In a recent paper [V. Karimipour and M. Asoudeh, Phys. Rev. A **92**, 030301(R) (2015)], a multiparty quantum secret-sharing protocol based on $d$-level single particles was proposed. We discussed the security of this protocol and found that it is not secure for any one dishonest participant who can recov…

[Phys. Rev. A 93, 062343] Published Tue Jun 28, 2016

]]>Violation of a Bell inequality guarantees the existence of quantum correlations in a shared quantum state. A pure bipartite quantum state, having nonvanishing quantum correlation, always violates a Bell inequality. Such correspondence is absent for multipartite pure quantum states in the case of mul…

[Phys. Rev. A 93, 062344] Published Tue Jun 28, 2016

]]>Temporal steering, which is a temporal analog of Einstein-Podolsky-Rosen steering, refers to temporal quantum correlations between the initial and final state of a quantum system. Our analysis of temporal steering inequalities in relation to the average quantum bit error rates reveals the interplay …

[Phys. Rev. A 93, 062345] Published Tue Jun 28, 2016

]]>We experimentally demonstrate robust selective excitation and attenuation of atomic Rydberg level populations in sodium vapor (Na i) using intense laser pulses in the strong-field limit $\left(>{10}^{12}\phantom{\rule{0.16em}{0ex}}\mathrm{W}/\mathrm{c}{\mathrm{m}}^{2}\right)$. Coherent control of the atomic population and related ionization channels is realized for intensi…

[Phys. Rev. A 93, 063426] Published Tue Jun 28, 2016

]]>We show that coupling ultracold atoms in optical lattices to quantized modes of an optical cavity leads to quantum phases of matter, which at the same time possess properties of systems with both short- and long-range interactions. This opens perspectives for novel quantum simulators of finite-range…

[Phys. Rev. A 93, 063632] Published Tue Jun 28, 2016

]]>We focus on a technique recently implemented for controlling the magnitude of synthetic spin-orbit coupling (SOC) in ultracold atoms in the Raman-coupling scenario. This technique uses a periodic modulation of the Raman-coupling amplitude to tune the SOC. Specifically, it has been shown that the eff…

[Phys. Rev. A 93, 063633] Published Tue Jun 28, 2016

]]>We study the expansion of an initially strongly confined wave packet in a one-dimensional weak random potential with short correlation length. At long times, the expansion of the wave packet comes to a halt due to destructive interferences leading to Anderson localization. We develop an analytical d…

[Phys. Rev. A 93, 063634] Published Tue Jun 28, 2016

]]>The exchange of orbital angular momentum (OAM) between paraxial optical vortex and a Bose-Einstein condensate (BEC) of atomic gases is well known. In this paper, we develop a theory for the microscopic interaction between matter and an optical vortex beyond paraxial approximation. We show how superp…

[Phys. Rev. A 93, 063852] Published Tue Jun 28, 2016

]]>We propose a scheme in which the cooling of a mechanical resonator is achieved by exposing the optomechanical system to a non-Markovian environment. Because of the backflow from the non-Markovian environment, the phonon number can go beyond the conventional cooling limit in a Markovian environment. …

[Phys. Rev. A 93, 063853] Published Tue Jun 28, 2016

]]>We examined the propagation of information encoded as nonanalytical points on temporally Gaussian-shaped optical pulses in fast- and slow-light systems. The bandwidth of the input pulses determined the sharpness of the nonanalytical points. A sharp bending nonanalytical point propagated with luminal…

[Phys. Rev. A 93, 063854] Published Tue Jun 28, 2016

]]>The problem of coupling multiple spin ensembles through cavity photons is revisited by using (3,5-dichloro-4-pyridyl)bis(2,4,6-trichlorophenyl)methyl (PyBTM) organic radicals and a high-${T}_{c}$ superconducting coplanar resonator. An exceptionally strong coupling is obtained and up to three spin ensembles…

[Phys. Rev. A 93, 063855] Published Tue Jun 28, 2016

]]>Intense spatio-spectral twin beams generated in the regime with pump depletion are analyzed applying a suggested quantum model that treats the signal, idler, and pump fields in the same way. The model assumes the signal and idler fields in the form of the generalized superposition of signal and nois…

