We derive a microscopic model for dissipative dynamics in a system of mutually interacting qubits coupled to a thermal bath that generalizes the dissipative model of Landau-Lifshitz-Gilbert to the case of anisotropic bath couplings. We show that the dissipation acts to bias the quantum trajectories …

[Phys. Rev. A 94, 062106] Published Fri Dec 09, 2016

]]>We investigate both theoretically and experimentally the dynamics of entanglement and nonlocality for two qubits immersed in a global pure dephasing environment. We demonstrate the existence of a class of states for which entanglement is forever frozen during the dynamics, even if the state of the s…

[Phys. Rev. A 94, 062107] Published Fri Dec 09, 2016

]]>We consider the problem of estimating multiple phases using a multimode interferometer. In this setting we show that while global strategies that estimate all the phases simultaneously can lead to high precision gains, the same enhancements can be obtained with local strategies in which each phase i…

[Phys. Rev. A 94, 062312] Published Fri Dec 09, 2016

]]>We have observed short-range photoassociation of ${}^{7}\mathrm{Li}{}^{85}\mathrm{Rb}$ to the two lowest vibrational states of the $d{\phantom{\rule{0.16em}{0ex}}}^{3}\mathrm{\Pi}$ potential. We have also observed several ${a}^{3}\phantom{\rule{0.16em}{0ex}}{\mathrm{\Sigma}}^{+}$ vibrational levels with generation rates between $\sim {10}^{2}$ and $\sim {10}^{3}$ molecules per second, resulting from the spontaneous decay of these $d{\phantom{\rule{0.16em}{0ex}}}^{3}\mathrm{\Pi}$ molecules. We …

[Phys. Rev. A 94, 062504] Published Fri Dec 09, 2016

]]>We present a theoretical study of the mixed-field-orientation of asymmetric-top molecules in tilted static electric field and nonresonant linearly polarized laser pulse by solving the time-dependent Schrödinger equation. Within this framework, we compute the mixed-field orientation of a state-select…

[Phys. Rev. A 94, 063408] Published Fri Dec 09, 2016

]]>Time delays of electrons emitted from an isotropic initial state with the absorption of a single photon and leaving behind an isotropic ion are angle independent. Using an interferometric method involving XUV attosecond pulse trains and an IR-probe field in combination with a detection scheme, which…

[Phys. Rev. A 94, 063409] Published Fri Dec 09, 2016

]]>As light propagates through a medium, absorption caused by electronic or rovibrational transitions is evident in the transmitted spectrum. The incident electromagnetic field polarizes the medium and the absorption is due to the imaginary part of the linear susceptibility. In the time domain, the fie…

[Phys. Rev. A 94, 063410] Published Fri Dec 09, 2016

]]>Shortcuts to adiabaticity in various quantum systems have attracted much attention with their wide applications in quantum information processing and quantum control. In this paper, we concentrate on a stimulated Raman shortcut-to-adiabatic passage in quantum three-level systems. To implement counte…

[Phys. Rev. A 94, 063411] Published Fri Dec 09, 2016

]]>We present a full theoretical analysis of quasi-phase-matching (QPM) in three-dimensional (3D) periodic structures and point up optimum nonlinear structures, which promote the best nonlinear conversion efficiencies and are close to real structures. The QPM properties of 14 Bravais lattices are inves…

[Phys. Rev. A 94, 063821] Published Fri Dec 09, 2016

]]>Solitons play a fundamental role in the dynamics of nonlinear excitations. Here we explore the motion of solitons in one-dimensional Bose-Einstein condensates subjected to a spin-orbit coupling (SOC). We demonstrate that the spin dynamics of solitons is governed by a nonlinear Bloch equation. The sp…

[Phys. Rev. A 94, 061602(R)] Published Thu Dec 08, 2016

]]>We present an efficient proposal for error-rejecting quantum computing with quantum dots (QDs) embedded in single-sided optical microcavities based on the interface between the circularly polarized photon and QDs. An almost unity fidelity of the quantum entangling gate (EG) can be implemented with a…

