A double-time correlation function of arbitrary two quantum operations is studied for a nonstationary open quantum system which is in contact with a thermal reservoir. It includes a usual correlation function, a linear response function, and a weak value of an observable. Time evolution of the corre...

[Phys. Rev. A 96, 042111] Published Tue Oct 17, 2017

]]>Using a tripartite framework consisting of an open quantum system, its environment, and a passive reference system, in this study we discuss quantum mutual information (QMI) and data processing inequality (DPI). Without any restriction on the initial correlations, the necessary and sufficient condit...

[Phys. Rev. A 96, 042112] Published Tue Oct 17, 2017

]]>We have measured fully differential cross sections for dissociative single capture and Coulomb explosion through double capture in 75 keV $p+{\mathrm{H}}_{2}$ collisions. Data were analyzed for fixed kinetic energy releases and molecular orientations as a function of scattering angle. Two-center interference was id...

[Phys. Rev. A 96, 042708] Published Tue Oct 17, 2017

]]>Apart from the electronic motion of the target in the molecular collision process, collision probabilities strongly depend on the dynamics of nuclear motions (rotation and vibration). Here we have studied this nuclear dynamical dependency of collision cross sections for a positron–carbon monoxide co...

[Phys. Rev. A 96, 042709] Published Tue Oct 17, 2017

]]>The single ionization triple differential cross sections (TDCS) of the Ar ($3p$) atoms are reported for the positron and electron impact at 1 keV. The calculated cross sections have been obtained using distorted wave Born approximation (DWBA) approach for the average ejected electron energies 13 and 2...

[Phys. Rev. A 96, 042710] Published Tue Oct 17, 2017

]]>We report calculated elastic integral and differential cross sections for electron collisions with the hydrocarbons 1,3-butadiene (${\mathrm{C}}_{4}{\mathrm{H}}_{6}$), 2-methyl-1,3-butadiene (${\mathrm{C}}_{5}{\mathrm{H}}_{8}$), and 2,3-dimethyl-1,3-butadiene (${\mathrm{C}}_{6}{\mathrm{H}}_{10}$) for impact energies up to 15 eV. Our calculations were performed with the Schwinger Multicha...

[Phys. Rev. A 96, 042711] Published Tue Oct 17, 2017

]]>The transfer of the linear photon momentum to the electron in the few-photon ionization of an atom is accurately computed through a numerical solution to the three-dimensional time-dependent Schrödinger equation (TDSE) beyond the dipole approximation. The characteristics of the transfer is studied i...

[Phys. Rev. A 96, 043414] Published Tue Oct 17, 2017

]]>The dynamics following laser-induced molecular photodissociation of gas-phase ${\mathrm{CH}}_{2}\mathrm{BrI}$ at 271.6 nm were investigated by time-resolved Coulomb-explosion imaging using intense near-IR femtosecond laser pulses. The observed delay-dependent photofragment momenta reveal that ${\mathrm{CH}}_{2}\mathrm{BrI}$ undergoes C-I cleavage, ...

[Phys. Rev. A 96, 043415] Published Tue Oct 17, 2017

]]>A system with externally polarized dipole molecules at half-filling moving along a one-dimensional zigzag chain is studied, including ground-state phase diagrams. The dipoles are oriented in-plane. Together with the geometry of the chain, this gives rise to a bond-alternating nearest-neighbor intera...

[Phys. Rev. A 96, 043615] Published Tue Oct 17, 2017

]]>A tetragonal photonic crystal composed of high-index pillars can exhibit a frequency-isolated accidental degeneracy at a high-symmetry point in the first Brillouin zone. A photonic band gap can be formed there by introducing a geometrical anisotropy in the pillars. In this gap, gapless surface and d...

[Phys. Rev. A 96, 043842] Published Tue Oct 17, 2017

]]>Using a nondegenerate four-wave mixing process based on a double-$\mathrm{\Lambda}$ scheme in hot cesium vapor, we generate quantum correlated twin beams with a maximum intensity-difference squeezing of 6.5 dB. The substantially improved squeezing can be mainly attributed to very good frequency and phase-difference ...