[Phys. Rev. A 93, 063857] Published Tue Jun 28, 2016

]]>We introduce a family of asymmetric Laguerre-Gaussian (aLG) laser beams. The beams have been derived via a complex-valued shift of conventional LG beams in the Cartesian plane. While propagating in a uniform medium, the first bright ring of the aLG beam becomes less asymmetric and the energy is redi…

[Phys. Rev. A 93, 063858] Published Tue Jun 28, 2016

]]>We find that all measures of coherence are frozen for an initial state in a strictly incoherent channel if and only if the relative entropy of coherence is frozen for the state. Our finding reveals the existence of measure-independent freezing of coherence, and provides an entropy-based dynamical co…

[Phys. Rev. A 93, 060303(R)] Published Mon Jun 27, 2016

]]>Weyl points in three-dimensional photonic crystals behave as monopoles of Berry flux in momentum space. Here, based on general symmetry analysis, we show that a minimal number of four symmetry-related (consequently equifrequency) Weyl points can be realized in time-reversal invariant photonic crysta…

[Phys. Rev. A 93, 061801(R)] Published Mon Jun 27, 2016

]]>We present a surprisingly simple three-dimensional Bloch sphere representation of a qutrit, i.e., a single three-level quantum system. We start with a symmetric state of a two-qubit system and relate it to the spin-1 representation. Using this representation we associate each qutrit state with a thr…

[Phys. Rev. A 93, 062126] Published Mon Jun 27, 2016

]]>We present a model of discrete quantum evolution based on quantum correlations between the evolving system and a reference quantum clock system. A quantum circuit for the model is provided, which in the case of a constant Hamiltonian is able to represent the evolution over ${2}^{n}$ time steps in terms of …

[Phys. Rev. A 93, 062127] Published Mon Jun 27, 2016

]]>The staggered quantum-walk model makes it possible to establish an unprecedented connection between discrete-time quantum walks and graph theory. We call attention to the fact that a large subclass of the coined model is included in Szegedy's model, which in its turn is entirely included in the stag…

[Phys. Rev. A 93, 062335] Published Mon Jun 27, 2016

]]>Quantum correlations present in a broadband two-line squeezed microwave state can induce entanglement in a spatially separated bipartite system consisting of either two single qubits or two-qubit ensembles. By using an appropriate master equation for a bipartite quantum system in contact with two se…

[Phys. Rev. A 93, 062336] Published Mon Jun 27, 2016

]]>In multiparty quantum systems, the monogamy inequality proposes an upper bound on the distribution of bipartite quantum correlation between a single party and each of the remaining parties in the system, in terms of the amount of quantum correlation shared by that party with the rest of the system t…

[Phys. Rev. A 93, 062337] Published Mon Jun 27, 2016

]]>Techniques for accelerating the evolutionary processes associated with an adiabatic passage have recently been developed. Given that the context for which these speeding-up protocols, such as the shortcut to adiabaticity, have been formulated, their presentation rests on the assumption of the validi…

[Phys. Rev. A 93, 062338] Published Mon Jun 27, 2016

]]>Quantum state transfer between distant nodes is at the heart of quantum processing and quantum networking. Stimulated by this, we propose a scheme where one can achieve quantum state transfer with a high fidelity between sites in a cavity quantum optomechanical network. In our lattice, each individu…

[Phys. Rev. A 93, 062339] Published Mon Jun 27, 2016

]]>In this paper, we study the monogamy inequality of Tsallis $q$-entropy entanglement. We first provide an analytic formula of Tsallis $q$-entropy entanglement in two-qubit systems for $\frac{5-\sqrt{13}}{2}\le q\le \frac{5+\sqrt{13}}{2}.$ The analytic formula of Tsallis $q$-entropy entanglement in $2\otimes d$ system is also obtained and we show that Tsa…

[Phys. Rev. A 93, 062340] Published Mon Jun 27, 2016

]]>Geometric entanglement (GE), as a measure of multipartite entanglement, has been investigated as a universal tool to detect phase transitions in quantum many-body lattice models. In this paper we outline a systematic method to compute GE for two-dimensional (2D) quantum many-body lattice models base…

[Phys. Rev. A 93, 062341] Published Mon Jun 27, 2016

]]>Heisenberg spin chains can act as quantum wires transferring quantum states either perfectly or with high fidelity. Gaussian packets of excitations passing through dual rails can encode the two states of a logical qubit, depending on which rail is empty and which rail is carrying the packet. With ex…

