The phenomenon of quantum phase transition is considered in the special case in which the evolution laws remain unitary and in which the bound-state energies remain observable. The conventional Hermiticity of observables is lost at the interface, replaced by the so-called quasi-Hermiticity. Several ...

[Phys. Rev. A 97, 042117] Published Fri Apr 20, 2018

]]>The generation of electron vortex states in ionization by intense and short laser pulses is analyzed under the scope of the lowest-order Born approximation. For near-infrared laser fields and nonrelativistic intensities of the order of ${10}^{16}\mathrm{W}/{\mathrm{cm}}^{2}$, we show that one has to modify the nonrelativistic t...

[Phys. Rev. A 97, 043421] Published Fri Apr 20, 2018

]]>During a collision of Bose-Einstein condensates correlated pairs of atoms are emitted. The scattered massive particles, in analogy to photon pairs in quantum optics, might be used in the violation of Bell's inequalities, demonstration of Einstein-Podolsky-Rosen correlations, or sub-shot-noise atomic...

[Phys. Rev. A 97, 043620] Published Fri Apr 20, 2018

]]>We study the one-dimensional dynamics of dark-dark solitons in the miscible regime of two density-coupled Bose-Einstein condensates having repulsive interparticle interactions within each condensate ($g>0$). By using an adiabatic perturbation theory in the parameter ${g}_{12}/g$, we show that, contrary to...

[Phys. Rev. A 97, 043621] Published Fri Apr 20, 2018

]]>Robust high-fidelity parity measurement is an important operation in many applications of quantum computing. In this work we show how in a circuit QED architecture, one can measure parity in a single shot at very high contrast by taking advantage of the nonlinear behavior of a strongly driven microw...

[Phys. Rev. A 97, 043849] Published Fri Apr 20, 2018

]]>We develop an approach to light-matter coupling in waveguide QED based upon scattering amplitudes evaluated via Dyson series. For optical states containing more than single photons, terms in this series become increasingly complex, and we provide a diagrammatic recipe for their evaluation, which is ...

[Phys. Rev. A 97, 043850] Published Fri Apr 20, 2018

]]>We present a general method to calculate the periodic steady state of a driven-dissipative system coupled to a transmission line (and more generally, to a reservoir) under periodic modulation of its parameters. Using Floquet's theorem, we formulate the differential equation for the system's density ...

[Phys. Rev. A 97, 043851] Published Fri Apr 20, 2018

]]>Quantum metrology overcomes standard precision limits and plays a central role in science and technology. Practically, it is vulnerable to imperfections such as decoherence. Here we demonstrate quantum metrology for noisy channels such that entanglement with ancillary qubits enhances the quantum Fis...

[Phys. Rev. A 97, 042112] Published Thu Apr 19, 2018

]]>Macroscopic realism (MR) *per se* specifies that a system which has two macroscopically distinct states available to it (such as a cat being dead or alive) is at all times predetermined to be in one or other of those two states. A minimal assumption of a macroscopic realistic theory therefore is the v...

[Phys. Rev. A 97, 042113] Published Thu Apr 19, 2018

]]>We construct quantifiable generalizations of Leggett-Garg tests for macro- and mesoscopic realism and noninvasive measurability that apply when not all outcomes of measurement can be identified as arising from one of two macroscopically distinguishable states. We show how quantum mechanics predicts ...

[Phys. Rev. A 97, 042114] Published Thu Apr 19, 2018

]]>In this work, we establish a general theory of phase transitions and quantum entanglement in the equilibrium state at arbitrary temperatures. First, we derive a set of universal functional relations between the matrix elements of a two-body reduced density matrix of the canonical density matrix and ...

[Phys. Rev. A 97, 042115] Published Thu Apr 19, 2018

]]>Quantum mechanics at present cannot be unified with the theory of gravity at the deepest level, and to guide research towards the solution of this fundamental problem, we need to look for ways to observe or refute predictions originating from attempts to combine quantum theory with gravity. The infl...

[Phys. Rev. A 97, 042116] Published Thu Apr 19, 2018

]]>We propose a sufficient criterion for the entanglement of tripartite systems based on local sum uncertainty relations for arbitrarily chosen observables of subsystems. This criterion generalizes the tighter criterion for bipartite systems introduced by Zhang *et al.* [C.-J. Zhang, H. Nha, Y.-S. Zhang,...