[Phys. Rev. A 94, 062310] Published Thu Dec 08, 2016

]]>We present a simplified model for dynamical diffraction of particles through a periodic thick perfect crystal based on repeated application of a coherent beam-splitting unitary at coarse-grained lattice sites. By demanding translational invariance and a computationally tractable number of sites in t…

[Phys. Rev. A 94, 062311] Published Thu Dec 08, 2016

]]>Two recent experimental papers reported the first measurements of *absolute* two-photon-ionization cross sections $\sigma \left(2\right)$ of helium, for EUV wavelengths, using free-electron laser (FEL) pulses [Sato *et al.*, J. Phys. B **44**, 161001 (2011); Fushitani *et al.*, Phys. Rev. A **88**, 063422 (2013)]. The wavelengths…

[Phys. Rev. A 94, 063406] Published Thu Dec 08, 2016

]]>Nonlocal potential models have been used in place of the Coulomb potential in the Schrödinger equation as an efficient means of exploring high-field laser-atom interaction in previous works. Although these models have found use in modeling phenomena including photoionization and ejected electron mom…

[Phys. Rev. A 94, 063407] Published Thu Dec 08, 2016

]]>The dynamic localization of a two-level atom in a periodic potential under the action of spin-orbit coupling and a weak harmonically varying linear force is studied. We consider optical and Zeeman potentials that are either in phase or out of phase in two spinor components, respectively. The expecta…

[Phys. Rev. A 94, 063606] Published Thu Dec 08, 2016

]]>We study three-dimensional Bose and Fermi gases in the upper branch, a phase defined by the absence of bound states in the repulsive interaction regime, within an approximation that considers only two-body interactions. Employing a formalism based on the $S$ matrix, we derive useful analytic expressio…

[Phys. Rev. A 94, 063608] Published Thu Dec 08, 2016

]]>We investigate the phenomenon of optical bistability in a driven ensemble of Rydberg atoms. By performing two experiments with thermal vapors of rubidium and cesium, we are able to shed light on the underlying interaction mechanisms causing such a nonlinear behavior. Due to the different properties …

[Phys. Rev. A 94, 063820] Published Thu Dec 08, 2016

]]>Random local measurements have recently been proposed to construct entanglement witnesses and thereby detect the presence of bipartite entanglement. We experimentally demonstrate the efficacy of one such scheme on a two-qubit NMR quantum-information processor. We show that a set of three random loca…

[Phys. Rev. A 94, 062309] Published Wed Dec 07, 2016

]]>We provide a comprehensive theoretical framework for describing the dynamics of a single trapped ion interacting with a neutral buffer gas, thus extending our previous studies on buffer-gas cooling of ions beyond the critical mass ratio [B. Höltkemeier *et al.*, Phys. Rev. Lett. **116**, 233003 (2016)]. …

[Phys. Rev. A 94, 062703] Published Wed Dec 07, 2016

]]>By using a sum-rule approach we investigate the transition between the hydrodynamic and the collisionless regime of the collective modes in a one-dimensional (1D) harmonically trapped Bose gas. Both the weakly interacting gas and the Tonks-Girardeau limits are considered. We predict that the excitat…

[Phys. Rev. A 94, 063605] Published Wed Dec 07, 2016

]]>We develop an approach to enable the full-wave simulation of stimulated Brillouin scattering and related phenomena in a frequency-domain, finite-element environment. The method uses transformation-optics techniques to implement a time-harmonic coordinate transform that reconciles the different frame…

[Phys. Rev. A 94, 063818] Published Wed Dec 07, 2016

]]>We investigate synchronization effects in quantum self-sustained oscillators theoretically using the micromaser as a model system. We use the probability distribution for the relative phase as a tool for quantifying the emergence of preferred phases when two micromasers are coupled together. Using p…

