investigated by means of the Grillakis-Shatah-Strauss framework, where some non-standard techniques have to be used to establish the needed properties of linearization operators.

  8. Density matrix averaged atomic natural orbital (ANO) basis sets for correlated molecular wave functionsIV. Medium size basis sets for the atoms H—Kr

    Microsoft Academic Search

    Kristine Pierloot; Birgit Dumez; Per-Olof Widmark; Björn O. Roos

    1995-01-01

    Summary. Generally contracted Basis sets for the atoms H–Kr have been constructed using the atomic natural orbital (ANO) approach, with modifications for allowing symmetry breaking and state averaging. The ANO’s are constructed by averaging over the most significant electronic states, the ground state of the cation, the ground state of the anion for some atoms and the homonuclear diatomic molecule

  9. Ionization potential for excited S states of the lithium atom

    SciTech Connect

    Puchalski, M. [Faculty of Physics, University of Warsaw, Hoza 69, PL-00681 Warsaw (Poland); Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, PL-60780 Poznan (Poland); KePdziera, D. [Faculty of Chemistry, Nicolaus Copernicus University, Gagarina 7, PL-87100 Torun (Poland); Pachucki, K. [Faculty of Physics, University of Warsaw, Hoza 69, PL-00681 Warsaw (Poland)

    2010-12-15

    Nonrelativistic, relativistic, quantum electrodynamic, and finite nuclear mass corrections to the energy levels are obtained for the nS{sub 1/2},n=3,...,9 states of the lithium atom. Computational approach is based on the explicitly correlated Hylleraas functions with the analytic integration and recursion relations. Theoretical predictions for the ionization potential of nS{sub 1/2} states and transition energies nS{sub 1/2{yields}}2S{sub 1/2} are compared to known experimental values for {sup 6,7}Li isotopes.

  10. Inelastic processes in atomic collisions involving ground state and laser-prepared atoms

    NASA Astrophysics Data System (ADS)

    Planje, Willem Gilles

    1999-11-01

    In dit proefschrift worden experimenten beschreven waarbij ionen of atomen met een bepaalde snelheid op een ensemble van doelwitatomen worden gericht. Wanneer twee deeltjes elkaar voldoende genaderd hebben, vindt er wissel- werking plaats waarbij allerlei processen kunnen optreden. Deze processen resulteren in specieke eindproducten. Kennis over de interactie tussen twee botsingspartners wordt verkregen door te bekijken welke eindproducten ontstaan, en in welke mate. Een belangrijke grootheid die van invloed is op mogelijke processen is de onderlinge snelheid van de twee kernen, oftewel de botsingssnelheid. Wanneer de botsingssnelheid voldoende klein is dan kunnen de verschillende reactiemechanismen zowel kwalitatief als kwanti- tatief vaak goed voorspeld worden door het systeem te beschouwen als een kort-stondig molecuul, opgebouwd uit de twee botsende deeltjes. De ver- schillende processen die kunnen optreden worden gekwaliceerd afhankelijk van de vorming van bepaalde eindproducten. Ruwweg de volgende indeling kan gemaakt worden: 1. de interne structuur van de eindproducten zijn identiek aan die van de beginproducten. We spreken dan van een elastische botsing. 2. e en van de deeltjes of beiden worden in een aangeslagen toestand ge- bracht (of geØoniseerd). Dit zijn processen waarbij de herschikte elek- tronen zich bij de oorspronkelijke kern bevinden. We spreken dan van excitatie of ionisatie. 3. e en of meerdere elektronen bevinden zich bij de andere kern na de botsing (eventueel in aangeslagen toestand). We spreken dan van elek- tronenoverdracht. In het eerste deel van deze dissertatie worden botsingsexperimenten tussen heliumionen en natriumatomen beschreven waarbij het proces van elek- tronenoverdracht wordt onderzocht. Bij dit mechanisme is het buitenste 117?Samenvatting natriumelektron betrokken. Deze kan relatief gemakkelijk `overspringen' naar het heliumion wanneer deze zich dicht in de buurt van het natrium- atoom bevindt. Het elektron kan hierbij een bepaalde (aangeslagen) toe- stand bezetten. Wij meten de bezetting van de heliumtoestanden die onder uitzending van XUV licht ( ? 58 nm) vervallen naar de heliumgrondtoe- stand. Door de lichtintensiteit te meten onderzoeken we de mate van elek- tronenoverdracht naar een selecte groep van singlet helium`eind'toestanden, namelijk He(1s2p), He(1s3s), He(1s3p) en He(1s3d). In een reactie- vergelijking ziet het mechanisme er als volgt uit: He + (1s) + ( Na(3s) Na(3p) e- -! He + Na + -! He(1s 2 ) +h(58 nm) + Na + Het experiment kent een extra dimensie door het feit dat het, in beginsel bol- symmetrische, natriumatoom een bepaalde ruimtelijk uitlijning kan worden meegegeven. Met behulp van laserlicht van een specieke frequentie en po- larisatie, wordt het buitenste natriumelektron in een aangeslagen p toestand gebracht. Het aanslaan naar deze toestand heeft als gevolg dat het valentie- elektron zich op grotere afstand van zijn kern bevindt dan voorheen. Daar- naast kan, afhankelijk van de gebruikte laserpolarisatie, het buitenste elek- tron zich nu rond de natriumkern bewegen volgens een bepaalde anisotrope verdeling, de bolsymmetrie is doorbroken. De eecten van de excitatie en ruimtelijk verdeling van dit natriumelektron op het proces van elektronen- overdracht zijn onderzocht voor botsingsenergieØen variØerend van 0.5 keV tot 6.0 keV. De metingen laten zien dat het eect van laserexcitatie een bezettingstoe- name van de beschouwde singlet heliumtoestanden betekent, ongeacht de uitlijning van het natrium 3p elektron. Dit is simpelweg te begrijpen uit het feit dat het 3p natrium elektron minder sterk gebonden is en elektro- nenoverdracht makkelijker gaat. Daarnaast is de uitlijning van het aanges- lagen elektron van invloed op de elektronenoverdracht. De resultaten zijn vergeleken met berekeningen van S.E. Nielsen en T.H. Rod [13], die de elek- tronoverdracht beschrijven in een model waarbij het betrokken elektron zich beweegt in bepaalde eectieve potentiaalvelden. De goede overeenkomsten van onze metingen met de berekeningen rechtvaardigen de theoretische be- naderin

  11. Breakdown of the Bardeen-Cooper-Schrieffer ground state at a quantum phase transtion.

    SciTech Connect

    Jaramillo, R.; Feng, Y.; Lang, J. C.; Islam, Z.; Srajer, G.; Littlewood, P. B.; Mc Whan, D. B.; Rosenbaum, T. F.; Univ. of Chicago; Univ. of Cambridge; Massachusetts Innst. of Tech.

    2009-05-21

    Advances in solid-state and atomic physics are exposing the hidden relationships between conventional and exotic states of quantum matter. Prominent examples include the discovery of exotic superconductivity proximate to conventional spin and charge order, and the crossover from long-range phase order to preformed pairs achieved in gases of cold fermions and inferred for copper oxide superconductors. The unifying theme is that incompatible ground states can be connected by quantum phase transitions. Quantum fluctuations about the transition are manifestations of the competition between qualitatively distinct organizing principles, such as a long-wavelength density wave and a short-coherence-length condensate. They may even give rise to 'protected' phases, like fluctuation-mediated superconductivity that survives only in the vicinity of an antiferromagnetic quantum critical point. However, few model systems that demonstrate continuous quantum phase transitions have been identified, and the complex nature of many systems of interest hinders efforts to more fully understand correlations and fluctuations near a zero-temperature instability. Here we report the suppression of magnetism by hydrostatic pressure in elemental chromium, a simple cubic metal that demonstrates a subtle form of itinerant antiferromagnetism formally equivalent to the Bardeen-Cooper-Schrieffer (BCS) state in conventional superconductors. By directly measuring the associated charge order in a diamond anvil cell at low temperatures, we find a phase transition at pressures of 10 GPa driven by fluctuations that destroy the BCS-like state but preserve the strong magnetic interaction between itinerant electrons and holes. Chromium is unique among stoichiometric magnetic metals studied so far in that the quantum phase transition is continuous, allowing experimental access to the quantum singularity and a direct probe of the competition between conventional and exotic order in a theoretically tractable material.

  12. An output coupler for Bose condensed atoms The observations of BEC have stimulated interest in atom lasers, coherent sources of

    E-print Network

    An output coupler for Bose condensed atoms The observations of BEC have stimulated interest in atom lasers, coherent sources of atomic matter waves. The build-up of atoms in the ground state of a magnetic. We demonstrated a scheme for doing this with Bose condensed atoms [1]. A variable fraction of atoms

  13. Ground-state phases in spin-crossover chains Carsten Timm1,

    E-print Network

    von Oppen, Felix

    .65. h I. INTRODUCTION One of the most active fields of materials science to emerge in recent years the HS state.7­10 In SCCs the LS state is the ground state and the HS state is at a moderate thermal. Also related are recent studies of magnetic models with mo- bile vacancies18 and of insulating phases

  14. Excitation of {sup 1}S and {sup 3}S Metastable Helium Atoms to Doubly Excited States

    SciTech Connect

    Alagia, M. [CNR-ISMN Sezione Roma, Piazzale A. Moro 5, I-00185 Roma (Italy); Laboratorio Nazionale TASC, CNR-INFM, I-34012 Trieste (Italy); Coreno, M. [CNR-IMIP, Montelibretti, I-00016 Roma (Italy); Farrokhpour, H.; Omidyan, R.; Tabrizchi, M. [Department of Chemistry, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Franceschi, P. [Dipartimento di Fisica, Universita di Trento, I-38050 Povo (Tunisia) (Italy); Mihelic, A.; Zitnik, M. [Jozef Stefan Institute, P.O. Box 3000, SI-1001 Ljubljana (Slovenia); Moise, A.; Prince, K. C.; Richter, R. [Sincrotrone Trieste, in Area Science Park, I-34012 Basovizza, Trieste (Italy); Soederstroem, J. [Department of Physics, Uppsala University, Box 530, S-75121 Uppsala (Sweden); Synchrotron SOLEIL, l'Orme des Merisiers, Saint-Aubin, BP 48, F-91192 Gif-sur-Yvette Cedex (France); Stranges, S. [Dipartimento di Chimica, Universita'La Sapienza', I-00185 Roma (Italy); Laboratorio Nazionale TASC, CNR-INFM, I-34012 Trieste (Italy)

    2009-04-17

    We present spectra of triplet and singlet metastable helium atoms resonantly photoexcited to doubly excited states. The first members of three dipole-allowed {sup 1,3}P{sup o} series have been observed and their relative photoionization cross sections determined, both in the triplet (from 1s2s {sup 3}S{sup e}) and singlet (from 1s2s {sup 1}S{sup e}) manifolds. The intensity ratios are drastically different with respect to transitions from the ground state. When radiation damping is included the results for the singlets are in agreement with theory, while for triplets spin-orbit interaction must also be taken into account.

  15. Ground-state modulation-enhancement by two-state lasing in quantum-dot laser devices

    NASA Astrophysics Data System (ADS)

    Röhm, André; Lingnau, Benjamin; Lüdge, Kathy

    2015-05-01

    We predict a significant increase of the 3 dB-cutoff-frequency on the ground-state lasing wavelength for two-state-lasing quantum-dot lasers using a microscopically motivated multi-level rate-equation model. After the onset of the second lasing line, the excited state acts as a high-pass filter, improving the ground-state response to faster modulation frequencies. We present both numerically simulated small-signal and large-signal modulation results and compare the performance of single and two-state lasing devices. Furthermore, we give dynamical arguments for the advantages of two-state lasing on data-transmission capabilities.

  16. Ground-state cooling of a mechanical oscillator and detection of a weak force using a Bose-Einstein condensate

    NASA Astrophysics Data System (ADS)

    Mahajan, Sonam; Kumar, Tarun; Bhattacherjee, Aranya B.; ManMohan

    2013-01-01

    We investigate the possibility of cooling a mechanical oscillator to its ground state and using it to detect a weak coherent force by means of a hybrid optomechanical quantum device formed by a Bose-Einstein condensate (BEC) confined in a high quality factor optical cavity with an oscillatory end mirror. We show using the stochastic cooling technique that the atomic two-body interaction can be utilized to cool the mirror and achieve position squeezing essential for making sensitive measurements of weak forces. We further show that for certain values of the system parameters and spectral range, the atomic two-body interaction can also increase the signal-to-noise ratio and decrease the noise of the off-resonant stationary spectral measurements. We show that the minimum noise is obtained only in the presence of BEC.

  17. Optomechanically-induced-transparency cooling of massive mechanical resonators to the quantum ground state

    E-print Network

    Yong-Chun Liu; Yun-Feng Xiao; Xingsheng Luan; Chee Wei Wong

    2015-04-17

    Ground state cooling of massive mechanical objects remains a difficult task restricted by the unresolved mechanical sidebands. We propose an optomechanically-induced-transparency cooling scheme to achieve ground state cooling of mechanical motion without the resolved sideband condition in a pure optomechanical system with two mechanical modes coupled to the same optical cavity mode. We show that ground state cooling is achievable for sideband resolution $\\omega_{m}/\\kappa$ as low as 0.003. This provides a new route for quantum manipulation of massive macroscopic devices and high-precision measurements.

  18. Optomechanically-induced-transparency cooling of massive mechanical resonators to the quantum ground state

    E-print Network

    Liu, Yong-Chun; Luan, Xingsheng; Wong, Chee Wei

    2015-01-01

    Ground state cooling of massive mechanical objects remains a difficult task restricted by the unresolved mechanical sidebands. We propose an optomechanically-induced-transparency cooling scheme to achieve ground state cooling of mechanical motion without the resolved sideband condition in a pure optomechanical system with two mechanical modes coupled to the same optical cavity mode. We show that ground state cooling is achievable for sideband resolution $\\omega_{m}/\\kappa$ as low as 0.003. This provides a new route for quantum manipulation of massive macroscopic devices and high-precision measurements.

  19. The ground state energy of the multi-polaron in the strong coupling limit

    E-print Network

    Ioannis Anapolitanos; Benjamin Landon

    2012-12-14

    We consider the Fr\\"ohlich $N$-polaron Hamiltonian in the strong coupling limit and bound the ground state energy from below. In particular, our lower bound confirms that the ground state energy of the Fr\\"ohlich polaron and the ground state energy of the associated Pekar-Tomasevich variational problem are asymptotically equal in the strong coupling limit. We generalize the operator approach that was used to prove a similar result in the N=1 case in Lieb and Thomas (1997) and apply a Feynman-Kac formula to obtain the same result for an arbitrary particle number $N \\geq 1$.

  20. Bulk-edge correspondence of entanglement spectrum in two-dimensional spin ground states

    NASA Astrophysics Data System (ADS)

    Santos, Raul A.

    2013-01-01

    General local spin S ground states, described by a valence bond solid (VBS) on a two-dimensional lattice are studied. The norm of these ground states is mapped to a classical O(3) model on the same lattice. Using this quantum-to-classical mapping, we obtain the partial density matrix ?A associated with a subsystem A of the original ground state. We show that the entanglement spectrum of ?A in a translation invariant lattice is related with the spectrum of a quantum XXX Heisenberg model and all its conserved charges on the boundary of the region A.

  1. Characterization of ground state entanglement by single-qubit operations and excitation energies

    E-print Network

    Giampaolo, S M; Illuminati, F; Verrucchi, P; Giampaolo, Salvatore M.; Illuminati, Fabrizio; Siena, Silvio De; Verrucchi, Paola

    2006-01-01

    We consider single-qubit unitary operations and study the associated excitation energies above the ground state of interacting quantum spins. We prove that there exists a unique operation such that the vanishing of the corresponding excitation energy determines a necessary and sufficient condition for the separability of the ground state. We show that the energy difference associated to factorization exhibits a monotonic behavior with the one-tangle and the entropy of entanglement, including non analiticity at quantum critical points. The single-qubit excitation energy thus provides an independent, directly observable characterization of ground state entanglement, and a simple relation connecting two universal physical resources, energy and nonlocal quantum correlations.

  2. Three Order Parameters in Quantum XZ Spin-Oscillator Models with Gibbsian Ground States

    NASA Astrophysics Data System (ADS)

    Dorlas, Teunis C.; Skrypnik, Wolodymyr I.

    2008-01-01

    Quantum models on the hyper-cubic d-dimensional lattice of spin-1/2 particles interacting with linear oscillators are shown to have three ferromagnetic ground state order parameters. Two order parameters coincide with the magnetization in the first and third directions and the third one is a magnetization in a continuous oscillator variable. The proofs use a generalized Peierls argument and two Griffiths inequalities. The class of spin-oscillator Hamiltonians considered manifest maximal ordering in their ground states. The models have relevance for hydrogen-bond ferroelectrics. The simplest of these is proven to have a unique Gibbsian ground state.

  3. Efficient sympathetic motional-ground-state cooling of a molecular ion

    NASA Astrophysics Data System (ADS)

    Wan, Yong; Gebert, Florian; Wolf, Fabian; Schmidt, Piet O.

    2015-04-01

    Cold molecular ions are promising candidates in various fields ranging from precision spectroscopy and test of fundamental physics to ultracold chemistry. Control of internal and external degrees of freedom is a prerequisite for many of these applications. Motional-ground-state cooling represents the starting point for quantum logic-assisted internal state preparation, detection, and spectroscopy protocols. Robust and fast cooling is crucial to maximize the fraction of time available for the actual experiment. We optimize the cooling rate of ground-state cooling schemes for single 25Mg+ ions and sympathetic ground-state cooling of 24MgH+ . In particular, we show that robust cooling is achieved by combining pulsed Raman sideband cooling with continuous quench cooling. Furthermore, we experimentally demonstrate an efficient strategy for ground-state cooling outside the Lamb-Dicke regime.

