The Foldy-Wouthuysen transformation is known to uncover the nonrelativistic limit of a generalized Dirac Hamiltonian, lending an intuitive physical interpretation to the effective operators within Schrödinger-Pauli theory. We here discuss the opposite, ultrarelativistic limit which requires the use …

[Phys. Rev. A 92, 012101] Published Thu Jul 02, 2015

]]>Uncertainty relations (URs) such as the Heisenberg-Robertson or the time-energy UR are often considered to be hallmarks of quantum theory. Here, a simple derivation of these URs is presented based on a single classical inequality from estimation theory, a Cramér-Rao-like bound. The Heisenberg-Robert…

[Phys. Rev. A 92, 012102] Published Thu Jul 02, 2015

]]>We address the question of finding the most unbalanced convex decompositions into boundary elements (so-called boundariness) for sets of quantum states, observables, and channels. We show that in general convex sets the boundariness essentially coincides with the question of the most distinguishable…

[Phys. Rev. A 92, 012304] Published Thu Jul 02, 2015

]]>The determination of many special types of quantum states has been studied thoroughly, such as the generalized $|\text{GHZ}\rangle $ states, stochastic local operations and classical communication equivalent $|W\rangle $ states, and Dicke states. In this paper, we study another special entanglement state, that is, stabilize…

[Phys. Rev. A 92, 012305] Published Thu Jul 02, 2015

]]>Compton scattering of twisted photons is investigated within a nonrelativistic framework using first-order perturbation theory. We formulate the problem in the density-matrix theory, which enables one to gain new insights into scattering processes of twisted particles by exploiting the symmetries of…

[Phys. Rev. A 92, 013401] Published Thu Jul 02, 2015

]]>We investigate the ground-state and finite-temperature properties of the Bose-Hubbard model using the standard basis operator method applied to the equation of motion for Green's functions. We show that by introducing the self-consistent approach, the theory goes significantly beyond the mean-field …

[Phys. Rev. A 92, 013602] Published Thu Jul 02, 2015

]]>We establish a nonequilibrium scaling regime in the short-time evolution of one-dimensional interacting open quantum systems subject to a generic heating mechanism. This dynamical regime is characterized by uncompensated phonon production and a superdiffusive, universal scaling of quasiparticle life…

[Phys. Rev. A 92, 013603] Published Thu Jul 02, 2015

]]>We systematically investigate the ground-state and elementary excitations of a Bose-Einstein condensate within a synthetic vector potential, which is induced by the many-body effects and atom-light coupling. For a sufficiently strong spin-dependent interaction, we find the condensate undergoes a Sto…

[Phys. Rev. A 92, 013604] Published Thu Jul 02, 2015

]]>A quantum-eraser experiment with photon pairs coupled via induced coherence is reported, and the complementarity between which-source information and two-photon-interference-fringe visibility is demonstrated.

[Phys. Rev. A 92, 013803] Published Thu Jul 02, 2015

]]>Arrays of evanescently coupled waveguides can be used to retrieve simultaneously the first-order correlation functions in multiple-field interferometry. Here it is shown that this remarkable property of waveguide arrays is enabled only by the existence of nonlocal interaction, i.e., non-nearest-neig…

[Phys. Rev. A 92, 013804] Published Thu Jul 02, 2015

]]>We examine a class of operations for topological quantum computation based on fusing and measuring topological charges for systems with $\mathrm{SU}{\left(2\right)}_{4}$ or $k=4$ Jones-Kauffman anyons. We show that such operations augment the braiding operations, which, by themselves, are not computationally universal. This aug…

[Phys. Rev. A 92, 012301] Published Wed Jul 01, 2015

]]>By coupling pairs of superconducting qubits through a small Josephson junction with a time-dependent flux bias, we show that arbitrary interactions involving any combination of Pauli matrices can be generated with a small number of drive tones applied through the flux bias of the coupling junction. …

[Phys. Rev. A 92, 012302] Published Wed Jul 01, 2015

]]>The quantum Zeno effect (QZE) is the phenomenon in which the unitary evolution of a quantum state is suppressed, e.g., due to frequent measurements. Here, we investigate the use of the QZE in a class of communication complexity problems (CCPs). Quantum entanglement is known to solve certain CCPs bey…