[Phys. Rev. A 93, 062342] Published Mon Jun 27, 2016

]]>Superconducting magnets enable precise control of nuclear and electron spins, and are used in experiments that explore biological and condensed-matter systems, and fundamental atomic particles. In high-precision applications, a common view is that slow $(<1\phantom{\rule{4.pt}{0ex}}\mathrm{Hz})$ drift of the homogeneous magnetic-fie…

[Phys. Rev. A 93, 062511] Published Mon Jun 27, 2016

]]>We propose a simple theoretical approach to consider negative-ion conversion of neutral atoms grazing on alkali-metal-halide crystal surfaces over the complete velocity range. The conversion process is viewed as a series of successive binary collisions between the projectile and the negatively charg…

[Phys. Rev. A 93, 062708] Published Mon Jun 27, 2016

]]>The absolute values of the cross section for formation of a $2p$ atom pair in the photoexcitation of ${\mathrm{H}}_{2}$ and ${\mathrm{D}}_{2}$ are measured against the incident photon energy in the range of doubly excited states by means of the coincidence detection of two Lyman-$\alpha $ photons. The cross-section curves are explained only…

[Phys. Rev. A 93, 063423] Published Mon Jun 27, 2016

]]>This paper investigates the fast Hamiltonian control of $n=2$ density operators by continuously varying the flag (i.e., the eigenspaces) as one moves away from the completely mixed state. In general, the critical points and zeros of the purity derivative can only be solved analytically in the limit of…

[Phys. Rev. A 93, 063424] Published Mon Jun 27, 2016

]]>A hydrogen atom, initially prepared in the $2s$ and/or $2p(m=\pm 1)$ states, is assumed irradiated by $0.8\phantom{\rule{0.28em}{0ex}}\mathrm{keV}$ ($1.5$ nm) photons in pulses of $1\u2013250$ fs duration and intensities in the range ${10}^{20}$ to ${10}^{23}\phantom{\rule{0.28em}{0ex}}\mathrm{W}/{\mathrm{cm}}^{2}$. Solving the corresponding time-dependent Schrödinger equation from first principles, we show that the …

[Phys. Rev. A 93, 063425] Published Mon Jun 27, 2016

]]>We investigate how confining a transverse spatial dimension influences the few- and many-body properties of nonrelativistic bosons with pointlike interactions. Our main focus is on the dimensional crossover from three to two dimensions, which is of relevance for ultracold-atom experiments. Using fun…

[Phys. Rev. A 93, 063631] Published Mon Jun 27, 2016

]]>A general method is introduced for verifying multitime quantum correlations through the characteristic function of the time-dependent $P$ functional that generalizes the Glauber-Sudarshan $P$ function. Quantum correlation criteria are derived which identify quantum effects for an arbitrary number of poi…

[Phys. Rev. A 93, 063843] Published Mon Jun 27, 2016

]]>An exact calculation of the local electric field $\mathbf{E}\left(\mathbf{r}\right)$ is described for the case of a time-dependent point electric dipole $\mathbf{p}{e}^{-i\omega t}$ in the top layer of an ${\epsilon}_{2},{\epsilon}_{1},{\epsilon}_{2}$ three parallel slabs composite structure, where the ${\epsilon}_{1}$ layer has a finite thickness $2d$ but the ${\epsilon}_{2}$ layers are infinitely thick. For this p…

[Phys. Rev. A 93, 063844] Published Mon Jun 27, 2016

]]>Superconducting circuits provide a new platform for study of nonstationary cavity QED phenomena. An example of such a phenomenon is the dynamical Lamb effect, which is the parametric excitation of an atom due to nonadiabatic modulation of its Lamb shift. This effect was initially introduced for a na…

[Phys. Rev. A 93, 063845] Published Mon Jun 27, 2016

]]>Materials with vanishing permittivity (epsilon-near-zero or ENZ materials) show unconventional optical behavior. Here we show that plasmonic dipole antennas on an ultrathin ENZ substrate have properties significantly different from antennas on a traditional substrate. Specifically, the presence of a…

[Phys. Rev. A 93, 063846] Published Mon Jun 27, 2016

]]>Time and space are dual variables which bring a lot of analogies during theoretical study. In this paper, we extend the concept of a spatial optical waveguide to the temporal domain. Here we show that it is possible to confine the optical pulse within a time interval by introducing the temporal inde…

