We study radiative processes of uniformly accelerated entangled atoms, interacting with an electromagnetic field prepared in the Minkowski vacuum state. We discuss the structure of the rate of variation of the atomic energy for two atoms traveling in different hyperbolic world lines. We identify the…

[Phys. Rev. A 93, 052117] Published Fri May 27, 2016

]]>The products of weak values of quantum observables are shown to be of value in deriving quantum uncertainty and complementarity relations, for both weak and strong measurement statistics. First, a “product representation formula” allows the standard Heisenberg uncertainty relation to be derived from…

[Phys. Rev. A 93, 052118] Published Fri May 27, 2016

]]>In this work we present the concept of a quantum flywheel coupled to a quantum heat engine. The flywheel stores useful work in its energy levels, while additional power is extracted continuously from the device. Generally, the energy exchange between a quantum engine and a quantized work repository …

[Phys. Rev. A 93, 052119] Published Fri May 27, 2016

]]>Doubly and triply differential cross sections for the bremsstrahlung emission by high-energy spin-polarized electrons in the field of heavy bare nuclei are calculated within a fully relativistic partial-wave approach at collision energies between 1 and 30 MeV. Investigating ${}^{208}\mathrm{Pb}$ as a test case, it …

[Phys. Rev. A 93, 052716] Published Fri May 27, 2016

]]>We theoretically investigate molecular photoelectron momentum distributions (MPMDs) by bichromatic [frequencies $({\omega}_{1},{\omega}_{2})]$ circularly polarized attosecond UV laser pulses. Simulations performed on aligned single-electron ${\mathrm{H}}_{2}{}^{+}$ by numerically solving the corresponding three-dimensional time-dependent Sch…

[Phys. Rev. A 93, 053425] Published Fri May 27, 2016

]]>Exploiting the correspondence between the Wigner distribution function and the frequency-resolved optical gating (FROG) measurement, we experimentally demonstrate the existence of chessboardlike interference patterns with a time-bandwidth product smaller than that of a transform-limited pulse in the…

[Phys. Rev. A 93, 053835] Published Fri May 27, 2016

]]>We use weak-value amplification to enhance the polarization-sensitive fast-light effect from induced Raman absorption in hot rubidium vapor. We experimentally demonstrate that projecting the output signal into an appropriate polarization state enables a pulse advancement of $4.2\phantom{\rule{0.16em}{0ex}}\mu \mathrm{s}$, which is more than…

[Phys. Rev. A 93, 053836] Published Fri May 27, 2016

]]>[Phys. Rev. A 93, 059905] Published Fri May 27, 2016

]]>Although there is a broad consensus on the fact that critical behavior in stacked triangular Heisenberg antiferromagnets—an example of frustrated magnets with competing interactions—is described by a Landau-Ginzburg-Wilson Hamiltonian with $\text{O}\left(3\right)\times \text{O}\left(2\right)$ symmetry, the nature of the phase transition in th…

[Phys. Rev. A 93, 051603(R)] Published Thu May 26, 2016

]]>Topologically ordered phase has emerged as one of most exciting concepts that not only broadens our understanding of phases of matter, but also has been found to have potential application in fault-tolerant quantum computation. The direct measurement of topological properties, however, is still a ch…

[Phys. Rev. A 93, 052116] Published Thu May 26, 2016

]]>We consider physical situations where the resource theories of coherence and thermodynamics play competing roles. In particular, we study the creation of quantum coherence using unitary operations with limited thermodynamic resources. We find the maximal coherence that can be created under unitary o…

[Phys. Rev. A 93, 052335] Published Thu May 26, 2016

]]>We present quantum fidelity benchmarks for continuous-variable (CV) quantum devices to outperform quantum channels which can transmit at most $k$-dimensional coherences for positive integers $k$. We determine an upper bound of an average fidelity over Gaussian distributed coherent states for quantum cha…

[Phys. Rev. A 93, 052336] Published Thu May 26, 2016

]]>The tune-out wavelength at 413 nm for the $2{\phantom{\rule{0.28em}{0ex}}}^{3}{S}_{1}$ state of helium is expected to be sensitive to finite nuclear mass, relativistic, and quantum electrodynamic (QED) corrections, which provides a scheme for testing atomic structure theory [J. Mitroy and L.-Y. Tang, Phys. Rev. A **88**, 052515 (2013)]. In th…