[Phys. Rev. A 94, 063819] Published Wed Dec 07, 2016

]]>[Phys. Rev. A 94, 069901] Published Wed Dec 07, 2016

]]>A new theory-independent noncontextuality inequality is presented [R. Kunjwal and R. W. Spekkens, Phys. Rev. Lett. **115**, 110403 (2015)] based on a Kochen-Specker (KS) set without imposing the assumption of determinism. By proposing noncontextuality inequalities, we show that such result can be genera…

[Phys. Rev. A 94, 062103] Published Tue Dec 06, 2016

]]>The phase-space description of bosonic quantum systems has numerous applications in such fields as quantum optics, trapped ultracold atoms, and transport phenomena. Extension of this description to the case of fermionic systems leads to formal Grassmann phase-space quasiprobability distributions and…

[Phys. Rev. A 94, 062104] Published Tue Dec 06, 2016

]]>The nonlinear Compton scattering rate in a rotating electric field is explicitly calculated. For this purpose, an approximate solution to the Klein-Gordon equation in the presence of a rotating electric field is applied. An analytical expression for the emission rate is obtained, as well as a simpli…

[Phys. Rev. A 94, 062105] Published Tue Dec 06, 2016

]]>Quantum information processing provides remarkable advantages over its classical counterpart. Quantum optical systems have been proved to be sufficient for realizing general quantum tasks, which, however, often rely on single-photon sources. In practice, imperfect single-photon sources, such as a we…

[Phys. Rev. A 94, 062305] Published Tue Dec 06, 2016

]]>We propose a scheme for frequency-domain quantum computation (FDQC) in which the errors due to crosstalk are suppressed using extra physical systems coupled to a cavity. FDQC is a promising method to realize large-scale quantum computation, but crosstalk is a major problem. When physical systems emp…

[Phys. Rev. A 94, 062306] Published Tue Dec 06, 2016

]]>We propose schemes of controlled-Z and controlled-not gates with ultracold neutral atoms based on deterministic phase accumulation during double adiabatic passage of the Stark-tuned Förster resonance of Rydberg states. The effect of deterministic phase accumulation during double adiabatic passage in…

[Phys. Rev. A 94, 062307] Published Tue Dec 06, 2016

]]>Simulating unitary dynamics unavailable in nature by finite perturbative expansion of its Hamiltonian is a straightforward and intuitive approach which often fails when continuous-variable systems are considered. We propose a solution to this problem, which lies in constructing these expansions from…

[Phys. Rev. A 94, 062308] Published Tue Dec 06, 2016

]]>We present the first spectroscopic studies of the $C{\phantom{\rule{0.16em}{0ex}}}^{1}{\mathrm{\Sigma}}^{+}$ electronic state and the $A{\phantom{\rule{0.16em}{0ex}}}^{1}{\mathrm{\Sigma}}^{+}$–$b{\phantom{\rule{0.16em}{0ex}}}^{3}{\mathrm{\Pi}}_{{0}^{+}}$ complex in ${}^{7}\mathrm{Li}-{}^{85}\mathrm{Rb}$. Using resonantly enhanced, two-photon ionization, we observed $v=7$, 9, 12, 13, and 26–45 of the $C{\phantom{\rule{0.16em}{0ex}}}^{1}{\mathrm{\Sigma}}^{+}$ state. We augment the REMPI data with a form of depletion spectra in regions of dense sp…

[Phys. Rev. A 94, 062503] Published Tue Dec 06, 2016

]]>Broad entrance-channel $p$-wave magnetic Feshbach resonances with widths up to about 140 G are observed in ultracold admixtures of ${}^{85}$Rb and ${}^{87}$Rb atoms. The broadness of the resonances is expected to significantly facilitate experimental studies of a variety of intriguing quantum few-/many-body phenomena near $p$-wave Feshbach resonances.

