Systems of four nonbinary particles, with each particle having d≥3 internal states, exhibit maximally entangled states that are inaccessible to four qubits. This breaks the pattern of two- and three-particle systems, in which the existing graph states are equally accessible to binary and nonbinary s...

[Phys. Rev. A 91, 012332] Published Fri Jan 23, 2015

]]>We propose a scheme to realize quantum networking of superconducting qubits based on the optomechanical interface. The superconducting qubits interact with the microwave photons, which then couple to the optical photons through the optomechanical interface. The interface generates a quantum link bet...

[Phys. Rev. A 91, 012333] Published Fri Jan 23, 2015

]]>In this work, we introduce different types of quantum simulations according to different operator topologies on a Hilbert space, namely, uniform, strong, and weak quantum simulations. We show that they have the same computational power that the efficiently solvable problems are in bounded-error quan...

[Phys. Rev. A 91, 012334] Published Fri Jan 23, 2015

]]>Double K-shell ionization of two-electron ions in Compton scattering of high-energy photons is investigated. The problem is treated analytically within the framework of nonrelativistic perturbation theory with respect to the interelectron interaction, using the Coulomb Green's and wave functions. Th...

[Phys. Rev. A 91, 013410] Published Fri Jan 23, 2015

]]>We develop a multiphoton adiabatic passage to realize a highly efficient Rydberg excitation in a four-level ladder-type atomic system. The adiabatic passage is based on the existence of a novel quasidark state in the cascade excitation system where the frequencies of the lasers are appropriately chi...

[Phys. Rev. A 91, 013411] Published Fri Jan 23, 2015

]]>We study the ground-state density profile of a spin-orbit-coupled f=2 spinor condensate in a quasi-one-dimensional trap. The Hamiltonian of the system is invariant under time reversal but not under parity. We identify different parity- and time-reversal symmetry-breaking states. The time-reversal sy...

[Phys. Rev. A 91, 013624] Published Fri Jan 23, 2015

]]>We study the relaxation and damping dynamics of an ultracold, but not quantum degenerate, gas consisting of dipolar particles. These simulations are performed using a direct simulation Monte Carlo method and employing the highly anisotropic differential cross section of dipoles in the Wigner thresho...

[Phys. Rev. A 91, 013625] Published Fri Jan 23, 2015

]]>An ultralow-temperature binary mixture of Bose-Einstein condensates adsorbed at an optical wall can undergo a wetting phase transition in which one of the species excludes the other from contact with the wall. Interestingly, while hard-wall boundary conditions entail the wetting transition to be of ...

[Phys. Rev. A 91, 013626] Published Fri Jan 23, 2015

]]>Quantum squeezing in mechanical systems is not only a key signature of macroscopic quantum effects, but can also be utilized to advance the metrology of weak forces. Here we show that strong mechanical squeezing in the steady state can be generated in an optomechanical system with mechanical nonline...

[Phys. Rev. A 91, 013834] Published Fri Jan 23, 2015

]]>A fermionic analog of a parametric amplifier is used to describe the joint quantum state of the two interacting fermionic modes. Based on a two-mode generalization of the time-dependent density operator, time evolution of the fermionic density operator is determined in terms of its two-mode Wigner a...

[Phys. Rev. A 91, 013835] Published Fri Jan 23, 2015

]]>Kerr-lens mode-locked Ti:sapphire lasers are known to display three coexistent modes of operation: continuous wave, transform limited pulses (P1), and positive chirped pulses (P2). Extreme events (sometimes also called optical rogue waves), in the form of pulses of high energy appearing much often t...

[Phys. Rev. A 91, 013836] Published Fri Jan 23, 2015

]]>There has been a surge of research activity recently on the role of joint measurability of unsharp observables in nonlocal features, viz., violation of Bell inequality and EPR steering. Here, we investigate the entropic uncertainty relation for a pair of noncommuting observables (of Alice's system) ...

[Phys. Rev. A 91, 012115] Published Thu Jan 22, 2015

]]>Universal quantum computation requires the implementation of arbitrary control operations on the quantum register. In most cases, this is achieved by external control fields acting selectively on each qubit to drive single-qubit operations. In combination with a drift Hamiltonian containing interact...