[Phys. Rev. A 93, 052516] Published Thu May 26, 2016

]]>Hyperfine-induced electric dipole contributions may significantly increase probabilities of otherwise very weak electric octupole and magnetic quadrupole atomic clock transitions (e.g., transitions between $s$ and $f$ electron orbitals). These transitions can be used for exceptionally accurate atomic cl…

[Phys. Rev. A 93, 052517] Published Thu May 26, 2016

]]>We report on an efficient production scheme for a large quantum degenerate sample of fermionic lithium. The approach is based on our previous work on narrow-line $2{S}_{1/2}\to 3{P}_{3/2}$ laser cooling resulting in a high phase-space density of up to $3\times {10}^{-4}$. This allows utilizing a large-volume crossed optical di…

[Phys. Rev. A 93, 053424] Published Thu May 26, 2016

]]>We demonstrate the relativistic electromagnetic force and power distributions of the field-kinetic and canonical electromagnetic subsystems with respect to light normally incident upon a moving, lossless magnetodielectric slab of material. Time-averaged and time-varying studies are preformed to demo…

[Phys. Rev. A 93, 053832] Published Thu May 26, 2016

]]>We demonstrate that a lateral optical force (LOF) can be induced on chiral nanoparticles immersed in the two interfering plane waves. The LOF can push the chiral nanoparticle sideways, in the direction relying on the helicity of the particle as well as the phase difference between two waves. Analyti…

[Phys. Rev. A 93, 053833] Published Thu May 26, 2016

]]>We analyze theoretically and investigate experimentally the transfer of phase to intensity power spectra of spatial frequencies through free-space Fresnel diffraction. Depending on $\lambda z$ (where $\lambda $ is the wavelength and $z$ is the free-space propagation distance) and the phase-modulation strength $S$, we dem…

[Phys. Rev. A 93, 053834] Published Thu May 26, 2016

]]>We present a family of quantum error-correcting codes that support a universal set of transversal logic gates using only local operations on a two-dimensional array of physical qubits. The construction is a subsystem version of color codes where gauge fixing through local measurements dynamically de…

[Phys. Rev. A 93, 052332] Published Wed May 25, 2016

]]>We generalize the efficient decomposition method for phase-sparse diagonal operators of J. Welch *et al.* [Quantum Info. Comput. **16**, 87 (2016)] to qudit systems. The phase-context-aware method focuses on cascaded entanglers, whose decomposition into multicontrolled inc gates can be optimized by the ch…

[Phys. Rev. A 93, 052333] Published Wed May 25, 2016

]]>We propose a quantum algorithm for solving the following problem: given the Hamiltonian of a physical system and one of its eigenvalues, how do we obtain the corresponding eigenstate? The algorithm is based on the resonance phenomenon. For a probe qubit coupled to a quantum system, the system exhibi…

[Phys. Rev. A 93, 052334] Published Wed May 25, 2016

]]>By using a well-established “*ab initio*” theoretical approach developed in the past to quantitatively study the superconductivity of condensed matter systems, based on the Kohn-Sham density functional theory, I study the superfluid properties and the BCS-BEC crossover of two parallel bi-dimensional l…

[Phys. Rev. A 93, 053627] Published Wed May 25, 2016

]]>Speed is a notion that formally sets bounds on the time that a quantum system takes to evolve. Here it is shown that speed is related to the notion of asymmetry, a result that provides direct connection with the problem of quantifying the coherence of quantum states.