[Phys. Rev. A 94, 062702] Published Tue Dec 06, 2016

]]>We simulate a one-dimensional fermionic optical lattice to analyze heating due to nonadiabatic lattice loading. Our simulations reveal that, similar to the bosonic case, density redistribution effects are the major cause of heating in harmonic traps. We suggest protocols to modulate the local-densit…

[Phys. Rev. A 94, 063404] Published Tue Dec 06, 2016

]]>Photoinduced dynamics of a weakly bound triatomic molecule $\mathrm{He}{{\mathrm{H}}_{2}}^{+}$ exposed to electromagnetic radiation is investigated by time-dependent quantum wave-packet propagation. Adopting a two-dimensional linear H-H-He model, the three lowest-lying potential energy surfaces (PESs) and corresponding dipole mo…

[Phys. Rev. A 94, 063405] Published Tue Dec 06, 2016

]]>Atom interferometers are a useful tool for precision measurements of fundamental physical phenomena, ranging from the local gravitational-field strength to the atomic fine-structure constant. In such experiments, it is desirable to implement a high-momentum-transfer “beam splitter,” which may be ach…

[Phys. Rev. A 94, 063604] Published Tue Dec 06, 2016

]]>We obtain the exact analytical self-similar bright-, dark-, and kink-solitary-wave solutions of the nonlinear Schrödinger equation with localized inhomogeneous cubic-quintic nonlinearity by employing a similarity transformation. This equation could be a model equation of stable pulse propagation bey…

[Phys. Rev. A 94, 063814] Published Tue Dec 06, 2016

]]>We study the internal rotational dynamics of electronic beams in relation to the phase singularities of their wave functions. Given their complex singularity structure, Hermite-Gaussian beams and other superpositions of Laguerre-Gaussian modes are studied here. We show that by inspecting the lowest …

[Phys. Rev. A 94, 063815] Published Tue Dec 06, 2016

]]>In this paper, we show that the polarization-entangled photon pairs can be generated using spontaneous parametric down conversion in a dual periodically poled planar waveguide. The proposed configuration is shown to have efficiencies higher than in the case of bulk crystals with the possibility of e…

[Phys. Rev. A 94, 063816] Published Tue Dec 06, 2016

]]>We demonstrate the possibility of designing efficient, nonreciprocal few-photon devices by exploiting the chiral coupling between two waveguide modes and a single quantum emitter. We show how this system can show nonreciprocal photon transport at the single-photon level by exploiting a single-photon…

[Phys. Rev. A 94, 063817] Published Tue Dec 06, 2016

]]>We propose a promising hybrid quantum system, where a highly excited atom strongly interacts with a superconducting $LC$ oscillator via the electric field of capacitor. An external electrostatic field is applied to tune the energy spectrum of the atom. The atomic qubit is implemented by two eigenstate…

[Phys. Rev. A 94, 062301] Published Mon Dec 05, 2016

]]>Rare-earth ions have exceptionally long coherence times, making them an excellent candidate for quantum information processing. A key part of this processing is quantum state transfer. We show that perfect state transfer can be achieved by time reversing the intermediate quantum channel, and suggest…

[Phys. Rev. A 94, 062302] Published Mon Dec 05, 2016

]]>The classical theories of communication rely on the assumption that there has to be a flow of particles from Bob to Alice in order for him to send a message to her. We develop a quantum protocol that allows Alice to perceive Bob's message “counterfactually”; that is, without Alice receiving any part…

[Phys. Rev. A 94, 062303] Published Mon Dec 05, 2016

]]>Quantum computers are the ideal platform for quantum simulations. Given enough coherent operations and qubits, such machines can be leveraged to simulate strongly correlated materials, where intricate quantum effects give rise to counterintuitive macroscopic phenomena such as high-temperature superc…

[Phys. Rev. A 94, 062304] Published Mon Dec 05, 2016

]]>A net force on a system of two dissimilar atoms, one of which is excited, is shown to result from their van der Waals interaction. It is accompanied by a net transfer of linear momentum to the quantum fluctuations of the electromagnetic field. This momentum results from the asymmetric interference o…