[Phys. Rev. A 96, 043843] Published Tue Oct 17, 2017

]]>It has previously been shown that a dye-filled microcavity can produce a Bose-Einstein condensate of photons. Thermalization of photons is possible via repeated absorption and reemission by the dye molecules. In this paper, we theoretically explore the behavior of the polarization of light in this s...

[Phys. Rev. A 96, 043844] Published Tue Oct 17, 2017

]]>Lidar is a well-known optical technology for measuring a target's range and radial velocity. We describe two lidar systems that use entanglement between transmitted signals and retained idlers to obtain significant quantum enhancements in simultaneous measurements of these parameters. The first enta...

[Phys. Rev. A 96, 040304(R)] Published Mon Oct 16, 2017

]]>The supersensitivity attained in quantum phase estimation is known to be compromised in the presence of decoherence. This is particularly patent at blind spots—phase values at which sensitivity is totally lost. One remedy is to use a precisely known reference phase to shift the operation point to a ...

[Phys. Rev. A 96, 042110] Published Mon Oct 16, 2017

]]>We propose a scheme for entangling a movable mirror and two atomic ensembles in a coupled hybrid optomechanical system. Using the logarithmic negativity for the entanglement measure, we analyze the effect of the coupling strength between the two cavities on the entanglement of the movable mirror and...

[Phys. Rev. A 96, 042320] Published Mon Oct 16, 2017

]]>The verification of quantum entanglement under the influence of realistic noise and decoherence is crucial for the development of quantum technologies. Unfortunately, a full entanglement characterization is generally not possible with most entanglement criteria such as entanglement witnesses or the ...

[Phys. Rev. A 96, 042321] Published Mon Oct 16, 2017

]]>Perturbative anticrossings have long been identified as a potential computational bottleneck for quantum annealing. This bottleneck can appear, for example, when a uniform transverse driver Hamiltonian is applied to each qubit. Previous theoretical research sought to alleviate such anticrossings by ...

[Phys. Rev. A 96, 042322] Published Mon Oct 16, 2017

]]>It is a challenging task to detect genuine multipartite nonlocality (GMNL). In this paper, the problem is considered via computing the maximal quantum value of Svetlichny operators for three-qubit systems and a tight upper bound is obtained. The constraints on the quantum states for the tightness of...

[Phys. Rev. A 96, 042323] Published Mon Oct 16, 2017

]]>The total correlation in a bipartite quantum system is measured by the quantum mutual information $\mathcal{I}$, which consists of quantum discord and classical correlation. However, recent results in quantum information show that coherence, which is a part of total correlation, is more general and more fundame...

[Phys. Rev. A 96, 042324] Published Mon Oct 16, 2017

]]>We study ionization dynamics of oriented polar molecules in strong elliptically polarized laser fields. The calculated photoelectron momentum distributions show an irregular half-ring structure from which we track the electron motion and identify two different ionization channels, i.e., the ground-s...

[Phys. Rev. A 96, 043413] Published Mon Oct 16, 2017

]]>Spatially anisotropic solitary vortices, i.e., bright anisotropic vortex solitons (AVSs), supported by anisotropic dipole-dipole interactions, were recently predicted in spin-orbit-coupled binary Bose–Einstein condensates (BECs), in the form of two-dimensional semivortices (complexes built of zero-v...

[Phys. Rev. A 96, 043613] Published Mon Oct 16, 2017

]]>We consider a small number of identical bosons trapped in a two-dimensional isotropic harmonic potential and also the $N$-boson system when it is feasible. The atom-atom interaction is modeled by means of a finite-range Gaussian interaction. The spectral properties of the system are scrutinized and, i...

[Phys. Rev. A 96, 043614] Published Mon Oct 16, 2017

]]>The Mollow spectrum for the light scattered by a driven two-level atom is derived in the resolvent operator formalism. The derivation is based on the construction of a master equation from the resolvent operator of the atom-field system. We show that the natural linewidth of the excited atomic level...

[Phys. Rev. A 96, 043835] Published Mon Oct 16, 2017

]]>Coupled semiconductor lasers are systems possessing complex dynamics that are interesting for numerous applications in photonics. In this work, we investigate the existence and the stability of asymmetric phase-locked states of the fundamental active photonic dimer consisting of two coupled lasers. ...