[Phys. Rev. A 93, 052331] Published Tue May 24, 2016

]]>The rovibrational eigenenergy set of molecular systems is a key feature needed to understand and model elementary chemical reactions. A unique class of molecular systems, represented by an ${}^{4}{A}^{\prime \prime}$ excited electronic state of the ${\left[\mathrm{H},\mathrm{S},\mathrm{N}\right]}^{-}$ system comprising several distinct dipole-bound isomers, is found…

[Phys. Rev. A 93, 052514] Published Tue May 24, 2016

]]>We use analytic (current) density-potential maps of time-dependent (current) density-functional theory [TD(C)DFT] to inverse engineer analytically solvable time-dependent quantum problems. In this approach the driving potential (the control signal) and the corresponding solution of the Schrödinger e…

[Phys. Rev. A 93, 052515] Published Tue May 24, 2016

]]>We present a comprehensive study of electron collisions with boron atoms by using the $B$-spline $R$-matrix method for electron energies ranging from threshold to 100 eV. Elastic, excitation, and ionization cross sections were obtained for all transitions between the lowest 11 states of boron. A multico…

[Phys. Rev. A 93, 052715] Published Tue May 24, 2016

]]>A magneto-optical trap (MOT) of atoms or molecules is studied when two lasers of different detunings and polarization are used. Especially for $J\to J,J-1$ transitions, a scheme using more than one frequency per transition and different polarization is required to create a significant force. Calculations…

[Phys. Rev. A 93, 053423] Published Tue May 24, 2016

]]>The liquid-to-ordered phase transition in a bilayer system of fermions is studied within the context of our recently proposed density-functional theory [B. P. van Zyl, W. Kirkby, and W. Ferguson, Phys. Rev. A **92**, 023614 (2015)]. In each two-dimensional layer, the fermions interact via a repulsive, i…

[Phys. Rev. A 93, 053626] Published Tue May 24, 2016

]]>The study of the spatiotemporal dynamics of two counterpropagating beams in optical fibers has recently been the subject of a growing renewed interest. This system has been shown to exhibit a phenomenon of polarization attraction which can be used to achieve a complete polarization of an initially u…

[Phys. Rev. A 93, 053830] Published Tue May 24, 2016

]]>We investigate squeezing of the resonance fluorescence of a laser-driven quantum dot (QD) close to a graphene sheet. The coupling between the QD and the surface plasmon around the graphene sheet is frequency dependent in the terahertz region, which can be adjusted by the laser intensity. Distinct de…

[Phys. Rev. A 93, 053831] Published Tue May 24, 2016

]]>[Phys. Rev. A 93, 059904] Published Tue May 24, 2016

]]>Suppose a quantum system starts to evolve under a Hamiltonian from some initial state. When, for the first time, will an observable attain a preassigned value? To answer this question, one method often adopted is to make instantaneous measurements periodically and note down the serial number for whi…

[Phys. Rev. A 93, 050103(R)] Published Mon May 23, 2016

]]>We propose a protocol for the manipulation of a three-level artificial atom in Lambda ($\mathrm{\Lambda}$) configuration. It allows faithful, selective and robust population transfer analogous to stimulated Raman adiabatic passage ($\mathrm{\Lambda}$-STIRAP), in last-generation superconducting artificial atoms, where protection from…

[Phys. Rev. A 93, 051801(R)] Published Mon May 23, 2016

]]>The relation between the incompatibility of general quantum measurements and quantum nonlocality is investigated, where it is shown that measurement incompatibility does not imply Bell nonlocality.

[Phys. Rev. A 93, 052115] Published Mon May 23, 2016

]]>Density functional theory is currently the most widely applied method in electronic structure theory. The Kohn-Sham method, based on a fictitious system of noninteracting particles, is the workhorse of the theory. The particular form of the Kohn-Sham wave function admits only idempotent one-electron…

[Phys. Rev. A 93, 052512] Published Mon May 23, 2016

]]>We analyze atomic structures of plasma-embedded aluminum (Al) atom and its ions in the weak- and strong-coupling regimes. The plasma screening effects in these atomic systems are accounted for using the Debye and ion-sphere (IS) potentials for the weakly and strongly coupled plasmas, respectively. W…

[Phys. Rev. A 93, 052513] Published Mon May 23, 2016

]]>We calculate near-threshold bound states and Feshbach resonance positions for atom–rigid-rotor models of the highly anisotropic systems Li+CaH and Li+CaF. We perform statistical analysis on the resonance positions to compare with the predictions of random matrix theory. For Li+CaH with total angular…

[Phys. Rev. A 93, 052713] Published Mon May 23, 2016

]]>We consider two ultracold particles confined in a spherically symmetric harmonic trap and interacting via isotropic potential with absorbing boundary conditions at short range that models reactive scattering. First, we apply the contact pseudopotential with complex scattering length and investigate …