[Phys. Rev. A 94, 062701] Published Mon Dec 05, 2016

]]>We investigate high-order harmonic generation in a solid, modeled as a multilevel system dressed by a strong infrared laser field. We show that the cutoff energies and the relative strengths of the multiple plateaus that emerge in the harmonic spectrum can be understood both qualitatively and quanti…

[Phys. Rev. A 94, 063403] Published Mon Dec 05, 2016

]]>We present a proposal for the local control of the nonlinearity in quasi-one-dimensional Bose-Einstein condensates induced by a local pinching of the transverse confining potential. We investigate the scattering of bright matter-wave solitons through a pinched potential using numerical simulations o…

[Phys. Rev. A 94, 063602] Published Mon Dec 05, 2016

]]>We investigate experimentally the dynamical relaxation of a nonintegrable quantum many-body system to its equilibrium state. A Bose-Einstein condensate is loaded into the first excited band of an optical lattice and let to evolve up to a few hundreds of milliseconds. Signs of quantum equilibration a…

[Phys. Rev. A 94, 063603] Published Mon Dec 05, 2016

]]>We have observed momentum- and position-resolved spectra and images of the photoluminescence from thermalized and condensed dye-microcavity photons. The spectra yield the dispersion relation and the potential energy landscape for the photons. From this dispersion relation, below condensation thresho…

[Phys. Rev. A 94, 063812] Published Mon Dec 05, 2016

]]>Experiments in the field of optomechanics do not yet fully exploit the photon polarization degree of freedom. Here experimental results for an optomechanical interaction in a polarization nondegenerate system are presented and schemes are proposed for how to use this interaction to perform accurate …

[Phys. Rev. A 94, 063813] Published Mon Dec 05, 2016

]]>We demonstrate a method to generate spatially homogeneous entangled, spin-squeezed states of atoms appropriate for maintaining a large amount of squeezing even after release into the arm of a matter-wave interferometer or other free-space quantum sensor. Using an effective intracavity dipole trap, w…

[Phys. Rev. A 94, 061601(R)] Published Fri Dec 02, 2016

]]>We report a group of unusually big molecular orbitals in the ${\mathrm{C}}_{60}$-pentacene complex. Our first-principles density-functional calculation shows that these orbitals are very delocalized and cover both ${\mathrm{C}}_{60}$ and pentacene, which we call superintermolecular orbitals (SIMOs). Their spatial extension can rea…

[Phys. Rev. A 94, 062501] Published Fri Dec 02, 2016

]]>We investigate the transition between the fine structure levels of the ground state, $3p{\phantom{\rule{0.16em}{0ex}}}^{2}{P}_{1/2}\to 3p{\phantom{\rule{0.16em}{0ex}}}^{2}{P}_{3/2}$, of the highly charged Al-like ${}^{51}\mathrm{V}^{10+},\phantom{\rule{0.16em}{0ex}}{}^{53}\mathrm{Cr}^{11+},\phantom{\rule{0.16em}{0ex}}{}^{55}\mathrm{Mn}^{12+},\phantom{\rule{0.16em}{0ex}}{}^{57}\mathrm{Fe}^{13+},\phantom{\rule{0.16em}{0ex}}{}^{59}\mathrm{Co}^{14+},\phantom{\rule{0.16em}{0ex}}{}^{61}\mathrm{Ni}^{15+}$, and ${}^{63}\mathrm{Cu}^{16+}$ ions for frequency standards. To comprehend them as prospective atomic clocks, we determine their transition…

[Phys. Rev. A 94, 062502] Published Fri Dec 02, 2016

]]>The origin of the characteristic features in the spatial distribution of high-order harmonic spectra is explored in a joint experiment-theory study. It is found that the spatio-spectral ring structures in the spectra can be well explained by the space- and time-dependent phase modulations of the long-trajectory contributions to the harmonic emission.