[Phys. Rev. A 93, 063847] Published Mon Jun 27, 2016

]]>The link of two concepts, indistinguishability and entanglement, with the energy-time uncertainty principle is demonstrated in a system composed of two strongly coupled bosonic modes. Working in the limit of a short interaction time, we find that the inclusion of the antiresonant terms to the coupli…

[Phys. Rev. A 93, 063848] Published Mon Jun 27, 2016

]]>A metasurface that absorbs waves from all directions of incidence can be achieved if the surface impedance is made to vary as a function of incidence angle in a specific manner. Here we show that a periodic array of planar nanoparticles coupled to a metal film can act as an absorbing metasurface wit…

[Phys. Rev. A 93, 063849] Published Mon Jun 27, 2016

]]>We study the direction- and wavelength-dependent polarization anisotropy in light scattering at the air–photonic crystal interface as a function of angle of incidence for TE and TM polarized light. This is done using optical reflectivity measurements at high-symmetry points in the Brillouin zone of …

[Phys. Rev. A 93, 063850] Published Mon Jun 27, 2016

]]>The quantum Talbot effects with orbital angular momentum (OAM) photons have been investigated theoretically. Two schemes, holographic ghost-image and twin-photon configuration, have been considered. They exhibit unique properties, which are different from the cases of previous classical and quantum …

[Phys. Rev. A 93, 063851] Published Mon Jun 27, 2016

]]>Recently, Lucamarini *et al.* proposed the device-independent entanglement-based Bennett 1992 protocol [Phys. Rev. A **86**, 032325 (2012)]. By exploiting the results in device-independent quantum key distribution with the Clauser-Horne-Shimony-Holt inequality, they claimed the security of their protocol.…

[Phys. Rev. A 93, 066303] Published Mon Jun 27, 2016

]]>Our paper [Phys. Rev. A **86**, 032325 (2012)], setting forth a previously unknown connection between the Bennett 1992 protocol and a Bell inequality, has recently received a Comment [Phys. Rev. A **93**, 066303 (2016)] about a possible flaw in its potential device-independent (DI) implementation. We point …

[Phys. Rev. A 93, 066304] Published Mon Jun 27, 2016

]]>We present improvements in both theoretical understanding and experimental implementation of the cross resonance (CR) gate that have led to shorter two-qubit gate times and interleaved randomized benchmarking fidelities exceeding 99%. The CR gate is an all-microwave two-qubit gate that does not requ…

[Phys. Rev. A 93, 060302(R)] Published Fri Jun 24, 2016

]]>Collapse in dipolar Bose-Einstein condensates may be arrested by quantum fluctuations. Due to the anisotropy of the dipole-dipole interactions, the dipole-driven collapse induced by soft excitations is compensated by the repulsive Lee-Huang-Yang contribution resulting from quantum fluctuations of ha…

[Phys. Rev. A 93, 061603(R)] Published Fri Jun 24, 2016

]]>We study the inverse problem of constructing an appropriate Hamiltonian from a physically reasonable set of orthogonal wave functions for a quantum spin system. Usually, we are given a local Hamiltonian and our goal is to characterize the relevant wave functions and energies (the spectrum) of the sy…

[Phys. Rev. A 93, 062125] Published Fri Jun 24, 2016

]]>Quantum walks (QWs) describe particles evolving coherently on a graph. The internal degree of freedom corresponds to a Hilbert space, called a *coin system*. We consider QWs on Cayley graphs of some group $G$. In the literature, investigations concerning infinite $G$ have been focused on graphs correspond…

[Phys. Rev. A 93, 062334] Published Fri Jun 24, 2016

]]>Electron correlation in sequential double ionization of helium is studied experimentally with the “attoclock” technique. Control of the two-electron emission dynamics is demonstrated on the time scale of a half laser cycle.