[Phys. Rev. A 91, 012330] Published Thu Jan 22, 2015

]]>Distinguishing hot from cold is the most primitive form of thermometry. Here we consider how well this task can be performed using a single qubit to distinguish between two different temperatures of a bosonic bath. In this simple setting, we find that letting the qubit equilibrate with the bath is n...

[Phys. Rev. A 91, 012331] Published Thu Jan 22, 2015

]]>We study tunneling ionization in a one-dimensional three-body model of a molecule, treating both electronic and nuclear degrees of freedom exactly. In a recent paper [Phys. Rev. Lett. 111, 153003 (2013)PRLTAO10.1103/PhysRevLett.111.153003] it was demonstrated using a finite-range potential that the ...

[Phys. Rev. A 91, 013408] Published Thu Jan 22, 2015

]]>We present a formalism to calculate phase-space acceptance in a Zeeman decelerator. Using parameters closely mimicking previous Zeeman deceleration experiments, this approach reveals a velocity dependence of the phase stability which we ascribe to the finite rise and fall times of the current pulses...

[Phys. Rev. A 91, 013409] Published Thu Jan 22, 2015

]]>We present an efficient tool capable of measuring the spectral correlations between photons emerging from a Hong-Ou-Mandel interferometer. We show that for our spectrally factorizable spontaneous down-conversion source, the Hong-Ou-Mandel interference visibility decreases as the photons' frequency s...

[Phys. Rev. A 91, 013830] Published Thu Jan 22, 2015

]]>We show that both the power and repetition rate of a frequency comb generated in a nonlinear ring resonator, pumped with continuous-wave (cw) coherent light, are modulated. The modulation is brought about by the interaction of the cw background with optical pulses excited in the resonator, and occur...

[Phys. Rev. A 91, 013831] Published Thu Jan 22, 2015

]]>The effects of small relativistic corrections to the off-resonant polarizability, hyperpolarizability, and second hyperpolarizability are investigated. Corrections to linear- and nonlinear-optical coefficients are demonstrated in the three-level ansatz, which includes corrections to the Kuzyk limits...

[Phys. Rev. A 91, 013832] Published Thu Jan 22, 2015

]]>Optomechanics is concerned with the coupling between optical cavities and mechanical resonators. Most early works are concentrated in the physics of optomechanics in the small-displacement regime and consider one single optical cavity mode participating in the optomechanical coupling. In this articl...

[Phys. Rev. A 91, 013833] Published Thu Jan 22, 2015

]]>The interaction of metastable 2s hydrogen atoms with a perfectly conducting wall is studied, finding the long-range asymptotics of the retarded Casimir–Polder potentials and s-p-mixing amplitudes, but no evidence for the so-called Sokolov effect.

[Phys. Rev. A 91, 010502] Published Wed Jan 21, 2015

]]>We numerically investigate entropic Bell inequalities for a pair of entangled qutrits using information-theoretic distances. We show that for this class of inequalities the Tsallis entropy is more suitable than the Shannon entropy, as it reveals nonclassicality for a larger set of quantum states. Fi...

[Phys. Rev. A 91, 012114] Published Wed Jan 21, 2015

]]>We study, in the paradigm of open quantum systems, the entanglement dynamics of two uniformly accelerated atoms with the same acceleration perpendicular to the separation. The two-atom system is treated as an open system coupled with a bath of fluctuating massless scalar fields in the Minkowski vacu...

[Phys. Rev. A 91, 012327] Published Wed Jan 21, 2015

]]>Exploiting multidimensional quantum walks as feasible platforms for quantum computation and quantum simulation attracts constantly growing attention from a broad experimental physics community. Here, we propose a two-dimensional quantum walk scheme with a single-qubit coin that presents, in the cons...

[Phys. Rev. A 91, 012328] Published Wed Jan 21, 2015

]]>In this paper, we mainly study the local indistinguishability of mutually orthogonal bipartite maximally entangled states. We construct sets of fewer than d orthogonal maximally entangled states which are not distinguished by one-way local operations and classical communication (LOCC) in the Hilbert...

[Phys. Rev. A 91, 012329] Published Wed Jan 21, 2015

]]> We study the 2e^{−}2e^{+} equal-mass charge-neutral four-body system in the adiabatic hyperspherical framework. The lowest few adiabatic potentials are calculated for zero orbital angular momentum, positive parity, and charge conjugation symmetries. Propagating the R matrix, the low-energy s-wave scatteri...