[Phys. Rev. A 92, 012303] Published Wed Jul 01, 2015

]]>We report the absolute frequency values of all (ten) hyperfine transitions of $5{P}_{3/2}-4{D}_{5/2}$ and $5{P}_{3/2}-4{D}_{3/2}$ for ${}^{87}\mathrm{Rb}$ and ${}^{85}\mathrm{Rb}$ atoms via the use of an optical frequency comb by measuring the frequency of a laser diode stabilized onto the line centers of the double-resonance optical pumping spectra. Her…

[Phys. Rev. A 92, 012501] Published Wed Jul 01, 2015

]]>We use quantum Monte Carlo and exact diagonalization calculations to study the Mott-insulator–to–superconductor quantum phase transition in a two-dimensional fermionic Hubbard model with attractive interactions in the presence of a superlattice potential. The model introduced offers unique possibili…

[Phys. Rev. A 92, 013601] Published Wed Jul 01, 2015

]]>Interaction of atoms with quantum states of light is a long-standing problem that apart from fundamental physics has potential applications for optical quantum-state storage, quantum communication, and quantum information. A fully quantum mechanical treatment of this problem is usually very complica…

[Phys. Rev. A 92, 013801] Published Wed Jul 01, 2015

]]>In conical refraction, when a focused Gaussian beam passes along one of the optic axes of a biaxial crystal, it is transformed into a pair of concentric bright rings at the focal plane. We demonstrate both theoretically and experimentally that this transformation is hardly affected by partially bloc…

[Phys. Rev. A 92, 013802] Published Wed Jul 01, 2015

]]>Mutually unbiased bases (MUBs) are interesting for various reasons. The most attractive example of (a complete set of) MUBs is the one constructed by Ivanović as well as Wootters and Fields, which is referred to as the canonical MUB. Nevertheless, little is known about anything that is unique to thi…

[Phys. Rev. A 91, 060301(R)] Published Tue Jun 30, 2015

]]>We improve upon a recently introduced efficient quantum state reconstruction procedure targeted to states well approximated by the multiscale entanglement renormalization ansatz (MERA), e.g., ground states of critical models. We show how to numerically select a subset of experimentally accessible me…

[Phys. Rev. A 91, 062128] Published Tue Jun 30, 2015

]]>Single-photon interference due to passage through a periodic grating is considered in a novel proposal for processing $D$-dimensional quantum systems (quDits) encoded in the spatial degrees of freedom of light. We show that free-space propagation naturally implements basic single-quDit gates by means …

[Phys. Rev. A 91, 062328] Published Tue Jun 30, 2015

]]>We present a critical assessment of the applicability of the Debye-Hückel (DH) approximation to the redshift of the Lyman-$\alpha $ emission line of the H-like ions under a dense plasma environment. By carefully considering the $2p\to 1s$ transition spatially and temporally, our investigation suggests that the D…

[Phys. Rev. A 91, 063422] Published Tue Jun 30, 2015

]]>We show theoretically that periodic density patterns are stabilized in two counterpropagating Bose-Einstein condensates of atoms in different hyperfine states under Rabi coupling. In the presence of coupling, the relative velocity between the two components is localized around density depressions in…

[Phys. Rev. A 91, 063635] Published Tue Jun 30, 2015

]]>We introduce a class of metamaterials with uniformly balanced gain and loss associated with complex permittivity and permeability constants. The refractive index of such a balanced pseudopassive metamaterial is real. An unbounded uniform pseudopassive medium has transport characteristics similar to …

[Phys. Rev. A 91, 063843] Published Tue Jun 30, 2015

]]>We theoretically investigate the nonadiabatic spectral redshift of high-order harmonics with the help of a VUV pulse. It is found that the nonadiabatic spectral redshift of high-order harmonics can be observed when a weak VUV pulse is properly added in the falling part of the fundamental laser due t…

[Phys. Rev. A 91, 063844] Published Tue Jun 30, 2015

]]>We show that the resonances of the Stark effect in hydrogen reported by Fernández-Menchero and Summers [Phys. Rev. A **88**, 022509 (2013)] are considerably less accurate than the number of digits appear to suggest. In particular, the imaginary part of the lowest resonance is several orders of magnitude…