[Phys. Rev. A 93, 063421] Published Fri Jun 24, 2016

]]>A generic scheme to trap atoms at the magic wavelengths ${\lambda}_{\mathrm{magic}}$ that are independent of vector and tensor components of the interactions of the atoms with the external electric field is presented. The ${\lambda}_{\mathrm{magic}}$ for the laser cooling ${D}_{2}$ lines in the Rb and Cs atoms are demonstrated and their correspondin…

[Phys. Rev. A 93, 063422] Published Fri Jun 24, 2016

]]>Recent advances in rapidly quenched ultracold atomic Fermi gases near a Feshbach resonance have brought about a number of interesting problems in the context of observing the long-sought Stoner ferromagnetic phase transition. The possibility of experimentally obtaining a “quasirepulsive” regime in t…

[Phys. Rev. A 93, 063629] Published Fri Jun 24, 2016

]]>We outline laser interferometer measurements to search for variation of the electromagnetic fine-structure constant $\alpha $ and particle masses (including a nonzero photon mass). We propose a strontium optical lattice clock—silicon single-crystal cavity interferometer as a small-scale platform for these m…

[Phys. Rev. A 93, 063630] Published Fri Jun 24, 2016

]]>We study how one-particle correlations transfer to manifest as two-particle correlations in the context of parametric down-conversion (PDC), a process in which a pump photon is annihilated to produce two entangled photons. We work in the polarization degree of freedom and show that for any two-qubit…

[Phys. Rev. A 93, 063842] Published Fri Jun 24, 2016

]]>[Phys. Rev. A 93, 069905] Published Fri Jun 24, 2016

]]>[Phys. Rev. A 93, 069906] Published Fri Jun 24, 2016

]]>The differential cross section of high-energy electroproduction in the electric field of heavy atoms is derived. The results are obtained with the exact account for the atomic field. We use the quasiclassical approximation to the wave functions in the external field. For heavy atoms, the Coulomb cor…

[Phys. Rev. A 93, 062120] Published Thu Jun 23, 2016

]]>Device-independent self-testing offers the possibility of certifying the quantum state and measurements, up to local isometries, using only the statistics observed by querying uncharacterized local devices. In this paper we study parallel self-testing of two maximally entangled pairs of qubits; in p…

[Phys. Rev. A 93, 062121] Published Thu Jun 23, 2016

]]>Decoherence-free-state (DFS) encoding supplies a useful way to avoid the detrimental influence of the environment on quantum information processing. The DFS was previously well established in either the two subsystems locating at the same spatial position or the dynamics under the Born–Markovian app…

[Phys. Rev. A 93, 062122] Published Thu Jun 23, 2016

]]>The uncertainty principle is a fundamental principle in quantum physics. It implies that the measurement outcomes of two incompatible observables cannot be predicted simultaneously. In quantum information theory, this principle can be expressed in terms of entropic measures. M. Berta *et al.* [Nat. Ph…

[Phys. Rev. A 93, 062123] Published Thu Jun 23, 2016

]]>It is shown that the nonlocal nonlinear Schrödinger equation recently proposed by Ablowitz and Musslimani [Phys. Rev. Lett. **110**, 064105 (2013)] is gauge equivalent to the unconventional system of coupled Landau-Lifshitz equations. The first integrals of motion and one-soliton solution of an obtained…

[Phys. Rev. A 93, 062124] Published Thu Jun 23, 2016

]]>We extend the research program initiated in [Phys. Rev. A **92**, 012338 (2015)] from noisy deterministic teleportation protocols to noisy probabilistic (conditional) protocols. Our main goal now is to study how we can increase the fidelity of the teleported state in the presence of noise by working wit…

[Phys. Rev. A 93, 062330] Published Thu Jun 23, 2016

]]>Pure dephasing processes limit the fidelities achievable in driven-dissipative schemes for stabilization of entangled states of qubits. We propose a scheme which, combined with already existing entangling methods, purifies the desired entangled state by driving out of equilibrium auxiliary dissipati…

[Phys. Rev. A 93, 062331] Published Thu Jun 23, 2016

]]>Matchgates are a restricted set of two-qubit gates known to be classically simulable under particular conditions. Specifically, if a circuit consists only of nearest-neighbor matchgates, an efficient classical simulation is possible if either (i) the input is a computational-basis state and the simu…

[Phys. Rev. A 93, 062332] Published Thu Jun 23, 2016

]]>We show that the class quantum-Arthur-Merlin (QAM) does not change even if the verifier's ability is restricted to only single-qubit measurements. To show the result, we use the idea of measurement-based quantum computing: the verifier, who can do only single-qubit measurements, can test the graph s…

