- Expansion of matter waves in static and driven periodic potentials
Author(s): C. E. Creffield, F. Sols, D. Ciampini, O. Morsch, and E. Arimondo We study the nonequilibrium dynamics of cold atoms held in an optical lattice subjected to a periodic driving potential. The expansion of an initially confined atom cloud occurs in two phases: an initial quadratic expansion followed by a ballistic behavior at long times. Accounting for this gives a ... [Phys. Rev. A 82, 035601] Published Thu Sep 02, 2010 - Lowest quartet states of heteronuclear alkali-metal trimers
Author(s): Pavel Soldán We analyze three-body nonadditive interactions and characterize critical points on potential energy surfaces of the lowest A_{2} B (A,B=Li,Na,K,Rb,Cs) quartet states using high-level ab initio calculations. Our calculations indicate that near equilibrium geometries, large nonadditive effects are sta... [Phys. Rev. A 82, 034701] Published Thu Sep 02, 2010 - Entangling power and local invariants of two-qubit gates
Author(s): S. Balakrishnan and R. Sankaranarayanan We show a simple relation connecting entangling power and local invariants of two-qubit gates. From the relation, a general condition under which gates have the same entangling power is derived. The relation also helps in finding the lower bound of entangling power for perfect entanglers, from which... [Phys. Rev. A 82, 034301] Published Thu Sep 02, 2010 - Schrödinger uncertainty relation with Wigner-Yanase skew information
Author(s): Shigeru Furuichi We shall give an alternative Schrödinger-type uncertainty relation for a quantity representing a quantum uncertainty, introduced by Luo [Phys. Rev. A 72, 042110 (2005)]. Our result improves the Heisenberg-type uncertainty relation shown in Luo's paper for a mixed state. [Phys. Rev. A 82, 034101] Published Thu Sep 02, 2010 - Controlling molecular scattering by laser-induced field-free alignment
Author(s): E. Gershnabel and I. Sh. Averbukh We consider deflection of polarizable molecules by inhomogeneous optical fields and analyze the role of molecular orientation and rotation in the scattering process. It is shown that molecular rotation induces spectacular rainbowlike features in the distribution of the scattering angle. Moreover, by... [Phys. Rev. A 82, 033401] Published Thu Sep 02, 2010 - Reply to “Comment on ‘Quenches in quantum many-body systems: One-dimensional Bose-Hubbard model reexamined’ ”
Author(s): Guillaume Roux In his Comment [see preceding Comment, Phys. Rev. A 82, 037601 (2010)] on the paper by Roux [Phys. Rev. A 79, 021608(R) (2009)], Rigol argued that the energy distribution after a quench is not related to standard statistical ensembles and cannot explain thermalization. The latter is proposed to stem... [Phys. Rev. A 82, 037602] Published Wed Sep 01, 2010 - Comment on “Quenches in quantum many-body systems: One-dimensional Bose-Hubbard model reexamined”
Author(s): Marcos Rigol In a recent paper, Roux [Phys. Rev. A 79, 021608(R) (2009)] argued that thermalization in a Bose-Hubbard system, after a quantum quench, follows from the approximate Boltzmann distribution of the overlap between the initial state and the eigenstates of the final Hamiltonian. We show here that the di... [Phys. Rev. A 82, 037601] Published Wed Sep 01, 2010 - Self-localization of a small number of Bose particles in a superfluid Fermi system
Author(s): Katarzyna Targońska and Krzysztof Sacha We consider self-localization of a small number of Bose particles immersed in a large homogeneous superfluid mixture of fermions in three- and one-dimensional space. Bosons distort the density of surrounding fermions and create a potential well where they can form a bound state analogous to a small ... [Phys. Rev. A 82, 033601] Published Wed Sep 01, 2010 - Qubit-induced phonon blockade as a signature of quantum behavior in nanomechanical resonators
Author(s): Yu-xi Liu, Adam Miranowicz, Y. B. Gao, Jiří Bajer, C. P. Sun, and Franco Nori The observation of quantized nanomechanical oscillations by detecting femtometer-scale displacements is a significant challenge for experimentalists. We propose that a phonon blockade can serve as a signature of quantum behavior in nanomechanical resonators. In analogy to the photon blockade and Cou... [Phys. Rev. A 82, 032101] Published Wed Sep 01, 2010 - Intense few-cycle hard-UV-pulse-induced internal conversion processes
Author(s): Dániel Kis, Péter Kálmán, and Tamás Keszthelyi The internal conversion coefficient for bound-free electron transition of originally energetically forbidden internal conversion processes induced by intense, few-cycle UV laser pulse of Gaussian shape in the case of isomers ^{107} Ag^{m} (K shell, E3, 25.47 keV), ^{90} Nb^{m} (L_{2} shell, M2+E3, ... [Phys. Rev. A 82, 025401] Published Tue Aug 31, 2010 - Phase-retrieval ghost imaging of complex-valued objects
Author(s): Wenlin Gong and Shensheng Han An imaging approach, based on ghost imaging, is reported to recover a pure-phase object or a complex-valued object. Our analytical results, which are backed up by numerical simulations, demonstrate that both the complex-valued object and its amplitude-dependent part can be separately and nonlocally ... [Phys. Rev. A 82, 023828] Published Tue Aug 31, 2010 - Superradiance, subradiance, and suppressed superradiance of dipoles near a metal interface