[Phys. Rev. A 94, 063401] Published Fri Dec 02, 2016

]]>We apply the Monte Carlo wave packet (MCWP) approach to investigate the kinetic energy release (KER) spectra of the protons following double ionization in ${\mathrm{H}}_{2}$ when interacting with laser pulses with central wavelengths ranging from the near-infrared (IR) (800 nm) to the mid-IR (6400 nm) regions and w…

[Phys. Rev. A 94, 063402] Published Fri Dec 02, 2016

]]>A comprehensive theory to investigate laser instabilities is developed. It is shown that quantum cascade lasers can display both amplitude- and phase-modulated emission, opening a promising route to ultrashort-pulse generation in the midinfrared, as well as the development of compact frequency-comb sources for spectroscopy.

[Phys. Rev. A 94, 063807] Published Fri Dec 02, 2016

]]>Decades of work on beam deformation on reflection and especially on lateral shifts have spread the idea that a reflected beam is larger than the incident beam. However, when the right conditions are met, a beam reflected by a multilayered resonant structure can be 10% narrower than the incoming beam…

[Phys. Rev. A 94, 063808] Published Fri Dec 02, 2016

]]>We develop reduced models that describe half-harmonic generation in a synchronously pumped optical parametric oscillator above threshold, where nonlinearity, dispersion, and group-velocity mismatch are all relevant. These models are based on (1) an eigenmode expansion for low pump powers, (2) a simu…

[Phys. Rev. A 94, 063809] Published Fri Dec 02, 2016

]]>Wave propagation through rapidly but continuously varying media is surprisingly subtle, and in a pair of recent papers [Horsley *et al.*, J. Opt. **18**, 044016 (2016); Longhi, Eur. Phys. Lett. **112**, 64001 (2015)] it was found that planar media with a spatially varying permittivity $\epsilon \left(x\right)$ obeying the spatia…

[Phys. Rev. A 94, 063810] Published Fri Dec 02, 2016

]]>By employing the full counting statistics formalism, we characterize the first moment of energy that is exchanged during a generally non-Markovian evolution in nondriven continuous-variable systems. In particular, we focus on the evaluation of the energy flowing back from the environment into the op…

[Phys. Rev. A 94, 062101] Published Thu Dec 01, 2016

]]>Real photon-photon scattering is a long-predicted phenomenon that is being searched for in experiment in the form of a birefringent vacuum at optical and x-ray frequencies. We present results of calculations and numerical simulations for a scenario to measure this effect using multi-MeV photons gene…

[Phys. Rev. A 94, 062102] Published Thu Dec 01, 2016

]]>We study analytically the superfluid flow of a Bose-Einstein condensate in a ring geometry in the presence of a rotating barrier. We show that a phase transition breaking a parity symmetry among two topological phases occurs at a critical value of the height of the barrier. Furthermore, a discontinu…

[Phys. Rev. A 94, 063601] Published Thu Dec 01, 2016

]]>Feasible setup for pulsed quantum nondemolition interaction between two distant mechanical oscillators through an optical or microwave mediator is proposed. The proposal uses homodyne measurement of the mediator and feedforward control of the mechanical oscillators to reach the interaction. To verif…

[Phys. Rev. A 94, 063801] Published Thu Dec 01, 2016

]]>We propose a method of producing steady-state coherent light with negative Wigner functions in nonlinear media combined with feedback control. While the nonlinearities are essential to produce the Wigner negativities, this alone is insufficient to stabilize steady-state light with negativities. Usin…

[Phys. Rev. A 94, 063802] Published Thu Dec 01, 2016

]]>We present a formula for the spectroscopically accessible level shifts and decay rates of an atom moving at an arbitrary angle relative to a surface. Our Markov formulation leads to an intuitive analytic description whereby the shifts and rates are obtained from the coefficients of the Heisenberg eq…

[Phys. Rev. A 94, 063803] Published Thu Dec 01, 2016

]]>We theoretically investigate a hybrid optomechanical system including two coupled optomechanical cavities in the presence of two strong pump fields and a weak probe field. The photon-hopping coupling of the cavities gives rise to two cavity supermodes whose resonant frequencies can be obtained in th…