[Phys. Rev. A 93, 062333] Published Thu Jun 23, 2016

]]>We investigate when Taylor expansions can be used to prove the Runge-Gross theorem, which is at the foundation of time-dependent density-functional theory (TDDFT). We start with a general analysis of the conditions for the Runge-Gross argument, especially the time differentiability of the density. T…

[Phys. Rev. A 93, 062510] Published Thu Jun 23, 2016

]]>We proposed and analyzed a scheme of precisely measuring orbital angular momentum (OAM) of the vortex beams with the help of weak measurement process. The orbital angular momentum information $l$ of the unknown OAM state can be obtained by its spatial displacements. The valid condition of precisely me…

[Phys. Rev. A 93, 063841] Published Thu Jun 23, 2016

]]>Cluster state plays a crucial role in one-way quantum computation. Here, we propose and experimentally demonstrate a scheme to prepare an ultrahigh-fidelity four-photon linear cluster state via a spontaneous parametric down-conversion process. The state fidelity is measured to be $0.9517\pm 0.0027$. Our …

[Phys. Rev. A 93, 062329] Published Wed Jun 22, 2016

]]>We report on the characterization of a dual cloud atom interferometer for gravity gradient measurements using third-order Bragg diffraction as atom optical elements. We study the dependence of the contrast and the gradiometer phase angle against the relevant experimental parameters and characterize …

[Phys. Rev. A 93, 063628] Published Wed Jun 22, 2016

]]>We study the effect of inversion symmetry breaking on properties of the ground state of a qubit-oscillator system within the ultrastrong-coupling regime. We obtain the solution of the ground state through the approximate analytical approach, which, under the near-resonance condition, agrees well wit…

[Phys. Rev. A 93, 063837] Published Wed Jun 22, 2016

]]>We demonstrate that a phase-insensitive parametric amplifier, when coupled to a quantum correlated source, can be used as a quantum information tap for noiseless three-way signal splitting. We find that the output signals are amplified noiselessly in two of the three output ports, while the other ca…

[Phys. Rev. A 93, 063838] Published Wed Jun 22, 2016

]]>The regions of existence and stability of dark solitons in the Lugiato-Lefever model with normal chromatic dispersion are described. These localized states are shown to be organized in a bifurcation structure known as collapsed snaking implying the presence of a region in parameter space with a fini…

[Phys. Rev. A 93, 063839] Published Wed Jun 22, 2016

]]>Electron vortex beams hold great promise for development in transmission electron microscopy but have yet to be widely adopted. This is partly due to the complex set of interactions that occur between a beam carrying orbital angular momentum (OAM) and a sample. Herein, the system is simplified to fo…

[Phys. Rev. A 93, 063840] Published Wed Jun 22, 2016

]]>We present and analyze a reservoir-engineering approach to stabilizing Fock states in a superconducting microwave cavity which does not require any microwave-frequency control drives. Instead, our system makes use of a Josephson junction biased by a dc voltage which is coupled to both a principal st…

[Phys. Rev. A 93, 060301(R)] Published Tue Jun 21, 2016

]]>We present a demonstration of two-photon double ionization of neon using an intense extreme ultraviolet (XUV) attosecond pulse train (APT) in a photon energy regime where both direct and sequential mechanisms are allowed. For an APT generated through high-order harmonic generation (HHG) in argon we …

[Phys. Rev. A 93, 061402(R)] Published Tue Jun 21, 2016

]]>We characterize the non-Gaussianity of continuous-variable quantum states in terms of the cumulant theory and derive the exact formula of the cumulant of any order for such states. Exploiting the fourth-order cumulant method, we evaluate the quantum non-Gaussianity of two-mode single-photon squeezed…

[Phys. Rev. A 93, 062119] Published Tue Jun 21, 2016

]]>We show that measurement-based quantum computation on scalable continuous-variable (CV) cluster states admits more quantum-circuit flexibility and compactness than similar protocols for standard square-lattice CV cluster states. This advantage is a direct result of the macronode structure of these s…

[Phys. Rev. A 93, 062326] Published Tue Jun 21, 2016

]]>The properties of quantum information in space-time can be investigated by studying operational tasks, such as “summoning,” in which an unknown quantum state is supplied at one point and a call is made at another for it to be returned at a third. Hayden and May [arXiv:1210.0913] recently proved nece…

[Phys. Rev. A 93, 062327] Published Tue Jun 21, 2016

]]>The passive states of a quantum system minimize the average energy among all the states with a given spectrum. We prove that passive states are the optimal inputs of single-jump lossy quantum channels. These channels arise from a weak interaction of the quantum system of interest with a large Markov…

[Phys. Rev. A 93, 062328] Published Tue Jun 21, 2016

]]>A scheme for probing molecular vibrations is proposed by analyzing inner-shell-photoionization signals that use a weak infrared laser pump pulse to excite the vibrational mode, followed by an ultrashort soft-x-ray probe. It is shown, for SF${}_{6}$ molecules, that the sensitivity of the photoionization cross section to the molecular structure can be used to extract nuclear dynamical information in real time.