[Phys. Rev. A 91, 012512] Published Wed Jan 21, 2015

]]> The local theory of relaxation of ^{3}He by Brownian motion in an inhomogeneous magnetic field, originally proposed by Gamblin and Carver [Phys. Rev. 138, A946 (1965)PHRVAO10.1103/PhysRev.138.A946] and by Schearer and Walters [Phys. Rev. 139, A1398 (1965)PHRVAO10.1103/PhysRev.139.A1398], is reconsidere...

[Phys. Rev. A 91, 013407] Published Wed Jan 21, 2015

]]>A one-dimensional model of bosons with repulsive short-range interactions, solved analytically by Lieb and Liniger many years ago, predicts the existence of two branches of elementary excitations. One of them represents Bogoliubov phonons; the other, as suggested by some authors, might be related to...

[Phys. Rev. A 91, 013621] Published Wed Jan 21, 2015

]]>Dynamics of solitons in a one-dimensional trap with motionless and moving walls is studied by the example of bright solitons of an atomic Bose-Einstein condensate. Newton-type equations of the soliton's center motion are proposed and analyzed, and regimes of periodic, almost-periodic, and determinis...

[Phys. Rev. A 91, 013622] Published Wed Jan 21, 2015

]]>We study quantum coherence properties of a dilute gas at temperatures above, but not much above, the transition temperature of Bose-Einstein condensation. In such a gas, a small proportion of the atoms may possess coherence lengths longer than the mean neighboring-atomic distance, implying the exist...

[Phys. Rev. A 91, 013623] Published Wed Jan 21, 2015

]]> We report on the production of a degenerate Fermi gas of ^{53}Cr atoms, polarized in the state F=9/2, m_{F}=−9/2, by sympathetic cooling with bosonic S=3, m_{S}=−3 ^{52}Cr atoms. We load in an optical dipole trap 3×10^{4}^{53}Cr atoms with 10^{6} ^{52}Cr atoms. Despite the initial small number of fermionic atoms, we reach ...

[Phys. Rev. A 91, 011603] Published Tue Jan 20, 2015

]]>We show that the origin of the nonequivalence of Hamiltonians in different representations is a change of the form of the time-derivative operator at a time-dependent unitary transformation. This nonequivalence does not lead to an ambiguity of the energy expectation values of a particle in nonstatio...

[Phys. Rev. A 91, 012111] Published Tue Jan 20, 2015

]]>The multipartite entangled state has drawn broad attention for both foundations of quantum mechanics and applications in quantum information processing. Here, we study the spatially separated N-partite continuous-variable Greenberger-Horne-Zeilinger–like states, which can be produced by a linear opt...

[Phys. Rev. A 91, 012112] Published Tue Jan 20, 2015

]]>Bipartite quantum entangled systems can exhibit measurement correlations that violate Bell inequalities, revealing the profoundly counter-intuitive nature of the physical universe. These correlations reflect the impossibility of constructing a joint probability distribution for all values of all the...

[Phys. Rev. A 91, 012113] Published Tue Jan 20, 2015

]]>The “Lewis-Riesenfeld phases” which play a crucial role in constructing shortcuts to adiabaticity may be a resource for the implementation of quantum phase gates. By combining “Lewis-Riesenfeld invariants” with “quantum Zeno dynamics,” we propose an effective scheme of rapidly implementing π phase g...

[Phys. Rev. A 91, 012325] Published Tue Jan 20, 2015

]]>Based on the mutually unbiased bases, the mutually unbiased measurements and the general symmetric informationally complete positive-operator-valued measures, we propose three separability criteria for d-dimensional bipartite quantum systems, which are more powerful than the corresponding ones intro...

[Phys. Rev. A 91, 012326] Published Tue Jan 20, 2015

]]> The radiative lifetime of the 4s^{2}4p^{4} ^{1}S_{0} metastable state in Kr^{2+} ions has been experimentally determined using an electrostatic ion trap of the ion-beam storage type. The radiative lifetime was obtained by measuring the number of 350-nm photons emitted during the ^{1}S_{0}→^{3}P_{1} magnetic dipole transition ...