[Phys. Rev. A 91, 066501] Published Tue Jun 30, 2015

]]>The numerical values of the resonances shown in L. Fernández-Menchero and H. P. Summers, L. Fernández-Menchero and H. P. Summers, Phys. Rev. A **88**, 022509 (2013) are less accurate than all the decimal ciphers that appear. The preceding Comment repeated the calculations and proved a global accuracy of…

[Phys. Rev. A 91, 066502] Published Tue Jun 30, 2015

]]>It is shown that negative ions are ejected from gas-phase water molecules when bombarded with positive ions at keV energies typical of solar-wind velocities. This finding is relevant for studies of planetary and cometary atmospheres, as well as for radiolysis and radiobiology. Emission of both ${\mathrm{H}}^{-}$ an…

[Phys. Rev. A 91, 060701(R)] Published Mon Jun 29, 2015

]]>Parametric down-conversion in a nonlinear crystal-generated photon pair in which photons have orthogonal polarization. The pair was emitted in a cone shape for each polarization and collimated by a lens to be doughnut shaped. The doughnutlike photon pair runs collinear to the pump laser. The group d…

[Phys. Rev. A 91, 062327] Published Mon Jun 29, 2015

]]>We propose a definitive test of whether plates involved in Casimir experiments should be modeled with ballistic or diffusive electrons—a prominent controversy highlighted by a number of conflicting experiments. The unambiguous test we propose is a measurement of the Casimir force between a disordere…

[Phys. Rev. A 91, 062512] Published Mon Jun 29, 2015

]]>We study the behavior of an unusual doubly quantized vortex in a harmonically trapped Bose gas at nonzero temperatures by using the time-dependent Hartree-Fock-Bogoliubov equations. This structure, which exhibits nontrivial features, generates spontaneously in the anomalous fraction when phases corr…

[Phys. Rev. A 91, 063633] Published Mon Jun 29, 2015

]]>Motivated by the fundamental question of the fate of interacting bosons in flat bands, we consider a two-dimensional Bose gas at zero temperature with an underlying quartic single-particle dispersion in one spatial direction. This type of band structure can be realized using the NIST scheme of spin-…

[Phys. Rev. A 91, 063634] Published Mon Jun 29, 2015

]]>We study the photon statistics properties of few-photon transport in an optomechanical system where an optomechanical cavity couples to two empty cavities. By analytically deriving the one- and two-photon currents in terms of a zero-time-delayed two-order correlation function, we show that a photon …

[Phys. Rev. A 91, 063836] Published Mon Jun 29, 2015

]]>We experimentally investigate cold thermal atoms in a single sidedly pumped optical ring resonator for temperatures between 0.4 and $9\phantom{\rule{0.28em}{0ex}}\mu \mathrm{K}$. The threshold for collective atomic recoil lasing (CARL) is recorded for various pump-cavity detunings. The resulting stability diagram is interpreted by simulatin…

[Phys. Rev. A 91, 063837] Published Mon Jun 29, 2015

]]>We examine a lossless Kerr-phase gate in a semiconductor quantum-well system via the tunneling interference effect for weak fields. We show that there exists a magic detuning for the signal field, at which the absorption or amplification for the probe field can be eliminated by increasing the tunnel…

[Phys. Rev. A 91, 063838] Published Mon Jun 29, 2015

]]>We experimentally demonstrate and theoretically explain the onset of optical frequency combs in a simple cavity-enhanced second-harmonic-generation system, exploiting second-order nonlinear interactions. Two combs are simultaneously generated around the fundamental pump frequency, with a spectral ba…

[Phys. Rev. A 91, 063839] Published Mon Jun 29, 2015

]]>We study a bosonic matter excitation coupled to a single-mode cavity field via electric dipole. Counter-rotating and ${A}^{2}$ terms are included in the interaction model, $\mathbf{A}$ being the vector potential of the cavity field. In the ultrastrong coupling regime the vacuum of the bare modes is no longer the grou…

[Phys. Rev. A 91, 063840] Published Mon Jun 29, 2015

]]>We provide a complete and exact quantum description of coherent light scattering in a one-dimensional multimode transmission line coupled to a two-level emitter. Using a recently developed scattering approach, we discuss transmission properties, the power spectrum, the full counting statistics, and …

[Phys. Rev. A 91, 063841] Published Mon Jun 29, 2015

]]>We study the closeness of an experimental unitary bosonic network with only partially indistinguishable bosons in an arbitrary mixed input state, in particular an experimental realization of the BosonSampling, to the ideal bosonic network, where the measure of closeness of two networks is the trace …

[Phys. Rev. A 91, 063842] Published Mon Jun 29, 2015

]]>[Phys. Rev. A 91, 069907] Published Mon Jun 29, 2015

]]>Using a relation between a biorthogonal set of equiseparable bases and the weak values of the density matrix we derive an explicit formula for its tomographic reconstruction completely analogous to the standard mutually unbiased bases expansion.