[Phys. Rev. A 96, 043836] Published Mon Oct 16, 2017

]]>Ensembles of quantum-mechanical spins offer a promising platform for quantum memories, but proper functionality requires accurate control of unavoidable system imperfections. We present an efficient control scheme for a spin ensemble strongly coupled to a single-mode cavity based on a set of Volterr...

[Phys. Rev. A 96, 043837] Published Mon Oct 16, 2017

]]>Conjugate metamaterials, in which the permittivity and the permeability are complex conjugates of each other, possess the elements of loss and gain simultaneously. By employing a conjugate metamaterial with a purely imaginary form, we propose a mechanism for realizing both coherent perfect absorber ...

[Phys. Rev. A 96, 043838] Published Mon Oct 16, 2017

]]>We analyze the quantum evolution of a weakly nonlinear resonator due to a classical near-resonant drive and damping. The resonator nonlinearity leads to squeezing and heating of the resonator state. Using a hybrid phase-space–Fock-space representation for the resonator state within the Gaussian appr...

[Phys. Rev. A 96, 043839] Published Mon Oct 16, 2017

]]>The thermodynamics of quantum coherence has attracted growing attention recently, where the thermodynamic advantage of quantum superposition is characterized in terms of quantum thermodynamics. We investigate the thermodynamic effects of quantum coherent driving in the context of the fluctuation the...

[Phys. Rev. A 96, 043840] Published Mon Oct 16, 2017

]]>Application of the phase-modulated pulsed light for advance spectroscopic measurements is the area of growing interest. The phase modulation of the light causes modulation of the signal. Separation of the spectral components of the modulations allows to distinguish the contributions of various inter...

[Phys. Rev. A 96, 043841] Published Mon Oct 16, 2017

]]>A nanomagnet precessing in an external magnetic field can be treated as a source of narrow-bandwidth magnetic noise, that leaves characteristic fingerprints in decoherence of a nearby spin qubit undergoing dynamical decoupling. We show how, by measurements of two-qubit coherence, a noise sensor comp...

[Phys. Rev. A 96, 042108] Published Fri Oct 13, 2017

]]>We assess two different nonequilibrium quantum Landauer bounds: the traditional approach based on the change in entropy, referred to as the “entropic bound,” and one based on the details of the dynamical map, referred to as the “thermodynamic bound.” By first restricting to a simple exactly solvable...

[Phys. Rev. A 96, 042109] Published Fri Oct 13, 2017

]]>To control and utilize quantum features in small scale for practical applications such as quantum transport, it is crucial to gain a deep understanding of the quantum characteristics of states such as coherence. Here by introducing a technique that simplifies solving the dynamical equation, we study...

[Phys. Rev. A 96, 042318] Published Fri Oct 13, 2017

]]>We develop a general theory to estimate magnetic field gradients in quantum metrology. We consider a system of $N$ particles distributed on a line whose internal degrees of freedom interact with a magnetic field. Usually gradient estimation is based on precise measurements of the magnetic field at two...

[Phys. Rev. A 96, 042319] Published Fri Oct 13, 2017

]]>We investigate the time evolution of quantum entanglement between an electron, liberated by a strong few-cycle laser pulse, and its parent ion core. Since the standard procedure is numerically prohibitive in this case, we propose a method to quantify the quantum correlation in such a system: we use ...

[Phys. Rev. A 96, 043412] Published Fri Oct 13, 2017

]]>We develop a quantum simulator architecture that is suitable for the simulation of $\text{U}\left(1\right)$ Abelian gauge theories such as quantum electrodynamics. Our approach relies on the ability to control the hopping of a particle through a barrier by means of the internal quantum states of a neutral or charged im...

[Phys. Rev. A 96, 043611] Published Fri Oct 13, 2017

]]>We consider the motion of individual two-dimensional vortices in general radially symmetric potentials in Bose-Einstein condensates. We find that although in the special case of the parabolic trap there is a logarithmic correction in the dependence of the precession frequency $\omega $ on the chemical poten...

[Phys. Rev. A 96, 043612] Published Fri Oct 13, 2017

]]>In this paper we show that the frequencies of propagating electromagnetic waves (photons) in a rotating dielectric medium obey Landau quantization. We show that the degeneracy of right and left helicities of photons is broken on the lowest Landau level. In homogeneous space this level is shown to be...