[Phys. Rev. A 91, 012508] Published Tue Jan 20, 2015

]]>The multiconfiguration time-dependent Hartree-Fock (MCTDHF) method has shown promise in calculating electronic dynamics in molecules driven by strong and high-energy lasers. It must incorporate restricted configuration spaces (meaning that a particular combination of Slater determinants is used, ins...

[Phys. Rev. A 91, 012509] Published Tue Jan 20, 2015

]]>In this paper we present results of ab initio calculations for the beryllium dimer with a basis set of Slater-type orbitals (STOs). Nonrelativistic interaction energy of the system is determined using the frozen-core full configuration interaction calculations combined with high-level coupled-cluste...

[Phys. Rev. A 91, 012510] Published Tue Jan 20, 2015

]]>Calculation of the differential cross section for dielectronic recombination with one-electron uranium within the framework of quantum electrodynamics is presented. The dielectronic recombination of nonpolarized and polarized incident electrons is considered. The polarization of the emitted photon i...

[Phys. Rev. A 91, 012511] Published Tue Jan 20, 2015

]]> A first principles study of the dynamics of ^{6}Li(^{2}S)+^{6}Li^{174}Yb(^{2}Σ^{+})→^{6}Li_{2}(^{1}Σ^{+}) + ^{174}Yb(^{1}S) reaction is presented at cold and ultracold temperatures. The computations involve determination and analytic fitting of a three-dimensional potential energy surface for the Li_{2}Yb system and quantum dynamics calc...

[Phys. Rev. A 91, 012708] Published Tue Jan 20, 2015

]]> We present measurements of the total elastic and resonant charge-exchange ion-atom collision rate coefficient k_{ia} of cold sodium (Na) with optically dark low-energy Na^{+} ions in a hybrid ion-neutral trap. To determine k_{ia}, we measured the trap loading and loss rates from both a Na magneto-optical tra...

[Phys. Rev. A 91, 012709] Published Tue Jan 20, 2015

]]> The resonant process of dielectronic recombination (DR) has been applied as a spectroscopic tool to investigate intra-L-shell excitations 2s-2p_{j} in Li-like ^{136}Xe^{51}+. The experiments were carried out at the electron cooler of the Experimental Storage Ring of the GSI-Helmholtzzentrum für Schwerionenfo...

[Phys. Rev. A 91, 012710] Published Tue Jan 20, 2015

]]>Photoionization of neutral atomic sulfur in the ground and metastable states was studied experimentally at a photon energy resolution of 44 meV (full width at half maximum). Relative cross section measurements were recorded by using tunable vacuum ultraviolet radiation in the energy range 9–30 eV ob...

[Phys. Rev. A 91, 013406] Published Tue Jan 20, 2015

]]>A generalized double-well-basis coupled representation is proposed to investigate excitation spectra and thermodynamics of bosonic atoms in double-well optical superlattices. In the hard-core limit and with a filling factor of one, excitations describing the creation of pairs of a doubly occupied st...

[Phys. Rev. A 91, 013617] Published Tue Jan 20, 2015

]]>Motivated by recent cold-atom experiments in optical lattices, we consider a lattice version of the Landau-Zener problem. Every single site is described by a Landau-Zener problem, but due to particle tunneling between neighboring lattice sites this on-site single-particle Landau-Zener dynamics coupl...

[Phys. Rev. A 91, 013618] Published Tue Jan 20, 2015

]]>We obtain analytically two kinds of inhomogeneous spin domain configurations endowed with time-dependent periodic domain walls in spin-1 Bose-Einstein condensate, which result from the positive and negative quadratic Zeeman effects, respectively. It is shown analytically that the topological defects...

[Phys. Rev. A 91, 013619] Published Tue Jan 20, 2015

]]>The transition from “few to many” has recently been probed experimentally in an ultracold harmonically confined one-dimensional lithium gas, in which a single impurity atom interacts with a background gas consisting of one, two, or more identical fermions [A. N. Wenz et al., Science 342, 457 (2013)S...

[Phys. Rev. A 91, 013620] Published Tue Jan 20, 2015

]]>We study a five-level quasi-Λ system of cold atoms for achieving high-order photonic band gaps (PBGs) probed by an ultraviolet field in two cases where either an infrared or a visible control field works in the standing-wave configuration to induce one atomic grating. Transfer-matrix calculations fo...