[Phys. Rev. A 91, 062127] Published Fri Jun 26, 2015

]]>Intense terahertz-frequency pulses induce coherent rotational dynamics and orientation of polar molecular ensembles. Exact numerical methods for rotational dynamics at room temperature are computationally not feasible for the vast majority of molecular rotors: the asymmetric top molecules at ambient…

[Phys. Rev. A 91, 063420] Published Fri Jun 26, 2015

]]>We use a few-cycle, carrier-envelope-phase (CEP) stabilized laser system to generate high-harmonic emission in argon, neon, and carbon dioxide. The high-harmonic spectra consist of discrete harmonic orders whose positions shift as a function of the CEP. Near the cutoff harmonic, the peaks are separa…

[Phys. Rev. A 91, 063421] Published Fri Jun 26, 2015

]]>Following the idea of the density-functional approach, we develop a generalized Bogoliubov theory of an interacting Bose gas confined in a one-dimensional harmonic trap by using a local chemical potential, calculated with the Lieb-Liniger exact solution, as the exchange energy. At zero temperature, …

[Phys. Rev. A 91, 063631] Published Fri Jun 26, 2015

]]>Finite systems of bosons and/or fermions described by the Hubbard model can be realized using ultracold atoms confined in optical lattices. The ground states of these systems often exhibit a coexistence of compressible superfluid and incompressible Mott insulating domains. We analyze such systems by…

[Phys. Rev. A 91, 063632] Published Fri Jun 26, 2015

]]>Recent demonstrations of cavity quantum electrodynamics (QED) with a single quantum emitter coupled to an optical microcavity have shown the great potential of this system for engineering the light-matter interaction and developing a wide range of robust quantum devices. Here, we study the creation …

[Phys. Rev. A 91, 063834] Published Fri Jun 26, 2015

]]>Magnetic resonance in an ensemble of laser-cooled trapped Rb atoms is excited using a microcantilever with a magnetic tip. The cantilever is mounted on a multilayer chip designed to capture, cool, and magnetically transport cold atoms. The coupling is observed by measuring the loss from a magnetic t…

[Phys. Rev. A 91, 063835] Published Fri Jun 26, 2015

]]>Single quantum dots (QDs) are frequently used as single-photon sources, taking advantage of the final exciton decay in a cascade that produces energetically detuned photons. We propose and analyze a new concept of single-photon source, namely, a few-QD microcavity system driven close to, but below t…

[Phys. Rev. A 91, 061804(R)] Published Thu Jun 25, 2015

]]>The Casimir force between two parallel plates separated by anisotropic media is investigated. We theoretically calculate the Casimir force between two parallel plates when the interspace between the plates is filled with anisotropic media. Our result shows that the anisotropy of the material between…

[Phys. Rev. A 91, 062126] Published Thu Jun 25, 2015

]]>Based on the scattering theory, simultaneously enhanced energy transport and suppressed momentum exchange are demonstrated by patterning doped-silicon surfaces in the near field. The radiative heat flux between doped-silicon gratings exceeds that between planar surfaces and can be one or even two or…

[Phys. Rev. A 91, 062510] Published Thu Jun 25, 2015

]]>The Lamb shift in the light hydrogenlike atoms is evaluated for the state-dependent part of the $S$ states $({n}^{3}\mathrm{\Delta}{E}_{n}-\mathrm{\Delta}{E}_{1})/{n}^{3}$ and ${P}_{1/2}$ states by means of a recently proposed relativistic generalization of multipole expansion. We obtain the results for $Z=1\u20135$ and $n=2\u201310$, where $Z$ is the charge of the nucleus…