  4. Quantum transport theory for atomic states through solids

    SciTech Connect

    Arbo, D.G.; Reinhold, C.O.; Kuerpick, P.; Yoshida, S.; Burgdoerfer, J. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6373 (United States)] [Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6373 (United States); Arbo, D.G.; Reinhold, C.O.; Kuerpick, P.; Yoshida, S.; Burgdoerfer, J. [Department of Physics, University of Tennessee, Knoxville, Tennessee 37996-1200 (United States)] [Department of Physics, University of Tennessee, Knoxville, Tennessee 37996-1200 (United States); Arbo, D.G. [Instituto de Astronomia y Fisica del Espacio, C.C. 67, Succursale 28, 1428 Buenos Aires (Argentina)] [Instituto de Astronomia y Fisica del Espacio, C.C. 67, Succursale 28, 1428 Buenos Aires (Argentina); Burgdoerfer, J. [Institute for Theoretical Physics, Vienna University of Technology, A-1040 Vienna (Austria)] [Institute for Theoretical Physics, Vienna University of Technology, A-1040 Vienna (Austria)

    1999-08-01

    We present a quantum description for the evolution of atomic states of fast projectiles traveling through matter. Our approach is based on the solution of a quantum Langevin equation, i.e., a stochastic time-dependent Schr{umlt o}dinger equation that describes electronic excitations of atoms during their transport through solids. The present description can be considered the quantized version of a previously developed classical transport theory. We analyze in detail the correspondence between classical and quantum transport simulations. Applications to the stripping of relativistic H{sup {minus}} and H through thin carbon foils and a comparison with experimental data are presented. {copyright} {ital 1999} {ital The American Physical Society}

  5. Density matrix averaged atomic natural orbital (ANO) basis sets for correlated molecular wave functions

    Microsoft Academic Search

    Kristine Pierloot; Birgit Dumez; Per-Olof Widmark; Björn O. Roos

    1995-01-01

    Summary Generally contracted Basis sets for the atoms H-Kr have been constructed using the atomic natural orbital (ANO) approach, with modifications for allowing symmetry breaking and state averaging. The ANO's are constructed by averaging over the most significant electronic states, the ground state of the cation, the ground state of the anion for some atoms and the homonuclear diatomic molecule

  6. Relaxation of an unstable state in parametrically excited cold atoms.

    PubMed

    Moon, Geol; Kim, Yonghee; Heo, Myoung-Sun; Park, Jina; Yum, Dahyun; Lee, Wanhee; Noh, Heung-Ryoul; Jhe, Wonho

    2011-09-01

    We investigate the scaling behavior of the relaxation process for an unstable state near a subcritical Hopf bifurcation point. When the parametric modulation is applied to a magneto-optical trap, the atomic cloud becomes unstable and decays to the dynamic bistable states. Near the subcritical Hopf bifurcation point, we experimentally show that the relaxation process exhibits the scaling behavior; the relaxation time shows a scaling exponent of -1.002 (±0.024). We also present the passage time distribution for the statistical interpretation of the escape process associated with the relaxation of the unstable state. We compare the experimental results to the numerical and analytic results, demonstrating the good agreement between them. PMID:22060485

  7. Explaining the Temperature Dependence of Spirilloxanthin’s S* Signal by an Inhomogeneous Ground State Model

    PubMed Central

    2013-01-01

    We investigate the nature of the S* excited state in carotenoids by performing a series of pump–probe experiments with sub-20 fs time resolution on spirilloxanthin in a polymethyl-methacrylate matrix varying the sample temperature. Following photoexcitation, we observe sub-200 fs internal conversion of the bright S2 state into the lower-lying S1 and S* states, which in turn relax to the ground state on a picosecond time scale. Upon cooling down the sample to 77 K, we observe a systematic decrease of the S*/S1 ratio. This result can be explained by assuming two thermally populated ground state isomers. The higher lying one generates the S* state, which can then be effectively frozen out by cooling. These findings are supported by quantum chemical modeling and provide strong evidence for the existence and importance of ground state isomers in the photophysics of carotenoids. PMID:23577754

  8. Explaining the temperature dependence of spirilloxanthin's S* signal by an inhomogeneous ground state model.

    PubMed

    Hauer, J; Maiuri, M; Viola, D; Lukes, V; Henry, S; Carey, A M; Cogdell, R J; Cerullo, G; Polli, D

    2013-07-25

    We investigate the nature of the S* excited state in carotenoids by performing a series of pump-probe experiments with sub-20 fs time resolution on spirilloxanthin in a polymethyl-methacrylate matrix varying the sample temperature. Following photoexcitation, we observe sub-200 fs internal conversion of the bright S2 state into the lower-lying S1 and S* states, which in turn relax to the ground state on a picosecond time scale. Upon cooling down the sample to 77 K, we observe a systematic decrease of the S*/S1 ratio. This result can be explained by assuming two thermally populated ground state isomers. The higher lying one generates the S* state, which can then be effectively frozen out by cooling. These findings are supported by quantum chemical modeling and provide strong evidence for the existence and importance of ground state isomers in the photophysics of carotenoids. PMID:23577754

  9. Switching between ground and excited states by optical feedback in a quantum dot laser diode

    SciTech Connect

    Virte, Martin, E-mail: mvirte@b-phot.org [Brussels Photonics Team, Department of Applied Physics and Photonics (B-PHOT TONA), Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels (Belgium); Supélec, OPTEL Research Group, Laboratoire Matériaux Optiques, Photonique et Systčmes (LMOPS) EA-4423, 2 Rue Edouard Belin, F-57070 Metz (France); Breuer, Stefan [Institute of Applied Physics, Technische Universität Darmstadt, 64289 Darmstadt (Germany); Sciamanna, Marc [Supélec, OPTEL Research Group, Laboratoire Matériaux Optiques, Photonique et Systčmes (LMOPS) EA-4423, 2 Rue Edouard Belin, F-57070 Metz (France); Panajotov, Krassimir [Brussels Photonics Team, Department of Applied Physics and Photonics (B-PHOT TONA), Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels (Belgium); Institute of Solid State Physics, 72 Tzarigradsko Chaussee Blvd., 1784 Sofia (Bulgaria)

    2014-09-22

    We demonstrate switching between ground state and excited state emission in a quantum-dot laser subject to optical feedback. Even though the solitary laser emits only from the excited state, we can trigger the emission of the ground state by optical feedback. We observe recurrent but incomplete switching between the two emission states by variation of the external cavity length in the sub-micrometer scale. We obtain a good qualitative agreement of experimental results with simulation results obtained by a rate equation that accounts for the variations of the feedback phase.

  10. Note on ultraviolet renormalization and ground state energy of the Nelson model

    E-print Network

    Fumio Hiroshima

    2015-07-19

    Ultraviolet (UV) renormalization of the Nelson model in quantum field theory is considered. A relationship between a ultraviolet renormalization term and the ground state energy of the Hamiltonian with total momentum zero is studied by functional integrations.

  11. Bott periodicity for $Z_2$ symmetric ground states of gapped free-fermion systems

    E-print Network

    Ricardo Kennedy; Martin R. Zirnbauer

    2015-01-31

    Building on the symmetry classification of disordered fermions, we give a proof of the proposal by Kitaev, and others, for a "Bott clock" topological classification of free-fermion ground states of gapped systems with symmetries. Our approach differs from previous ones in that (i) we work in the standard framework of Hermitian quantum mechanics over the complex numbers, (ii) we directly formulate a mathematical model for ground states rather than spectrally flattened Hamiltonians, and (iii) we use homotopy-theoretic tools rather than K-theory. Key to our proof is a natural transformation that squares to the standard Bott map and relates the ground state of a d-dimensional system in symmetry class s to the ground state of a (d+1)-dimensional system in symmetry class s+1. This relation gives a new vantage point on topological insulators and superconductors.

  12. Exact ground states and correlation functions of chain and ladder models of interacting hardcore bosons or spinless fermions

    E-print Network

    Henley, Christopher L.

    Exact ground states and correlation functions of chain and ladder models of interacting hardcore By removing one empty site between two occupied sites, we map the ground states of chains of hardcore bosons and spinless fermions with infinite nearest-neighbor repulsion to ground states of chains of hardcore bosons

  13. Taming the ground-state and optical properties of transition metal oxides

    Microsoft Academic Search

    O. Bengone; M. Alouani; J. Hugel; P. Blöchl

    2000-01-01

    We have implemented the so-called local density approximation (LDA) plus the Hubbard parameter U method (LDA+U), in a formalism based on the projector augmented wave (PAW) method and calculated the ground-state properties of NiO and its optical properties. Good agreement with the measured ground-state antiferromagnetic magnetic moment and optical properties are obtained for U=5 eV. The enhancement of the O

  14. Stability of the ground state of a harmonic oscillator in a monochromatic wave

    Microsoft Academic Search

    Gennady P. Berman; Daniel F. V. James; Dmitry I. Kamenev

    2001-01-01

    The stability of the ground state of a harmonic oscillator in a monochromatic wave is studied. This model describes, in particular, the dynamics of a cold ion in a linear ion trap, interacting with two laser fields with close frequencies. The stability of the ``classical ground state''-the vicinity of the point (x=0,p=0)-is analyzed analytically and numerically. For the quantum case,

  15. Model valence-fluctuation systems: Variational ground states and magnetic responses

    Microsoft Academic Search

    B. Brandow

    1980-01-01

    Variational ground-state wavefunctions are presented and optimized for two model valence-fluctuation systems, based on Anderson lattice Hamiltonians in the U ..-->.. infinity limit. Although these wavefunctions are approximate, they are treated in an essentially exact manner. The )fĀ°, fĀ¹; n = 1) system has an intuitively reasonable ground-state susceptibility, while the )fĀ¹, fĀ²; n = 2) system is found to

  16. Cold collisions of alkali-metal atoms and chromium atoms

    Microsoft Academic Search

    G.-H. Jeung; D. Hagebaum-Reignier; M. J. Jamieson

    2010-01-01

    We present ab initio potentials for ground state lithium, sodium, potassium and rubidium atoms interacting with ground state chromium atoms via the 6Sigma+ and 8Sigma+ states of the corresponding dimers. Each potential is matched to the leading van der Waals dispersion energy -C6\\/R6 - C8\\/R8 and an exchange energy; we list the values of C6, C8 and the exchange fitting

  17. Raman - Nath approximation for diffraction of atoms in the laser field taking into account spontaneous emission of atoms for ground and high energy level

    NASA Astrophysics Data System (ADS)

    Hovhannisayan, L.; Muradyan, A. Zh

    2012-03-01

    The problem of resonant Kapitza - Dirac diffraction is solved in Raman - Nath approximation out of familiar Bessel function approximation (applicable in zero and very large resonance detuning cases). It shows new and promising results for the atom optics and atom interferometry if the atomic momentum state has been prepared in a form of discrete Gaussian distribution. Namely, instead of monotonic broadening within the Bessel function approximation, our formula yields in splitting of initial distribution into two identical peaks, whith preserving form, which symmetrically move away from the distribution center for the interaction time. A table-shaped form for the ultimate momentum distribution also is in frame of new distributions. As to relaxation processes, they have only quantitative influence on the pattern of diffraction.

  18. Electronic structure and magnetic ground state properties of SrCoO2.5

    NASA Astrophysics Data System (ADS)

    Mitra, Chandrima; Fishman, Randy S.; Okamoto, Satoshi; Lee, Ho Nyung; Reboredo, Fernando A.

    2014-03-01

    ABO3-? type perovskite oxides are potential candidates for solid oxide fuel cells. The ones that crystallize in the orthorhombic brownmillerite-phase (ABO2.5) , such as SrCoO2.5, are particularly interesting due to their crystal structure which contains ordered channels of oxygen vacancies. In this work we investigate theoretically the ground state electronic structure and magnetic properties of the brownmillerite phase of SrCoO2.5. Strong correlations of the Co d electrons are treated within the local spin density approximations of Density Functional theory (DFT) with Hubbard U corrections (LSDA +U). The results are compared with the Heyd Scuzeria Ernzerhof (HSE) functional. The parameters computed with a U value of 7.5 eV are found to match closely to those computed within the HSE functional. Consistent with experimental observation a G-type antiferromagnetic structure is found to be the most stable one. From a Heisenberg Hamiltonian we compute the magnetic exchange interaction parameters, J, between the Co atoms which are then used to compute the spin-wave frequencies and inelastic neutron scattering intensities. The system has four spin-wave branches. The lowest energy mode was found to have the largest scattering intensity at the magnetic zone center. This work was supported by the U.S. Department of Energy, Basic Energy Sciences, Materials Sciences and Engineering Division.

  19. Ground-State Phases of Anisotropic Mixed Diamond Chains with Spins 1 and 1/2

    NASA Astrophysics Data System (ADS)

    Hida, Kazuo

    2014-11-01

    The ground-state phases of anisotropic mixed diamond chains with spins 1 and 1/2 are investigated. Both single-site and exchange anisotropies are considered. We find the phases consisting of an array of uncorrelated spin-1 clusters separated by singlet dimers. Except in the simplest case where the cluster consists of a single S = 1 spin, this type of ground state breaks the translational symmetry spontaneously. Although the mechanism leading to this type of ground state is the same as that in the isotropic case, it is nonmagnetic or paramagnetic depending on the competition between two types of anisotropy. We also find the Néel, period-doubled Néel, Haldane, and large-D phases, where the ground state is a single spin cluster of infinite size equivalent to the spin-1 Heisenberg chain with alternating anisotropies. The ground-state phase diagrams are determined for typical sets of parameters by numerical analysis. In various limiting cases, the ground-state phase diagrams are determined analytically. The low-temperature behaviors of magnetic susceptibility and entropy are investigated to distinguish each phase by observable quantities. The relationship of the present model with the anisotropic rung-alternating ladder with spin-1/2 is also discussed.

  20. Detecting Positron-Atom Bound States through Resonant Annihilation V. A. Dzuba* and V. V. Flambaum

    E-print Network

    Gribakin, Gleb

    Detecting Positron-Atom Bound States through Resonant Annihilation V. A. Dzuba* and V. V. Flambaum) A method is proposed for detecting positron-atom bound states by observing enhanced positron annihilation of open-shell transition-metal atoms which are likely to bind the positron: Fe, Co, Ni, Tc, Ru, Rh, Sn, Sb

  1. Slow ground state molecules from matrix isolation sublimation

    NASA Astrophysics Data System (ADS)

    Oliveira, A. N.; Sacramento, R. L.; Alves, B. X.; Silva, B. A.; Wolff, W.; Cesar, C. L.

    2014-12-01

    We describe the generation and properties of a cryogenic beam of 7Li2 dimers from sublimation of a neon matrix where lithium atoms have been implanted via laser ablation of solid precursors of metallic lithium or lithium hydride (LiH). Different sublimation regimes lead to pulsed molecular beams with different temperatures, densities and forward velocities. With laser absorption spectroscopy these parameters were measured using the molecular 7Li2 (R) transitions A1? u+(v\\prime =4,J\\prime =J\\prime\\prime +1) ?ftarrow X 1? g+(v\\prime\\prime =0,J\\prime\\prime =0,1,3). In a typical regime, sublimating a matrix at 16 K, translational temperatures of 6–8 K with a drift velocity of 130 m s?1 in a free expanding pulsed beam with molecular density of 109 cm?3, averaged along the laser axis, were observed. Rotational temperatures around 5–7 K were obtained. In recent experiments we were able to monitor the atomic Li signal—in the D2 line—concomitantly with the molecular signal in order to compare them as a function of the number of ablation pulses. Based on the data and a simple model, we discuss the possibility that a fraction of these molecules are being formed in the matrix, by mating atoms from different ablation pulses, which would open up the way to formation of other more interesting and difficult molecules to be studied at low temperatures. Such a source of cryogenic molecules have possible applications encompassing fundamental physics tests, quantum information studies, cold collisions, chemistry, and trapping.

  2. Ground and ionic states of 1,2,5-thiadiazoles: An UV-photoelectron spectroscopic and theoretical study

    NASA Astrophysics Data System (ADS)

    Pasinszki, Tibor; Krebsz, Melinda; Vass, Gįbor

    2010-03-01

    Electronic structures of 1,2,5-thiadiazoles (X 2C 2N 2S, where X = H, F, Cl, CH 3, CN) have been investigated in the gas phase by He I and He II UV-photoelectron spectroscopy, as well as by calculations at the B3LYP and SAC-CI levels using aug-cc-pV(T+d)Z basis sets. The ground state geometry of the neutral molecules has been obtained from quantum-chemical calculations at the B3LYP level. Thiadiazoles are predicted to be planar, not considering methyl-group hydrogen atoms, with C 2v symmetry. Equilibrium structures of the four lowest energy cationic states have been determined at the UB3LYP level, and calculations predicted that the sequence of ionic states is 2B 1(ground state) < 2B 2 < 2A 2 < 2A 1. Photoelectron spectroscopy and theory applied to thiadiazoles has provided information on the valence occupied levels, on the ionisation energies, and on the fundamental vibrations of the cations.

  3. Effects Induced by Nuclear Motion on the Ground State Energies of Helium and 1s-Helium Isoelectronic Series from Lithium to Xenon

    Microsoft Academic Search

    R. L. Pavlov; J. Maruani; L. M. Mihailov; L. I. Pavlov; Ch. J. Velchev; M. Dimitrova-Ivanovich; V. O. Nesterenko

    The non-relativistic energy magnitudes for the ground state of He and He isoelec- tronic series with atomic number Z =3 ÷ 54, are calculated. Calculations are performed using an explicitly correlated trial wave-functions of the generalized Hylleraas type. We have developed a variational procedure that allows solving the two-particle Schroedinger equation for a practically unlimited number of parameters in a

  4. Ground-state properties of alkali dimers and their cations (including the elements Li, Na, and K) from ab initio calculations with effective core polarization potentials

    Microsoft Academic Search

    Wolfgang Müller; Wilfried Meyer

    1984-01-01

    Extensive all-electron SCF and valence CI calculations are presented for alkali dimer systems with consideration of intershell correlation effects by use of an effective core polarization potential (CPP), which contains only a single adjustable atomic parameter. High accuracy is obtained for the ground-state spectroscopic constants of the studied molecules. The maximum deviations from accurate experimental data are as follows: 1%

  5. Velocity and electronic state distributions of sputtered Fe atoms by laser-induced fluorescence spectroscopy

    SciTech Connect

    Young, C.E.; Calaway, W.F.; Pellin, M.J.; Gruen, D.M.

    1983-01-01

    Velocity distributions and relative populations in the fine-structure levels of the a/sup 5/D/sub J/ ground state of Fe atoms, produced by sputtering with 3 keV argon ions, have been investigated by Doppler shifted laser induced fluorescence. The laser system employs a single-mode, scanning ring dye laser, amplified by a sequence of three excimer-pumped flowing-dye cells. Frequency doubling in a KD*P crystal was used to produce high energy (> .5 mJ) pulses of narrowband tunable UV output near 300 nm. Laser power influence on effective velocity bandwidth was investigated. Favorable light-collection geometry minimized distortion of the velocity spectra from apparatus-averaging effects. In impurity flux diagnostic applications in fusion devices, substantial spatial averaging may occur. In the latter case, the narrow velocity bandwidth (70 m/s, transform limit) of the present laser system is particularly useful.

  6. Relativistic configuration interaction calculation on the ground and excited states of iridium monoxide

    E-print Network

    Suo, Bingbing; Han, Huixian

    2014-01-01

    We present the fully relativistic multi-reference configuration interaction calculations of the ground and low-lying excited electronic states of IrO for individual spin-orbit component. The lowest states for four spin-orbit components 1/2, 3/2, 5/2, and 7/2 are calculated intensively to clarify the ground state of IrO. Our calculation suggests that the ground state is of 1/2 spin-orbit component, which is highly mixed with $^4\\Sigma^-$ and $^2\\Pi$ states in $\\Lambda-S$ notation. The two low-lying states of the 5/2 and 7/2 spin-orbit components are nearly degenerate with the ground state and locate only 234 and 260 cm$^{-1}$ above, respectively. The equilibrium bond length 1.712 \\AA \\ and harmonic vibrational frequency 903 cm$^{-1}$ of the 5/2 spin-orbit component are close to the experimental measurement of 1.724 \\AA \\ and 909 cm$^{-1}$, which suggests the 5/2 state should be the low-lying state contributed to spectra in experimental study. Moreover, the electronic states that give rise to the observed trans...