[Phys. Rev. A 93, 063419] Published Tue Jun 21, 2016

]]>Spin-orbit-coupled bosons can exhibit rich equilibrium phases at low temperature and in the presence of particle-particle interactions. In the case with a 1D synthetic spin-orbit interaction, it has been observed that the ground state of a Bose gas can be a normal phase, stripe phase, or magnetized …

[Phys. Rev. A 93, 063420] Published Tue Jun 21, 2016

]]>Using an anyon-fermion mapping method, we investigate the ground-state properties of hard-core anyons confined in a one-dimensional harmonic trap. The concise analytical formula of the reduced one-body density matrix is obtained. Based on this formula, we evaluated the momentum distribution, the nat…

[Phys. Rev. A 93, 063627] Published Tue Jun 21, 2016

]]>We propose a scheme to demonstrate the existence of optical Peregrine rogue waves and Akhmediev and Kuznetsov-Ma breathers and realize their active control via electromagnetically induced transparency (EIT). The system we suggest is a cold, $\mathrm{\Lambda}$-type three-level atomic gas interacting with a probe and …

[Phys. Rev. A 93, 063836] Published Tue Jun 21, 2016

]]>We experimentally address the significance of fidelity as a figure of merit in quantum state reconstruction of discrete (DV) and continuous-variable (CV) quantum optical systems. In particular, we analyze the use of fidelity in quantum homodyne tomography of CV states and maximum-likelihood polariza…

[Phys. Rev. A 93, 062118] Published Mon Jun 20, 2016

]]>We represent a two-qubit density matrix in the basis of Pauli matrix tensor products, with the coefficients constituting a Bloch matrix, analogous to the single qubit Bloch vector. We find the quantum state positivity requirements on the Bloch matrix components, leading to three important inequaliti…

[Phys. Rev. A 93, 062320] Published Mon Jun 20, 2016

]]>We propose a scheme for generating a type of novel tree-type three-dimensional entangled state. In the scheme, an atom and two Bose–Einstein condensates (BECs) are individually trapped in three spatially separated optical cavities which are connected by two optical fibers. Because the system evolves…

[Phys. Rev. A 93, 062321] Published Mon Jun 20, 2016

]]>Quantum correlations in a physical system are usually studied with respect to a unique and fixed decomposition of the system into subsystems, without fully exploiting the rich structure of the state space. Here, we show several examples in which the consideration of different ways to decompose a phy…

[Phys. Rev. A 93, 062322] Published Mon Jun 20, 2016

]]>We present a general approach to calculating the entanglement of formation for superpositions of two-mode coherent states, placed equidistantly on a circle in phase space. We show that in the particular case of rotationally invariant circular states the Schmidt decomposition of two modes, and theref…

[Phys. Rev. A 93, 062323] Published Mon Jun 20, 2016

]]>The recently developed framework for quantum theory with no global causal order allows for quantum processes in which operations in local laboratories are neither causally ordered nor in a probabilistic mixture of definite causal orders. The causal relation between the laboratories is described by t…

[Phys. Rev. A 93, 062324] Published Mon Jun 20, 2016

]]>In this work we address the problem of realizing a reliable quantum memory based on zero-energy Majorana modes in the presence of experimental constraints on the operations aimed at recovering the information. In particular, we characterize the best recovery operation acting only on the zero-energy …

[Phys. Rev. A 93, 062325] Published Mon Jun 20, 2016

]]>We have observed resonant microwave transitions between pairs of atoms. Specifically, we have observed the processes $n{d}_{5/2}n{d}_{5/2}\to (n+1){d}_{j}(n-2){f}_{7/2}$ and $n{d}_{5/2}n{d}_{5/2}\to (n+2){p}_{3/2}(n-1){d}_{5/2}$ for $35\le n\le 44$. These transitions are allowed due to the dipole-dipole-induced configuration interaction between the $n{d}_{5/2}n{d}_{\mathrm{\dots}}$