[Phys. Rev. A 93, 052714] Published Mon May 23, 2016

]]>The polarization correlations in doubly differential cross sections are investigated for photoionization and ordinary bremsstrahlung. These correlations describe the polarization transfer between incident light and ejected photoelectrons as well as between an incoming electron beam and bremsstrahlun…

[Phys. Rev. A 93, 053421] Published Mon May 23, 2016

]]>Selected features of nonsequential double ionization have been qualitatively reproduced by a multitude of different (quantum and classical) approaches. In general, however, the typical uncertainty of laser pulse parameters and the restricted number of observables measured in individual experiments l…

[Phys. Rev. A 93, 053422] Published Mon May 23, 2016

]]>Hysteresis can be found in driven many-body systems such as magnets and superfluids. Rate-dependent hysteresis arises when a system is driven periodically while relaxing towards equilibrium. A two-state paramagnet driven by an oscillating magnetic field in the relaxation approximation clearly demons…

[Phys. Rev. A 93, 053617] Published Mon May 23, 2016

]]>We calculate the first two moments and full probability distribution of the work performed on a system of bosonic particles in a two-mode Bose-Hubbard Hamiltonian when the self-interaction term is varied instantaneously or with a finite-time ramp. In the instantaneous case, we show how the irreversi…

[Phys. Rev. A 93, 053618] Published Mon May 23, 2016

]]>Estimating the temperature of a cold quantum system is difficult. Usually one measures a well-understood thermal state and uses that prior knowledge to infer its temperature. In contrast, we introduce a method of thermometry that assumes minimal knowledge of the state of a system and is potentially …

[Phys. Rev. A 93, 053619] Published Mon May 23, 2016

]]>We investigate the dynamics following a global parameter quench for two one-dimensional models with variable-range power-law interactions: a long-range transverse Ising model, which has recently been realized in chains of trapped ions, and a long-range lattice model for spinless fermions with long-r…

[Phys. Rev. A 93, 053620] Published Mon May 23, 2016

]]>We study the quench dynamics of a Bose-Einstein condensate under a Raman-assisted synthetic spin-orbit coupling. To model the dynamical process, we adopt a self-consistent Bogoliubov approach, which is equivalent to applying the time-dependent Bogoliubov–de Gennes equations. We investigate the dynam…

[Phys. Rev. A 93, 053621] Published Mon May 23, 2016

]]>The Berezinskii-Kosterlitz-Thouless (BKT) theorem predicts that two-dimensional bosonic condensates exhibit quasi-long-range order which is characterized by a slow decay of the spatial coherence. However previous measurements on exciton-polariton condensates revealed that their spatial coherence can…

[Phys. Rev. A 93, 053622] Published Mon May 23, 2016

]]>In the context of Gross-Pitaevskii theory, we investigate the unconventional Bose-Einstein condensations in the two-species mixture with $p$-wave symmetry in the second band of a bipartite optical lattice. An imaginary-time propagation method is developed to numerically determine the $p$-orbital condens…

[Phys. Rev. A 93, 053623] Published Mon May 23, 2016

]]>We study finite-temperature properties of ultracold four-component mixtures of alkaline-earth-metal-like atoms in optical lattices that can be effectively described by the two-band spin-$1/2$ Hubbard model including Hund's exchange coupling term. Our main goal is to investigate the effect of exchange …

[Phys. Rev. A 93, 053624] Published Mon May 23, 2016

]]>In analogy with quantum optics it is possible to impose nonseparability between different degrees of freedom of an optical beam. The resulting correlations between these degrees of freedom can be investigated with correlations functions traditionally employed in quantum mechanics, such as the well-k…

[Phys. Rev. A 93, 053829] Published Mon May 23, 2016

]]>[Phys. Rev. A 93, 059902] Published Mon May 23, 2016

]]>[Phys. Rev. A 93, 059903] Published Mon May 23, 2016

]]>Fibonacci anyons are non-Abelian particles for which braiding is universal for quantum computation. Reichardt has shown how to systematically generate nontrivial braids for three Fibonacci anyons which yield unitary operations with off-diagonal matrix elements that can be made arbitrarily small in a…