  7. Ground-state properties of a triangular triple quantum dot connected to superconducting leads

    NASA Astrophysics Data System (ADS)

    Oguri, Akira; Sato, Izumi; Shimamoto, Masashi; Tanaka, Yoichi

    2015-03-01

    We study ground-state properties of a triangular triple quantum dot connected to two superconducting (SC) leads. In this system orbital motion along the triangular configuration causes various types of quantum phases, such as the SU(4) Kondo state and the Nagaoka ferromagnetic mechanism, depending on the electron filling. The ground state also evolves as the Cooper pairs penetrate from the SC leads. We describe the phase diagram in a wide range of the parameter space, varying the gate voltage, the couplings between the dots and leads, and also the Josephson phase between the SC gaps. The results are obtained in the limit of large SC gap, carrying out exact diagonalization of an effective Hamiltonian. We also discuss in detail a classification of the quantum states according to the fixed point of the Wilson numerical renormalization group (NRG). Furthermore, we show that the Bogoliubov zero-energy excitation determines the ground state of a ? Josephson junction at small electron fillings.

  8. Exact ground states of a staggered supersymmetric model for lattice fermions

    SciTech Connect

    Huijse, L. [Department of Physics, Harvard University, Cambridge, Massachusetts 02138 (United States); Moran, N. [Laboratoire Pierre Aigrain, ENS and CNRS, 24 rue Lhomond, F-75005 Paris (France); Department of Mathematical Physics, National University of Ireland, Maynooth (Ireland); Vala, J. [Department of Mathematical Physics, National University of Ireland, Maynooth (Ireland); School of Theoretical Physics, Dublin Institute for Advanced Studies, 10 Burlington Road, Dublin 4 (Ireland); Schoutens, K. [Institute for Theoretical Physics, University of Amsterdam, Science Park 904, P.O. Box 94485, NL-1090 GL Amsterdam (Netherlands)

    2011-09-15

    We study a supersymmetric model for strongly interacting lattice fermions in the presence of a staggering parameter. The staggering is introduced as a tunable parameter in the manifestly supersymmetric Hamiltonian. We obtain analytic expressions for the ground states in the limit of small and large staggering for the model on the class of doubly decorated lattices. On this type of lattice there are two ground states, each with a different density. In one limit we find these ground states to be a simple Wigner crystal and a valence bond solid state. In the other limit we find two types of quantum liquids. As a special case, we investigate the quantum liquid state on the one dimensional chain in detail. It is characterized by a massless kink that separates two types of order.

  9. An N-atom Collective State Atomic Clock with Root-N Fold Increase in Effective Frequency and Root-N Fold Reduction in

    E-print Network

    Shahriar, Selim

    An N-atom Collective State Atomic Clock with Root-N Fold Increase in Effective Frequency and Root IN PROGRESS. VERSION 1.5) The short term stability of atomic frequency standards is limited by the transit time. However, the Ramsey fringes of the collective state of an N atom system become narrower by N

  10. The ground X 1Sigmag+ electronic state of the cesium dimer: application of a direct potential fitting procedure.

    PubMed

    Coxon, John A; Hajigeorgiou, Photos G

    2010-03-01

    A collection of 16,544 fluorescence series spectroscopic line positions involving the A (1)Sigma(u)(+)-->X (1)Sigma(g)(+) transition in Cs(2) has been analyzed by a modern direct potential fitting procedure to generate the first fully analytical potential energy function for the ground electronic state, and precise energy term values for the excited A (1)Sigma(u)(+) state. The potential function yields an accurate representation of spectroscopic data that span 99.24% of the well depth and the number of fitted parameters is significantly less than half the number of parameters determined in conventional Dunham analyses. A novel variant of the Morse/long-range potential model has been employed in the representation of the ground state potential, and a critical comparison has been made with an extended modified Lennard-Jones potential model. Proper account has been taken of the known long-range van der Waals form of the potential, and our final potential function is determined with constrained literature values of the C(8) and C(10) dispersion energy coefficients, along with a fitted value of C(6)=3.31(5) x 10(7) cm(-1) A(6)=6870(100) a.u. The fitted dissociation energy (D(e)) is compared with the precisely known value based on the recent analysis of data from a two-photon transfer process (STIRAP) in ultracold Cs atoms. It is concluded that hyperfine effects in the X (1)Sigma(g)(+) state are not negligible, and that the estimate of D(e)=3649.84(7) cm(-1) obtained in this work represents an effective dissociation limit lying between the two lowest hyperfine limits. Precise rotational and centrifugal distortion constants for the ground electronic state have also been calculated through conventional perturbation theory. These estimates are fully consistent with the derived potential function and the experimental spectroscopic information. PMID:20210387

  11. Theory of Zeeman Effect in the Ground Multiplets of Rare-Earth Atoms

    Microsoft Academic Search

    B. R. Judd; I. Lindgren

    1961-01-01

    A number of corrections are made to the simple Landé formula for the g values of levels deriving from the ground term of configurations of the type 4fn. These include (a) the Schwinger correction, to give an accurate value of the gyromagnetic ratio for the electron spin; (b) a correction to allow for the deviations from perfect RS coupling; (c)

  12. Methods and Indicators for Assessment of Regional Ground-Water Conditions in the Southwestern United States

    USGS Publications Warehouse

    Tillman, Fred D.; Leake, Stanley A.; Flynn, Marilyn E.; Cordova, Jeffrey T.; Schonauer, Kurt T.; Dickinson, Jesse E.

    2008-01-01

    Monitoring the status and trends in the availability of the Nation's ground-water supplies is important to scientists, planners, water managers, and the general public. This is especially true in the semiarid to arid southwestern United States where rapid population growth and limited surface-water resources have led to increased use of ground-water supplies and water-level declines of several hundred feet in many aquifers. Individual well observations may only represent aquifer conditions in a limited area, and wells may be screened over single or multiple aquifers, further complicating single-well interpretations. Additionally, changes in ground-water conditions may involve time scales ranging from days to many decades, depending on the timing of recharge, soil and aquifer properties, and depth to the water table. The lack of an easily identifiable ground-water property indicative of current conditions, combined with differing time scales of water-level changes, makes the presentation of ground-water conditions a difficult task, particularly on a regional basis. One approach is to spatially present several indicators of ground-water conditions that address different time scales and attributes of the aquifer systems. This report describes several methods and indicators for presenting differing aspects of ground-water conditions using water-level observations in existing data-sets. The indicators of ground-water conditions developed in this study include areas experiencing water-level decline and water-level rise, recent trends in ground-water levels, and current depth to ground water. The computer programs written to create these indicators of ground-water conditions and display them in an interactive geographic information systems (GIS) format are explained and results illustrated through analyses of ground-water conditions for selected alluvial basins in the Lower Colorado River Basin in Arizona.

  13. Average ground-state energy of finite Fermi systems

    SciTech Connect

    Centelles, M.; Vinas, X. [Departament d'Estructura i Constituents de la Materia, Facultat de Fisica, Universitat de Barcelona, Diagonal 647, E-08028 Barcelona (Spain); Leboeuf, P.; Roccia, J. [Laboratoire de Physique Theorique et Modeles Statistiques, CNRS, Universite de Paris-Sud, UMR 8626, F-91405 Orsay Cedex (France); Monastra, A. G. [TU Dresden Institut fuer Theoretische Physik, D-01062 Dresden (Germany); Schuck, P. [Institut de Physique Nucleaire, IN2P3-CNRS, Universite de Paris-Sud, F-91406 Orsay Cedex (France)

    2006-09-15

    Semiclassical theories such as the Thomas-Fermi and Wigner-Kirkwood methods give a good description of the smooth average part of the total energy of a Fermi gas in some external potential when the chemical potential is varied. However, in systems with a fixed number of particles N, these methods overbind the actual average of the quantum energy as N is varied. We describe a theory that accounts for this effect. Numerical illustrations are discussed for fermions trapped in a harmonic oscillator potential and in a hard-wall cavity, and for self-consistent calculations of atomic nuclei. In the latter case, the influence of deformations on the average behavior of the energy is also considered.

  14. A new simple exotic atom, H-+: e+ bound to H- in an atomic state

    NASA Astrophysics Data System (ADS)

    Guevara, I.; Weel, M.; George, M. C.; Hessels, E. A.; Storry, C. H.

    2014-05-01

    A beam of H- ions is directed along the axis of a solenoidal magnet winding. Within this magnet, cylindrical electrodes with applied potentials slow the ions to an energy of ~ 50 eV in a magnetic field of ~ 0.13 Tesla. This apparatus also acts as a charged particle trap. e+ from a radioactive source are slowed in frozen neon, guided by magnetic fields and captured in this Surko-style accumulator with ~107 e+ trapped and cooled for experiments. H- ions are directed through these e+ producing long-lived H-+ atoms. H-+ is not bound in the charged particle trap and continues with the initial momentum of the H- ion into a metal plate. Upon impact the e+ quickly annihilates into back-to-back gammas. Detection of these coincident gammas indicates H-+ that traveled the 2 meter to the detector and indicates a survival time of ~ 5 ?s . Typically systems with antimatter bound to matter particles have short lifetimes (and hence wide transition widths) due annihilation. Rydberg states of H-+, however, have the long radiative lifetimes of normal matter atoms because there is little overlap of the e+ wavefunction with the core. The detected rates or H-+ are consistent with those expected for radiative recombination. NSERC, CFI, ORF.

  15. State-to-state dynamics of elementary chemical reactions using Rydberg H-atom translational spectroscopy

    Microsoft Academic Search

    Xueming Yang

    2005-01-01

    In this review, a few examples of state-to-state dynamics studies of both unimolecular and bimolecular reactions using the H-atom Rydberg tagging TOF technique were presented. From the H2O photodissociation at 157 nm, a direction dissociation example is provided, while photodissociation of H2O at 121.6 has provided an excellent dynamical case of complicated, yet direct dissociation process through conical intersections. The

  16. Operation Crossroads. Atomic Bomb Tests. Volume 2, Appendix V. Final report of Army ground group

    Microsoft Academic Search

    1946-01-01

    With the exception of Searchlights and far Infrared devices (Penrod), Corps of Engineers Equipment will probably withstand the effect of an air burst of an atomic bomb of present design at a distance of 1000 yards. Improved resistance to blast can be provided by shock-mounting, shielding, and strengthening more fragile parts of equipment. Similarly, resistance to radiant heat can be

  17. The ground electronic state of KCs studied by Fourier transform spectroscopy.

    PubMed

    Ferber, R; Klincare, I; Nikolayeva, O; Tamanis, M; Knöckel, H; Tiemann, E; Pashov, A

    2008-06-28

    We present here the first analysis of laser induced fluorescence (LIF) of the KCs molecule obtaining highly accurate data and perform a direct potential construction for the X (1)Sigma(+) ground state in a wide range of internuclear distances. KCs molecules were produced by heating a mixture of K and Cs metals in a heat pipe at a temperature of about 270 degrees C. KCs fluorescence was induced by different laser sources: the 454.5, 457.9, 465.8, and 472.7 nm lines of an Ar(+) laser, a dye laser with Rhodamine 6G dye (excitation at around 16 870 cm(-1)), and 850 and 980 nm diode lasers (11 500-11 900 and 10 200-10 450 cm(-1) tuning ranges, respectively). The LIF to the ground state was recorded by a Bruker IFS-125HR Fourier transform spectrometer with a spectral resolution of 0.03 cm(-1). Particularly, by applying the 850 nm laser diode we were able to observe LIF progressions to very high vibrational levels of the ground state close to the dissociation limit. The present data field contains 7226 term values for the ground state X (1)Sigma(+) and covers a range from v(")=0 to 97 with J(") varying from 12 to 209. More than 10 000 fluorescence lines were used to fit the ground state potential energy curve via the inverted perturbation approach procedure. The present empirical potential extends up to approximately 12.6 A and covers more than 99% of the potential well depth, it describes most of the spectral lines with an accuracy of about 0.003 cm(-1) and yields a dissociation energy of 4069.3+/-1.5 cm(-1) for the ground state X (1)Sigma(+). First observations of the triplet ground state a (3)Sigma(+) of KCs are presented, and preliminary values of few main molecular constants could be derived. PMID:18601341

  18. Ground states and dynamics of spin-orbit-coupled Bose-Einstein condensates

    E-print Network

    Weizhu Bao; Yongyong Cai

    2014-07-22

    We study analytically and asymptotically as well as numerically ground states and dynamics of two-component spin-orbit-coupled Bose-Einstein condensates (BECs) modeled by the coupled Gross-Pitaevskii equations (CGPEs). In fact, due to the appearance of the spin-orbit (SO) coupling in the two-component BEC with a Raman coupling, the ground state structures and dynamical properties become very rich and complicated. For the ground states, we establish the existence and non-existence results under different parameter regimes, and obtain their limiting behaviors and/or structures with different combinations of the SO and Raman coupling strengths. For the dynamics, we show that the motion of the center-of-mass is either non-periodic or with different frequency to the trapping frequency when the external trapping potential is taken as harmonic and the initial data is chosen as a stationary state (e.g. ground state) with a shift, which is completely different from the case of a two-component BEC without the SO coupling, and obtain the semiclassical limit of the CGPEs in the linear case via the Wigner transform method. Efficient and accurate numerical methods are proposed for computing the ground states and dynamics, especially for the case of box potentials. Numerical results are reported to demonstrate the efficiency and accuracy of the numerical methods and show the rich phenomenon in the SO-coupled BECs.

  19. Distribution of the GT strength starting from the ground state of 14N

    SciTech Connect

    Negret, A.; Frenne, D. de; Jacobs, E.; Popescu, L. [Vakgroep Subatomaire en Stralingsfysica, Universiteit Gent, B-9000 Gent, (Belgium); Adachi, T.; Fujita, Y.; Ogama, T.; Shimbara, Y. [Department of Physics, Osaka University, Toyonaka, Osaka 560-0043, (Japan); Baeumer, C.; Frekers, D.; Grewe, E.-W.; Haefner, P.; Korff, A.; Rakers, S. [Institut fuer Kernphysik, Westfaelische Wilhelms-Universitaet Muenster, D-48149 Muenster (Germany); Berg, A.M. van den; Berg, G.P.A.; Hunyadi, M.; Huu, M.A. de; Woertche, H.J. [Kernfysisch Versneller Instituut, Rijksuniversiteit Groningen, NL-9747 AA Groningen (Netherlands); Brentano, P. von [Institut fuer Kernphysik, Universitaet zu Koeln, 50937 Cologne (Germany)] [and others

    2004-09-13

    The Gamow-Teller (GT) strength distribution in the {beta}- and {beta}+ directions starting from the ground state of 14N has been investigated. A (d,2He) experiment has been performed at KVI, Groningen with Ed=170 MeV and a (3He,t) experiment at RCNP, Osaka with E3He=420 MeV. It is found that, in both cases, the GT mechanism is populating mainly the 2+ excited states in the final nuclei, while the ground state transitions are strongly suppressed. The analysis is ongoing.

  20. From spin glass to quantum spin liquid ground states in molybdate pyrochlores.

    PubMed

    Clark, L; Nilsen, G J; Kermarrec, E; Ehlers, G; Knight, K S; Harrison, A; Attfield, J P; Gaulin, B D

    2014-09-12

    We present new magnetic heat capacity and neutron scattering results for two magnetically frustrated molybdate pyrochlores: S=1 oxide Lu_{2}Mo_{2}O_{7} and S=1/2 oxynitride Lu_{2}Mo_{2}O_{5}N_{2}. Lu_{2}Mo_{2}O_{7} undergoes a transition to an unconventional spin glass ground state at T_{f}?16??K. However, the preparation of the corresponding oxynitride tunes the nature of the ground state from spin glass to quantum spin liquid. The comparison of the static and dynamic spin correlations within the oxide and oxynitride phases presented here reveals the crucial role played by quantum fluctuations in the selection of a ground state. Furthermore, we estimate an upper limit for a gap in the spin excitation spectrum of the quantum spin liquid state of the oxynitride of ??0.05??meV or ?/|?|?0.004, in units of its antiferromagnetic Weiss constant ??-121??K. PMID:25260001

  1. Short-range correlations in the magnetic ground state of Na4 Ir3 O8

    NASA Astrophysics Data System (ADS)

    Dally, Rebecca; Hogan, Tom; Amato, Alex; Luetkens, Hubertus; Baines, Chris; Rodriguez-Rivera, Jose; Graf, Michael; Wilson, Stephen

    2015-03-01

    The magnetic ground state of the candidate three-dimensional quantum spin liquid Na4 Ir3O8 has been studied through bulk magnetization, muon spin relaxation and neutron scattering measurements. Na4 Ir3O8 possesses a unique hyper-Kagome lattice of Ir moments that is potentially accompanied by a novel realization of Heisenberg-Kitaev exchange. This fact combined with the absence of previously reported magnetic ordering has led to its candidacy as a three-dimensional quantum spin liquid. Our combined experimental data show that a short-range, frozen, ground state comprised of quasi-static moments develops in this material below a characteristic temperature TF = 6 K , persisting down until at least 20 mK. The expected dynamical ground state of a quantum spin liquid was not observed but rather an inhomogeneous quasi-static spin state that survives with persistent long timescale fluctuations.

  2. Charge ordered normal ground state and its interplay with superconductivity in the underdoped cuprates

    NASA Astrophysics Data System (ADS)

    Sebastian, Suchitra

    2015-03-01

    Over the last few years, evidence has gradually built for a charge ordered normal ground state in the underdoped region of the cuprate high temperature superconductors. I will address the electronic structure of the normal ground state of the underdoped cuprates as accessed by quantum oscillations, and relate it to complementary measurements by other experimental techniques. The interplay of the charge ordered ground state with the antinodal gapped pseudogap state, and overarching magnetic and superconducting correlations will be further explored. This work was performed in collaboration with N. Harrison, G. G. Lonzarich, B. J. Ramshaw, B. S. Tan, P. A. Goddard, F. F. Balakirev, C. H. Mielke, R. Liang, D. A. Bonn, and W. N. Hardy

  3. From Spin Glass to Quantum Spin Liquid Ground States in Molybdate Pyrochlores

    NASA Astrophysics Data System (ADS)

    Clark, L.; Nilsen, G. J.; Kermarrec, E.; Ehlers, G.; Knight, K. S.; Harrison, A.; Attfield, J. P.; Gaulin, B. D.