[Phys. Rev. A 93, 062509] Published Mon Jun 20, 2016

]]>Experimental and theoretical triple differential cross sections for intermediate-energy (250 eV) electron-impact single ionization of the ${\mathrm{CO}}_{2}$ are presented for three fixed projectile scattering angles. Results are presented for ionization of the outermost $1{\pi}_{g}$ molecular orbital of $\mathrm{C}{\mathrm{O}}_{2}$ in a coplanar a…

[Phys. Rev. A 93, 062707] Published Mon Jun 20, 2016

]]>A theory of above-threshold ionization of atoms by a strong laser field is formulated. Two versions of the strong-field approximation (SFA) are considered, the direct SFA and the improved SFA, which do not and do, respectively, take into account rescattering of the freed electron off the parent ion.…

[Phys. Rev. A 93, 063418] Published Mon Jun 20, 2016

]]>We study properties of the single-site reduced density matrix in the Bose-Bose resonance model as a function of system parameters. This model describes a single-component Bose gas with a resonant coupling to a diatomic molecular state, here defined on a lattice. A main goal is to demonstrate that th…

[Phys. Rev. A 93, 063624] Published Mon Jun 20, 2016

]]>We study the quantum walks of two interacting spin-1 bosons. We derive an exact solution for the time-dependent wave function, which describes the two-particle dynamics governed by the one-dimensional spin-1 Bose-Hubbard model. We show that propagation dynamics in real space and mixing dynamics in s…

[Phys. Rev. A 93, 063625] Published Mon Jun 20, 2016

]]>We propose a scheme to realize a ${Z}_{2}$ topological insulator in a square optical lattice. Different from the conventional topological insulator protected by the time-reversal symmetry, here the optical lattice possesses a hidden symmetry, which is responsible for the present ${Z}_{2}$ topological order. With …

[Phys. Rev. A 93, 063626] Published Mon Jun 20, 2016

]]>We consider a periodic waveguide array whose unit cell consists of a $\mathcal{PT}$-symmetric quadrimer with two competing loss-gain parameter pairs which lead to qualitatively different symmetry-broken phases. It is shown that the transitions between the phases are described by a symmetry-adapted nonlocal curr…

[Phys. Rev. A 93, 063831] Published Mon Jun 20, 2016

]]>We present, discuss, and validate an adapted $S$-matrix formalism for an efficient, simplified treatment of stacked homogeneous periodically structured metasurfaces operated under normally incident plane wave excitation. The proposed formalism can be applied to any material system, arbitrarily shaped …

[Phys. Rev. A 93, 063832] Published Mon Jun 20, 2016

]]>Multiple filamentation of an infrared high-power laser pulse in air is considered. Based on the numerical solution to the unidirectional pulse propagation equation, the effect of radiation external focusing on the spatial structure of the plasma area produced in the filamentation region is studied. …

[Phys. Rev. A 93, 063833] Published Mon Jun 20, 2016

]]>We study the dissipative dynamics of a two-level system under ultrastrong driving when the frequency and strength of the exciting field exceed significantly the transition frequency. We find three qualitatively different regimes of such dynamics: (1) the collapse and revival of oscillations in the p…

[Phys. Rev. A 93, 063834] Published Mon Jun 20, 2016

]]>We analyze resonant light scattering by a cloud of cold atoms with randomly distributed positions in a regime where resonant dipole-dipole interactions between scatterers cannot be neglected. Using a microscopic approach we calculate numerically the collective eigenmodes of the cloud for many realiz…

[Phys. Rev. A 93, 063835] Published Mon Jun 20, 2016

]]>[Phys. Rev. A 93, 069904] Published Mon Jun 20, 2016

]]>$\mathcal{PT}$ symmetry, that is, a combined parity and time-reversal symmetry, is a key milestone for non-Hermitian systems exhibiting entirely real eigenenergy. In the present work, motivated by a recent experiment, we study $\mathcal{PT}$ symmetry of the time-evolution operator of nonunitary quantum walks. We present th…

[Phys. Rev. A 93, 062116] Published Fri Jun 17, 2016

]]>