[Phys. Rev. A 96, 043830] Published Fri Oct 13, 2017

]]>We perform Raman spectroscopy of optically trapped noninteracting ${}^{87}\mathrm{Rb}$ atoms, and observe revivals of the atomic coherence at integer multiples of the trap period. The effect of coherence control methods such as echo and dynamical decoupling is investigated experimentally, analytically, and numeric...

[Phys. Rev. A 96, 043831] Published Fri Oct 13, 2017

]]>Cavity optomechanics has proven to be a field of research rich with possibilities for studying motional cooling, squeezing, quantum entanglement, and metrology in solid-state systems. While to date most studies have focused on the modulation of the cavity frequency by the moving element, the emergen...

[Phys. Rev. A 96, 043832] Published Fri Oct 13, 2017

]]>We present a model to describe a generic circuit QED system which consists of multiple artificial three-level atoms, namely, qutrits, strongly coupled to a cavity mode. When the state transition of the atoms disobeys the selection rules the process that does not conserve the number of excitations ca...

[Phys. Rev. A 96, 043833] Published Fri Oct 13, 2017

]]>We introduce a simple, physically motivated variational ground state for the quantum Rabi model and demonstrate that it provides a high-fidelity approximation of the true ground state in all parameter regimes (including intermediate- and strong-coupling regimes). Our variational state is constructed...

[Phys. Rev. A 96, 043834] Published Fri Oct 13, 2017

]]>[Phys. Rev. A 96, 049906] Published Fri Oct 13, 2017

]]>Parity- and time-reversal-symmetry violating interaction constants required for the interpretation of a recent measurement [W. B. Cairncross *et al.*, Phys. Rev. Lett. **119**, 153001 (2017)] of corresponding symmetry violations in the $\mathrm{\Omega}=1$ (${{}^{3}\mathrm{\Delta}}_{1}$) science state of the ${\mathrm{HfF}}^{+}$ molecular ion are reported. Using...

[Phys. Rev. A 96, 040502(R)] Published Thu Oct 12, 2017

]]>The crossover from two to three spatial dimensions is explored for a strongly interacting atomic Fermi superfluid. It is found that the location of the maximum critical velocity in the quasi-two-dimensional regime behaves differently from its two- and three-dimensional asymptotic scalings, and this behavior may be experimentally probed using Bragg spectroscopy.

[Phys. Rev. A 96, 041604(R)] Published Thu Oct 12, 2017

]]>We study the laser-driven Dicke model beyond the rotating-wave approximation. For weak coupling of the system to environmental degrees of freedom, the dissipative dynamics of the emitter-cavity system is described by the Floquet master equation. Projection of the system evolution onto the emitter de...

[Phys. Rev. A 96, 041802(R)] Published Thu Oct 12, 2017

]]>Standard Leggett-Garg inequalities (SLGIs) were formulated for testing incompatibility between the classical world view of macrorealism and quantum mechanics. In recent times, various other formulations such as the Wigner form of Leggett-Garg inequalities (WLGIs), entropic Leggett-Garg inequalities ...

[Phys. Rev. A 96, 042107] Published Thu Oct 12, 2017

]]>We study an implementation of the open GRAPE (gradient ascent pulse engineering) algorithm well suited for large open quantum systems. While typical implementations of optimal control algorithms for open quantum systems rely on explicit matrix exponential calculations, our implementation avoids thes...

[Phys. Rev. A 96, 042315] Published Thu Oct 12, 2017

]]>The construction of topological error correction codes requires the ability to fabricate a lattice of physical qubits embedded on a manifold with a nontrivial topology such that the quantum information is encoded in the global degrees of freedom (i.e., the topology) of the manifold. However, the man...

[Phys. Rev. A 96, 042316] Published Thu Oct 12, 2017

]]>We introduce unitary quantum gates for photon pair creation in spontaneous parametric down-conversion nonlinear crystals (NLs) and for photon path alignment. These are the two key ingredients for the method of *induced coherence without induced emission* and many ensuing variations thereof. The diffic...

[Phys. Rev. A 96, 042317] Published Thu Oct 12, 2017

]]>The present work reports results from systematic multiconfiguration Dirac-Hartree-Fock calculations of electronic isotope-shift factors for a set of transitions between low-lying states in neutral zinc. These electronic quantities, together with observed isotope shifts between different pairs of iso...