    2014-09-01

    We present new magnetic heat capacity and neutron scattering results for two magnetically frustrated molybdate pyrochlores: S=1 oxide Lu2Mo2O7 and S=1/2 oxynitride Lu2Mo2O5N2. Lu2Mo2O7 undergoes a transition to an unconventional spin glass ground state at Tf˜16 K. However, the preparation of the corresponding oxynitride tunes the nature of the ground state from spin glass to quantum spin liquid. The comparison of the static and dynamic spin correlations within the oxide and oxynitride phases presented here reveals the crucial role played by quantum fluctuations in the selection of a ground state. Furthermore, we estimate an upper limit for a gap in the spin excitation spectrum of the quantum spin liquid state of the oxynitride of ? ˜0.05 meV or ? /|?|˜0.004, in units of its antiferromagnetic Weiss constant ? ˜-121 K.

  4. Determination and Comparison of Carbonyl Stretching Frequency of a Ketone in Its Ground State and the First Electronic Excited State

    ERIC Educational Resources Information Center

    Bandyopadhyay, Subhajit; Roy, Saswata

    2014-01-01

    This paper describes an inexpensive experiment to determine the carbonyl stretching frequency of an organic keto compound in its ground state and first electronic excited state. The experiment is simple to execute, clarifies some of the fundamental concepts of spectroscopy, and is appropriate for a basic spectroscopy laboratory course. The…

  5. Theoretical Studies of the Ground and Excited State Structures of Stilbene

    NASA Astrophysics Data System (ADS)

    Chaudhuri, Rajat K.; Freed, Karl F.; Chattopadhyay, Sudip; Mahapatra, Uttam Sinha

    2013-10-01

    Optimized geometries are evaluated for the ground and low lying excited states of cis-stilbene, trans-stilbene, and 4a,4b-dihydrophenanthrene (DHP) from calculations performed with the improved virtual orbital, complete active space configuration interaction (IVO-CASCI) method. The calculations indicate that a nonplanar conformer of trans-stilbene is the most stable among the isomers. The calculated ground and low lying excited state geometries agree well with experiment and with prior theoretical estimates where available. Our IVO-CASCI based multireference Möller-Plesset (MRMP) computations place the 1Bu state of trans stilbene to be -4.0 eV above the ground X1Ag state, which is in accord with experiment and with earlier theoretical estimates. The 11Bu state of trans-stilbene can be represented by the highest occupied molecular orbital (HOMO) - lowest unoccupied molecular orbital (LUMO) transition (ionic type) from the ground state, whereas its 21Bu state is dominated by the HOMO - LUMO+1 and HOMO-1 - LUMO transitions (covalent type). Likewise, the 11B and 21B states of cis-stilbene and DHP are also found to be of ionic and covalent types, respectively.

  6. Ground water contaminants and their sources—a review of state reports

    Microsoft Academic Search

    Larry W. Canter; Katie M. Maness

    1995-01-01

    Pursuant to section 305(B) of the Clean Water Act of 1987, each state submits biennially a water quality report to the U.S. Environmental Protection Agency (EPA). This paper contains a review of 42 such reports in relation to public ground water supplies. Nineteen states provided monitoring data on a total of 51 organic and 21 inorganic chemicals. Frequently detected contaminants

  7. GROUND WATER CONTAMINANTS AND THEIR SOURCES - A REVIEW OF STATE REPORTS

    EPA Science Inventory

    Pursuant to section 305(B) of the Clean Water Act of 1987, each state submits biennially a water quality report to the U.S. Environmental Protection Agency (EPA). his paper contains a review of 42 such reports in relation to public ground water supplies. ineteen states provided m...

  8. Onset of collectivity in the ground-state band of [sup 50]Cr

    SciTech Connect

    Pakou, A.A. (Department of Physics, The University of Ioannina, GR451 10, Ioannina (Greece) Department of Physics, The University of Manchester, M13 9PL (United Kingdom)); Billowes, J.; Mountford, A.W. (Department of Physics, The University of Manchester, M13 9PL (United Kingdom)); Warner, D.D. (Daresbury Laboratory, Warrington WA44AD (United Kingdom))

    1994-11-01

    Transient field precessions of the first excited states in [sup 50]Cr have been measured. The states were excited by the inverse [sup 12]C([sup 40]Ca, 2[ital p])[sup 50]Cr reaction and the recoil nuclei traversed a thick gadolinium foil, where they experienced the rotation. The observed precessions, for the 2[sup +],4[sup +],6[sup +],8[sup +] states of the ground-state band, were equal within experimental error indicating these states have [ital g] factors similar to that of the 2[sup +] state value of 0.55[plus minus]0.10 measured previously. This feature is contrary to the predictions of the shell model and suggests a higher collectivity for the ground-state band. Limited results were also obtained for the cross conjugate nucleus [sup 46]Ti supporting this conclusion.

  9. Ordered ground states of metallic hydrogen and deuterium

    NASA Technical Reports Server (NTRS)

    Ashcroft, N. W.

    1981-01-01

    The physical attributes of some of the more physically distinct ordered states of metallic hydrogen and metallic deuterium at T = 0 and nearby are discussed. The likelihood of superconductivity in both is considered with respect to the usual coupling via the density fluctuations of the ions.

  10. Variational ground states for the periodic Anderson model

    Microsoft Academic Search

    P. Fazekas

    1987-01-01

    A trial state of the kind suggested by Brandow is used for the nondegenerate periodic Anderson model with arbitrary band filling. An approximate N-parameter minimisation is carried out analytically. A Gutzwiller-type approximation leads to predicting a magnetic instability even in the valence fluctuation regime.

  11. Joint Accreditation and State Program Reviews: Breaking New Ground.

    ERIC Educational Resources Information Center

    LeMon, R. E.; Pitter, Gita Wijesinghe

    To meet increasing demand, the State University System (SUS) of Florida has initiated joint program evaluations with the major professional accrediting bodies. As accreditation and program reviews typically demand similar information and similar procedures the two activities can be synchronized. The purpose of assessing and enhancing quality, a…

  12. HYPERFINE TRANSITIONS IN GROUND STATE HYDROGEN-LIKE

    E-print Network

    Savin, Daniel Wolf

    rhenium isotopes 185Re and 187Re.We use the re- sults to determine their respective nuclear magnetic mo- ments. EXPERIMENT Hydrogen-like holmium and rhenium ions are produced and stored in a high 6 %, that of bare Ho 67+ around 0.5%. Lower charge states made up the rest. For the rhenium

  13. New evidence for ground state deformation of 18O

    Microsoft Academic Search

    F. Resmini; R. M. Lombard; M. Pignanelli; J. L. Escudie; A. Tarrats

    1971-01-01

    This letter reports the experimental results of (p, p') scattering, with polarized protons, on 18O and the analysis for low-lying positive-parity states based on the rotational model. Values of beta2 = 0.37 +\\/- 0.03 and of beta4 = 0.18 +\\/- 0.04 are obtained.

  14. Hydrogeologic factors that influence ground water movement in the desert southwest United States

    USGS Publications Warehouse

    Chuang, Frank C.; McKee, Edwin H.; Howard, Keith A.

    2003-01-01

    A project to study ground-water and surface-water interactions in the desert southwestern United States was initiated in 2001 by the Tucson, Arizona office of the Water Resources Division, U.S. Geological Survey (USGS). One of the goals of the Southwest Ground-water Resources Project was to develop a regional synthesis that includes the use of available digital geologic data, which is growing rapidly due to the increasing use of Geographic Information Systems (GIS). Included in this report are the digital maps and databases of geologic information that should have a direct impact on the studies of ground-water flow and surface-water interaction. Ground-water flow is governed by many geologic factors or elements including rock and soil permeability, stratigraphy and structural features. These elements directly influence ground-water flow, which is key to understanding the possible inter-connectivity of aquifer systems in desert basins of the southwestern United States. We derive these elements from the evaluation of regional geology and localized studies of hydrogeologic basins. These elements can then be applied to other unstudied areas throughout the desert southwest. This report presents a regional perspective of the geologic elements controlling ground-water systems in the desert southwest that may eventually lead to greater focus on smaller sub-regions and ultimately, to individual ground-water basins.

  15. Deformation change between isomeric and ground states in the {sup 184}Au and {sup 183}Pt isotones

    SciTech Connect

    Sauvage, J.; Le Blanc, F.; Obert, J.; Oms, J.; Putaux, J. C.; Roussiere, B. [Institut de Physique Nucleaire, 91406 Orsay cedex (France); Boos, N.; Huber, G.; Krieg, M.; Sebastian, V. [Institut fuer Physik der Universitaet Mainz, 55099 Mainz (Germany); Cabaret, L.; Duong, H. T.; Pinard, J. [Laboratoire Aime Cotton, 91405 Orsay cedex (France); Crawford, J.; Lee, J. K. P. [Foster Radiation Laboratory, McGill University, H3A2T8 Montreal (Canada); Genevey, J.; Ibrahim, F. [Institut des Sciences Nucleaires, 38026 Grenoble cedex (France); Girod, M. [Service de Physique Nucleaire, CEA, BP 12, 91680 Bruyeres-le-Chatel (France); Libert, J. [Centre d'Etudes Nucleaires de Bordeaux Gradignan, 33175 Gradignan cedex (France); Zemlyanoi, S. [Flerov Laboratory of Nuclear Reaction, JINR, Dubna 141980, Moscow Region (Russian Federation)

    1998-12-21

    Deformation changes {delta}{beta} have been found out between isomeric and ground states of the {sup 183}Pt and {sup 184}Au isotones. Atomic spectroscopy measurements by laser were carried out using the COMPLIS setup. Hyperfine structure (HFS) spectra and isotope shift (IS) were obtained for the 5d{sup 9}6s {sup 3}D{sub 3}{yields}5d{sup 9}6p {sup 3}P{sub 2} and 5d{sup 10}6s {sup 2}S{sub 1/2}{yields}5d{sup 10}6p {sup 2}P{sub 3/2} optical transitions in Pt and Au atoms respectively, providing deformation parameters {beta} and nuclear moments {mu} and Q{sub s}. The influence of the proton-neutron coupling on the {delta}{beta} value in {sup 184}Au relatively to its isotone {sup 183}Pt has been determined. Besides, the h9/2 proton state that is decoupled from the core in {sup 183,185}Au, becomes the 3/2[532] state (h9/2 parentage) strongly coupled in the doubly-odd {sup 184}Au nucleus.

  16. Ground radiation tests and flight atomic oxygen tests of ITO protective coatings for Galileo Spacecraft

    NASA Technical Reports Server (NTRS)

    Bouquet, Frank L.; Maag, Carl R.

    1986-01-01

    Radiation simulation tests (protons and electrons) were performed along with atomic oxygen flight tests aboard the Shuttle to space qualify the surface protective coatings. The results, which contributed to the selection of indium-tin-oxide (ITO) coated polyester as the material for the thermal blankets of the Galileo Spacecraft, are given here. Two candidate materials, polyester and Fluorglas, were radiation-tested to determine changes at simulated Jovian radiation levels. The polyester exhibited a smaller weight loss (2.8) than the Fluorglas (8.8 percent). Other changes of polyester are given. During low-earth orbit, prior to transit to Jupiter, the thermal blankets would be exposed to atomic oxygen. Samples of uncoated and ITO-coated polyesters were flown on the Shuttle. Qualitative results are given which indicated that the ITO coating protected the underlying polyester.

  17. Comparison of Hyperthermal Ground Laboratory Atomic Oxygen Erosion Yields With Those in Low Earth Orbit

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A.; Dill, Grace C.; Loftus, Ryan J.; deGroh, Kim K.; Miller, Sharon K.

    2013-01-01

    The atomic oxygen erosion yields of 26 materials (all polymers except for pyrolytic graphite) were measured in two directed hyperthermal radio frequency (RF) plasma ashers operating at 30 or 35 kHz with air. The hyperthermal asher results were compared with thermal energy asher results and low Earth orbital (LEO) results from the Materials International Space Station Experiment 2 and 7 (MISSE 2 and 7) flight experiments. The hyperthermal testing was conducted to a significant portion of the atomic oxygen fluence similar polymers were exposed to during the MISSE 2 and 7 missions. Comparison of the hyperthermal asher prediction of LEO erosion yields with thermal energy asher erosion yields indicates that except for the fluorocarbon polymers of PTFE and FEP, the hyperthermal energy ashers are a much more reliable predictor of LEO erosion yield than thermal energy asher testing, by a factor of four.

  18. Cloud-to-ground lightning flash characteristics in the contiguous United States: 1989-1991

    Microsoft Academic Search

    Richard E. Orville

    1994-01-01

    Wideband magnetic direction finders have been used to obtain a cloud-to-ground lightning flash count for the contiguous United States, an area of 7.7×106 km2, for the period 1989 through 1991. Over 46 million flashes to ground were recorded and are divided among the three years, 13.4 million in 19898, 15.9 million in 1990, and 16.9 million in 1991. Maximum flash

  19. Stability of the ground state of a harmonic oscillator in a monochromatic wave.

    PubMed

    Berman, Gennady P.; James, Daniel F. V.; Kamenev, Dmitry I.

    2001-09-01

    The stability of the ground state of a harmonic oscillator in a monochromatic wave is studied. This model describes, in particular, the dynamics of a cold ion in a linear ion trap, interacting with two laser fields with close frequencies. The stability of the "classical ground state"-the vicinity of the point (x=0,p=0)-is analyzed analytically and numerically. For the quantum case, a method for studying a stability of the quantum ground state is developed, based on the quasienergy representation. It is demonstrated that stability of the ground state may be substantially improved by increasing the resonance number, l, where l=Omega/omega+delta, Omega and omega are, respectively, the wave frequency and the oscillator frequency, l=1,2, em leader, mid R:deltamid R:<1; or by detuning the system from exact resonance, so that delta not equal 0. The influence of a large-amplitude wave (in the presence of chaos) on the stability of the ground state is analyzed for different parameters of the model in both the quantum and classical cases. (c) 2001 American Institute of Physics. PMID:12779482

  20. Collective Two-Atom Effects and Trapping States in the Micromaser

    E-print Network

    Per K. Rekdal; Bo-Sture K. Skagerstam

    2006-06-28

    We investigate signals of trapping states in the micromaser system in terms of the average number of cavity photons as well as a suitably defined correlation length of atoms leaving the cavity. In the description of collective two-atom effects we allow the mean number of pump atoms inside the cavity during the characteristic atomic cavity transit time to be as large as of order one. The master equation we consider, which describes the micromaser including collective two-atom effects, still exhibits trapping states for even for a mean number of atoms inside the cavity close to one. We, however, argue more importantly that the trapping states are more pronounced in terms of the correlation length as compared to the average number of cavity photons, i.e. we suggest that trapping states can be more clearly revealed experimentally in terms of the atom correlation length. For axion detection in the micromaser this observable may therefore be an essential ingredient.

  1. Ground Water

    NSDL National Science Digital Library

    This United States Geological Survey (USGS) general interest publication presents a description of ground water in the U.S. This includes what ground water is, how it occurs, aquifers and wells, ground water quality and what affects it, and the state of U.S. ground water resources.

  2. Electron binding capabilities of some silylenes having small singlet-triplet splittings or triplet ground states.

    PubMed

    Kalcher, Josef; Skurski, Piotr; Simons, Jack

    2007-01-18

    Several silyl and alkaline metal substituted silylenes have been investigated using the CAS-ACPF method in conjunction with the aug-cc-pVTZ basis sets. Silylsilylene and disilylsilylene are found to have singlet ground states with DeltaEST(-) values of 0.676 and 0.319 eV, respectively. The adiabatic ground state electron affinities are found to be 1.572 and 2.361 eV for HSiSiH(3) and Si(SiH(3))(2). respectively. Both silylenes possesses a stable 2A1 excited negative ion state, with respective adiabatic EA values of 0.037 and 1.000 eV. In contrast, all silylenes with at least one akaline metal substituent exhibit triplet neutral ground states. The metalated silylenes HSiLi, HSiNa, LiSiSiH(3), NaSiLi, SiLi(2), and SiNa(2) have adiabatic ground state EAs somewhat below 1 eV, but each of these negatively charged system possesses up to three bound excited negative ion states, some of which are dipole-bound states. PMID:17214478

  3. Synergistic Mechanisms of DNA Demethylation during Transition to Ground-State Pluripotency

    PubMed Central

    Hackett, Jamie A.; Dietmann, Sabine; Murakami, Kazuhiro; Down, Thomas A.; Leitch, Harry G.; Surani, M. Azim

    2013-01-01

    Summary Pluripotent stem cells (PSCs) occupy a spectrum of reversible molecular states ranging from a naive ground-state in 2i, to metastable embryonic stem cells (ESCs) in serum, to lineage-primed epiblast stem cells (EpiSCs). To investigate the role of DNA methylation (5mC) across distinct pluripotent states, we mapped genome-wide 5mC and 5-hydroxymethycytosine (5hmC) in multiple PSCs. Ground-state ESCs exhibit an altered distribution of 5mC and 5hmC at regulatory elements and dramatically lower absolute levels relative to ESCs in serum. By contrast, EpiSCs exhibit increased promoter 5mC coupled with reduced 5hmC, which contributes to their developmental restriction. Switch to 2i triggers rapid onset of both the ground-state gene expression program and global DNA demethylation. Mechanistically, repression of de novo methylases by PRDM14 drives DNA demethylation at slow kinetics, whereas TET1/TET2-mediated 5hmC conversion enhances both the rate and extent of hypomethylation. These processes thus act synergistically during transition to ground-state pluripotency to promote a robust hypomethylated state. PMID:24371807

  4. Selection of factorizable ground state in a frustrated spin tube: Order by disorder and hidden ferromagnetism

    NASA Astrophysics Data System (ADS)

    Plat, X.; Fuji, Y.; Capponi, S.; Pujol, P.

    2015-02-01

    The interplay between frustration and quantum fluctuation in magnetic systems is known to be the origin of many exotic states in condensed matter physics. In this paper, we consider a frustrated four-leg spin tube under a magnetic field. This system is a prototype to study the emergence of a nonmagnetic ground state factorizable into local states and the associated order parameter without quantum fluctuation that appears in a wide variety of frustrated systems. The one-dimensional nature of the system allows us to apply various techniques: a path-integral formulation based on the notion of order by disorder, strong-coupling analysis where magnetic excitations are gapped, and density-matrix renormalization group. All methods point toward an interesting property of the ground state in the magnetization plateaus, namely, a quantized value of relative magnetizations between different sublattices (spin imbalance). The ground-state properties can be understood in terms of a direct product of local states on each rung, which is the exact ground state on certain plateaus in the strong-coupling limit.

  5. Optical emission spectroscopy of metal-halide lamps: Radially resolved atomic state distribution functions of Dy and Hg

    Microsoft Academic Search

    T. Nimalasuriya; A. J. Flikweert; W. W. Stoffels; M. Haverlag; J. J. A. M. van der Mullen; N. B. M. Pupat

    2006-01-01

    Absolute line intensity measurements are performed on a metal-halide lamp. Several transitions of atomic and ionic Dy and atomic Hg are measured at different radial positions from which we obtain absolute atomic and ionic Dy intensity profiles. From these profiles we construct the radially resolved atomic state distribution function (ASDF) of the atomic and ionic Dy and the atomic Hg.