[Phys. Rev. A 91, 062511] Published Thu Jun 25, 2015

]]>We have obtained accurate *ab initio* ${}^{4}\mathrm{\Sigma}^{+}$ quartet potentials for the diatomic metastable triplet helium+alkali-metal (Li, Na, K, Rb) systems, using all-electron restricted open-shell coupled cluster singles and doubles with noniterative triples corrections CCSD(T) calculations and accurate calculation…

[Phys. Rev. A 91, 062711] Published Thu Jun 25, 2015

]]>The electron angular distribution after atomic photoionization by the fundamental frequency and its second harmonic is analyzed for a case when the frequency of the fundamental scans the region of an intermediate atomic state. The angular distribution and its left-right asymmetry, due to the two-pat…

[Phys. Rev. A 91, 063418] Published Thu Jun 25, 2015

]]>We report about possible formation of highly correlated electron pairs in the heterocyclic aromatic hydrocarbons pyridine, pyrimidine, and 1,3,5-triazine. Previously, these electron pairs have been observed in the acenes and in coronene, but not in pyrrole and furan. Our measurements presented here …

[Phys. Rev. A 91, 063419] Published Thu Jun 25, 2015

]]>We have studied computationally the collision dynamics of spin-2 Bose-Einstein condensates initially confined in a triple-well trap. Depending on the phase structure of the initial-state spinor wave function, the collision of the three condensate fragments produces one of many possible vortex-antivo…

[Phys. Rev. A 91, 063630] Published Thu Jun 25, 2015

]]>We theoretically analyze the Einstein-Podolsky-Rosen (EPR) correlation, the quadrature squeezing, and the continuous-variable quantum teleportation when considering non-Gaussian entangled states generated by applying multiple-photon subtraction and multiple-photon addition to a two-mode squeezed vac…

[Phys. Rev. A 91, 063832] Published Thu Jun 25, 2015

]]>Strong deformation of ultrashort laser pulse shapes is unavoidable when delivering high intensities at remote distances due to nonlinear effects taking place while propagating. Relying on the reversibility of laser filamentation, we propose to explicitly design laser pulse shapes so that propagation…

[Phys. Rev. A 91, 063833] Published Thu Jun 25, 2015

]]>[Phys. Rev. A 91, 069906] Published Thu Jun 25, 2015

]]>We give a necessary condition that a separable measurement can be implemented by local quantum operations and classical communication (LOCC) in any finite number of rounds of communication, generalizing and strengthening a result obtained previously. That earlier result involved a bound that is tigh…

[Phys. Rev. A 91, 062125] Published Wed Jun 24, 2015

]]>A physical realization of self-correcting quantum code would be profoundly useful for constructing a quantum computer. In this theoretical work, we provide a partial solution to major challenges preventing self-correcting quantum code from being engineered in realistic devices. We consider a variant…

[Phys. Rev. A 91, 062324] Published Wed Jun 24, 2015

]]>With the local resonant interaction between a nitrogen-vacancy-center ensemble (NVE) and a superconducting coplanar resonator, and the single-qubit operation, we propose two protocols for the state transfer between two remote NVEs and for a fast controlled-phase (cphase) gate on these NVEs, respecti…

[Phys. Rev. A 91, 062325] Published Wed Jun 24, 2015

]]>We study the problem of remote one-qubit mixed state creation using a pure initial state of two-qubit sender and spin-1/2 chain as a connecting line. We express the parameters of creatable states in terms of transition amplitudes. We show that the creation of a complete receiver's state space can be…

[Phys. Rev. A 91, 062326] Published Wed Jun 24, 2015

]]>Energy levels, radiative transition probabilities, and autoionization rates for $\text{[Ar]}3{d}^{10}4{l}^{\prime}nl(n=4\u201312,l\le n-1),\text{[Ar]}3{d}^{10}5{l}^{\prime}nl(n=5\u20138,l\le n-1)$, and $\text{[Ar]}3{d}^{9}4{l}^{\prime}4{l}^{\prime \prime}nl(n=4\u20135,l\le n-1$) states in Zn-like tungsten (${\mathrm{W}}^{44+}$) are calculated using the relativistic Hartree-Fock method (cowan code), the multiconfiigu…

[Phys. Rev. A 91, 062507] Published Wed Jun 24, 2015

]]>A recent $S$-matrix-based QED calculation of energy levels of the lithium isoelectronic sequence is extended to the general case of a valence electron outside an arbitrary filled core. Emphasis is placed on modifications of the lithiumlike formulas required because more than one core state is present,…