Author(s): J. J. Choquette, Karl-Peter Marzlin, and B. C. Sanders We theoretically characterize the collective radiative behavior of N classical emitters near an interface between different dielectrics that supports the transfer of surface plasmon modes into the far-field of electromagnetic radiation. The phenomena of superradiance and surface plasmons can be comb... [Phys. Rev. A 82, 023827] Published Tue Aug 31, 2010 - Two-body recombination in a quantum-mechanical lattice gas: Entropy generation and probing of short-range magnetic correlations
Author(s): Stefan K. Baur and Erich J. Mueller We study entropy generation in a one-dimensional (1D) model of bosons in an optical lattice experiencing two-particle losses. Such heating is a major impediment to observing exotic low temperature states, and “simulating” condensed matter systems. Developing intuition through numerical simulatio... [Phys. Rev. A 82, 023626] Published Tue Aug 31, 2010 - Numerical simulation of a multilevel atom interferometer
Author(s): B. Barrett, I. Yavin, S. Beattie, and A. Kumarakrishnan We present a comprehensive numerical simulation of an echo-type atom interferometer. The simulation confirms an interesting theoretical description of this interferometer that includes effects due to spontaneous emission and magnetic sublevels. Both the simulation and the theoretical model agree wit... [Phys. Rev. A 82, 023625] Published Tue Aug 31, 2010 - Splitting and oscillation of Majorana zero modes in the p-wave BCS-BEC evolution with plural vortices
Author(s): T. Mizushima and K. Machida We investigate how the vortex-vortex separation changes Majorana zero modes in the vicinity of the BCS-BEC (Bose-Einstein condensation) topological phase transition of p-wave resonant Fermi gases. By analytically and numerically solving the Bogoliubov–de Gennes equation for spinless p-wave superfl... [Phys. Rev. A 82, 023624] Published Tue Aug 31, 2010 - Potential barrier effects in high-order harmonic generation by transition-metal ions
Author(s): M. V. Frolov, N. L. Manakov, and Anthony F. Starace The experimental finding of significant enhancement or suppression of particular harmonics generated by the ionic component of laser-produced plasmas of transition-metal atoms is explained theoretically in terms of the standard three-step scenario for strong-field harmonic generation, taking into ac... [Phys. Rev. A 82, 023424] Published Tue Aug 31, 2010 - Relativistic many-body calculation of low-energy dielectronic resonances in Be-like carbon
Author(s): A. Derevianko, V. A. Dzuba, and M. G. Kozlov We apply the relativistic configuration-interaction method coupled with the many-body perturbation theory (CI+MBPT) to describe low-energy dielectronic recombination. We combine the CI+MBPT approach with the complex rotation method (CRM) and compute the dielectronic recombination spectrum for Li-lik... [Phys. Rev. A 82, 022720] Published Tue Aug 31, 2010 - Spin-state transfer in laterally coupled quantum-dot chains with disorders
Author(s): Song Yang, Abolfazl Bayat, and Sougato Bose Quantum dot arrays are a promising medium for transferring quantum information between two distant points without resorting to mobile qubits. Here we study the two most common disorders, namely hyperfine interaction and exchange coupling fluctuations, in quantum dot arrays and their effects on quant... [Phys. Rev. A 82, 022336] Published Tue Aug 31, 2010 - Protocol for high-fidelity readout in the photon-blockade regime of circuit QED
Author(s): E. Ginossar, Lev S. Bishop, D. I. Schuster, and S. M. Girvin The driven-damped Jaynes-Cummings model in the regime of strong coupling is found to exhibit a coexistence between the quantum photon blockaded state and a quasicoherent bright state. We characterize the slow time scales and the basin of attraction of these metastable states using full quantum simul... [Phys. Rev. A 82, 022335] Published Tue Aug 31, 2010 - Isospectral potentials from modified factorization
Author(s): Micheal S. Berger and Nail S. Ussembayev Factorization of quantum-mechanical potentials has a long history extending back to the earliest days of the subject. In the present article, the nonuniqueness of the factorization is exploited to derive new isospectral nonsingular potentials. Many one-parameter families of potentials can be generat... [Phys. Rev. A 82, 022121] Published Tue Aug 31, 2010 - Quantum Zeno suppression of three-body losses in Bose-Einstein condensates
Author(s): R. Schützhold and G. Gnanapragasam We study the possibility of suppressing three-body losses in atomic Bose-Einstein condensates via the quantum Zeno effect, which means the delay of quantum evolution by frequent measurements. It turns out that this requires very fast measurements with the rate being determined by the spatial structu... [Phys. Rev. A 82, 022120] Published Tue Aug 31, 2010 - Calibration of single-photon detectors using quantum statistics
Author(s): D. Mogilevtsev I show that calibration of the single-photon detector can be performed without knowledge of the signal parameters. Only partial information about the state statistics is sufficient for that. If one knows that the state is the squeezed one or the squeezed one mixed with the incoherent radiation, one ...