  6. The preformation probability inside Alpha-emitters having different ground state spin-parity than daughters

    E-print Network

    W. M. Seif; M. M. Botros; A. I. Refaie

    2015-07-23

    The ground-state spin and parity of a formed daughter in the radioactive Alpha-emitter is expected to influence the preformation probability of the Alpha and daughter clusters inside it. We investigate the Alpha and daughter preformation probability inside odd-A and doubly-odd radioactive nuclei when the daughter and parent are of different spin and/or parity. We consider only the ground-state to ground-state unfavored decays. This is to extract precise information about the effect of the difference in the ground states spin-parity of the involved nuclei far away any influences from the excitation energy if the decays are coming from isomeric states. The calculations are done for 161 Alpha-emitters, with Z=65-112 and N=84-173, in the framework of the extended cluster model, with WKB penetrability and assault frequency. We used a Hamiltonian energy density scheme based on Skyrme-SLy4 interaction to compute the interaction potential. The Alpha plus cluster preformation probability is extracted from the calculated decay width and the experimental half-life time. We discussed in detailed steps the effect of angular momentum of the emitted Alpha-particle on the various physical quantities involved in the unfavored decay process and how it is finally increases the half-life time. We found that if the ground states spin and/or parity of parent and daughter nuclei are different, then the preformation probability of the Alpha-cluster inside parent is less than it would be if they have similar spin-parity. We modified the formula that gives the Alpha preformation probability in terms of the numbers of protons and neutrons outside the shell closures of parent, to account for this hindrance in the preformation probability for the unfavored decays between ground states.

  7. Atomic states, potential energies, volumes, stability, and brittleness of ordered FCC TiAl 3-type alloys

    Microsoft Academic Search

    Y. Q. Xie; X. B. Liu; K. Peng; H. J. Peng

    2004-01-01

    It has been proved that according to the basic information of sequences of characteristic atoms in the FCC Ti–Al lattice system, not only the states, potential energies, volumes of atoms at the lattice points, and average atomic states, average atomic potential energies, average atomic volumes, and lattice constants of the cells, as well as cohesive energies, heats of formation and

  8. Influence of periodically modulated cavity field on the generation of atomic-squeezed states

    NASA Astrophysics Data System (ADS)

    Aggarwal, Neha; Bhattacherjee, Aranya B.; Banerjee, Arup; Mohan, Man

    2015-06-01

    We investigate the influence of a periodically time-modulated cavity frequency on the generation of atomic squeezed states for a collection of N two-level atoms confined in a non-stationary cavity with a moving mirror. We show that the two-photon character of the field generated from the vacuum state of the field plays a significant role in producing the atomic or spin squeezed states. We further show that the maximum amount of persistent atomic squeezing is obtained for the initial cavity field prepared in the vacuum state.

  9. Allowed Gamow-Teller Excitations from the Ground State of 14N

    E-print Network

    S. Aroua; P. Navratil; L. Zamick; M. S. Fayache; B. R. Barrett; J. P. Vary; N. Smirnova; K. Heyde

    2002-10-18

    Motivated by the proposed experiment $^{14}N(d,{^2He})^{14}C$, we study the final states which can be reached via the allowed Gamow-Teller mechanism. Much emphasis has been given in the past to the fact that the transition matrix element from the $J^{\\pi}=1^+ T=0$ ground state of $^{14}N$ to the $J^{\\pi}=0^+ T=1$ ground state of $^{14}C$ is very close to zero, despite the fact that all the quantum numbers are right for an allowed transition. We discuss this problem, but, in particular, focus on the excitations to final states with angular momenta $1^+$ and $2^+$. We note that the summed strength to the $J^{\\pi}=2^+ T=1$ states, calculated with a wide variety of interactions, is significantly larger than that to the $J^{\\pi}=1^+ T=1$ final states.

  10. State-selective photofragment imaging of iodine atoms via photodissociation of CF3I at 277 nm

    NASA Astrophysics Data System (ADS)

    Kim, Yong Shin; Kang, Wee Kyung; Jung, Kyung-Hoon

    1996-07-01

    The photodissociation of CF3I cooled in a supersonic molecular beam has been investigated at 277 nm by state-selective photofragment imaging. Fragmented iodine atoms of two spin-orbit states are state-selectively ionized and projected onto a two-dimensional position-sensitive detector, to obtain their speed and angular distribution. The anisotropy parameter for an excited iodine atom I*(2P1/2), ?(I*), is found to be 1.83 and is consistent with a dissociation lifetime in the order of 150-350 fs from rotational correlation function. Contrary to earlier reports, the parallel-like distribution for the ground state iodine atom I(2P3/2) at this wavelength, shows a more favorable curve-crossing dissociation path (68%) from 3Q0 to 1Q1 and a less favorable direct dissociation path (32%) from 3Q1. The recoil energy distribution of I is found to be broader than that of I* and is correlated with a variety of energy disposal channels by an e symmetry vibration at the crossing point. The results are compared with previous works, and the strong photon energy dependence of the energy partitioning in CF3+I* channel and curve crossing are interpreted in terms of the final state interaction and curve crossing probability, respectively.

  11. Hall response of interacting bosonic atoms in strong gauge fields: From condensed to fractional-quantum-Hall states

    NASA Astrophysics Data System (ADS)

    Pino, H.; Alba, E.; Taron, J.; Garcia-Ripoll, J. J.; Barberįn, N.

    2013-05-01

    Interacting bosonic atoms under strong gauge fields undergo a series of phase transitions that take the cloud from a simple Bose-Einstein condensate all the way to a family of fractional-quantum-Hall-type states [M. Popp, B. Paredes, and J. I. Cirac, Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.70.053612 70, 053612 (2004)]. In this work we demonstrate that the Hall response of the atoms can be used to locate the phase transitions and characterize the ground state of the many-body state. Moreover, the same response function reveals within some regions of the parameter space, the structure of the spectrum and the allowed transitions to excited states. We verify numerically these ideas using exact diagonalization for a small number of atoms, and provide an experimental protocol to implement the gauge fields and probe the linear response using a periodically driven optical lattice. Finally, we discuss our theoretical results in relation to recent experiments with condensates in artificial magnetic fields [L. J. LeBlanc, K. Jimenez-Garcia, R. A. Williams, M. C. Beeler, A. R. Perry, W. D. Phillips, and I. B. Spielman, Proc. Natl. Acad. Sci. USAPNASA60027-842410.1073/pnas.1202579109 109, 10811 (2012)] and we analyze the role played by vortex states in the Hall response.

  12. Arsenic in ground water of the United States: occurrence and geochemistry

    USGS Publications Warehouse

    Welch, Alan H.; Westjohn, D.B.; Helsel, Dennis R.; Wanty, Richard B.

    2000-01-01

    Concentrations of naturally occurring arsenic in ground water vary regionally due to a combination of climate and geology. Although slightly less than half of 30,000 arsenic analyses of ground water in the United States were ? 1 µg/L, about 10% exceeded 0 µg/L. At a broad regional scale, arsenic concentrations exceeding 10 µg/L appear to be more frequently observed in the western United States than in the eastern half. Arsenic concentrations in ground water of the Appalachian Highlands and the Atlantic plain generally are very low (? 1 µg/L). Concentrations are somewhat greater in the Interior Plains and the Rocky Mountain System, investigations of ground water in New England, Michigan, Minnesota, South Dakota, Oklahoma, and Wisconsin within the last decade suggest that arsenic concentrations exceeding 10 µg/L are more widespread and common than previously recognized. Arsenic release from iron oxide appears to be the most common cause of widespread arsenic concentrations exceeding 10 µg/L a ground water. This can occur in response to different geochemical conditions, including release of arsenic to ground water through reaction of iron oxide with either natural or anthropogenic (i.e., petroleum products) organic carbon. Iron oxide also can release arsenic to alkaline ground water, such as that found in some felsic volcanic rocks and alkaline aquifers of the Western United States. Sulfide minerals are both a source and sink for arsenic. Geothermal water and high evaporation rates also are associated with arsenic concentrations ? 10g/L in ground and surface water, particularly in the west.

  13. Search for the ground states of Ising spin clusters by using the genetic algorithms

    NASA Astrophysics Data System (ADS)

    Oda, Akifumi; Nagao, Hidemi; Kitagawa, Yasutaka; Shigeta, Yasuteru; Shoji, Mitsuo; Nitta, Hiroya; Okumura, Mitsutaka; Yamaguchi, Kizashi

    Genetic algorithms (GAs) were applied to the search for ground states of randomly generated spin clusters. Two types of hybrid GAs and one type of pure GA modified by crossover operation were developed especially for the search for the ground state on Ising spin clusters. In the hybrid GAs, we used the 1-neighborhood search and the hill-climbing search for local searches. For modification of GAs, we also proposed a new crossover operator, xÆ crossover, which turns all spins upside down. The fitness function (F(x)) was defined in terms of the energies obtained by the Ising Hamiltonian. For the Ising spin clusters, the effective magnetic interaction (Jab) values were calculated with the unrestricted Hartree-Fock method. These GAs worked well on the searches for the ground states, because the improved GAs avoided being trapped in the local minima frequently and picked up the global minima more effectively than the standard GAs.

  14. The ground states of Perovskite nickelates: A dynamical mean field approach

    NASA Astrophysics Data System (ADS)

    Misra, D.; Taraphder, A.

    2014-04-01

    The Perovskite Nickelates (RNiO3,R=Rare-earth) exhibit a strong connection between their structural, transport and magnetic properties. All the members of Nickelate series have orthorhombic structure except LaNiO3 which has a rhombohedral symmetry. While the ground states of most of the Nickelates are antiferromagnetic insulators, and they undergo a sharp, temperature driven metal-Insulator transition, LaNiO3 is a paramagnetic metal irrespective of the temperature and does not undergo any metal-insulator transition. Whether the AFM insulating ground state of Nickelates (R?La) is due to charge or orbital ordering or both, is a matter of current dispute. Here we give a theoretical account of the metallic property of LaNiO3 and insulating ground states of other Nickelates, using LCAO and static mean field calculation, followed by a dynamical mean field analysis.

  15. Antibonding hole ground state in InAs quantum dot molecules

    NASA Astrophysics Data System (ADS)

    Planelles, Josep

    2015-01-01

    Using four-band k?p Hamiltonians, we study how strain and position-dependent effective masses influence hole tunneling in vertically coupled InAs/GaAs quantum dots. Strain reduces the tunneling and hence the critical interdot distance required for the ground state to change from bonding to antibonding. Variable mass has the opposite effect and a rough compensation leaves little affected the critical bonding-to-antibonding ground state crossover. An alternative implementation of the magnetic field in the envelope function Hamiltonian is given which retrieves the experimental denial of possible after growth reversible magnetically induced bonding-to-antibonding ground state transition, predicted by the widely used Luttinger-Kohn Hamiltonian.

  16. Calculation of inner-shell photoionization of ground state Na: relativistic vs. nonrelativistic calculation

    Microsoft Academic Search

    H.-L. Zhou; S. T. Manson; A. Hibbert

    2007-01-01

    Calculations of inner-shell photoionization of ground state Na over the photon energy range 40-100 eV have been performed using nonrelativistic LS coupling and relativistic Breit-Pauli (BP) R-matrix approximations. The BP R-matrix calculation adds the spin-orbit, mass-correction and Darwin terms to the non-relativistic Hamiltonian in order to include relativistic effects, giving 111 J-dependent states of Na^+ from 61 LS states; the

  17. Core-level spectroscopy to probe the oxidation state of single europium atoms.

    PubMed

    Tizei, Luiz H G; Nakanishi, Ryo; Kitaura, Ryo; Shinohara, Hisanori; Suenaga, Kazu

    2015-05-15

    The valence of individual europium atoms confined in carbon nanotubes is successfully measured by using core-level electron energy loss spectroscopy. Changes in the oxidation state at the atomic scale have been observed in Eu atomic chains exposed to oxygen. A transitory behavior has been identified where multiple atoms show a signal consistent with a sum of Eu^{2+} and Eu^{3+}. This indicates that single atoms change their valence state multiple times during the reaction, suggesting that oxidation in confined spaces and with extra energy input (from the electron beam) might not be a simple one step electron transfer event. PMID:26024198

  18. Core-Level Spectroscopy to Probe the Oxidation State of Single Europium Atoms

    NASA Astrophysics Data System (ADS)

    Tizei, Luiz H. G.; Nakanishi, Ryo; Kitaura, Ryo; Shinohara, Hisanori; Suenaga, Kazu

    2015-05-01

    The valence of individual europium atoms confined in carbon nanotubes is successfully measured by using core-level electron energy loss spectroscopy. Changes in the oxidation state at the atomic scale have been observed in Eu atomic chains exposed to oxygen. A transitory behavior has been identified where multiple atoms show a signal consistent with a sum of Eu2 + and Eu3 +. This indicates that single atoms change their valence state multiple times during the reaction, suggesting that oxidation in confined spaces and with extra energy input (from the electron beam) might not be a simple one step electron transfer event.

  19. Preparing ground States of quantum many-body systems on a quantum computer.

    PubMed

    Poulin, David; Wocjan, Pawel

    2009-04-01

    Preparing the ground state of a system of interacting classical particles is an NP-hard problem. Thus, there is in general no better algorithm to solve this problem than exhaustively going through all N configurations of the system to determine the one with lowest energy, requiring a running time proportional to N. A quantum computer, if it could be built, could solve this problem in time sqrt[N]. Here, we present a powerful extension of this result to the case of interacting quantum particles, demonstrating that a quantum computer can prepare the ground state of a quantum system as efficiently as it does for classical systems. PMID:19392338

  20. Model valence-fluctuation systems: variational ground states and magnetic responses

    SciTech Connect

    Brandow, B.H.

    1980-04-01

    Variational ground-state wavefunctions are presented and optimized for two model valence-fluctuation systems, based on Anderson lattice Hamiltonians in the U ..-->.. infinity limit. Although these wavefunctions are approximate, they are treated in an essentially exact manner. The )f/sup 0/, f/sup 1/; n = 1) system has an intuitively reasonable ground-state susceptibility, while the )f/sup 1/, f/sup 2/; n = 2) system is found to exhibit an insulating gap. Due to their different crystal symmetries, this gap should be realized in SmB/sub 6/ but not in SmS.

  1. Ground-state and finite-temperature energetics and topologies of germanium microclusters

    SciTech Connect

    Antonio, G.A.; Feuston, B.P.; Kalia, R.K.; Vashishta, P.

    1988-06-15

    We have investigated the ground-state and finite-temperature properties of Ge microclusters (N = 2 to 14) using molecular dynamics (MD) simulation along with the method of steepest-descent quench (SDQ). The interaction potential adopted is the three-body Stillinger--Weber potential as modified by Ding and Andersen for amorphous Ge. Our results indicate that the experimentally observed greater stability of certain cluster sizes can be explained by the topology and energetics of the clusters at finite temperature rather than by the binding energies of the ground-state structures.

  2. On Asymptotic Stability in Energy Space of Ground States for Nonlinear Schrödinger Equations

    NASA Astrophysics Data System (ADS)

    Cuccagna, Scipio; Mizumachi, Tetsu

    2008-11-01

    We consider nonlinear Schrödinger equations iu_t +? u +? (|u|^2)u=0 , text{for} (t,x)in mathbb{R}× mathbb{R}^d, where d ? 3 and ? is smooth. We prove that symmetric finite energy solutions close to orbitally stable ground states converge to a sum of a ground state and a dispersive wave as t ? ? assuming the so called the Fermi Golden Rule (FGR) hypothesis. We improve the “sign condition” required in a recent paper by Gang Zhou and I.M.Sigal.

  3. Ground-state structure and dynamics in a toy model for granular compaction

    NASA Astrophysics Data System (ADS)

    Luck, J. M.

    2006-04-01

    We report on a toy model for the glassy compaction dynamics of granular systems, introduced and investigated in collaboration with Anita Mehta and Peter Stadler. A stochastic dynamics is defined on a column of grains. Grains are anisotropic and possess a discrete orientational degree of freedom. Gravity induces long-range directional interactions down the column. The key control parameter of the model, ?, is a representation of granular shape. Rational and irrational values of ? correspond to very different kinds of behavior, both in statics (structure of ground states) and in low-temperature dynamics (retrieval of ground states).

  4. High-fidelity rapid ground-state loading of an ultracold gas into an optical lattice.

    PubMed

    Masuda, Shumpei; Nakamura, Katsuhiro; del Campo, Adolfo

    2014-08-01

    A protocol is proposed for the rapid coherent loading of a Bose-Einstein condensate into the ground state of an optical lattice, without residual excitation associated with the breakdown of adiabaticity. The driving potential required to assist the rapid loading is derived using the fast-forward technique, and generates the ground state in any desired short time. We propose an experimentally feasible loading scheme using a bichromatic lattice potential, which approximates the fast-forward driving potential with high fidelity. PMID:25148323

  5. v-representability and density functional theory. [for nonrelativistic electrons in nondegenerate ground state

    NASA Technical Reports Server (NTRS)

    Kohn, W.

    1983-01-01

    It is shown that if n(r) is the discrete density on a lattice (enclosed in a finite box) associated with a nondegenerate ground state in an external potential v(r) (i.e., is 'v-representable'), then the density n(r) + mu(r), with m(r) arbitrary (apart from trivial constraints) and mu small enough, is also associated with a nondegenerate ground state in an external potential v'(r) near v(r); i.e., n(r) + m(r) is also v-representable. Implications for the Hohenberg-Kohn variational principle and the Kohn-Sham equations are discussed.

  6. Permanent dipole moment of LiCs in the ground state

    SciTech Connect

    Deiglmayr, J.; Grochola, A.; Repp, M.; Dulieu, O.; Wester, R.; Weidemueller, M. [Ruprecht-Karls-Universitaet Heidelberg, Physikalisches Institut, Philosophenweg 12, D-69120 Heidelberg (Germany)

    2010-09-15

    Recently we demonstrated the formation of ultracold polar LiCs molecules in deeply bound levels of the X{sup 1}{Sigma}{sup +} ground state, including the rovibrational ground state [J. Deiglmayr et al., Phys. Rev. Lett. 101, 133004 (2008)]. Here we report on an experimental determination of the permanent electric dipole moment of deeply bound LiCs molecules. For X{sup 1}{Sigma}{sup +}, v{sup ''}=2, and v{sup ''}=3 we measure values of {mu}=5.5(2) D and 5.3(2) D, respectively.

  7. Ground-state properties of third-row elements with nonlocal density functionals

    SciTech Connect

    Bagno, P.; Jepsen, O.; Gunnarsson, O.