[Phys. Rev. A 97, 042333] Published Thu Apr 19, 2018

]]>We study quasibound states and scattering with short-range potentials in three dimensions, subject to an axial periodic driving. We find that poles of the scattering $S$ matrix can cross the real energy axis as a function of the drive amplitude, making the $S$ matrix nonanalytic at a singular point. For...

[Phys. Rev. A 97, 042705] Published Thu Apr 19, 2018

]]>We report a complete kinematic study of ${\mathrm{O}}^{-}$-ion formation due to dissociative electron attachment to ${\mathrm{SO}}_{2}$ using the velocity slice imaging technique in the incident electron energy range over the resonances. Two resonances are observed at 5.2 and 7.5 eV, respectively. From the kinetic energy distribut...

[Phys. Rev. A 97, 042706] Published Thu Apr 19, 2018

]]>In the past few years, harmonic generation in solids has attracted tremendous attention. Recently, some experiments of two-dimensional (2D) monolayer or few-layer materials have been carried out. These studies demonstrated that harmonic generation in the 2D case shows a strong dependence on the lase...

[Phys. Rev. A 97, 043420] Published Thu Apr 19, 2018

]]>In this work, we consider a three-dimensional (3D) cubic optical lattice composed of coupled 1D wires with 1D spin-orbit coupling. When the $s$-wave pairing is induced through Feshbach resonance, the system becomes a topological superfluid with ring nodes, which are the ring nodal degeneracies in the ...

[Phys. Rev. A 97, 043618] Published Thu Apr 19, 2018

]]>We investigate theoretically a hybrid system consisting of a Bose-Einstein condensate (BEC) trapped inside a laser-driven membrane-in-the-middle optomechanical cavity assisted with squeezed vacuum injection whose moving membrane interacts both linearly and quadratically with the radiation pressure o...

[Phys. Rev. A 97, 043619] Published Thu Apr 19, 2018

]]>We propose a two-beam pumped cascaded four-wave-mixing (CFWM) scheme with a double-$\mathrm{\Lambda}$ energy-level configuration in ${}^{85}\mathrm{Rb}$ vapor cell and experimentally observe the emission of up to 10 quantum correlated beams from such CFWM scheme. During this process, the seed beam is amplified; four new signal beam...

[Phys. Rev. A 97, 043846] Published Thu Apr 19, 2018

]]>We demonstrate two approaches for unbalanced interferometers as time-bin qubit analyzers for quantum communication, robust against mode distortions and polarization effects as expected from free-space quantum communication systems including wavefront deformations, path fluctuations, pointing errors,...

[Phys. Rev. A 97, 043847] Published Thu Apr 19, 2018

]]>We investigate the optical properties of a two-level system (TLS) coupled to a one-dimensional array of $N$ other TLSs with dipole-dipole coupling between the first neighbors. The first TLS is probed by a weak field, and we assume that it has a decay rate much greater than the decay rates of the other...

[Phys. Rev. A 97, 043848] Published Thu Apr 19, 2018

]]>The ${\mathrm{Ni}}^{12+},{\mathrm{Cu}}^{13+},{\mathrm{Pd}}^{12+}$, and ${\mathrm{Ag}}^{13+}$ highly charged ions (HCIs) are proposed for making very accurate optical clocks with the fractional uncertainties below ${10}^{-19}$ level. These HCIs have simple atomic energy levels, clock transitions with quality factors larger than ${10}^{15}$, and optical magnetic-dipole $(M\mathrm{...}$

[Phys. Rev. A 97, 041403(R)] Published Wed Apr 18, 2018

]]>We systematically investigate scrambling (or delocalizing) processes of quantum information encoded in quantum many-body systems by using numerical exact diagonalization. As a measure of scrambling, we adopt the tripartite mutual information (TMI) that becomes negative when quantum information is de...

[Phys. Rev. A 97, 042330] Published Wed Apr 18, 2018

]]>We present an analysis for measurement-device-independent quantum key distribution with correlated source-light-intensity errors. Numerical results show that the results here can greatly improve the key rate especially with large intensity fluctuations and channel attenuation compared with prior res...