[Phys. Rev. A 93, 052328] Published Fri May 20, 2016

]]>Adiabatic pulses are used extensively to enable robust control of quantum operations. We introduce an approach to adiabatic control that uses the superadiabatic quality factor as a performance metric to design robust, high-fidelity pulses. This approach permits the systematic design of quantum contr…

[Phys. Rev. A 93, 052329] Published Fri May 20, 2016

]]>We investigate two special classes of two-mode Gaussian states of light that are important from both the experimental and theoretical points of view: the mode-mixed thermal states and the squeezed thermal ones. Aiming to a parallel study, we write the Uhlmann fidelity between pairs of states belongi…

[Phys. Rev. A 93, 052330] Published Fri May 20, 2016

]]>Ongoing improvements in the measurement of positronium transition intervals motivate the calculation of the $O\left(m{\alpha}^{7}\right)$ corrections to these intervals. In this work we focus on corrections to the spin-singlet parapositronium energies involving virtual annihilation to two photons in an intermediate state.…

[Phys. Rev. A 93, 052511] Published Fri May 20, 2016

]]>Double-differential cross sections for ionization of tetrahydrofuran by protons with energies from 300 to $3000\phantom{\rule{0.16em}{0ex}}\mathrm{keV}$ were measured at the Physikalisch-Technische Bundesanstalt ion accelerator facility. The electrons emitted at angles between ${15}^{\circ}$ and ${150}^{\circ}$ relative to the ion-beam direction were detected…

[Phys. Rev. A 93, 052711] Published Fri May 20, 2016

]]>Predicted 20 years ago, positron binding to neutral atoms has not yet been observed experimentally. A scheme is proposed to detect positron-atom bound states by colliding Rydberg positronium (Ps) with neutral atoms. Estimates of the charge-transfer reaction cross section are obtained using the first…

[Phys. Rev. A 93, 052712] Published Fri May 20, 2016

]]>We study the classical dynamics of many interacting particles in a periodically driven one-dimensional (1D) system. We show that under the rotating wave approximation (RWA), a short-distance 1D interaction ($\delta $ function or hard-core interaction) becomes a long-distance two-dimensional (2D) interaction…

[Phys. Rev. A 93, 053616] Published Fri May 20, 2016

]]>We present a proposal for reversing the weak (partial-collapse) quantum measurement on a cavity field with arbitrary maximum photon number. We start by putting forth a protocol to realize quantum phase gates between the cavity field and an ancilla qubit. Afterward, adopting these phase gates and som…

[Phys. Rev. A 93, 053826] Published Fri May 20, 2016

]]>In this paper, we theoretically investigate the displacement and momentum fluctuations spectra of the movable mirror in a standard optomechanical system driven by a finite-bandwidth squeezed vacuum light accompanying a coherent laser field. Two cases in which the squeezed vacuum is generated by dege…

[Phys. Rev. A 93, 053827] Published Fri May 20, 2016

]]>So far, Brillouin scattering and cavity optomechanics have been mostly disconnected branches of research, although both deal with photon-phonon coupling. This begs for the development of a broader theory that contains both fields. Here, we derive the dynamics of optomechanical cavities from that of …

[Phys. Rev. A 93, 053828] Published Fri May 20, 2016

]]>For systems analogous to a linear harmonic oscillator, the simplest way to characterize the state is by a covariance matrix containing the symmetrically ordered moments of operators analogous to position and momentum. We show that using Stokes-like detectors without direct access to either position …

[Phys. Rev. A 93, 052114] Published Thu May 19, 2016

]]>Three-level quantum systems, which possess some unique characteristics beyond two-level ones, such as electromagnetically induced transparency, coherent trapping, and Raman scatting, play important roles in solid-state quantum information processing. Here, we introduce an approach to implement the p…

[Phys. Rev. A 93, 052324] Published Thu May 19, 2016

]]>Recently, W. Lechner, P. Hauke, and P. Zoller [Sci. Adv. **1**, e1500838 (2015)] have proposed a quantum annealing architecture, in which a classical spin glass with all-to-all pairwise connectivity is simulated by a spin glass with geometrically local interactions. We interpret this architecture as a c…