    1989-07-15

    The cohesive energy, the lattice parameter, and the bulk modulus of third-row elements are calculated using the Langreth-Mehl-Hu (LMH), the Perdew-Wang (PW), and the gradient expansion functionals. The PW functional is found to give somewhat better results than the LMH functional and both are found to typically remove half the errors in the local-spin-density (LSD) approximation, while the gradient expansion gives worse results than the local-density approximation. For Fe both the LMH and PW functionals correctly predict a ferromagnetic bcc ground state, while the LSD approximation and the gradient expansion predict a nonmagnetic fcc ground state.

  8. Inversion symmetry breaking of atomic bound states in strong and short laser fields

    E-print Network

    Stooß, Veit; Ott, Christian; Blättermann, Alexander; Ding, Thomas; Pfeifer, Thomas

    2015-01-01

    In any atomic species, the spherically symmetric potential originating from the charged nucleus results in fundamental symmetry properties governing the structure of atomic states and transition rules between them. If atoms are exposed to external electric fields, these properties are modified giving rise to energy shifts such as the AC Stark-effect in varying fields and, contrary to this in a constant (DC) electric field for high enough field strengths, the breaking of the atomic symmetry which causes fundamental changes in the atom's properties. This has already been observed for atomic Rydberg states with high principal quantum numbers. Here, we report on the observation of symmetry breaking effects in Helium atoms for states with principal quantum number n=2 utilizing strong visible laser fields. These findings were enabled by temporally resolving the dynamics better than the sub-optical cycle of the applied laser field, utilizing the method of attosecond transient absorption spectroscopy (ATAS). We ident...

  9. ATOMIC AND MOLECULAR PHYSICS: Experimental study of highly excited even-parity bound states of the Sm atom

    NASA Astrophysics Data System (ADS)

    Qin, Wen-Jie; Dai, Chang-Jian; Xiao, Ying; Zhao, Hong-Ying

    2009-08-01

    In this work, a three-step autoionization detection method and direct photoionization detection method are employed to measure the highly excited even-parity states of the Sm atom in the energy region between 36360 cm-1 and 40800 cm-1. Comparisons between the results from the two detection techniques enable us to discriminate the Rydberg states from the valence states in the same energy region with the information of level energies, possible J values and their relative intensities. Furthermore, in the experiment two different excitation schemes are designed to obtain the spectra of highly excited even-parity states of the Sm atom. With a detailed analysis of the experimental data, this work not only confirms the results about many spectral data from the literature with different excitation schemes, but also reports new spectral data on 29 Rydberg states and 23 valence states.

  10. Electric properties of the oxonium ion in its ground and two lowest excited states

    NASA Astrophysics Data System (ADS)

    Klein, Stéphane; Kochanski, Elise; Strich, Alain

    1996-09-01

    The electric dipole moments and dipole polarizabilities of the oxonium ion have been calculated for the ground and two lowest excited states from the CASSCF and CASPT2 approaches. Two basis sets — an extended ANO and a smaller segmented basis — have been compared. The best values obtained at the CASPT2 level are ? = -0.5878 au (calculated at the centre of the nuclear charges), ?? = 6.93 au and ?? = 5.66 au for the ground state, ?? = 47.1 au and ?? = 10.8 au for the 1A? 2 excited state, ? ? = 45.9 au and ? ? = 11.5 au for the3A? 2 excited state. To our knowledge, these are the first values available in the literature for the excited states.

  11. Prediction of In-Space Durability of Protected Polymers Based on Ground Laboratory Thermal Energy Atomic Oxygen

    SciTech Connect

    Banks, B.A.; Degroh, K.K.; Rutledge, S.; Difilippo, F.J.

    1996-04-01

    The probability of atomic oxygen reacting with polymeric materials is orders of magnitude lower at thermal energies (greater than O.1 eV) than at orbital impact energies (4.5 eV). As a result, absolute atomic oxygen fluxes at thermal energies must be orders of magnitude higher than orbital energy fluxes, to produce the same effective fluxes (or same oxidation rates) for polymers. These differences can cause highly pessimistic durability predictions for protected polymers and polymers which develop protective metal oxide surfaces as a result of oxidation if one does not make suitable calibrations. A comparison was conducted of undercut cavities below defect sites in protected polyimide Kapton samples flown on the Long Duration Exposure Facility (LDEF) with similar samples exposed in thermal energy oxygen plasma. The results of this comparison were used to quantify predicted material loss in space based on material loss in ground laboratory thermal energy plasma testing. A microindent hardness comparison of surface oxidation of a silicone flown on the Environmental Oxygen Interaction with Materials-III (EOIM-III) experiment with samples exposed in thermal energy plasmas was similarly used to calibrate the rate of oxidation of silicone in space relative to samples in thermal energy plasmas exposed to polyimide Kapton effective fluences.

  12. Reactive ground-state pathways are not ubiquitous in red/green cyanobacteriochromes.

    PubMed

    Chang, Che-Wei; Gottlieb, Sean M; Kim, Peter W; Rockwell, Nathan C; Lagarias, J Clark; Larsen, Delmar S

    2013-09-26

    Recent characterization of the red/green cyanobacteriochrome (CBCR) NpR6012g4 revealed a high quantum yield for its forward photoreaction [J. Am. Chem. Soc. 2012, 134, 130-133] that was ascribed to the activity of hidden, productive ground-state intermediates. The dynamics of the pathways involving these ground-state intermediates was resolved with femtosecond dispersed pump-dump-probe spectroscopy, the first such study reported for any CBCR. To address the ubiquity of such second-chance initiation dynamics (SCID) in CBCRs, we examined the closely related red/green CBCR NpF2164g6 from Nostoc punctiforme. Both NpF2164g6 and NpR6012g4 use phycocyanobilin as the chromophore precursor and exhibit similar excited-state dynamics. However, NpF2164g6 exhibits a lower quantum yield of 32% for the generation of the isomerized Lumi-R primary photoproduct, compared to 40% for NpR6012g4. This difference arises from significantly different ground-state dynamics between the two proteins, with the SCID mechanism deactivated in NpF2164g6. We present an integrated inhomogeneous target model that self-consistently fits the pump-probe and pump-dump-probe signals for both forward and reverse photoreactions in both proteins. This work demonstrates that reactive ground-state intermediates are not ubiquitous phenomena in CBCRs. PMID:23725062

  13. Calculated ground state potential surface and excitation energies for the copper trimer

    NASA Technical Reports Server (NTRS)

    Walch, S. P.; Laskowski, B. C.

    1986-01-01

    In the context of their relevance to catalysis and to materials science problems, transition metals and transition metal (TM) compounds are currently of considerable interest, and studies have been conducted of the copper trimer, Cu3. The present investigation is concerned with a study of the ground state surface and several groups of excited states in order to improve the understanding of the spectroscopy of Cu3. Differences of the current study from previous investigations are related to an employment of larger basis sets and a more extensive electron correlation. This was done with the objective to obtain a more accurate definition of the ground state surface. Features of the bonding in the copper dimer are considered to obtain a basis for an understanding of the copper trimer. Attention is given to calculational details, the ground state surface, and calculated vertical excitation energies. The results of SCF/SDCI calculations are reported for portions of the ground surface, for two groups of excited states, and for the ionization potential of Cu3.

  14. The preformation probability inside Alpha-emitters having different ground state spin-parity than daughters

    E-print Network

    Seif, W M; Refaie, A I

    2015-01-01

    The ground-state spin and parity of a formed daughter in the radioactive Alpha-emitter is expected to influence the preformation probability of the Alpha and daughter clusters inside it. We investigate the Alpha and daughter preformation probability inside odd-A and doubly-odd radioactive nuclei when the daughter and parent are of different spin and/or parity. We consider only the ground-state to ground-state unfavored decays. This is to extract precise information about the effect of the difference in the ground states spin-parity of the involved nuclei far away any influences from the excitation energy if the decays are coming from isomeric states. The calculations are done for 161 Alpha-emitters, with Z=65-112 and N=84-173, in the framework of the extended cluster model, with WKB penetrability and assault frequency. We used a Hamiltonian energy density scheme based on Skyrme-SLy4 interaction to compute the interaction potential. The Alpha plus cluster preformation probability is extracted from the calculat...

  15. Theory of a compound large-angle atom beam splitter. II. Initial state deflection

    SciTech Connect

    Muradyan, A.Zh.; Muradyan, G.A.; Berman, P.R. [Department of Physics, Yerevan State University, 1 Alex Manookian, Yerevan 375025 (Armenia); Michigan Center for Theoretical Physics, FOCUS Center, and Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1012 (United States)

    2004-12-01

    The theory of a compound, large-angle atom beam splitter [A. Zh. Muradyan, A. A. Poghosyan, and P. R. Berman, Phys. Rev. A 68, 033604 (2003)] is generalized to allow for initial-state deflection. Atoms are prepared in an initial state by an off-resonant standing-wave field and then subject to two-standing-wave fields that couple the initial state to a final state. By a proper choice of parameters, atoms in the initial state can be deflected or split as a result of the interactions with the fields. The role of relaxation is considered.

  16. Rayleigh approximation to ground state of the Bose and Coulomb glasses

    DOE PAGESBeta

    Ryan, S. D.; Mityushev, V.; Vinokur, V. M.; Berlyand, L.

    2015-01-16

    Glasses are rigid systems in which competing interactions prevent simultaneous minimization of local energies. This leads to frustration and highly degenerate ground states the nature and properties of which are still far from being thoroughly understood. We report an analytical approach based on the method of functional equations that allows us to construct the Rayleigh approximation to the ground state of a two-dimensional (2D) random Coulomb system with logarithmic interactions. We realize a model for 2D Coulomb glass as a cylindrical type II superconductor containing randomly located columnar defects (CD) which trap superconducting vortices induced by applied magnetic field. Ourmore »findings break ground for analytical studies of glassy systems, marking an important step towards understanding their properties.« less

  17. In-reservoir coherent control of an atom-photon bound state

    SciTech Connect

    Mogilevtsev, D. [Institute of Physics, Belarus National Academy of Sciences, F. Skarina Avenue 68, Minsk 220072 (Belarus); Departamento de Fisica, Universidade Federal de Alagoas Cidade Universitria, 57072-970, Macei, Alagoas (Brazil); Kilin, S. [Institute of Physics, Belarus National Academy of Sciences, F. Skarina Avenue 68, Minsk 220072 (Belarus); Cavalcanti, S.B.; Hickmann, J.M. [Departamento de Fisica, Universidade Federal de Alagoas Cidade Universitria, 57072-970, Macei, Alagoas (Brazil)

    2005-10-15

    In this work we show that the atom-photon bound state (APBS) in zero-temperature structured reservoir without an external excitation is always an entangled state of two qubits. The maximal degree of achievable entanglement depends on the atomic frequency detuning from the band edge. APBS can be produced and effectively controlled by the coherent excitation of the reservoir modes with frequencies outside the gap. The proposed scheme can be used for the single-atom optical memory device.

  18. Generation of Two-Flavor Vortex Atom Laser from a Five-State Medium

    E-print Network

    Xiong-Jun Liu; Hui Jing; Xin Liu; Mo-Lin Ge

    2007-02-14

    Two-flavor atom laser in a vortex state is obtained and analyzed via electromagnetically induced transparency (EIT) technique in a five-level $M$ type system by using two probe lights with $\\pm z$-directional orbital angular momentum $\\pm l\\hbar$, respectively. Together with the original transfer technique of quantum states from light to matter waves, the present result can be extended to generate continuous two-flavor vortex atom laser with non-classical atoms.

  19. Engineering two-mode squeezed states of cold atomic clouds with a superconducting stripline resonator

    E-print Network

    Pengbo Li; Fuli Li

    2010-09-16

    A scheme is proposed for engineering two-mode squeezed states of two separated cold atomic clouds positioned near the surface of a superconducting stripline resonator. Based on the coherent magnetic coupling between the atomic spins and a stripline resonator mode, the desired two-mode squeezed state can be produced via precisely control on the dynamics of the system. This scheme may be used to realize scalable on-chip quantum networks with cold atoms coupling to stripline resonators.

  20. Summary of informal workshop on state of ion beam facilities for atomic physics research

    SciTech Connect

    Jones, K.W.; Cocke, C.L.; Datz, S.; Kostroun, V.

    1984-11-13

    The present state of ion beam facilities for atomic physics research in the United States is assessed by means of a questionnaire and informal workshop. Recommendations for future facilities are given. 3 refs.

  1. Beam Splitter-Mediated Quantum Information Processing Employing Momentum States of the Neutral Atoms

    NASA Astrophysics Data System (ADS)

    Abbas, Tasawar; Ul-Islam, Rameez; Ikram, Manzoor

    2015-04-01

    We propose various schemes for the generation and manipulation of a variety of atomic external transverse momentum states. The fundamental ingredient of all such states is a simple bipartite cavity field-atomic momentum entangled state generated through second order, off-resonant Bragg diffraction of the neutral two-level atoms. Further multipartite entangled state engineering and manipulation including Bell, GHZ, Dicke and W-state production, remote state-assisted entanglement swapping, and teleportation of a cavity field superposition as well as the entanglement onto atomic momentum states are carried out by simultaneously projecting the cavity field(s) over symmetric beam splitter(s). It is further discussed that generation and manipulation of such decoherence resistant momentum states is quite feasible under prevailing experimental research scenario in cavity QED.

  2. Unitary photoassociation: One-step production of ground-state bound molecules

    SciTech Connect

    Kallush, S.; Kosloff, R. [Fritz Haber Research Center, Hebrew University of Jerusalem, Jerusalem 91904 (Israel)

    2008-02-15

    Bound-state molecules can be photoassociated directly from ultracold free-atom pairs by excitation to a purely repulsive electronic state. The process is explained on the basis of quantum unitarity: the initially free-scattering state is transformed by an impulsive light pulse to a deformed superposition which contains bound-state components. For pulse durations which are short compared to the ultracold dynamics, the maximal rate of photoassociation was found to be determined by the initial stationary distribution of scattering states of the atom pairs. The process was simulated for an ultracold gas of {sup 87}Rb with a temperature of T=44 {mu}K and a density of {approx_equal}10{sup 11} cm{sup -3}. Transform-limited pulses maximize the photoassociation, yielding {approx}1 bound molecule per pulse. Coherent control calculated by a local control scheme can increase the photoassociation yield by two orders of magnitude.

  3. Resetting Transcription Factor Control Circuitry toward Ground-State Pluripotency in Human

    PubMed Central

    Takashima, Yasuhiro; Guo, Ge; Loos, Remco; Nichols, Jennifer; Ficz, Gabriella; Krueger, Felix; Oxley, David; Santos, Fatima; Clarke, James; Mansfield, William; Reik, Wolf; Bertone, Paul; Smith, Austin

    2014-01-01

    Summary Current human pluripotent stem cells lack the transcription factor circuitry that governs the ground state of mouse embryonic stem cells (ESC). Here, we report that short-term expression of two components, NANOG and KLF2, is sufficient to ignite other elements of the network and reset the human pluripotent state. Inhibition of ERK and protein kinase C sustains a transgene-independent rewired state. Reset cells self-renew continuously without ERK signaling, are phenotypically stable, and are karyotypically intact. They differentiate in vitro and form teratomas in vivo. Metabolism is reprogrammed with activation of mitochondrial respiration as in ESC. DNA methylation is dramatically reduced and transcriptome state is globally realigned across multiple cell lines. Depletion of ground-state transcription factors, TFCP2L1 or KLF4, has marginal impact on conventional human pluripotent stem cells but collapses the reset state. These findings demonstrate feasibility of installing and propagating functional control circuitry for ground-state pluripotency in human cells. PMID:25215486

  4. Exafs studies of nanocrystalline materials exhibiting a new solid state structure with randomly arranged atoms

    Microsoft Academic Search

    T. Haubold; R. Birringer; B. Lengeler; H. Gleiter

    1989-01-01

    Nanocrystalline materials are polycrystals with a typical crystallite diameter of 5 to 15 nm. They structurally consist of two components with comparable volume fractions: a crystalline component and a grain boundary component, which is shown by means of EXAFS to exhibit a new solid state structure with random atomic arrangement to exhibit a new solid state structure with random atomic

  5. CH3I low-n Rydberg states in supercritical atomic fluids near the critical point

    E-print Network

    Findley, Gary L.

    CH3I low-n Rydberg states in supercritical atomic fluids near the critical point Luxi Li a states doped into supercritical argon, krypton, and xenon perturbers were measured from low density effects, especially in supercritical fluids [2]. Both atomic [3­5] and molecular [6­11] dopant low

  6. LBNL-42730 1 Collisional Perturbation of States in Atomic Ytterbium by Helium and Neon

    E-print Network

    Budker, Dmitry

    LBNL-42730 1 Collisional Perturbation of States in Atomic Ytterbium by Helium and Neon D, CA 94720 Results of an investigation of collisional de-excitation of the metastable 6s6p 3 P0 state in atomic ytterbium by helium and neon buffer gases are reported. We find upper limits for the quenching

  7. Squeezed states in the two-atom model with intensity-dependent coupling

    NASA Astrophysics Data System (ADS)

    Bashkirov, Eugene K.

    2015-03-01

    Squeezing for one- and two-mode two-atom Jaynes-Cummings model with intensity-dependent coupling has been investigated assuming the field to be initially in the coherent state. The time-dependent squeezing parameters have been calculated. The influence of the intensity of the cavity field and initial atomic state on the squeezing parameters has been analyzed.

  8. Populating excited states of incoherent atoms using coherent light.

    NASA Technical Reports Server (NTRS)

    Mcilrath, T. J.; Carlsten, J. L.

    1972-01-01

    Study of the influence of various experimental parameters on the interaction between a multimode high-intensity laser light and the absorbing atoms of an atomic gas. Using a simplified treatment of line broadening which does not include correlations between momentum-changing collisions and pressure-broadening collisions, expressions are obtained that show the effect of pressure, laser-pulse length, and intensity on the excitation. It is found that, as long as the dephasing time of the atomic system is sufficiently short, the interaction reduces to a two-body collision between the atoms and photons, where coherence effects do not occur.

  9. Ground Tests of Einstein's Equivalence Principle: From Lab-based to 10-m Atomic Fountains

    E-print Network

    Schlippert, D; Richardson, L L; Nath, D; Heine, H; Meiners, C; Wodey, É; Billon, A; Hartwig, J; Schubert, C; Gaaloul, N; Ertmer, W; Rasel, E M

    2015-01-01

    To date, no framework combining quantum field theory and general relativity and hence unifying all four fundamental interactions, exists. Violations of the Einstein's equivalence principle (EEP), being the foundation of general relativity, may hold the key to a theory of quantum gravity. The universality of free fall (UFF), which is one of the three pillars of the EEP, has been extensively tested with classical bodies. Quantum tests of the UFF, e.g. by exploiting matter wave interferometry, allow for complementary sets of test masses, orders of magnitude larger test mass coherence lengths and investigation of spin-gravity coupling. We review our recent work towards highly sensitive matter wave tests of the UFF on ground. In this scope, the first quantum test of the UFF utilizing two different chemical elements, Rb-87 and K-39, yielding an E\\"otv\\"os ratio $\\eta_{\\,\\text{Rb,K}}=(0.3\\pm 5.4)\\times 10^{-7}$ has been performed. We assess systematic effects currently limiting the measurement at a level of parts in...