[Phys. Rev. A 96, 042502] Published Thu Oct 12, 2017

]]>The dynamic dipole polarizabilities of low-lying states of ${\mathrm{Ca}}^{+}$ ions for circularly polarized light are calculated by using the relativistic configuration interaction plus core polarization approach. The magic wavelengths are determined for the magnetic sublevel transitions $4{s}_{\frac{1}{2},m}\to 4{p}_{{j}^{\prime},{m}^{\prime}}$ and $4{s}_{\frac{1}{2},m}\to \mathrm{...}$

[Phys. Rev. A 96, 042503] Published Thu Oct 12, 2017

]]>We investigate theoretically the use of energy-resolved ultrafast electron diffraction to image laser-driven electronic motion in atoms. A chirped laser pulse is used to transfer the valence electron of the lithium atom from the ground state to the first excited state. During this process, the elect...

[Phys. Rev. A 96, 042706] Published Thu Oct 12, 2017

]]>We calculate the rates of inelastic collisions for ultracold alkali-metal atoms in radio-frequency-dressed traps, using coupled-channel scattering calculations on accurate potential energy surfaces. We identify a radio-frequency-induced loss mechanism that does not exist in the absence of radio freq...

[Phys. Rev. A 96, 042707] Published Thu Oct 12, 2017

]]>We study the intensity-dependent photoelectron differential momentum distributions from tunneling ionization of Kr and Xe atoms in circularly polarized laser fields. We measure the width of photoelectron momentum distribution along the laser propagation direction in conjunction with the most probabl...

[Phys. Rev. A 96, 043410] Published Thu Oct 12, 2017

]]>We present experimental results on the controlled deexcitation of Rydberg states in a cold gas of Rb atoms. The effect of the van der Waals interactions between the Rydberg atoms is clearly seen in the deexcitation spectrum and dynamics. Our observations are confirmed by numerical simulations. In pa...

[Phys. Rev. A 96, 043411] Published Thu Oct 12, 2017

]]>We show that the performances of a Stern-Gerlach apparatus can be improved by using a magnetic field profile for the atomic spin evolution designed with the shortcut-to-adiabaticity technique. Interestingly, it can be made more compact, for atomic beams propagating at a given velocity, and more resi...

[Phys. Rev. A 96, 043609] Published Thu Oct 12, 2017

]]>A constructive theoretical platform for the description of quantum space-time crystals uncovers for $N$ interacting and ring-confined rotating particles the existence of low-lying states with proper space-time crystal behavior. The construction of the corresponding many-body trial wave functions proce...

[Phys. Rev. A 96, 043610] Published Thu Oct 12, 2017

]]>We describe AlGaAs photonic-crystal architectures that simultaneously realize strong exciton-photon coupling, long polariton lifetime, and room-temperature polariton Bose-Einstein condensation (BEC). Strong light trapping, induced by a 3D photonic band gap (PBG), leads to peak field intensity 20 tim...

[Phys. Rev. A 96, 043827] Published Thu Oct 12, 2017

]]>We present a general method for the modeling of semiconductor lasers such as a vertical-cavity surface-emitting laser and a vertical-external-cavity surface-emitting laser containing multiple quantum wells and involving anisotropies that may reveal (i) a local linear birefringence due to the strain ...

[Phys. Rev. A 96, 043828] Published Thu Oct 12, 2017

]]>Plasmonics allows manipulating light at the nanoscale, but has limitations due to the static nature of nanostructures and lack of reconfigurability. We propose and theoretically analyze a room-temperature liquid-metal nanodroplet that changes its shape, and therefore dynamically reconfigures the pla...

[Phys. Rev. A 96, 043829] Published Thu Oct 12, 2017

]]>[Phys. Rev. A 96, 049905] Published Thu Oct 12, 2017

]]>Binary coherent state alphabets can be represented in a two-dimensional Hilbert space. We capitalize this formal connection between the otherwise distinct domains of qubits and continuous variable states to map binary phase-shift keyed coherent states onto the Bloch sphere and to derive their quantu...

[Phys. Rev. A 96, 042311] Published Wed Oct 11, 2017

]]>In continuous-variable quantum key distribution, the loss and excess noise of the quantum channel are key parameters that determine the secure key rate and the maximal distribution distance. We investigate the imperfect quantum state preparation in Gaussian modulation coherent-state protocol both th...