[Phys. Rev. A 91, 062508] Published Wed Jun 24, 2015

]]>A method and a code for calculations of diatomic molecules in the external variable electromagnetic field have been developed. The code is applied for calculation of systematics in the electron's electric-dipole-moment search experiment on ThO ${H}^{3}{\mathrm{\Delta}}_{1}$ state related to geometric phases, including depend…

[Phys. Rev. A 91, 062509] Published Wed Jun 24, 2015

]]>We describe a collective state atomic clock (COSAC) with Ramsey fringes narrowed by a factor of $\sqrt{N}$ compared to a conventional clock—$N$ being the number of noninteracting atoms—without violating the uncertainty relation. This narrowing is explained as being due to interferences among the collective sta…

[Phys. Rev. A 91, 063629] Published Wed Jun 24, 2015

]]>We present Hong-Ou-Mandel interference of single photons generated via two different physical processes by two independent atomic systems: scattering by a single atom, and parametric generation via four-wave mixing in a cloud of cold atoms. Without any spectral filtering, we observe a visibility of $\dots $

[Phys. Rev. A 91, 063829] Published Wed Jun 24, 2015

]]>Control over mechanical motion of nanoscale particles is a valuable functionality desired in a variety of multidisciplinary applications, e.g., biophysics, and it is usually achieved by employing optical forces. Hyperbolic metamaterials enable tailoring and enhancing electromagnetic scattering and, …

[Phys. Rev. A 91, 063830] Published Wed Jun 24, 2015

]]>The article addresses the possibility of entanglement-specific infrared-visible sum-frequency generation spectroscopy. In the case of an anisotropic interface, it is possible to employ *SSS* and *PSS* polarizations to detect responses not only specific to ${\chi}_{YYY}$ and ${\chi}_{XYY}$ nonlinearities, but also to higher…

[Phys. Rev. A 91, 063831] Published Wed Jun 24, 2015

]]>Incompatible measurements in quantum theory always lead to Einstein-Podolsky-Rosen (EPR)-Schrödinger steering. Channel steering, which is a generalized notion of EPR-Schrödinger steering, has been introduced recently. Here we establish a connection between lack of joint measurability and channel ste…

[Phys. Rev. A 91, 062124] Published Tue Jun 23, 2015

]]>Quantum chemical results for the lowest four potentials of the HeH molecule and the corresponding rotational and radial nonadiabatic coupling matrix elements are reported. Close-coupling calculations of the integral cross sections for the excitation processes $\mathrm{H}\left(1s\right)+\text{He}\to \phantom{\rule{4pt}{0ex}}\mathrm{H}(2s,2p)+\text{He}$ are performed on th…

[Phys. Rev. A 91, 062709] Published Tue Jun 23, 2015

]]>We study three-body recombination in two dimensions for systems interacting via short-range two-body interactions in the regime of large scattering lengths. Using the adiabatic hyperspherical representation, we derive semianalytical formulas for three-body recombination in both weakly and deeply bou…

[Phys. Rev. A 91, 062710] Published Tue Jun 23, 2015

]]>We propose a strategy of isotope-selective ionization for a binary mixture of isotopologues of homonuclear diatomic molecules, utilizing field-free alignment with a train of femtosecond laser pulses. Field-free alignment can be achieved simultaneously for two isotopologues consisting of two atoms wi…

[Phys. Rev. A 91, 063416] Published Tue Jun 23, 2015

]]>In this paper, we explore the intensity-dependent strong-field double ionization of Ne with orthogonally polarized two-color laser pulses consisting of 800- and 400-nm laser fields. The yield of ${\text{Ne}}^{2+}$ as a function of the relative phase $\mathrm{\Delta}\varphi $ of the two colors experiences a qualitative transition as the…

[Phys. Rev. A 91, 063417] Published Tue Jun 23, 2015

]]>Recent advances in realizing artificial gauge fields on optical lattices promise experimental detection of topologically nontrivial energy spectra. Self-similar fractal energy structures generally known as Hofstadter butterflies depend sensitively on the geometry of the underlying lattice, as well a…