[Phys. Rev. A 91, 013826] Published Tue Jan 20, 2015

]]>We theoretically investigate a two-cavity optomechanical system in which a cavity (cavity a) couples to a mechanical resonator via radiation pressure and to another cavity (cavity c) via a common waveguide. In the excitation of a strong pump filed to cavity a, the steady-state entanglement between c...

[Phys. Rev. A 91, 013827] Published Tue Jan 20, 2015

]]>We obtained a propagation equation for an optical pulse at an electromagnetically induced transparency window guided on a gas-filled hollow-core photonic crystal fiber. This equation admits dissipative solitons whose analytical expression was also obtained. Depending on the parameter region, they ma...

[Phys. Rev. A 91, 013828] Published Tue Jan 20, 2015

]]>We present a theoretical model of photon counting measurements on conditionally generated narrowband single-photon states that are produced via cavity-enhanced spontaneous parametric down-conversion, then frequency up-converted from the telecom wavelength of 1550 nm to the visible wavelength of 532 ...

[Phys. Rev. A 91, 013829] Published Tue Jan 20, 2015

]]>It is found that the measurement disturbance relation (MDR) determines the strength of quantum correlation and hence is one of the essential facets of the nature of quantum nonlocality. In reverse, the exact form of MDR may be ascertained through measuring the correlation function. To this aim, an o...

[Phys. Rev. A 91, 012110] Published Fri Jan 16, 2015

]]> We report measurements of the absolute excitation frequencies of ^{165}Ho 4f^{11}6sns and 4f^{11}6snd odd-parity Rydberg series. The states are detected through depletion of a magneto-optical trap via a two-photon excitation scheme. Measurements of 162 Rydberg levels in the range n=40–101 yield quantum defec...

[Phys. Rev. A 91, 012507] Published Fri Jan 16, 2015

]]>We investigate the dynamics of a homogenous Bose-Einstein condensate (BEC) following a sudden quench of the scattering length. Our focus is the time evolution of short-range correlations via the dynamical contact. We compute the dynamics using a combination of two- and many-body models and we propos...

[Phys. Rev. A 91, 013616] Published Fri Jan 16, 2015

]]>Although a number of measures for quantum non-Markovianity have been proposed recently, it is still an open question whether these measures directly characterize the memory effect of the environment, i.e., the dependence of a quantum state on its past in a time evolution. In this paper, we present a...

[Phys. Rev. A 91, 012109] Published Thu Jan 15, 2015

]]>All classical and quantum technologies that encode in and retrieve information from optical fields rely on the ability to selectively manipulate orthogonal field modes of light. Such manipulation can be achieved with high selectivity for polarization modes and transverse-spatial modes. For the time-...

[Phys. Rev. A 91, 012323] Published Thu Jan 15, 2015

]]>Characterizing noisy quantum processes is important to quantum computation and communication (QCC), since quantum systems are generally open. To date, all methods of characterization of quantum dynamics (CQD), typically implemented by quantum process tomography, are off-line, i.e., QCC and CQD are n...

[Phys. Rev. A 91, 012324] Published Thu Jan 15, 2015

]]> The cesium 6P_{3/2} excited-state lifetime is measured using ultrafast laser pulse excitation and ionization in counterpropagating thermal atomic beams achieving an overall uncertainty of 0.15%, which represents a modest improvement over the best previous direct measurement of this lifetime.

[Phys. Rev. A 91, 012506] Published Thu Jan 15, 2015

]]> We analyze sound waves (phonons, i.e. Bogoliubov excitations) propagating on continuous-wave (cw) solutions of repulsive F=1 spinor Bose-Einstein condensates (BECs) such as ^{23}Na (which is antiferromagnetic or polar) and ^{87}Rb (which is ferromagnetic). Zeeman splitting by a uniform magnetic field is i...

[Phys. Rev. A 91, 013615] Published Thu Jan 15, 2015

]]>Ground-state cooling of mesoscopic mechanical resonators is a fundamental requirement for testing of quantum theory and for implementation of quantum information. We analyze the cavity optomechanical cooling limits in the intermediate coupling regime, where the light-enhanced optomechanical coupling...

[Phys. Rev. A 91, 013824] Published Thu Jan 15, 2015

]]>We demonstrate quantum bath engineering for preparation of any orbital state with the controllable phase factor of a superconducting flux qubit assisted by a microwave coplanar waveguide resonator. We investigate the polarization efficiency of the arbitrary direction rotating on the Bloch sphere, an...