[Phys. Rev. A 96, 042312] Published Wed Oct 11, 2017

]]>The (im)possibility of local distinguishability of orthogonal multipartite quantum states still remains an intriguing question. Beyond ${\mathbb{C}}^{3}\otimes {\mathbb{C}}^{3}$, the problem remains unsolved even for maximally entangled states (MESs). So far, the only known condition for the local distinguishability of states is the we...

[Phys. Rev. A 96, 042314] Published Wed Oct 11, 2017

]]>The lifetimes and decay channels of ultralong-range Rydberg molecules created in a dense Bose-Einstein condensate are examined by monitoring the time evolution of the Rydberg population using field ionization. Studies of molecules with values of the principal quantum number, $n$, in the range $n=49$ to $\mathrm{...}$

[Phys. Rev. A 96, 042702] Published Wed Oct 11, 2017

]]>A multicenter distorted-wave method is used to study the electron impact single ionization from the outer (${1t}_{2}$) and inner (${2a}_{1}$) valence orbitals of a ${\mathrm{CH}}_{4}$ molecule. The triple differential cross sections are calculated in coplanar asymmetric kinematics with the scattered electron energy at 500 eV and...

[Phys. Rev. A 96, 042703] Published Wed Oct 11, 2017

]]>A detailed understanding of the dissociative electron ionization dynamics of $\mathrm{S}{\mathrm{F}}_{6}$ is important in the modeling and tuning of dry-etching plasmas used in the semiconductor manufacture industry. This paper reports a crossed-beam electron ionization velocity-map imaging study on the dissociative ionizat...

[Phys. Rev. A 96, 042704] Published Wed Oct 11, 2017

]]>We describe procedures for converging on and characterizing zero-energy Feshbach resonances that appear in scattering lengths for ultracold atomic and molecular collisions as a function of an external field. The elastic procedure is appropriate for purely elastic scattering, where the scattering len...

[Phys. Rev. A 96, 042705] Published Wed Oct 11, 2017

]]>Electrons in plasmas produced by next-generation ultraintense lasers ($I>5\times {10}^{22}\phantom{\rule{0.16em}{0ex}}\mathrm{W}/{\mathrm{cm}}^{2}$) can be spin polarized to a high degree (10%–70%) by the laser pulses on a femtosecond time scale. This is due to electrons undergoing spin-flip transitions as they radiate $\gamma $-ray photons, preferentially spin polar...

[Phys. Rev. A 96, 043407] Published Wed Oct 11, 2017

]]>The many-electron weak-field asymptotic theory (ME-WFAT) for static tunneling ionization [O. I. Tolstikhin *et al.*, Phys. Rev. A **89**, 013421 (2014)] is applied to diatomic molecules. In the ME-WFAT, the dependence of the ionization rate on the molecular orientation with respect to the static field di...

[Phys. Rev. A 96, 043408] Published Wed Oct 11, 2017

]]>Fully quantum and classical calculations on a helium atom with two excited, radially localized Rydberg wave packets are performed. The differences between classical and quantum methods are compared for a wide range of principal quantum numbers to study the validity of the classical method for low-ly...

[Phys. Rev. A 96, 043409] Published Wed Oct 11, 2017

]]>We present a table-top quantum estimation protocol to measure the gravitational acceleration $g$ by using an optomechanical cavity. In particular, we exploit the nonlinear quantum light-matter interaction between an optical field and a massive mirror acting as mechanical oscillator. The gravitational ...

[Phys. Rev. A 96, 043824] Published Wed Oct 11, 2017

]]>A study on the spatial characteristics of a near-field optical trap is presented. For analysis, a plasmonic near-field trap consisting of a C-shaped engraving is considered. Numerical simulations are performed to calculate the optical force exerted on a spherical nanoparticle by the trap. A Brownian...

[Phys. Rev. A 96, 043825] Published Wed Oct 11, 2017

]]>We demonstrate tunable pulling and pushing optical forces on plasmonic nanostructures at plasmon singularity and Fano resonance. The plasmonic nanostructure containing a spherical core with optical gain and a metallic shell shows much larger optical pulling force than a pure gain sphere. When the si...