 [Phys. Rev. A 82, 021807] Published Tue Aug 31, 2010 - Cooling and squeezing via quadratic optomechanical coupling
Author(s): A. Nunnenkamp, K. Børkje, J. G. E. Harris, and S. M. Girvin We explore the physics of optomechanical systems in which an optical cavity mode is coupled parametrically to the square of the position of a mechanical oscillator. We derive an effective master equation describing two-phonon cooling of the mechanical oscillator. We show that for high temperatures a...
 [Phys. Rev. A 82, 021806] Published Tue Aug 31, 2010 - Simple quantum model of ultracold polar molecule collisions
Author(s): Zbigniew Idziaszek, Goulven Quéméner, John L. Bohn, and Paul S. Julienne We present a unified formalism for describing chemical reaction rates of trapped, ultracold molecules. This formalism reduces the scattering to its essential features, namely, a propagation of the reactant molecules through a gauntlet of long-range forces before they ultimately encounter one another...
 [Phys. Rev. A 82, 020703] Published Tue Aug 31, 2010 - Bound on quantum computation time: Quantum error correction in a critical environment
Author(s): E. Novais, Eduardo R. Mucciolo, and Harold U. Baranger We obtain an upper bound on the time available for quantum computation for a given quantum computer and decohering environment with quantum error correction implemented. First, we derive an explicit quantum evolution operator for the logical qubits and show that it has the same form as that for the ...
 [Phys. Rev. A 82, 020303] Published Tue Aug 31, 2010 - Quantum superadditivity in linear optics networks: Sending bits via multiple-access Gaussian channels
Author(s): Ł. Czekaj, J. K. Korbicz, R. W. Chhajlany, and P. Horodecki Superadditivity effects of communication capacities are known in the case of discrete variable quantum channels. We describe the continuous variable analog of one of these effects in the framework of Gaussian multiple access channels (MACs). Classically, superadditivity-type effects are strongly res...
 [Phys. Rev. A 82, 020302] Published Tue Aug 31, 2010 - Publisher’s Note: Controlling metamaterial resonances with light [Phys. Rev. A 82, 023810 (2010)]
Author(s): Sangeeta Chakrabarti, S. Anantha Ramakrishna, and Harshawardhan Wanare [Phys. Rev. A 82, 029903] Published Mon Aug 30, 2010 - Variational study of a two-level system coupled to a harmonic oscillator in an ultrastrong-coupling regime
Author(s): Myung-Joong Hwang and Mahn-Soo Choi The nonclassical behavior of a two-level system coupled to a harmonic oscillator is investigated in the ultrastrong coupling regime. We revisit the variational solution of the ground state and find that the existing solutions do not account accurately for nonclassical effects such as squeezing. We s... [Phys. Rev. A 82, 025802] Published Mon Aug 30, 2010 - Directed coherent transport due to the Bloch oscillation in two dimensions
Author(s): J. M. Zhang and W. M. Liu We point out that in higher dimensions, in contrast to the one-dimensional case considered usually, Bloch oscillation driven by a static force can induce transport of the wave packet. The wave packet oscillates constantly, but on a larger time scale it drifts at a constantly velocity permanently. As... [Phys. Rev. A 82, 025602] Published Mon Aug 30, 2010 - Transition probability measurements for some strong and weak lines of N i
Author(s): J. M. Bridges and W. L. Wiese We operated a high-current wall-stabilized arc to generate a low-temperature, steady-state plasma in nitrogen, with admixtures of argon, helium, and oxygen. We measured the relative atomic transition probabilities for several strong and weak 3s-3p and 3p-3d lines of neutral nitrogen and placed them ... [Phys. Rev. A 82, 024502] Published Mon Aug 30, 2010 |