[Phys. Rev. A 91, 013825] Published Thu Jan 15, 2015

]]>We construct a nonequilibrium theory for the dynamics of two interacting finite-temperature atomic Bose-Einstein condensates and use it to numerically estimate the relative rates of the arising collisional processes near equilbrium. The condensates are described by dissipative Gross-Pitaevskii equat...

[Phys. Rev. A 91, 011602] Published Wed Jan 14, 2015

]]>We establish a quantitative relation between Hardy's paradox and the breaking of the uncertainty principle in the sense of measurement-disturbance relations in the conditional measurement of noncommuting operators. The analysis of the inconsistency of local realism with entanglement by Hardy is simp...

[Phys. Rev. A 91, 012105] Published Wed Jan 14, 2015

]]>The Clauser-Horne-Shimony-Holt inequality applies when measurements with binary outcomes are performed on physical systems under the assumption of local realism. Testing such inequalities in the quantum realm usually involves either measurements of two-valued quantum observables or predefining a con...

[Phys. Rev. A 91, 012106] Published Wed Jan 14, 2015

]]>Motivated by very recent experiments, we consider a scenario “à la Bell” in which two protagonists test the Clauser-Horne-Shimony-Holt (CHSH) inequality using a photon-pair source based on spontaneous parametric down conversion and imperfect photon detectors. The conventional wisdom says that (i) if...

[Phys. Rev. A 91, 012107] Published Wed Jan 14, 2015

]]>We derive an upper bound for the distinguishability-based non-Markovianity measure of a two-level system and prove that for certain master equations the exact value of the measure achieves this bound. Furthermore, we obtain an easily calculable lower bound for the divisibility-based non-Markovianity...

[Phys. Rev. A 91, 012108] Published Wed Jan 14, 2015

]]>We investigate the problem of computing optimal quantum measurements in both minimal measuring and minimax strategies. A Belavkin weighted square-root measurement (BWSRM) with appropriate weights can represent the measurement that maximizes the correct probability for any given prior probabilities o...

[Phys. Rev. A 91, 012318] Published Wed Jan 14, 2015

]]> Applying a magnetic-field gradient to a trapped ion allows long-wavelength radiation to produce a mechanical force on the ion's motion when internal transitions are driven. We demonstrate such a coupling using a single trapped ^{171}Yb^{+} ion and use it to produce entanglement between the spin and motion...

[Phys. Rev. A 91, 012319] Published Wed Jan 14, 2015

]]>We quantitatively analyze and evaluate the controller's power in N-qubit controlled teleportation schemes. We calculate the minimum control power required to ensure the controller's authority such that the teleportation fidelity without the controller's permission is no more than the classical bound...

[Phys. Rev. A 91, 012320] Published Wed Jan 14, 2015

]]>We consider an infinite class of unambiguous quantum state discrimination problems on multipartite systems, described by Hilbert space H, of any number of parties. Restricting consideration to measurements that act only on H, we find the optimal global measurement for each element of this class, ach...

[Phys. Rev. A 91, 012321] Published Wed Jan 14, 2015

]]>A method for preparing and detecting all eigenstates of a three-level microwave dressed system with a single trapped ion is developed, thereby significantly reducing the experimental complexity of gate operations with dressed-state qubits, as well as allowing the preparation and the detection of all three of the dressed states.

[Phys. Rev. A 91, 012322] Published Wed Jan 14, 2015

]]> Accurate frequency measurements of molecular transitions around 2 μm are performed by using a direct-frequency-comb spectroscopy approach that combines an Er^{+} frequency-comb oscillator at 1.5 μm, a Tm-Ho fiber amplifier, and a Fabry-Perot-filter, high-resolution dispersive spectrometer optical multi...

[Phys. Rev. A 91, 012505] Published Wed Jan 14, 2015

]]>We find that, for sufficiently strong mid-IR fields, transitions between different conduction bands play an important role in the generation of high-order harmonics in a dielectric. The transitions make a significant contribution to the harmonic signal, and they can create a single effective band fo...

[Phys. Rev. A 91, 013405] Published Wed Jan 14, 2015

]]>We analyze the non-Markovianity degree for random unitary evolution of d-level quantum systems. It is shown how the non-Markovianity degree is characterized in terms of local decoherence rates. In particular we derive a sufficient condition for vanishing of the backflow of information and relate thi...