  10. Experimental preparation of pure superposition states of atoms via elliptically polarized bichromatic radiation

    E-print Network

    Zibrov, S A; Velichansky, V L; Yudin, V I; Zibrov, A S; Zibrov, Sergei A.

    2005-01-01

    We propose a simple and effective way of creating pure dark superposition states. The generation of pure states is carried out by using bichromatic radiation with controllable polarization ellipticity. We derived analytic formulas for polarization elipticity to obtain pure dark states of different Zeeman sublevels of alkali atoms. Experimentally we accumulated ~60% of the atoms in the 0-0 dark state of the D1 line of Rb87

  11. 9. In the Kondo ground state, the localized spin is screened by the conduction electrons, suppressing

    E-print Network

    Mojzsis, Stephen J.

    9. In the Kondo ground state, the localized spin is screened by the conduction electrons spin fluctuations and Kondo correlations (26). 10. N. Sergueev et al., Phys. Rev. B 65, 165303 (2002 (2004). 23. In addition to the Kondo signals, tunneling through the independent electron resonances

  12. Green's function Monte Carlo calculation for the ground state of helium trimers

    SciTech Connect

    Cabral, F.; Kalos, M.H.

    1981-02-01

    The ground state energy of weakly bound boson trimers interacting via Lennard-Jones (12,6) pair potentials is calculated using a Monte Carlo Green's Function Method. Threshold coupling constants for self binding are obtained by extrapolation to zero binding.

  13. The Random Field Ising Model on Hierarchical Lattices II: Ground State Critical Properties

    Microsoft Academic Search

    Alexandre Rosas; Sérgio Coutinho

    2001-01-01

    The ground state critical properties of the Random Field Ising Model (RFIM) on the diamond hierarchical lattice are investigated via a combining method encompassing real space renormalization group and an exact recurrence procedure. The local magnetization and the nearest neighbors pair correlation function are exactly calculated. The fixed-point joint probability distribution of couplings and local fields are numerically obtained and

  14. The ground state energy of a polaron in a strong magnetic field

    E-print Network

    Rupert L. Frank; Leander Geisinger

    2013-03-10

    We show that the ground state of a polaron in a homogeneous magnetic field $B$ and its energy are described by an effective one-dimensional minimization problem in the limit $B\\to\\infty$. This holds both in the linear Fr\\"ohlich and in the non-linear Pekar model and makes rigorous an argument of Kochetov, Leschke and Smondyrev.

  15. N'eel Order in the Ground State of Spin1/2 Heisenberg

    E-print Network

    N'eel Order in the Ground State of SpinĀ­1/2 Heisenberg Antiferromagnetic Multilayer Systems J.O. Box 66318 05389Ā­970 S~ao Paulo Brazil July, 1996 Abstract We show existence of N'eel order by CAPES. y Supported by FAPESP. z Partially supported by CNPq. 1 #12; 1 Introduction The existence of N'eel

  16. Classical versus Jennings model for the ground state of H near a metallic surface

    NASA Astrophysics Data System (ADS)

    Gutierrez, F. A.; Jequier, S.; Jouin, H.

    1998-12-01

    We show that, contrary to earlier reports, application of the one-parameter variational technique to the classical (image) model for H in front of an Al surface leads to energy shifts for the ground state which are very close to those obtained numerically with a more sophisticated model of the system.

  17. Local-energy calculations on the ground state of the hydrogen molecule ion

    Microsoft Academic Search

    R. G. Clark; E. T. Stewart

    1971-01-01

    This paper reports some new wave functions for the ground state of the hydrogen molecule ion which give lower values for the mean energy than do previously published functions of comparable complexity. The wave functions were optimized first by the local-energy method and then by the variation principle. With wave functions of as high quality as those discussed here, the

  18. Ground state entanglement in one-dimensional translationally invariant quantum systems

    SciTech Connect

    Irani, Sandy [Department of Computer Science, University of California, Irvine, California 2697-3435 (United States)

    2010-02-15

    We examine whether it is possible for one-dimensional translationally invariant Hamiltonians to have ground states with a high degree of entanglement. We present a family of translationally invariant Hamiltonians (H{sub n}) for the infinite chain. The spectral gap of H{sub n} is {omega}(1/poly(n)). Moreover, for any state in the ground space of H{sub n} and any m, there are regions of size m with entanglement entropy {omega}(min(m,n)). A similar construction yields translationally invariant Hamiltonians for finite chains that have unique ground states exhibiting high entanglement. The area law proven by Hastings ['An area law for one dimensional quantum systems', J. Stat. Mech.: Theory Exp. 2007 (08024)] gives a constant upper bound on the entanglement entropy for one-dimensional ground states that is independent of the size of the region but exponentially dependent on 1/{delta}, where {delta} is the spectral gap. This paper provides a lower bound, showing a family of Hamiltonians for which the entanglement entropy scales polynomially with 1/{delta}. Previously, the best known such bound was logarithmic in 1/{delta}.

  19. On the equation $Du+Xu=0$ and its relation to Schroedinger ground states

    E-print Network

    Kurt Pagani

    2013-05-12

    We present some simple relations between the absolute minimizers of the functional $||Du+Xu||$, where $X$ is a vector field on $R^n$, and ground state solutions to the (non-relativistic) Schroedinger equation. This article is a byproduct of the study of the more general functional $||ADu+F'(u)X||$.

  20. Cloud-to-Ground Lightning Activity in the Contiguous United States from 1995 to 1999

    Microsoft Academic Search

    Bard A. Zajac; Steven A. Rutledge

    2001-01-01

    The spatial and temporal distributions of cloud-to-ground lightning are examined over the contiguous United States from 1995 to 1999 using data from the National Lightning Detection Network. Annual flash density, annual lightning days, cumulative frequency distributions of daily flash counts, and annual and summertime diurnal distributions of lightning are documented. The spatial, annual, and summertime diurnal distributions of positive and

  1. Many-particle ground states and excitations in nanometer-size quantum structures

    E-print Network

    Lorke, Axel

    Many-particle ground states and excitations in nanometer-size quantum structures Axel Lorke *, Richard J. Luyken Sektion Physik, LMU Munchen, Geschwister-Scholl-Platz 1, 80539 Munchen, Germany Abstract 256±258 (1998) 424±430 * Corresponding author. Fax: +49 89 2180 3182; e-mail: axel

  2. Improved quantum Monte Carlo calculation of the ground-state energy of the hydrogen molecule

    E-print Network

    Anderson, James B.

    Improved quantum Monte Carlo calculation of the ground-state energy of the hydrogen molecule Bin more accurate than that of previous quantum Monte Carlo calculations. The energy is less accurate than predictions has most often been the analytic variational method, but the quantum Monte Carlo method has

  3. A quantum Monte Carlo calculation of the ground state energy of the hydrogen molecule

    E-print Network

    Anderson, James B.

    A quantum Monte Carlo calculation of the ground state energy of the hydrogen molecule Carol A of the hydrogen molecule using the quantum Monte Carlo (QMC) method of solving the Schrodinger equation, without protons). Two different methods were employed: the diffusion quantum Monte Carlo (DQMC) method

  4. First-row hydrides: Dissociation and ground state energies using quantum Monte Carlo

    E-print Network

    Anderson, James B.

    First-row hydrides: Dissociation and ground state energies using quantum Monte Carlo Arne Lu to or better than the best previous ab initio results can be obtained using the fixed-node quantum Monte Carlo, the dissociation energies are consistent with experimental values. The fixed-node quantum Monte Carlo method can

  5. Searching for Ground States of Ising Spin Glasses with Hierarchical BOA and Cluster

    E-print Network

    Hartmann, Alexander K.

    1 Searching for Ground States of Ising Spin Glasses with Hierarchical BOA and Cluster Exact@physik.uni­goettingen.de Summary. This chapter applies the hierarchical Bayesian optimization algorithm (hBOA) to the problem. The performance of hBOA is com­ pared to that of the simple genetic algorithm (GA) and the univariate marginal

  6. Ground State Destabilization by Anionic Nucleophiles Contributes to the Activity of Phosphoryl Transfer

    E-print Network

    Herschlag, Dan

    . Alkaline Phosphatase (AP) and other nonspecific phosphatases are some of Nature's most impressive catalysts that no competing interests exist. Abbreviations: AP, alkaline phosphatase; Pi, inorganic phosphate; PTP, protein binding measurements with a protein tyrosine phosphatase suggest the generality of this ground state

  7. Ground-state-entanglement bound for quantum energy teleportation of general spin-chain models

    NASA Astrophysics Data System (ADS)

    Hotta, Masahiro

    2013-03-01

    Many-body quantum systems in the ground states have zero-point energy due to the uncertainty relation. In many cases, the system in the ground state accompanies spatially entangled energy density fluctuation via the noncommutativity of the energy density operators, though the total energy takes a fixed value, i.e., the lowest eigenvalue of the Hamiltonian. Quantum energy teleportation (QET) is a protocol for the extraction of the zero-point energy out of one subsystem using information of a remote measurement of another subsystem. From an operational viewpoint of protocol users, QET can be regarded as an effective rapid energy transportation without breaking all physical laws, including causality and local energy conservation. In the protocol, the ground-state entanglement plays a crucial role. In this paper, we show analytically for a general class of spin-chain systems that the entanglement entropy is lower bounded by a positive quadratic function of the teleported energy between the regions of a QET protocol. This supports a general conjecture that ground-state entanglement is an evident physical resource for energy transportation in the context of QET. The result may also deepen our understanding of the energy density fluctuation in condensed-matter systems from a perspective of quantum information theory.

  8. Unified description of ground and excited states of finite systems: the self-consistent GW approach

    E-print Network

    calculations ­ based on the iterative solution of the Dyson equation ­ provide an approach for consistently and permit us to assess the quality of ground state properties such as bond lengths and vibrational of choice for the spectral properties of solids [4, 5], has steadily gained popularity for molecules

  9. Ground and Excited State Intramolecular Proton Transfer in Salicylic Acid: an Ab Initio Electronic Structure Investigation

    E-print Network

    Chowdhury, Arindam

    emission in the fluorescence spectrum of salicylic acid and methyl salicylate and attributedGround and Excited State Intramolecular Proton Transfer in Salicylic Acid: an Ab Initio Electronic in salicylic acid have been studied by ab initio molecular orbital calculations using the 6-31G** basis set

  10. Scaling of the giant dipole resonance widths in hot rotating nuclei from the ground state values

    E-print Network

    Srijit Bhattacharya; Deepak Pandit; S. Mukhopadhyay; Surajit Pal; S. R. Banerjee

    2008-11-11

    The systematics of the giant dipole resonance (GDR) widths in hot and rotating nuclei are studied in terms of temperature T, angular momentum J and mass A. The different experimental data in the temperature range of 1 - 2 MeV have been compared with the thermal shape fluctuation model (TSFM) in the liquid drop formalism using a modified approach to estimate the average values of T, J and A in the decay of the compound nucleus. The values of the ground state GDR widths have been extracted from the TSFM parametrization in the liquid drop limit for the corrected T, J and A for a given system and compared with the corresponding available systematics of the experimentally measured ground state GDR widths for a range of nuclei from A = 45 to 194. Amazingly, the nature of the theoretically extracted ground state GDR widths matches remarkably well, though 1.5 times smaller, with the experimentally measured ground state GDR widths consistently over a wide range of nuclei.

  11. Measurement of ground-state decoherence via interruption of coherent population trapping

    E-print Network

    Patnaik, Anil K.; Hsu, Paul S.; Agarwal, Girish S.; Welch, George R.; Scully, Marlan O.

    2007-01-01

    Measurement of ground-state decoherence via interruption of coherent population trapping Anil K. Patnaik,1,2 Paul S. Hsu,1 Girish S. Agarwal,3 George R. Welch,1 and Marlan O. Scully1,2,4 1Institute for Quantum Studies and Department of Physics...

  12. Ground state entanglement in one-dimensional translationally invariant quantum systems

    NASA Astrophysics Data System (ADS)

    Irani, Sandy

    2010-02-01

    We examine whether it is possible for one-dimensional translationally invariant Hamiltonians to have ground states with a high degree of entanglement. We present a family of translationally invariant Hamiltonians {Hn} for the infinite chain. The spectral gap of Hn is ?(1/poly(n )). Moreover, for any state in the ground space of Hn and any m, there are regions of size m with entanglement entropy ?(min{m,n}). A similar construction yields translationally invariant Hamiltonians for finite chains that have unique ground states exhibiting high entanglement. The area law proven by Hastings ["An area law for one dimensional quantum systems," J. Stat. Mech.: Theory Exp. 2007 (08024)] gives a constant upper bound on the entanglement entropy for one-dimensional ground states that is independent of the size of the region but exponentially dependent on 1/?, where ? is the spectral gap. This paper provides a lower bound, showing a family of Hamiltonians for which the entanglement entropy scales polynomially with 1/?. Previously, the best known such bound was logarithmic in 1/?.

  13. Characterizing the spin state of an atomic ensemble using the magneto-optical resonance method

    E-print Network

    B. Julsgaard; J. Sherson; J. L. Sorensen; E. S. Polzik

    2003-09-29

    Quantum information protocols utilizing atomic ensembles require preparation of a coherent spin state (CSS) of the ensemble as an important starting point. We investigate the magneto-optical resonance method for characterizing a spin state of cesium atoms in a paraffin coated vapor cell. Atoms in a constant magnetic field are subject to an off-resonant laser beam and an RF magnetic field. The spectrum of the Zeeman sub-levels, in particular the weak quadratic Zeeman effect, enables us to measure the spin orientation, the number of atoms, and the transverse spin coherence time. Notably the use of 894nm pumping light on the D1-line, ensuring the state F=4, m_F=4 to be a dark state, helps us to achieve spin orientation of better than 98%. Hence we can establish a CSS with high accuracy which is critical for the analysis of the entangled states of atoms.

  14. Autioionizing states in the photionization of the 3s(2)3p(4) (3)Pe ground state of sulfur

    NASA Technical Reports Server (NTRS)

    Tayal, S. S.

    1988-01-01

    The partial and total photoionization cross sections for the S(3s/2/3p/4/ /3/Pe) ground state are calculated in both the dipole length and velocity forms. The prominent features in the cross sections are the autoionization Rydberg series converging to S+(3s/2/p/3/ /2/D/0/, /2/P/0/) excited-state thresholds. The results are pertinent to the study of sulfur in the plasma of Jupiter's satellite Io.

  15. Magnetic ground state of LBa Co2 O5.5/5.44 cobalt oxides

    NASA Astrophysics Data System (ADS)

    Khalyavin, D. D.

    2005-10-01

    The magnetic properties of LBaCo2O5+? cobalt oxides with different types of oxygen ions ordering within [LO?] layers are discussed. Symmetry arguments are used to analyze the models of the magnetic ground state proposed for these compounds. By postulating the ordering between octahedraly coordinated cobalt ions in different spin states the magnetic structures explaining a variety of observed experimental data and consisting with the symmetry analysis are presented.

  16. Ground-state selection from anharmonic zero-point energy in the pyrochlore antiferromagnet

    Microsoft Academic Search

    Uzi Hizi; Christopher L. Henley

    2004-01-01

    In the pyrochlore lattice Heisenberg antiferromagnet, for large spin length S, the massive classical ground state degeneracy is partly lifted by the zero-point energy of quantum fluctuations at harmonic order in spin waves. [1] In a system of O(L^3) spins, there remained O(exp(const L)) collinear states, exactly degenerate to that order. We have extended the calculation to quartic order, assuming

  17. Ground state properties of the two-band Anderson-type model in one dimension

    Microsoft Academic Search

    H. Kaga; T. Fujiwara

    1986-01-01

    We study the ground states of the one-dimensional two-band Anderson type model in both the symmetric and the asymmetric cases. In the symmetric case the analytical expression of the charge-complex distribution function is formally derived, which is then applied to calculate the binding energy of the Kondo state. In the general asymmetric cases the behaviors of localized- and conduction-electron numbers

  18. Valence Fluctuation from f2 Singlet Crystal-Field Ground State in Generalized Periodic Anderson Model

    Microsoft Academic Search

    Ryousuke Shiina

    2005-01-01

    A generalized periodic Anderson model with stable f2 configuration is examined through a Gutzwiller-type variational method (GM). In particular, we focus on the effect of the f2 crystal-field (CF) level scheme with singlet ground and triplet low-lying excited states. It is demonstrated that valence fluctuation from the f2 states is slightly enhanced by a small singlet--triplet CF splitting whereas it

  19. Half-metallic ferromagnetic ground state in CePdSb

    Microsoft Academic Search

    Andrzej ?lebarski

    2006-01-01

    The CeMX compounds, where M is a transition metal, and X is an sp element, have a number of different types of ground state including magnetic, metallic, and insulating, and they exhibit anomalous physical properties, such as the Kondo effect, heavy-fermion behavior, valence fluctuations, etc. Recently, a Kondo-lattice state has been proposed for ferromagnetic CePdSb, which seems to be unusual.

  20. Variational theory of valence fluctuations: Ground states and quasiparticle excitations of the Anderson lattice model

    Microsoft Academic Search

    B. H. Brandow

    1986-01-01

    A variational study of ground states of the orbitally nondegenerate Anderson lattice model, using a wave function with one variational parameter per Bloch state k, has been extended to deal with essentially metallic systems having a nonintegral number of electrons per site. Quasiparticle excitations are obtained by direct appeal to Landau's original definition for interacting Fermi liquids, scrEqp(k,sigma)=deltaEtotal\\/deltan qp(k,sigma). This

  1. Variational theory of valence fluctuations: Ground states and quasiparticle excitations of the Anderson lattice model

    Microsoft Academic Search

    B. Brandow

    1986-01-01

    A variational study of ground states of the orbitally nondegenerate Anderson lattice model, using a wave function with one variational parameter per Bloch state k, has been extended to deal with essentially metallic systems having a nonintegral number of electrons per site. Quasiparticle excitations are obtained by direct appeal to Landau's original definition for interacting Fermi liquids, scrE\\/sub qp\\/(k,sigma) =

  2. Electronic Structure and Ground State Properties of Non-Magnetic NiPt Systems

    Microsoft Academic Search

    DURGA PAUDYAL; ABHIJIT MOOKERJEE

    2003-01-01

    We have studied the electronic properties like density of states and band structures and also the ground state properties like formation energy, cohesive energy, bulk modulus and structural energy of NiPt system using the linearized muffin-tin orbital method introduced by Andersen.1,2 In an earlier communication we had argued that both charge neutrality and scalar relativistic corrections are very important for

  3. Long-range interactions between polar bialkali ground-state molecules in arbitrary vibrational levels.

    PubMed

    Vexiau, R; Lepers, M; Aymar, M; Bouloufa-Maafa, N; Dulieu, O

    2015-06-01

    We have calculated the isotropic C6 coefficients characterizing the long-range van der Waals interaction between two identical heteronuclear alkali-metal diatomic molecules in the same arbitrary vibrational level of their ground electronic state X(1)?(+). We consider the ten species made up of (7)Li, (23)Na, (39)K, (87)Rb, and (133)Cs. Following our previous work [Lepers et al., Phys. Rev. A 88, 032709 (2013)], we use the sum-over-state formula inherent to the second-order perturbation theory, composed of the contributions from the transitions within the ground state levels, from the transition between ground-state and excited state levels, and from a crossed term. These calculations involve a combination of experimental and quantum-chemical data for potential energy curves and transition dipole moments. We also investigate the case where the two molecules are in different vibrational levels and we show that the Moelwyn-Hughes approximation is valid provided that it is applied for each of the three contributions to the sum-over-state formula. Our results are particularly relevant in the context of inelastic and reactive collisions between ultracold bialkali molecules in deeply bound or in Feshbach levels. PMID:26049492

  4. Long-range interactions between polar bialkali ground-state molecules in arbitrary vibrational levels

    NASA Astrophysics Data System (ADS)

    Vexiau, R.; Lepers, M.; Aymar, M.; Bouloufa-Maafa, N.; Dulieu, O.