[Phys. Rev. A 91, 063628] Published Tue Jun 23, 2015

]]>A tunable double optomechanically induced transparency (OMIT) with a squeezed field is investigated in a system consisting of an optomechanical cavity coupled to a charged nanomechanical resonator via Coulomb interaction. Such a double OMIT can be achieved by adjusting the strength of the Coulomb in…

[Phys. Rev. A 91, 063827] Published Tue Jun 23, 2015

]]>In this work we study numerically and analytically the interaction of two qubits in a one-dimensional waveguide, as mediated by the photons that propagate through the guide. We develop strategies to assert the Markovianity of the problem, the effective qubit-qubit interactions, and their individual …

[Phys. Rev. A 91, 063828] Published Tue Jun 23, 2015

]]>[Phys. Rev. A 91, 069905] Published Tue Jun 23, 2015

]]>Photon absorption spectroscopy is a powerful tool for uncovering the structure of atoms, molecules, and solids. Symmetric Lorentzian and asymmetric Fano line shapes are fundamental spectroscopic signatures related to the structural and dynamical properties. Recently, Ott *et al.* [Science **340**, 716 (20…

[Phys. Rev. A 91, 060502(R)] Published Mon Jun 22, 2015

]]>Quantum paradoxes show that quantum statistics can exceed the limits of positive joint probabilities for physical properties that cannot be measured jointly. It is therefore impossible to describe the relations between the different physical properties of a quantum system by assigning joint realitie…

[Phys. Rev. A 91, 062123] Published Mon Jun 22, 2015

]]>The effects of quantum-mechanical interference with a far-off-resonant transition on saturated-absorption measurements of atomic fine-structure intervals are found to be substantially larger than measurement uncertainty, and it is shown how properly taking them into account brings several previous measurements into agreement.

[Phys. Rev. A 91, 062506] Published Mon Jun 22, 2015

]]>We determine and analyze the quantum phases and time delays in photoionization and photorecombination of valence $3p$ and $3s$ electrons of argon using the Kohn-Sham local-density-functional approach. The time-dependent local-density approximation is used to account for the electron correlation. Resulti…

[Phys. Rev. A 91, 063415] Published Mon Jun 22, 2015

]]>An understanding of the possible ways in which interactions can produce fundamentally new emergent many-body states is a central problem of condensed-matter physics. We ask if a Fermi sea can arise in a system of bosons subject to contact interaction. Based on exact diagonalization studies and varia…

[Phys. Rev. A 91, 063623] Published Mon Jun 22, 2015

]]>Ultracold mixtures of different atomic species have great promise for realizing novel many-body phenomena. In a binary mixture of fermions with a large mass difference and repulsive interspecies interactions, a disordered Mott-insulator phase can occur. This phase displays an incompressible total de…

[Phys. Rev. A 91, 063624] Published Mon Jun 22, 2015

]]>We analyze the nucleation of persistent currents in Bose-Einstein condensates of ultracold gases confined in a ring. This phenomenon has been recently investigated in an experiment [S. Eckel, J. G. Lee, F. Jendrzejewski, N. Murray, C. W. Clark, C. J. Lobb, W. D. Phillips, M. Edwards, and G. K. Campb…

[Phys. Rev. A 91, 063625] Published Mon Jun 22, 2015

]]>Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) superfluids, Cooper pairings with finite momentum, and Majorana fermions (MFs), quasiparticles with non-Abelian exchange statistics, are two topics under intensive investigation in the past several decades, but unambiguous experimental evidence for them has no…

[Phys. Rev. A 91, 063626] Published Mon Jun 22, 2015

]]>Spin-orbit coupling (SOC) plays a crucial role in many branches of physics. In this context, the recent experimental realization of the coupling between spin and linear momentum of ultracold atoms opens a completely new avenue for exploring new spin-related superfluid physics. Here we propose that a…

[Phys. Rev. A 91, 063627] Published Mon Jun 22, 2015

]]>[Phys. Rev. A 91, 069904] Published Mon Jun 22, 2015

]]>Heisenberg-like and Fisher-information-based uncertainty relations which extend and generalize previous similar expressions are obtained for $N$-fermion $d$-dimensional systems. The contributions of both spatial and spin degrees of freedom are taken into account. The accuracy of some of these generalize…