[Phys. Rev. A 91, 012104] Published Tue Jan 13, 2015

]]>Qubit-qubit interactions can significantly boost quantum coherence times for Bell states. The coherence-time enhancements are, however, not monotonic and there exists a phase where further increasing the interaction is unhelpful. A resonator in a suggested circuit QED-type implementation of the Tavi...

[Phys. Rev. A 91, 012317] Published Tue Jan 13, 2015

]]>In a recent experiment, Kwon et al. [Phys. Rev. A 90, 063627 (2014)PLRAAN10.1103/PhysRevA.90.063627] generated a disordered state of quantum vortices by translating an oblate Bose-Einstein condensate past a laser-induced obstacle and studied the subsequent decay of vortex number. Using mean-field si...

[Phys. Rev. A 91, 013612] Published Tue Jan 13, 2015

]]>We calculate the stability diagram for a trapped normal Fermi or Bose gas with dipole-dipole interactions. Our study characterizes the roles of trap geometry and temperature on the stability using Hartree-Fock theory. We find that exchange appreciably reduces stability and that, for bosons, the doub...

[Phys. Rev. A 91, 013613] Published Tue Jan 13, 2015

]]>We show that periodically doped, flat surfaces can act as reflective diffraction gratings for atomic and molecular matter waves. The diffraction element is realized by exploiting the fact that charged dopants locally suppress quantum reflection from the Casimir-Polder potential. We present a general...

[Phys. Rev. A 91, 013614] Published Tue Jan 13, 2015

]]>Extended wavefronts are used for coherent full field imaging of objects based on solving the inverse Fresnel diffraction problem. To this end, the conventional data correction step is given by division of the recorded object image by the intensity pattern of the empty beam. This division of intensit...

[Phys. Rev. A 91, 013821] Published Tue Jan 13, 2015

]]>We test current numerical implementations of laser-matter interactions by comparison with exact analytical results. Focusing on photon emission processes, it is found that the numerics accurately reproduce analytical emission spectra in all considered regimes, except for the harmonic structures ofte...

[Phys. Rev. A 91, 013822] Published Tue Jan 13, 2015

]]>We introduce one kind of partially coherent beam with a nonconventional correlation function named the Hermite-Gaussian correlated Schell-model (HGCSM) beam. It is found that a HGCSM beam exhibits self-splitting properties on propagation in free space, i.e., the initial single beam spot evolves into...

[Phys. Rev. A 91, 013823] Published Tue Jan 13, 2015

]]> We demonstrate photodissociation of BeH^{+} ions within a Coulomb crystal of thousands of ^{9}Be^{+} ions confined in a Penning trap. Because BeH^{+} ions are created via exothermic reactions between trapped, laser-cooled Be^{+}(^{2}P_{3/2}) and background H_{2} within the vacuum chamber, they represent a major contaminant...

[Phys. Rev. A 91, 011401] Published Mon Jan 12, 2015

]]>We use microscopic Bogoliubov–de Gennes formalism to explore the ground-state phase diagram of the single-band attractive Hofstadter-Hubbard model on a square lattice. We show that the interplay between the Hofstadter butterfly and superfluidity breaks spatial symmetry, and gives rise to stripe-orde...

[Phys. Rev. A 91, 011601] Published Mon Jan 12, 2015

]]>Linear-optical interferometers play a key role in designing circuits for quantum information processing and quantum communications. Even though nested Mach-Zehnder interferometers appear easy to describe, there are occasions when they provide unintuitive results. This paper explains the results of a...

[Phys. Rev. A 91, 012103] Published Mon Jan 12, 2015

]]>We investigate the entanglement dynamics of two harmonic oscillators with a weak time-dependent coupling. We find strong connections between the dynamical behaviors of the entanglement and the stability of the normal modes. An abrupt transition of the entanglement dynamics from periodic and bounded ...

[Phys. Rev. A 91, 012312] Published Mon Jan 12, 2015

]]>Quantum entanglement between an arbitrary number of remote qubits is examined analytically. We show that there is a nonprobabilistic way to address in one context the management of entanglement of an arbitrary number of mixed-state qubits by engaging quantitative measures of entanglement and a speci...