[Phys. Rev. A 96, 043826] Published Wed Oct 11, 2017

]]>[Phys. Rev. A 96, 049903] Published Wed Oct 11, 2017

]]>[Phys. Rev. A 96, 049904] Published Wed Oct 11, 2017

]]>We investigate the existence of topological phases in a dense two-dimensional atomic lattice gas. The coupling of the atoms to the radiation field gives rise to dissipation and a nontrivial coherent long-range exchange interaction whose form goes beyond a simple power law. The far-field terms of the...

[Phys. Rev. A 96, 041603(R)] Published Tue Oct 10, 2017

]]>The adiabatic theorem and shortcuts to adiabaticity for time-dependent open quantum systems are explored in this paper. Starting from the definition of dynamical stable decoherence-free subspace, we show that, under a compact adiabatic condition, the quantum state remains in the time-dependent decoh...

[Phys. Rev. A 96, 042104] Published Tue Oct 10, 2017

]]>We discuss how one calculates the coherent path integrals for locally interacting systems, where some inconsistencies with exact results have been reported previously. It is shown that the operator ordering subtlety that is hidden in the local interaction term modifies the Hubbard-Stratonovich trans...

[Phys. Rev. A 96, 042105] Published Tue Oct 10, 2017

]]>In a seminal work, Horsley and collaborators [S. A. R. Horsley, *et al.*, Nat. Photon. **9**, 436 (2015)] showed that, in the framework of non-Hermitian extensions of the Schrödinger and Helmholtz equations, a localized complex scattering potential with spatial distributions of the real and imaginary par...

[Phys. Rev. A 96, 042106] Published Tue Oct 10, 2017

]]>We study the problem to infer the original ground state of a spin-glass Hamiltonian out of the information from the Hamiltonian with interactions deviated from the original ones. Our motivation comes from quantum annealing on a real device in which the values of interactions are degraded by noise. W...

[Phys. Rev. A 96, 042310] Published Tue Oct 10, 2017

]]>Laser-assisted scattering of electrons on diatomic molecules is considered using the $S$-matrix theory within the second Born approximation. The first term of the expansion in powers of the scattering potential corresponds to the direct or single laser-assisted scattering of electrons on molecular tar...

[Phys. Rev. A 96, 043406] Published Tue Oct 10, 2017

]]>By means of the Boltzmann-Vlasov kinetic equation we investigate dynamical properties of a trapped one-component Fermi gas at zero temperature, featuring the anisotropic and long-range dipole-dipole interaction. To this end, we determine an approximate solution by rescaling both space and momentum v...

[Phys. Rev. A 96, 043608] Published Tue Oct 10, 2017

]]>We study the two-photon laser excitation to the $5{D}_{5/2}$ energy level of ${}^{85}\mathrm{Rb}$ atoms contained in the interstices of a porous material made from sintered ground glass with typical pore dimensions in the 10–100 $\mu \mathrm{m}$ range. The excitation spectra show unusual flat-top line shapes, which are shown to be the ...

[Phys. Rev. A 96, 043819] Published Tue Oct 10, 2017

]]>We find exact solutions describing bidirectional pulses propagating in fiber Bragg gratings. They are derived by solving the coupled-mode theory equations and are expressed in terms of products of modified Bessel functions with algebraic functions. Depending on the values of the two free parameters,...

[Phys. Rev. A 96, 043820] Published Tue Oct 10, 2017

]]>Photons do not directly interact with magnetic fields. Recent progress in synthetic gauge fields have stimulated investigations in various fields. In this study, we explore the enclosed synthetic magnetic flux in a parity-time ($\mathcal{PT}$)-symmetric system of three coupled optical resonators; this flux supp...

[Phys. Rev. A 96, 043821] Published Tue Oct 10, 2017

]]>We present a method to produce pure single photons with an arbitrary designed temporal shape in a heralded way. As an indispensable resource, the method uses pairs of time-energy entangled photons. One photon of a pair undergoes temporal amplitude-phase modulation according to the desired shape. Sub...

[Phys. Rev. A 96, 043822] Published Tue Oct 10, 2017

]]>Quantum fluids of light are an emerging tool employed in quantum many-body physics. Their amazing properties and versatility allow using them in a wide variety of fields including gravitation, quantum information, and simulation. However the implications of the quantum nature of light in nonlinear o...