[Phys. Rev. A 97, 042331] Published Wed Apr 18, 2018

]]>We provide a generalization for the polygamy constraint of multiparty entanglement in arbitrary-dimensional quantum systems. By using the $\beta \mathrm{th}$ power of entanglement of assistance for $0\le \beta \le 1$ and the Hamming weight of the binary vector related with the distribution of subsystems, we establish a class of...

[Phys. Rev. A 97, 042332] Published Wed Apr 18, 2018

]]>We apply quantum trajectory Monte Carlo computations in order to model strong-field ionization of atoms by twisted Bessel pulses and calculate photoelectron momentum distributions (PEMD). Since Bessel beams can be considered as an infinite superposition of circularly polarized plane waves with the s...

[Phys. Rev. A 97, 043418] Published Wed Apr 18, 2018

]]>Recently, studies of high-order harmonics (HHG) from atoms driven by bichromatic counter-rotating circularly polarized laser fields as a source of coherent circularly polarized extreme ultraviolet (XUV) and soft-x-ray beams in a tabletop-scale setup have received considerable attention. Here, we dem...

[Phys. Rev. A 97, 043419] Published Wed Apr 18, 2018

]]>We report on a method to calibrate the depth of an optical lattice. It consists of triggering the intrasite dipole mode of the cloud by a sudden phase shift. The corresponding oscillatory motion is directly related to the interband frequencies on a large range of lattice depths. Remarkably, for a mo...

[Phys. Rev. A 97, 043617] Published Wed Apr 18, 2018

]]>We developed a method to calculate two-photon processes in quantum mechanics that replaces the infinite summation over the intermediate states by a perturbation expansion. This latter consists of a series of commutators that involve position, momentum, and Hamiltonian quantum operators. We analyzed ...

[Phys. Rev. A 97, 043842] Published Wed Apr 18, 2018

]]>The rigid-intensity-shift model of differential-phase-contrast imaging assumes that the phase gradient imposed on the transmitted probe by the sample causes the diffraction pattern intensity to shift rigidly by an amount proportional to that phase gradient. This behavior is seldom realized exactly i...

[Phys. Rev. A 97, 043843] Published Wed Apr 18, 2018

]]>Optical media endowed with large nonlinear susceptibilities are highly prized for their employment in frequency conversion and the generation of nonclassical states of light. Although the presence of an optical resonance can greatly increase the nonlinear response (e.g., in epsilon-near-zero materia...

[Phys. Rev. A 97, 043844] Published Wed Apr 18, 2018

]]>Dielectric spheres moving in a dissipative medium are subjected to the effects of optical binding, i.e., a net force resulting from the collective scattering of light. Optical binding is now shown to exist with frictionless cold atoms, bringing as an additional feature the existence of rotating bound states.

[Phys. Rev. A 97, 043845] Published Wed Apr 18, 2018

]]>Synthetic spin-orbit-coupled quantum gases have been widely studied both experimentally and theoretically in the past decade. As shown in previous studies, this modification of single-body dispersion will in general couple different partial waves of the two-body scattering and thus distort the wave ...

[Phys. Rev. A 97, 040701(R)] Published Tue Apr 17, 2018

]]>We prove that temporal control of the strengths of springs connecting $N$ harmonic oscillators in a chain provides complete access to all Gaussian states of $N-1$ collective modes. The proof relies on the construction of a suitable basis of cradle modes for the system. An iterative algorithm to reach an...

[Phys. Rev. A 97, 042111] Published Tue Apr 17, 2018

]]>The method of improving the performance of continuous-variable quantum key distribution protocols by postselection has been recently proposed and verified. In continuous-variable measurement-device-independent quantum key distribution (CV-MDI QKD) protocols, the measurement results are obtained from...

[Phys. Rev. A 97, 042328] Published Tue Apr 17, 2018

]]>It has been found that non-Gaussian operations can be applied to increase and distill entanglement between Gaussian entangled states. We show the successful use of the non-Gaussian operation, in particular, photon subtraction operation, on the continuous-variable measurement-device-independent quant...

[Phys. Rev. A 97, 042329] Published Tue Apr 17, 2018

]]>Ultracold molecules with both electron spin and an electric dipole moment offer new possibilities in quantum science. We use density-functional theory to calculate hyperfine coupling constants for a selection of molecules important in this area, including RbSr, LiYb, RbYb, CaF, and SrF. We find subs...