[Phys. Rev. A 91, 062122] Published Fri Jun 19, 2015

]]>Improved measurements of hyperfine splittings in the $6\phantom{\rule{0.16em}{0ex}}{}^{2}{D}_{3/2}$ and $6\phantom{\rule{0.16em}{0ex}}{}^{2}{D}_{5/2}$ states of ${}^{87}\mathrm{Rb}$ and ${}^{85}\mathrm{Rb}$ have been performed using Doppler-free, double-resonance, optical pumping laser spectroscopy. The small sizes of the splittings and their associated coupling constants limit the fractional precision of the…

[Phys. Rev. A 91, 062505] Published Fri Jun 19, 2015

]]>Photoelectron momentum distributions of a hydrogen atom in an elliptically polarized laser field and a hydrogen molecular ion in a circularly polarized laser field are studied by simulating the time-dependent Schrödinger equation. We demonstrate that, in both systems, the Coulomb interaction between…

[Phys. Rev. A 91, 063413] Published Fri Jun 19, 2015

]]>We report a high-resolution microscope system for imaging ultracold ytterbium atoms trapped in a two-dimensional optical lattice. By using the ultraviolet strong transition combined with a solid immersion lens and high-resolution optics, our system resolved individual sites in an optical lattice wit…

[Phys. Rev. A 91, 063414] Published Fri Jun 19, 2015

]]>We report a thorough investigation of finite-temperature effects on three-body recombination near a triatomic Efimov resonance in an ultracold gas of cesium atoms. Our measurements cover a wide range from a near-ideal realization of the zero-temperature limit to a strongly temperature-dominated regi…

[Phys. Rev. A 91, 063622] Published Fri Jun 19, 2015

]]>Quantum Langevin formalism with noise operators is used to provide quantum descriptions of photon pairs (the Stokes and anti-Stokes fields) emitted by a mesoscopic spherical particle composed of quantum particles in a double Raman configuration. The spectra of the fields obtained are sensitive to th…

[Phys. Rev. A 91, 063826] Published Fri Jun 19, 2015

]]>The spectral density (SD) function has a central role in the study of open quantum systems (OQSs). We discover a method allowing for a “static” measurement of the SD—i.e., it requires neither the OQS to be initially excited nor its time evolution tracked in time—which is not limited to the weak-coup…

[Phys. Rev. A 91, 062121] Published Thu Jun 18, 2015

]]>Quantum walks have been very useful in developing search algorithms in quantum information, in particular for devising of spatial search algorithms. However, the construction of continuous-time quantum search algorithms in two-dimensional lattices has proved difficult, requiring additional degrees o…

[Phys. Rev. A 91, 062323] Published Thu Jun 18, 2015

]]>An accurate three-dimensional numerical scheme for the De Broglie–Bohm framework of Bohmian mechanics is presented. This method is utilized to explore the subcycle multiphoton ionization dynamics of the hydrogen atom subject to intense near-infrared laser fields on the subfemtosecond time scale. The…

[Phys. Rev. A 91, 063412] Published Thu Jun 18, 2015

]]>In the presence of *nonrelativistic* supersymmetry, a sharp fermionic collective mode similar to the Goldstino mode in high-energy physics was proposed to be realized in Bose-Fermi mixtures. The Goldstino mode is relaxed (i.e., decays) if supersymmetry is explicitly broken, which can be revealed as th…

[Phys. Rev. A 91, 063620] Published Thu Jun 18, 2015

]]>The occupation of more than one single-particle state, and hence the emergence of fragmentation, is a many-body phenomenon occurring for systems of spatially confined strongly interacting bosons. In the present study, we investigate the effect of the range of the interparticle interactions on the fr…

[Phys. Rev. A 91, 063621] Published Thu Jun 18, 2015

]]>A detailed theoretical and numerical analysis of the localization length in alternating metamaterial-birefringent random layered stacks, under uncorrelated thickness disorder, has been performed. Similar structures have recently been reported to suppress the Brewster delocalization for $p$-polarized l…

[Phys. Rev. A 91, 063822] Published Thu Jun 18, 2015

]]>We analytically treat the scattering of two counterpropagating photons on a two-level emitter embedded in an optical waveguide. We find that the nonlinearity of the emitter can give rise to significant pulse-dependent directional correlations in the scattered photonic state, which could be quantifie…

[Phys. Rev. A 91, 063823] Published Thu Jun 18, 2015

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