[Phys. Rev. A 91, 012313] Published Mon Jan 12, 2015

]]>We describe a methodology and standard of proof for experimental claims of quantum random-number generation (QRNG), analogous to well-established methods from precision measurement. For appropriately constructed physical implementations, lower bounds on the quantum contribution to the average min-en...

[Phys. Rev. A 91, 012314] Published Mon Jan 12, 2015

]]>Application of the adiabatic model of quantum computation requires efficient encoding of the solution to computational problems into the lowest eigenstate of a Hamiltonian that supports universal adiabatic quantum computation. Experimental systems are typically limited to restricted forms of two-bod...

[Phys. Rev. A 91, 012315] Published Mon Jan 12, 2015

]]>A new technique is developed to find existence conditions on entanglement transformations between bipartite pure Gaussian states that go beyond Gaussian local operations and classical communication.

[Phys. Rev. A 91, 012316] Published Mon Jan 12, 2015

]]> Bound and resonance states of the dipole-bound anion of hydrogen cyanide HCN^{−} are studied using a nonadiabatic pseudopotential method and the Berggren expansion technique involving bound states, decaying resonant states, and nonresonant scattering continuum. We devise an algorithm to identify the re...

[Phys. Rev. A 91, 012503] Published Mon Jan 12, 2015

]]>We study a hybrid quantum system composed of an ion and an electric dipole. We show how a trapped ion can be used to measure the small electric field generated by a classical dipole. We discuss the application of this scheme to measure the electric dipole moment of cold polar molecules, whose intern...

[Phys. Rev. A 91, 012504] Published Mon Jan 12, 2015

]]>The triple differential cross section for ionization of the inert gases He, Ne, Ar, Kr, and Xe in energy-sharing perpendicular plane geometry is investigated. Encouraging agreement with recent experiments is found using the distorted-wave Born approximation (DWBA). Mechanisms are discussed which exp...

[Phys. Rev. A 91, 012706] Published Mon Jan 12, 2015

]]>The differential cross sections for exciting the three lowest electronically excited states are measured in furan both as a function of the electron energy and of the scattering angle, revealing the resonant structure and permitting conclusions about the excitation mechanism.

[Phys. Rev. A 91, 012707] Published Mon Jan 12, 2015

]]>Supersolid is a long-sought exotic phase of matter, which is characterized by the coexistence of a diagonal long-range order of solid and an off-diagonal long-range order of superfluid. Possible candidates to realize such a phase have been previously considered, including hard-core bosons with long-...

[Phys. Rev. A 91, 013607] Published Mon Jan 12, 2015

]]>We investigate the properties of a neutral impurity atom coupled with the Tkachenko modes of a two-dimensional vortex lattice in a Bose-Einstein condensate. In contrast with polarons in homogeneous condensates, the marginal impurity-boson interaction in the vortex lattice leads to infrared singulari...

[Phys. Rev. A 91, 013608] Published Mon Jan 12, 2015

]]>In Bose-Einstein condensates with an attractive contact interaction the stable ground state and an unstable excited state emerge in a tangent bifurcation at a critical value of the scattering length. At the bifurcation point both the energies and the wave functions of the two states coalesce, which ...

[Phys. Rev. A 91, 013609] Published Mon Jan 12, 2015

]]>We investigate the phase structure of spin-imbalanced unitary Fermi gases beyond mean-field theory by means of the functional renormalization group. In this approach, quantum and thermal fluctuations are resolved in a systematic manner. The discretization of the effective potential on a grid allows ...

[Phys. Rev. A 91, 013610] Published Mon Jan 12, 2015

]]>We introduce a detector that selectively probes the phononic excitations of a cold Bose gas. The detector is composed of a single impurity atom confined by a double-well potential, where the two lowest eigenstates of the impurity form an effective probe qubit that is coupled to the phonons via densi...

[Phys. Rev. A 91, 013611] Published Mon Jan 12, 2015

]]>We propose an all-optical antiwaveguide mechanism for steering, splitting, and cloning of an optical beam without diffraction. We use a spatially inhomogeneous pump beam to create an antiwaveguide structure in a Doppler broadened N-type four-level Raman gain medium for a copropagating weak probe bea...

[Phys. Rev. A 91, 013820] Published Mon Jan 12, 2015

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