[Phys. Rev. A 97, 042505] Published Tue Apr 17, 2018

]]>Electron scattering states in combined Coulomb and laser fields are investigated with a nonperturbative approach based on the Hermitian Floquet theory. Taking into account the Coulomb-specific asymptotic behavior of the electron wave functions at large distances, a Lippmann-Schwinger-Floquet equatio...

[Phys. Rev. A 97, 043417] Published Tue Apr 17, 2018

]]>We propose a method to prepare states of given quantized circulation in annular Bose-Einstein condensates (BEC) confined in a ring trap using the method of phase imprinting without relying on a two-photon angular momentum transfer. The desired phase profile is imprinted on the atomic wave function u...

[Phys. Rev. A 97, 043615] Published Tue Apr 17, 2018

]]>We investigate the nature of superfluid pairing in a strongly interacting Fermi gas near orbital Feshbach resonances with spin-population imbalance in three dimensions, which can be well described by a two-band or two-channel model. We show that a Sarma superfluid with gapless single-particle excita...

[Phys. Rev. A 97, 043616] Published Tue Apr 17, 2018

]]>We experimentally demonstrate simultaneous spatial and temporal compression in the propagation of light pulses in multimode nonlinear optical fibers. We reveal that the spatial beam self-cleaning recently discovered in graded-index multimode fibers is accompanied by significant temporal reshaping an...

[Phys. Rev. A 97, 043836] Published Tue Apr 17, 2018

]]>We introduce a formalism to solve the problem of photon scattering from a system of multilevel quantum emitters. Our approach provides a direct solution of the scattering dynamics. As such the formalism gives the scattered fields' amplitudes in the limit of a weak incident intensity. Our formalism i...

[Phys. Rev. A 97, 043837] Published Tue Apr 17, 2018

]]>In a preceding paper we introduced a formalism to study the scattering of low-intensity fields from a system of multilevel emitters embedded in a three-dimensional ($3\mathrm{D}$) dielectric medium. Here we show how this photon-scattering relation can be used to analyze the scattering of single photons and wea...

[Phys. Rev. A 97, 043838] Published Tue Apr 17, 2018

]]>Optical interfaces for quantum emitters are a prerequisite for implementing quantum networks. Here, we couple single molecules to the guided modes of an optical nanofiber. The molecules are embedded within a crystal that provides photostability and, due to the inhomogeneous broadening, a means to sp...

[Phys. Rev. A 97, 043839] Published Tue Apr 17, 2018

]]>Laboratory optics, typically dealing with monochromatic light beams in a single reference frame, exhibits numerous spin-orbit interaction phenomena due to the coupling between the spin and orbital degrees of freedom of light. Similar phenomena appear for electrons and other spinning particles. Here ...

[Phys. Rev. A 97, 043840] Published Tue Apr 17, 2018

]]>The large number of available orbital-angular-momentum (OAM) states of photons provides a unique resource for many important applications in quantum information and optical communications. However, conventional OAM switching devices usually rely on precise parameter control and are limited by slow s...

[Phys. Rev. A 97, 043841] Published Tue Apr 17, 2018

]]>Composite pulses are essential for universal manipulation of singlet-triplet spin qubits. In the absence of noise, they are required to perform arbitrary single-qubit operations due to the special control constraint of a singlet-triplet qubit, while in a noisy environment, more complicated sequences...

[Phys. Rev. A 97, 042324] Published Mon Apr 16, 2018

]]>The entanglement properties of multipartite Gaussian fermionic states are investigated. It is shown that there exist no nontrivial Gaussian local operations assisted by classical communication among pure fully entangled Gaussian fermionic states.

[Phys. Rev. A 97, 042325] Published Mon Apr 16, 2018

]]>A triple-quantum-dot system can be operated as either an exchange-only qubit or a resonant-exchange qubit. While it is generally believed that the decisive advantage of the resonant-exchange qubit is the suppression of charge noise because it is operated at a sweet spot, we show that the leakage is ...

[Phys. Rev. A 97, 042326] Published Mon Apr 16, 2018

]]>A divisible binary classical code is one in which every code word has weight divisible by a fixed integer. If the divisor is ${2}^{\nu}$ for a positive integer $\nu $, then one can construct a Calderbank-Shor-Steane (CSS) code, where $X$-stabilizer space is the divisible classical code, that admits a transversal ga...