[Phys. Rev. A 93, 052325] Published Thu May 19, 2016

]]>As large-scale multimode Gaussian states begin to become accessible in the laboratory, their representation and analysis become a useful topic of research in their own right. The graphical calculus for Gaussian pure states provides powerful tools for their representation, while this work presents a …

[Phys. Rev. A 93, 052326] Published Thu May 19, 2016

]]>Spontaneous Raman scattering (SRS) in atomic ensembles provides a promising method to generate spin-wave–photon entangled states. In the past experiments, a spin-wave–photon entangled state was produced via SRS from an atomic ensemble. Here, we report a scheme of simultaneously generating two spin-w…

[Phys. Rev. A 93, 052327] Published Thu May 19, 2016

]]>We present an experimental and theoretical study of the emission and absorption spectra of the ${\mathrm{Ba}}^{+}$ ions and ${\mathrm{Ba}}^{+*}\mathrm{He}$ excimer quasimolecules in the cryogenic Ba-He plasma. We observe several spectral features in the emission spectrum, which we assign to the electronic transitions between bound states o…

[Phys. Rev. A 93, 052510] Published Thu May 19, 2016

]]>We investigate high-order-harmonic generation in inhomogeneous media for reduced dimensionality models. We perform a phase-space analysis, in which we identify specific features caused by the field inhomogeneity. We compute high-order-harmonic spectra using the numerical solution of the time-depende…

[Phys. Rev. A 93, 053419] Published Thu May 19, 2016

]]>Coupled atom-cavity arrays, such as those described by the Jaynes-Cummings-Hubbard model, have the potential to emulate a wide range of condensed-matter phenomena. In particular, the strongly correlated states of the fractional quantum Hall effect can be realized. At some filling fractions, the frac…

[Phys. Rev. A 93, 053614] Published Thu May 19, 2016

]]>The mechanism of light-shift-related uncertainty in an atom-interferometry gravimeter is investigated systematically, which arises from the inhomogeneous intensity of Raman beams and the Gaussian distribution of an atomic cloud. Experiments using atom interferometry are performed to verify this syst…

[Phys. Rev. A 93, 053615] Published Thu May 19, 2016

]]>We construct the photon-added coherent states of a noncommutative harmonic oscillator associated to a $q$-deformed oscillator algebra. Various nonclassical properties of the corresponding system are explored, first, by studying two different types of higher-order quadrature squeezing, namely, the Hill…

[Phys. Rev. A 93, 053824] Published Thu May 19, 2016

]]>We present a detailed quantum electrodynamical description of Vavilov-Cherenkov radiation emitted by a relativistic twisted electron in the transparent medium. Simple expressions for the spectral and spectral-angular distributions as well as for the polarization properties of the emitted radiation a…

[Phys. Rev. A 93, 053825] Published Thu May 19, 2016

]]>We consider a quantum particle on a one-dimensional lattice subject to weak local measurements and study its stochastic dynamics conditioned on the measurement outcomes. Depending on the measurement strength our analysis of the quantum trajectories reveals dynamical regimes ranging from quasicoheren…

[Phys. Rev. A 93, 052113] Published Wed May 18, 2016

]]>Both simulated quantum annealing and physical quantum annealing have shown the emergence of “heavy tails” in their performance as optimizers: The total time needed to solve a set of random input instances is dominated by a small number of very hard instances. Classical simulated annealing, in contra…

[Phys. Rev. A 93, 052320] Published Wed May 18, 2016

]]>Recent theoretical investigations treat quantum computations as functions, quantum processes which operate on other quantum processes, rather than circuits. Much attention has been given to the $N$-switch function which takes $N$ black-box quantum operators as input, coherently permutes their ordering, …

[Phys. Rev. A 93, 052321] Published Wed May 18, 2016

]]>An algorithm is proposed that serves to handle full-rank density matrices when coming from a lower-rank method to compute the convex roof. This is in order to calculate an upper bound for any polynomial SL-invariant multipartite entanglement measure $E$. This study exemplifies how this algorithm works…