    2015-06-01

    We have calculated the isotropic C6 coefficients characterizing the long-range van der Waals interaction between two identical heteronuclear alkali-metal diatomic molecules in the same arbitrary vibrational level of their ground electronic state X1?+. We consider the ten species made up of 7Li, 23Na, 39K, 87Rb, and 133Cs. Following our previous work [Lepers et al., Phys. Rev. A 88, 032709 (2013)], we use the sum-over-state formula inherent to the second-order perturbation theory, composed of the contributions from the transitions within the ground state levels, from the transition between ground-state and excited state levels, and from a crossed term. These calculations involve a combination of experimental and quantum-chemical data for potential energy curves and transition dipole moments. We also investigate the case where the two molecules are in different vibrational levels and we show that the Moelwyn-Hughes approximation is valid provided that it is applied for each of the three contributions to the sum-over-state formula. Our results are particularly relevant in the context of inelastic and reactive collisions between ultracold bialkali molecules in deeply bound or in Feshbach levels.

  5. Long-range interactions between polar bialkali ground-state molecules in arbitrary vibrational levels

    E-print Network

    R. Vexiau; M. Lepers; M. Aymar; N. Bouloufa-Maafa; O. Dulieu

    2015-02-19

    We have calculated the isotropic $C\\_6$ coefficients characterizing the long-range van der Waals interaction between two identical heteronuclear alkali-metal diatomic molecules in the same arbitrary vibrational level of their ground electronic state $X^1\\Sigma^+$. We consider the ten species made up of $^7$Li, $^{23}$Na, $^{39}$K, $^{87}$Rb and $^{133}$Cs. Following our previous work [M.~Lepers \\textit{et.~al.}, Phys.~Rev.~A \\textbf{88}, 032709 (2013)] we use the sum-over-state formula inherent to the second-order perturbation theory, composed of the contributions from the transitions within the ground state levels, from the transition between ground-state and excited state levels, and from a crossed term. These calculations involve a combination of experimental and quantum-chemical data for potential energy curves and transition dipole moments. We also investigate the case where the two molecules are in different vibrational levels and we show that the Moelwyn-Hughes approximation is valid provided that it is applied for each of the three contributions to the sum-over-state formula. Our results are particularly relevant in the context of inelastic and reactive collisions between ultracold bialkali molecules, in deeply bound or in Feshbach levels.

  6. Ion mobility of ground and excited states of laser-generated transition metal cations.

    PubMed

    Ibrahim, Yehia; Alsharaeh, Edreese; Mabrouki, Ridha; Momoh, Paul; Xie, Enli; El-Shall, M Samy

    2008-02-14

    The application of ion mobility to separate the electronic states of first-, second-, and third-row transition metal cations generated by the laser vaporization/ionization (LVI) technique is presented. The mobility measurements for most of the laser-generated transition metal cations reveal the presence of two or three mobility peaks that correspond to ground and excited states of different electronic configurations. The similarity of the measured reduced mobilities for the metal cations generated by LVI, electron impact, and glow discharge ion sources indicates that the same electronic configurations are produced regardless of the ion source. However, in comparison with electron impact of volatile organometallic compounds, the LVI populates fewer excited states due to the thermal nature of the process. Significant contributions to the production and populations of excited states of Ni+, Nb+, and Pt+ cations have been observed in the presence of argon during the LVI process and attributed to the Penning ionization mechanism. The origin of the mobility difference between the ground and the excited states is mainly due to the different interaction with helium. The ratio of the reduced mobilities of the excited and ground states decreases as one goes from the first- to the second- to the third-row transition metal cations. This trend is attributed to the ion size, which increases in the order 6sd(n-1) > 5sd(n-1) > 4sd(n-1). This work helps to understand the mechanisms by which transition metal cations react in the gas phase by identifying the ground and excited states that can be responsible for their reactivity. PMID:18205338

  7. Quantum atom-heteronuclear molecule dark state: Role of population imbalance

    SciTech Connect

    Jing Hui; Cui Shuai [Department of Physics, Henan Normal University, Xinxiang 453007 (China)

    2010-08-15

    Recently, the finite-number effect of initial atoms in coherent atom-molecule conversion was investigated by Zhao et al. [Phys. Rev. Lett. 101, 010401 (2008)]. Here, by extending to the atom-heteronuclear molecule dark state, we find that the initial populations imbalance of the atoms plays a significant role in quantum conversion rate and adiabatic fidelity. In particular, even for the finite total number of imbalanced two-species atoms, the mean-field conversion rate, contrary to the general belief, still can be remarkably close to the exact quantum results.

  8. Classification of matrix-product ground states corresponding to one-dimensional chains of two-state sites of nearest neighbor interactions

    SciTech Connect

    Fatollahi, Amir H.; Khorrami, Mohammad; Shariati, Ahmad; Aghamohammadi, Amir [Department of Physics, Alzahra University, Tehran 19938-93973 (Iran, Islamic Republic of)

    2011-04-15

    A complete classification is given for one-dimensional chains with nearest-neighbor interactions having two states in each site, for which a matrix product ground state exists. The Hamiltonians and their corresponding matrix product ground states are explicitly obtained.

  9. Ground state potential energy curve and dissociation energy of MgH.

    PubMed

    Shayesteh, Alireza; Henderson, Robert D E; Le Roy, Robert J; Bernath, Peter F

    2007-12-13

    New high-resolution visible emission spectra of the MgH molecule have been recorded with high signal-to-noise ratios using a Fourier transform spectrometer. Many bands of the A 2Pi-->X 2Sigma+ and B' 2Sigma+-->X 2Sigma+ electronic transitions of 24MgH were analyzed; the new data span the v' = 0-3 levels of the A 2Pi and B'2Sigma+ excited states and the v''=0-11 levels of the X 2Sigma+ ground electronic state. The vibration-rotation energy levels of the perturbed A 2Pi and B' 2Sigma+ states were fitted as individual term values, while those of the X 2Sigma+ ground state were fitted using the direct-potential-fit approach. A new analytic potential energy function that imposes the theoretically correct attractive potential at long-range, and a radial Hamiltonian that includes the spin-rotation interaction were employed, and a significantly improved value for the ground state dissociation energy of MgH was obtained. The v''=11 level of the X 2Sigma+ ground electronic state was found to be the highest bound vibrational level of 24MgH, lying only about 13 cm(-1) below the dissociation asymptote. The equilibrium dissociation energy for the X 2Sigma+ ground state of 24MgH has been determined to be De=11104.7+/-0.5 cm(-1) (1.37681+/-0.00006 eV), whereas the zero-point energy (v''=0) is 739.11+/-0.01 cm(-1). The zero-point dissociation energy is therefore D0=10365.6+/-0.5 cm(-1) (1.28517+/-0.00006 eV). The uncertainty in the new experimental dissociation energy of MgH is more than 2 orders of magnitude smaller than that for the best value available in the literature. MgH is now the only hydride molecule other than H2 itself for which all bound vibrational levels of the ground electronic state are observed experimentally and for which the dissociation energy is determined with subwavenumber accuracy. PMID:18020428

  10. The dispersed fluorescence spectrum of NaAr - Ground and excited state potential curves

    NASA Technical Reports Server (NTRS)

    Tellinghuisen, J.; Ragone, A.; Kim, M. S.; Auerbach, D. J.; Smalley, R. E.; Wharton, L.; Levy, D. H.

    1979-01-01

    Potential curves for the ground state and the first excited state of NaAr were determined. The van der Waals molecule NaAr was prepared by supersonic free jet expansion of a mixture of sodium, argon, and helium. The electronic transition from the ground state to the first excited state A2pi was excited by a tunable dye laser and the resulting fluorescence was studied. The dispersed fluorescence spectra show discrete and diffuse features, corresponding to transitions from excited vibrational levels of the A state to bound and unbound levels of the x state. The characteristic reflection structure in the bound-free spectra permits an unambiguous assignment of the vibrational numbering in the A state, and this assignment together with previously measured spectroscopic constants are used to calculate the potential curve of the A state. The discrete structure in the fluorescence spectra is used to determine the potential curve of the x state in the well region, and the repulsive part of the X curve is then deduced through trial-and-error simulation of the bound-free spectra.

  11. Two-color multiphoton excitation of autoionizing states of atomic iodine

    NASA Astrophysics Data System (ADS)

    Pratt, S. T.; Dehmer, P. M.; Dehmer, J. L.

    1986-04-01

    Two-color multiphoton excitation spectra of autoionizing ( 1D 2) ns and nd Rydberg series in atomic iodine are presented in the region of the I +1D 2 ionization threshold. The first laser is used to produce atomic iodine by photodissociation of methyl iodide and to pump the iodine atoms to low-lying ( 1D 2) 6p states via a two-photon transition. The second laser excites single photon transitions from these states to autoionizing Rydberg series, resolved to n ? 35. Extension of this technique for other open shell atoms is discussed.

  12. Vibrationally resolved ionization cross sections for the ground state and electronically excited states of the hydrogen molecule

    NASA Astrophysics Data System (ADS)

    Tyutnev, Andrey; Saenko, Vladimir; Pozhidaev, Evgenii

    2011-11-01

    Ionization cross sections for the hydrogen molecule have been calculated by applying the classical Gryzinski theory combined with the Franck-Condon theory. It is shown that—if the reaction channels, Franck-Condon factors and Franck-Condon densities are taken into account properly—the calculated cross sections for ionization of the molecular ground state X1?g+(v'=0) are in almost perfect agreement with the latest and most reliable experimental results. A comprehensive database is established which includes vibrationally resolved cross sections for non-dissociative and dissociative ionization of the molecular ground state as well as for the first five non-repulsive electronically excited states in the molecule.

  13. Ground state of a tightly bound composite dimer immersed in a Fermi Sea

    E-print Network

    Christophe Mora; Frédéric Chevy

    2009-08-15

    In this paper we present a theoretical investigation for the ground state of an impurity immersed in a Fermi sea. The molecular regime is considered where a two-body bound state between the impurity and one of the fermions is formed. Both interaction and exchange of the bound fermion take place between the dimer and the Fermi sea. We develop a formalism based on a two channel model allowing us to expand systematically the ground state energy of this immersed dimer with the scattering length $a$. Working up to order $a^3$, associated to the creation of two particle-hole pairs, reveals the first signature of the composite nature of the bosonic dimer. Finally, a complementary variational study provides an accurate estimate of the dimer energy even at large scattering length.

  14. Short-Range Correlations in the Magnetic Ground State of Na4Ir3O8

    NASA Astrophysics Data System (ADS)

    Dally, Rebecca; Hogan, Tom; Amato, Alex; Luetkens, Hubertus; Baines, Chris; Rodriguez-Rivera, Jose; Graf, Michael J.; Wilson, Stephen D.

    2014-12-01

    The magnetic ground state of the Jeff=1 /2 hyperkagome lattice in Na4Ir3O8 is explored via combined bulk magnetization, muon spin relaxation, and neutron scattering measurements. A short-range, frozen state comprised of quasistatic moments develops below a characteristic temperature of TF=6 K , revealing an inhomogeneous distribution of spins occupying the entirety of the sample volume. Quasistatic, short-range spin correlations persist until at least 20 mK and differ substantially from the nominally dynamic response of a quantum spin liquid. Our data demonstrate that an inhomogeneous magnetic ground state arises in Na4Ir3O8 driven either by disorder inherent to the creation of the hyperkagome lattice itself or stabilized via quantum fluctuations.

  15. Ab initio study of the ground state surface of Cu3

    NASA Technical Reports Server (NTRS)

    Langhoff, Stephen R.; Bauschlicher, Charles W., Jr.; Walch, Stephen P.; Laskowski, Bernard C.

    1986-01-01

    The ground state surface of the metallic trimer Cu3 is investigated theoretically. Relativistic and correlation effects are taken into account in ab initio computations, which are calibrated against analogous computations for the 1Sigma(g)+ state of Cu2; the results are presented in tables and analyzed. The Cu3 ground state is found to have a 2B2 C(2v) structure with angle greater than 60 deg, lying 59/cm below a 2A1 C(2v) geometry and 280/cm below the D(3h) equilateral geometry. These findings are shown to be in good agreement with the experimental measurements of Rohlfing and Valentini (1986) and their analysis (in terms of a Jahn-Teller distortion of 2E-prime equilateral-triangle geometry) by Truhlar et al. (1986).

  16. Dissipative ground-state preparation of a spin chain by a structured environment

    NASA Astrophysics Data System (ADS)

    Cormick, Cecilia; Bermudez, Alejandro; Huelga, Susana F.; Plenio, Martin B.

    2013-07-01

    We propose a dissipative method to prepare the ground state of the isotropic XY spin Hamiltonian in a transverse field. Our model consists of a spin chain with nearest-neighbor interactions and an additional collective coupling of the spins to a damped harmonic oscillator. The latter provides an effective environment with a Lorentzian spectral density and can be used to drive the chain asymptotically toward its multipartite-entangled ground state at a rate that depends on the degree of non-Markovianity of the evolution. We also present a detailed proposal for the experimental implementation with a chain of trapped ions. The protocol does not require individual addressing, concatenated pulses, or multi-particle jump operators, and is capable of generating the desired target state in small ion chains with very high fidelities.

  17. Short-range correlations in the magnetic ground state of Na?Ir?O?.

    PubMed

    Dally, Rebecca; Hogan, Tom; Amato, Alex; Luetkens, Hubertus; Baines, Chris; Rodriguez-Rivera, Jose; Graf, Michael J; Wilson, Stephen D

    2014-12-12

    The magnetic ground state of the J(eff)=1/2 hyperkagome lattice in Na?Ir?O? is explored via combined bulk magnetization, muon spin relaxation, and neutron scattering measurements. A short-range, frozen state comprised of quasistatic moments develops below a characteristic temperature of T(F)=6??K, revealing an inhomogeneous distribution of spins occupying the entirety of the sample volume. Quasistatic, short-range spin correlations persist until at least 20 mK and differ substantially from the nominally dynamic response of a quantum spin liquid. Our data demonstrate that an inhomogeneous magnetic ground state arises in Na?Ir?O? driven either by disorder inherent to the creation of the hyperkagome lattice itself or stabilized via quantum fluctuations. PMID:25541804

  18. Ground State of a System of N Hard Core Quantum Particles in 1D Box

    E-print Network

    Yatendra S Jain

    2006-06-15

    The ground state of a system of $N$ impenetrable hard core quantum particles in a 1-D box is analyzed by using a new scheme applied recently to study a similar system of two such particles {\\it [Centl. Eur. J. Phys., 2(4), 709 (2004)]}. Accordingly, each particle of the system behaves like an independent entity represented by a {\\it macro-orbital}, -a kind of pair waveform identical to that of a pair of particles moving with ($q$, $-q$) momenta at their {\\it center of mass} which may have any momentum $K$ in the laboratory frame. It concludes: (i) $ = 0$, (ii) $ \\ge \\lambda/2$ and (iii) $q \\ge q_o (= \\pi/d)$ (with $d = L/N$ being the average nearest neighbour distance), {\\it etc.} While all bosons in their ground state have $q = q_o$ and $K = 0$, fermions have $q= q_o$ with different $K$ ranging between 0 and $K = K_F$ (the Fermi wave vector). Independent of their bosonic or fermionic nature, all particles in the ground state define a close packed arrangement of their equal size wave packets representing an ordered state in phase ($\\phi-$)space with $\\Delta\\phi = 2n\\pi$ (with $n$ = 1,2,3, ...), $ = \\lambda/2 = d$, and $q = q_o$. As such our approach uses greatly simplified mathematical formulation and renders a visibly clear picture of the low energy states of the systems and its results supplement earlier studies in providing their complete understanding.

  19. Experimental and theoretical dipole moments of purines in their ground and lowest excited singlet states

    NASA Astrophysics Data System (ADS)

    Aaron, Jean-Jacques; Diabou Gaye, Mame; Pįrkįnyi, Cyril; Cho, Nam Sook; Von Szentpįly, Lįszló

    1987-01-01

    The ground-state dipole moments of seven biologically important purines (purine, 6-chloropurine, 6-mercaptopurine, hypoxanthine, theobromine, theophylline and caffeine) were determined at 25°C in acetic acid (all the above compounds with the exception of purine) and in ethyl acetate (purine, theophylline and caffeine). Because of its low solubility, it was not possible to measure the dipole moment of uric acid. The first excited singlet-state dipole moments were obtained on the basis of the Bakhshiev and Chamma—Viallet equations using the variation of the Stokes shift with the solvent dielectric constant-refractive index term. The theoretical dipole moments for all the purines listed above and including uric acid were calculated by combining the use of the PPP (?-LCI-SCF-MO) method for the ?-contribution to the overall dipole moment with the ?-contribution obtained as a vector sum of the ?bond moments and group moments. The experimental and theoretical values were compared with the data available in the literature for some of the purines under study. For several purines, the calculations were carried out for different tautomeric forms. Excited singlet-state dipole moments are smaller than the ground-state values by 0.8 to 2.2 Debye units for all purines under study with the exception of 6-chloropurine. The effects of the structure upon the ground- and excited-state dipole moments of the purines are discussed.

  20. Atomic states, potential energies, volumes, stability and brittleness of ordered FCC TiAl 2 type alloys

    Microsoft Academic Search

    Y. Q. Xie; H. J. Tao; H. J. Peng; X. B. Li; X. B. Liu; K. Peng

    2005-01-01

    In this paper, the framework of the systematic science of alloys (SSA) is presented. It has been proved that according to the basic information of sequences of characteristic crystals in the FCC Ti–Al system, not only the states, potential energies and volumes of atoms at various lattice points, and average atomic states, average atomic potential energies, average atomic volumes and