[Phys. Rev. A 97, 042327] Published Mon Apr 16, 2018

]]>Collinear laser spectroscopy has been performed on doubly charged ions of radioactive yttrium in order to study the isotope shifts of the 294.6-nm $5s\phantom{\rule{0.16em}{0ex}}{}^{2}S_{1/2}\to 5p\phantom{\rule{0.16em}{0ex}}{}^{2}P_{1/2}$ line. The potential of such an alkali-metal-like transition to improve the reliability of atomic-field-shift and mass-shift factor calcul...

[Phys. Rev. A 97, 042504] Published Mon Apr 16, 2018

]]>Fully differential cross sections (FDCSs) have been calculated for the single ionization of helium by 1- and 3-MeV proton and 100-MeV/u ${\mathrm{C}}^{6+}$ ion impact using the classical trajectory Monte Carlo (CTMC) method in the nonrelativistic, three-body approximation. The calculations were made employing a Wig...

[Phys. Rev. A 97, 042703] Published Mon Apr 16, 2018

]]>A simulation is performed to study the transmission of low-energy $\mathrm{C}{\mathrm{l}}^{-}$ ions through $\mathrm{A}{\mathrm{l}}_{2}{\mathrm{O}}_{3}$ nanocapillaries. For the trajectory simulations, there are several processes involved: the image forces induced by the projectile; the electrostatic force from the deposited charges; the scattering from the inne...

[Phys. Rev. A 97, 042704] Published Mon Apr 16, 2018

]]>Spin-lattice models play a central role in the studies of quantum magnetism and nonequilibrium dynamics of spin excitations—–magnons. We show that a spin lattice with strong nearest-neighbor interactions and tunable long-range hopping of excitations can be realized by a regular array of laser-driven...

[Phys. Rev. A 97, 043415] Published Mon Apr 16, 2018

]]>A method is developed to dispersively detect alkali-metal atoms in radio-frequency-dressed states, allowing for low-noise measurements of atom numbers due to modulation of the atomic response at radio frequencies.

[Phys. Rev. A 97, 043416] Published Mon Apr 16, 2018

]]>We investigate theoretically the effects of pairing fluctuations in an ultracold Fermi gas near a Feshbach resonance with a negative effective range. By employing a many-body $T$-matrix theory with a coupled fermion-boson model, we show that the single-particle density of states exhibits the so-called...

[Phys. Rev. A 97, 043613] Published Mon Apr 16, 2018

]]>We investigated the low-lying collective excitations of quasi-two-dimensional dipolar Bose-Einstein condensates confined in a rotating harmonic potential using the Bogoliubov–de Gennes equation. By varying the trap rotation frequency and dipolar interaction strength, we show how the anisotropic dipo...

[Phys. Rev. A 97, 043614] Published Mon Apr 16, 2018

]]>We analyze nonlinear magneto-optical rotation (NMOR) in rubidium vapor subjected to a continuously scanned magnetic field. By varying the magnetic-field sweep rate, a transition from traditionally observed dispersivelike NMOR signals (low sweep rate) to oscillating signals (higher sweep rates) is de...

[Phys. Rev. A 97, 043832] Published Mon Apr 16, 2018

]]>As superconductor quantum technologies are moving towards large-scale integrated circuits, a robust and flexible approach to routing photons at the quantum level becomes a critical problem. Active circuits, which contain parametrically driven elements selectively embedded in the circuit, offer a via...

[Phys. Rev. A 97, 043833] Published Mon Apr 16, 2018

]]>Optical refrigeration of solids holds tremendous promise for applications in thermal management. It can be achieved through multiple mechanisms including inelastic anti-Stokes Brillouin and Raman scattering. However, engineering of these mechanisms remains relatively unexplored. The major challenge ...

[Phys. Rev. A 97, 043835] Published Mon Apr 16, 2018

]]>Interference patterns from subcycle electron trajectories are experimentally observed in three-dimensional electron momentum distributions of helium atoms in counter-rotating two-color laser fields. Such patterns may be used to extract ultrafast electronic phase information in atoms and molecules.