[Phys. Rev. A 93, 052322] Published Wed May 18, 2016

]]>The existence of incompatible measurements, epitomized by Heisenberg's uncertainty principle, is one of the distinctive features of quantum theory. So far, quantum incompatibility has been studied for measurements that test the preparation of physical systems. Here we extend the notion to measuremen…

[Phys. Rev. A 93, 052323] Published Wed May 18, 2016

]]>Charge exchange in ${\mathrm{C}}^{6+}\text{-He}$ and ${\text{-H}}_{2}$ collisions followed by x-ray emission is examined using the two-center basis generator method for low to intermediate projectile energies. Within the independent electron model, we calculate capture cross sections and perform a radiative cascade analysis to obtain L…

[Phys. Rev. A 93, 052710] Published Wed May 18, 2016

]]>We study, numerically and experimentally, the momentum distribution of atoms cooled in optical lattices. Using semiclassical simulations, we show that this distribution is bimodal, made up of a central feature corresponding to “cold,” trapped atoms, with tails of “hot,” untrapped atoms, and that thi…

[Phys. Rev. A 93, 053416] Published Wed May 18, 2016

]]>An excitation scheme for transferring alkaline-earth-metal atoms from their ground state to metastable states is proposed, where the employed three-photon process is demonstrated to have transfer efficiencies as high as about 90% and can be managed to avoid momentum transfer to the degenerate gas during the excitation.

[Phys. Rev. A 93, 053417] Published Wed May 18, 2016

]]>We present a monotonic convergent quantum optimal control method that can be utilized to optimize the control field while exactly enforcing multiple equality constraints for steering quantum systems from an initial state towards desired quantum states. For illustration, special consideration is give…

[Phys. Rev. A 93, 053418] Published Wed May 18, 2016

]]>We present an exploratory study that suggests that Efimov physics, a leading research theme in few-body quantum physics, can also induce stable many-body ground states whose building blocks are universal clusters. We identify a range of parameters in a mass-and-density-imbalanced two-species fermion…

[Phys. Rev. A 93, 053611] Published Wed May 18, 2016

]]>Bose-Einstein condensates (BECs) offer the potential to examine quantum behavior at large length and time scales, as well as forming promising candidates for quantum technology applications. Thus, the manipulation of BECs using control fields is a topic of prime interest. We consider BECs in the mea…

[Phys. Rev. A 93, 053612] Published Wed May 18, 2016

]]>We consider analytically the dynamics of an arbitrary number and configuration of vortices in an annular Bose-Einstein condensate obtaining expressions for the free energy and vortex precession rates to logarithmic accuracy. We also obtain lower bounds for the lifetime of a single vortex in the annu…

[Phys. Rev. A 93, 053613] Published Wed May 18, 2016

]]>The certification of Bell nonlocality or quantum steering implies the use of incompatible measurements. Here we make this connection quantitative. We show how to strengthen robustness-based steering and nonlocality quantifiers in order that they give strong lower bounds to previously proposed incomp…

[Phys. Rev. A 93, 052112] Published Tue May 17, 2016

]]>The standard closed-orbit theory is extended for the photodetachment of negative ions in a time-dependent electric field. The time-dependent photodetachment rate is specifically studied in the presence of a single-cycle terahertz pulse, based on exact quantum simulations and semiclassical analysis. …

[Phys. Rev. A 93, 053413] Published Tue May 17, 2016

]]>We study the photodetachment of an electron from the hydrogen anion due to short, high-frequency laser pulses by numerically solving the time-dependent Schrödinger equation. Simulations are performed to investigate the dependence of the photoelectron spectra on the duration, chirp, and intensity of …

[Phys. Rev. A 93, 053414] Published Tue May 17, 2016

]]>Motional ground state cooling and internal state preparation are important elements for quantum logic spectroscopy (QLS), a class of quantum information processing. Since QLS does not require the high gate fidelities usually associated with quantum computation and quantum simulation, it is possible …

[Phys. Rev. A 93, 053415] Published Tue May 17, 2016

]]>We report an alternate type of nonlinear waveguides, photorefractive surface nonlinearly chirped waveguide arrays, which can be directly induced by photorefractive surface waves in virtue of diffusion and drift nonlinearities. The amplitude of such nonlinearly chirped waveguide arrays has an apodize…