[Phys. Rev. A 96, 043823] Published Tue Oct 10, 2017

]]>Li and Miao [Phys. Rev. A **85**, 042110 (2012)] proposed a non-Hermitian Hamiltonian that is neither Hermitian nor $PT$ symmetric but exhibits real eigenvalues for some values of the model parameters. In order to explain this fact, they resorted to $PT$-pseudo Hermiticity and to a so-called permutation sym...

[Phys. Rev. A 96, 046101] Published Tue Oct 10, 2017

]]>In a recent article, Banerji *et al.* introduced a novel quantum state of light, coined as the perfect quantum optical vortex state [Phys. Rev. A **94**, 053838 (2016)] due to its mathematical similarity with the classical perfect vortex beam. This state is obtained by means of the Fourier transform of a ...

[Phys. Rev. A 96, 047802] Published Tue Oct 10, 2017

]]>Saturation properties are directly linked to the short-range scale of the two-body interaction of the particles. The case of helium is special; on one hand, the two-body potential has a strong repulsion at short distances. On the other hand, the extremely weak binding of the helium dimer locates thi...

[Phys. Rev. A 96, 040501(R)] Published Mon Oct 09, 2017

]]>Understanding and probing phase transitions in nonequilibrium systems is an ongoing challenge in physics. A particular instance are phase transitions that occur between a nonfluctuating absorbing phase, e.g., an extinct population, and one in which the relevant order parameter, such as the populatio...

[Phys. Rev. A 96, 041602(R)] Published Mon Oct 09, 2017

]]>A modified Rydberg blockade gate that employs adiabatic following of a two-atom dark state is proposed. The scheme is resilient to the uncertainty in the interaction strength and can be employed to achieve fault-tolerant quantum computation with neutral atoms.

[Phys. Rev. A 96, 042306] Published Mon Oct 09, 2017

]]>The process of heralded noiseless amplification, and the inverse process of heralded noiseless attenuation, have potential applications in the context of quantum communications. Although several different physical implementations of heralded noiseless amplifiers have now been demonstrated, the resea...

[Phys. Rev. A 96, 042307] Published Mon Oct 09, 2017

]]>Multiparticle singlet states are special quantum entangled states that have been shown to have many interesting applications. We develop a simple scheme to prepare a steady three-atom singlet state with a dissipative Rydberg pumping process, which combines dissipative dynamics and Rydberg interactio...

[Phys. Rev. A 96, 042308] Published Mon Oct 09, 2017

]]>The state comparison amplifier is a recently proposed probabilistic quantum amplifier, intended especially for amplifying coherent states. Its realization is simple and uses only linear optics and photodetectors, and the preparation of a “guess” state, typically a coherent state. Fidelity and succes...

[Phys. Rev. A 96, 042309] Published Mon Oct 09, 2017

]]>The analytic Sommerfeld-Maue theory, including the next-to-leading-order correction, and the relativistic Dirac partial-wave theory are probed by a systematic comparison of the bremsstrahlung spectra with available experimental data. These measurements cover a wide range of nuclear charge numbers ($\mathrm{1...}$

[Phys. Rev. A 96, 042701] Published Mon Oct 09, 2017

]]>We study effects of a potential barrier on collective modes of superfluid Bose gases in optical lattices. We assume that the barrier is created by local suppression of the hopping amplitude. When the system is in a close vicinity of the Mott transition at commensurate fillings, where an approximate ...

[Phys. Rev. A 96, 043606] Published Mon Oct 09, 2017

]]>We make use of numerical exact diagonalization calculations to explore the physics of $\nu =1/2$ bosonic fractional quantum Hall droplets in the presence of experimentally realistic cylindrically symmetric hard-wall potentials. This kind of confinement is found to produce very different many-body spectra...

[Phys. Rev. A 96, 043607] Published Mon Oct 09, 2017

]]>With rotating-wave approximation, we show in this paper that exciton transmission in a one-dimensional two-level molecule chain embedded in a cavity can be enhanced or suppressed by strong cavity-chain couplings. This exciton transmission is closely related to the number of molecules and the distrib...

[Phys. Rev. A 96, 043815] Published Mon Oct 09, 2017

]]>