[Phys. Rev. A 97, 041402(R)] Published Fri Apr 13, 2018

]]>We introduce a class of structured polychromatic surface electromagnetic fields, reminiscent of conventional optical axicon fields, through a judicious superposition of partially correlated surface plasmon polaritons. We show that such partially coherent axiconic surface plasmon polariton fields are...

[Phys. Rev. A 97, 041801(R)] Published Fri Apr 13, 2018

]]>We investigate how the combined effects of strong Ohmic dissipation and monochromatic driving affect the stability of a quantum system with a metastable state. We find that, by increasing the coupling with the environment, the escape time makes a transition from a regime in which it is substantially...

[Phys. Rev. A 97, 042109] Published Fri Apr 13, 2018

]]>Considering the system of three interacting qubits, we analyze four families of states from the point of view of bipartite correlations appearing in two-qubit subsystems of a three-qubit model, such as Einstein-Podolsky-Rosen steering, entanglement, and coherence. We reveal mutual relations among th...

[Phys. Rev. A 97, 042110] Published Fri Apr 13, 2018

]]>We investigate the resonance dipole-dipole interaction energy between two identical atoms, one in the ground state and the other in the excited state, interacting with the electromagnetic field in the presence of a perfectly reflecting plane boundary. The atoms are prepared in a correlated (symmetri...

[Phys. Rev. A 97, 042503] Published Fri Apr 13, 2018

]]>Using a model molecular system (${A}_{2}$) with two active electrons restricted to one dimension, we examine high-order harmonic generation (HHG) enhanced by rescattering. Our results show that even at intensities well below the single ionization saturation, harmonics generated from the cation (${A}_{2}{}^{+}$) can be...

[Phys. Rev. A 97, 043414] Published Fri Apr 13, 2018

]]>Motivated by the recent experimental progress in the study of $p$-wave resonant Fermi gases, we investigate the normal-state properties of such a gas. We calculate the universal equation of state and the two $p$-wave contacts that characterize the universal properties of the system, in good agreement wi...

[Phys. Rev. A 97, 043612] Published Fri Apr 13, 2018

]]>This paper models light scattering through flat surfaces with finite transmission, reflection, and absorption rates, with wave packets approaching the mirror from both sides. While using the same notion of photons as in free space, our model also accounts for the presence of mirror images and the po...

[Phys. Rev. A 97, 043827] Published Fri Apr 13, 2018

]]>Bound states in the continuum (BICs) are trapped or guided modes with their frequencies in the frequency intervals of the radiation modes. On periodic structures, a BIC is surrounded by a family of resonant modes with their quality factors approaching infinity. Typically the quality factors are prop...

[Phys. Rev. A 97, 043828] Published Fri Apr 13, 2018

]]>We present measurements of the third-order optical nonlinearity of Kr, Xe, ${\mathrm{N}}_{2},{\mathrm{O}}_{2}$, and air at a wavelength near 10 µm by using four-wave mixing of $\sim 15-\mathrm{GW}/\mathrm{c}{\mathrm{m}}^{2}$, 200-ps (full width at half maximum) $\mathrm{C}{\mathrm{O}}_{2}$ laser pulses. Measurements in molecular gases resulted in an asymmetric four-wave mixing spectrum ind...

[Phys. Rev. A 97, 043829] Published Fri Apr 13, 2018

]]>Photon catalysis is an intriguing quantum mechanical operation during which no photon is added to or subtracted from the relevant optical system. However, we prove that photon catalysis is in essence equivalent to the simpler but more efficient noiseless linear amplifier. This provides a simple and ...

[Phys. Rev. A 97, 043830] Published Fri Apr 13, 2018

]]>In this work we study the quantum dynamics emerging when quantum emitters exchange excitations with a two-dimensional bosonic bath with a Dirac cone dispersion. We show that a single quantum emitter spectrally tuned in the vicinity of the Dirac point relaxes following a logarithmic law in time. More...

[Phys. Rev. A 97, 043831] Published Fri Apr 13, 2018

]]>In a recent paper [Phys. Rev. A **95**, 032110 (2017)], Duprey and Matzkin investigated the meaning of vanishing weak values and their role in the retrodiction of the past of a preselected and postselected quantum system in the presence of interference. Here we argue that any proposition regarding the w...