[Phys. Rev. A 93, 053822] Published Tue May 17, 2016

]]>Quantum transition probabilities and quantum entanglement for two-qubit states of a four-level trapped ion quantum system are computed for time-evolving ionic states driven by Jaynes-Cummings Hamiltonians with interactions mapped onto a $\text{SU}\left(2\right)\otimes \text{SU}\left(2\right)$ group structure. Using the correspondence of the me…

[Phys. Rev. A 93, 053823] Published Tue May 17, 2016

]]>We experimentally investigate a scheme for studying lattice transport phenomena, based on the controlled momentum-space dynamics of ultracold atomic matter waves. In the effective tight-binding models that can be simulated, we demonstrate that this technique allows for a local and time-dependent con…

[Phys. Rev. A 93, 051602(R)] Published Mon May 16, 2016

]]>A quantum-state preparation scheme is demonstrated for the next generation ACME experiment searching for the electron electric dipole moment in ThO molecules, where the stimulated Raman adiabatic passage technique, together with other experimental improvements, brings in at least a 75 times increase in combined preparation and detection efficiency of the molecules in the target state.

[Phys. Rev. A 93, 052110] Published Mon May 16, 2016

]]>A well-known situation in which a non-Markovian dynamics of an open quantum system $S$ arises is when this is coherently coupled to an auxiliary system $M$ in contact with a Markovian bath. In such cases, while the joint dynamics of $S\text{\u2212}M$ is Markovian and obeys a standard (bipartite) Lindblad-type master …

[Phys. Rev. A 93, 052111] Published Mon May 16, 2016

]]>The predictive information required for proper trajectory sampling of a stochastic process can be more efficiently transmitted via a quantum channel than a classical one. This recent discovery allows quantum information processing to drastically reduce the memory necessary to simulate complex classi…

[Phys. Rev. A 93, 052317] Published Mon May 16, 2016

]]>We experimentally demonstrate the underlying physical mechanism of the recently proposed protocol for superreplication of quantum phase gates [W. Dür, P. Sekatski, and M. Skotiniotis, Phys. Rev. Lett. **114**, 120503 (2015)], which allows producing up to ${N}^{2}$ high-fidelity replicas from $N$ input copies in …

[Phys. Rev. A 93, 052318] Published Mon May 16, 2016

]]>The topological phases in a one-dimensional quantum walk can be classified by the coin parameters. By solving for the general exact solutions of bound states in a one-dimensional quantum walk with boundaries specified by different coin parameters, we show that these bound states are Majorana modes w…

[Phys. Rev. A 93, 052319] Published Mon May 16, 2016

]]>I revisit the problem of the interaction between two dissimilar atoms with one atom in an excited state, recently addressed by Berman [Phys. Rev. A **91**, 042127 (2015)], Donaire *et al.* [Phys. Rev. Lett. **115**, 033201 (2015)], and Milonni and Rafsanjani [Phys. Rev. A **92**, 062711 (2015)], for which precede…

[Phys. Rev. A 93, 052706] Published Mon May 16, 2016

]]>The method of complex scaling is used to calculate $S$- and $P$-wave resonance energies and widths below the $\mathrm{Li}(3s,3p,4s,4p)$ excitation thresholds and positronium $n=2$ formation threshold in the positron-lithium system. We use two different types of model potentials to determine the interaction between t…

[Phys. Rev. A 93, 052707] Published Mon May 16, 2016

]]>We report on energy loss measurements of slow $\left(v\ll {v}_{0}\right)$, highly charged $\left(Q>10\right)$ ions upon transmission through a 1-nm-thick carbon nanomembrane. We emphasize here the scaling of the energy loss with the velocity and charge exchange or loss. We show that a weak linear velocity dependence exists, where…

[Phys. Rev. A 93, 052708] Published Mon May 16, 2016

]]>A model for charge-dependent energy loss of slow ions is developed based on the Thomas-Fermi statistical model of atoms. Using a modified electrostatic potential which takes the ionic charge into account, nuclear and electronic energy transfers are calculated, the latter by an extension of the Firso…

[Phys. Rev. A 93, 052709] Published Mon May 16, 2016

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