[Phys. Rev. A 97, 046102] Published Fri Apr 13, 2018

]]>We discuss the preceding Comment [D. Sokolovski, preceding Comment, Phys. Rev. A **97**, 046102 (2018)] and conclude that the arguments given there against the relevance of null weak values as representing the absence of a system property are not compelling. We give an example in which the transition ma...

[Phys. Rev. A 97, 046103] Published Fri Apr 13, 2018

]]>An experiment on randomness generation is performed with a quantum optical setup, which shows that nonprojective measurements improve randomness generation against the standard protocols that lack such measurements.

[Phys. Rev. A 97, 040102(R)] Published Thu Apr 12, 2018

]]>Are human players suitable to deliver good strategies for developing quantum protocols? While recent results suggest a positive answer to this question, here a simple stochastic local optimization method is shown to outperform all players.

[Phys. Rev. A 97, 040302(R)] Published Thu Apr 12, 2018

]]>We study the properties of transmissivity of a beam of atoms traversing an optical lattice loaded with ultracold atoms. The transmission properties as a function of the energy of the incident particles are dependent on the quantum phase of the atoms in the lattice. In fact, in contrast to an insulat...

[Phys. Rev. A 97, 041602(R)] Published Thu Apr 12, 2018

]]>Investigating the geometric effects resulting from the detailed behaviors of the confining potential, we consider square and circular confinements to constrain a particle to a space curve. We find a torsion-induced geometric potential and a curvature-induced geometric momentum just in the square cas...

[Phys. Rev. A 97, 042108] Published Thu Apr 12, 2018

]]>A quantum appointment-scheduling protocol based on coherent states and basic linear optics operations is proposed. The protocol is shown to perform better than a classical one in terms of information leakage.

[Phys. Rev. A 97, 042320] Published Thu Apr 12, 2018

]]>We propose a strategy for engineering multiqubit quantum gates. As a first step, it employs an *eigengate* to map states in the computational basis to eigenstates of a suitable many-body Hamiltonian. The second step employs resonant driving to enforce a transition between a single pair of eigenstates,...

[Phys. Rev. A 97, 042321] Published Thu Apr 12, 2018

]]>Quantum Fisher information matrix (QFIM) is a cornerstone of modern quantum metrology and quantum information geometry. Apart from optimal estimation, it finds applications in description of quantum speed limits, quantum criticality, quantum phase transitions, coherence, entanglement, and irreversib...

[Phys. Rev. A 97, 042322] Published Thu Apr 12, 2018

]]>We study strong-field dissociative molecular double ionization with momentum-resolved quadruple coincidence measurements, measuring the two electrons and two ionic fragments produced with a coincidence velocity map imaging apparatus. We contrast measurements for two different molecules. In one case,...

[Phys. Rev. A 97, 043412] Published Thu Apr 12, 2018

]]>We studied the ultrafast dynamics of high-order harmonic generation (HHG) from solids numerically. It is found that a superposition of Bloch oscillation in the same band and Zenner tunneling to its neighboring conduction band (i.e., Bloch-Zener oscillation effect) play significant roles in HHG when ...

[Phys. Rev. A 97, 043413] Published Thu Apr 12, 2018

]]>We investigate the transient optical response property of an electromagnetically induced transparency (EIT) in a cold Rydberg atomic gas. We show that both the transient behavior and the steady-state EIT spectrum of the system depend strongly on Rydberg interaction. Especially, the response speed of...

[Phys. Rev. A 97, 043821] Published Thu Apr 12, 2018

]]>We study the effect of focusing of the radially and azimuthally polarized vector beams on the spin angular momentum (SAM) density and Poynting vector of scattered waves from a Mie particle. Remarkably, the study reveals that the SAM density of the scattered field is solely transverse in nature for r...

[Phys. Rev. A 97, 043823] Published Thu Apr 12, 2018

]]>We present a general derivation of the frequency-domain volume integral equation (VIE) for the electric field inside a nonmagnetic scattering object from the differential Maxwell equations, transmission boundary conditions, radiation condition at infinity, and locally-finite-energy condition. The de...

[Phys. Rev. A 97, 043824] Published Thu Apr 12, 2018

]]>We theoretically study laser-scanning confocal fluorescence microscopy using elliptically polarized cylindrical vector excitation light as a tool for visualization of arbitrarily oriented single quantum dipole emitters located (1) near planar surfaces enhancing fluorescence, (2) in a thin supported ...

[Phys. Rev. A 97, 043825] Published Thu Apr 12, 2018

]]>A major objective in photonics is to tailor the emission properties of microcavities which is usually achieved with specific cavity shapes. Yet the dynamical change of the emission properties during operation would often be advantageous. The implementation of such a method is still a challenging iss...

[Phys. Rev. A 97, 043826] Published Thu Apr 12, 2018

]]>A method is proposed to extract local transport properties of unitary Fermi gases with energy-absorption spectroscopy, where such measurements of the kinetic coefficients of the unitary gases are estimated to be within the reach of current experiments.

[Phys. Rev. A 97, 041601(R)] Published Wed Apr 11, 2018

]]>The $\mathcal{PT}$-symmetry-breaking threshold in discrete realizations of systems with balanced gain and loss is determined by the effective coupling between the gain and loss sites. In one-dimensional chains, this threshold is maximum when the two sites are closest to each other or the farthest. We investigat...

[Phys. Rev. A 97, 042107] Published Wed Apr 11, 2018

]]>We consider the task of verifying the correctness of quantum computation for a restricted class of circuits which contain at most two basis changes. This contains circuits giving rise to the second level of the Fourier hierarchy, the lowest level for which there is an established quantum advantage. ...

[Phys. Rev. A 97, 042319] Published Wed Apr 11, 2018

]]>The single ionization of ${\mathrm{H}}_{2}$ in strong laser fields creates the correlated electron-${{\mathrm{H}}_{2}}^{+}$ pair. Based on such a correlation, we conceive a strategy to control the energy spectra of the freed electron or dissociative fragments by simulating the time-dependent Schrödinger equation. Two attosecond pulses ...

[Phys. Rev. A 97, 043411] Published Wed Apr 11, 2018

]]>We numerically examine slow and hierarchical relaxation dynamics of interacting bosons described by a tilted two-band Bose-Hubbard model. The system is found to exhibit signatures of quantum chaos within the spectrum and the validity of the eigenstate thermalization hypothesis for relevant physical ...

[Phys. Rev. A 97, 043610] Published Wed Apr 11, 2018

]]>Cherently splitting a one-dimensional Bose gas provides an attractive, experimentally established platform to investigate many-body quantum dynamics. At short enough times, the dynamics is dominated by the dephasing of single quasiparticles, and well described by the relaxation towards a generalized...

[Phys. Rev. A 97, 043611] Published Wed Apr 11, 2018

]]>We study an optomechanical transistor, where an input field can be transferred and amplified unidirectionally in a cyclic three-mode optomechanical system. In this system, the mechanical resonator is coupled simultaneously to two cavity modes. We show that it only requires a finite mechanical gain t...

[Phys. Rev. A 97, 043818] Published Wed Apr 11, 2018

]]>We study a generic cavity-QED system where a set of (artificial) two-level dipoles is coupled to the electric field of a single-mode $LC$ resonator. This setup is used to derive a minimal quantum mechanical model for cavity QED, which accounts for both dipole-field and direct dipole-dipole interaction...

[Phys. Rev. A 97, 043820] Published Wed Apr 11, 2018

]]>[Phys. Rev. A 97, 049902] Published Wed Apr 11, 2018

]]>Two topics, evolving rapidly in separate fields, were combined recently: the out-of-time-ordered correlator (OTOC) signals quantum-information scrambling in many-body systems. The Kirkwood-Dirac (KD) quasiprobability represents operators in quantum optics. The OTOC was shown to equal a moment of a s...

[Phys. Rev. A 97, 042105] Published Tue Apr 10, 2018

]]>Building on recent work by Gammelmark *et al.* [Phys. Rev. Lett. **111**, 160401 (2013)] we develop a formalism for prediction and retrodiction of Gaussian quantum systems undergoing continuous measurements. We apply the resulting formalism to study the advantage of incorporating a full measurement record...

[Phys. Rev. A 97, 042106] Published Tue Apr 10, 2018

]]>The nuclear spin in the vicinity of a nitrogen-vacancy (NV) center possesses long coherence time and convenient manipulation assisted by the strong hyperfine interaction with the NV center. It is suggested for the subsequent quantum information storage and processing after appropriate initialization...

[Phys. Rev. A 97, 042313] Published Tue Apr 10, 2018

]]>