[Phys. Rev. A 94, 063804] Published Thu Dec 01, 2016

]]>We investigate two coupled nonlinear cavities that are coherently driven in a dissipative environment. We perform semiclassical, numerical, and analytical quantum studies of this dimer model when both cavities are symmetrically driven. In the semiclassical analysis, we find steady-state solutions wi…

[Phys. Rev. A 94, 063805] Published Thu Dec 01, 2016

]]>The analytical and numerical study of the radiation self-action in a system of coupled light guides is fulfilled on the basis of the discrete nonlinear Schrödinger equation (DNSE). We develop a variational method for qualitative study of DNSE and classify self-action modes. We show that the diffract…

[Phys. Rev. A 94, 063806] Published Thu Dec 01, 2016

]]>The non-Markovian dynamics of open quantum systems is still a challenging task, particularly in the nonperturbative regime at low temperatures. While the stochastic Liouville–von Neumann equation (SLN) provides a formally exact tool to tackle this problem for both discrete and continuous degrees of …

[Phys. Rev. A 94, 052137] Published Wed Nov 30, 2016

]]>A resource theory of quantum coherence attempts to characterize the quantum coherence that exists in a given quantum system. Many different approaches to a resource theory of coherence have recently been proposed, with their differences lying primarily in the identification of “free” or “incoherent”…

[Phys. Rev. A 94, 052336] Published Wed Nov 30, 2016

]]>We theoretically investigate the implementation of a quantum controlled-phase gate in a system constituted by a single atom inside an optical cavity, based on the electromagnetically induced transparency effect. First we show that a probe pulse can experience a $\pi $ phase shift due to the presence or a…

[Phys. Rev. A 94, 052337] Published Wed Nov 30, 2016

]]>This paper investigates continuous-time quantum walks on directed bipartite graphs based on a graph's adjacency matrix. We prove that on bipartite graphs, probability transport between the two node partitions can be completely suppressed by tuning a model parameter $\alpha $. We provide analytic solutions t…

[Phys. Rev. A 94, 052338] Published Wed Nov 30, 2016

]]>Dissipation can be used as a resource to control and simulate quantum systems. We discuss a modular model based on fast dissipation capable of performing universal quantum computation, and simulating arbitrary Lindbladian dynamics. The model consists of a network of elementary dissipation-generated …

[Phys. Rev. A 94, 052339] Published Wed Nov 30, 2016

]]>Recent experimental progress in creating and controlling singular electron beams that carry orbital angular momentum allows for new types of local spectroscopies. We investigate theoretically the twisted-electron-energy-loss spectroscopy (EELS) from the ${\mathrm{C}}_{60}$ fullerene. Of particular interest are the …

[Phys. Rev. A 94, 052710] Published Wed Nov 30, 2016

]]>We propose the use of stimulated Raman adiabatic passage to offer a fast high fidelity method of performing SU(2) rotations on spinor Bose-Einstein condensates (BECs). Past demonstrations of BECs optical control suffer from difficulties arising from collective enhancement of spontaneous emission and…

[Phys. Rev. A 94, 053636] Published Wed Nov 30, 2016

]]>The global coupling of few-level quantum systems (“spins”) to a discrete set of bosonic modes is a key ingredient for many applications in quantum science, including large-scale entanglement generation, quantum simulation of the dynamics of long-range interacting spin models, and hybrid platforms fo…

[Phys. Rev. A 94, 053637] Published Wed Nov 30, 2016

]]>We model the dynamics of attractively interacting ultracold bosonic atoms in a quasi-one-dimensional wave guide with additional harmonic trapping. Initially, we prepare the system in its ground state and then shift the zero of the harmonic trap and switch on an additional narrow scattering potential…

[Phys. Rev. A 94, 053638] Published Wed Nov 30, 2016

]]>The generalized Gross-Pitaevskii equation (gGPE) is an effective phenomenological description for the dynamics of incoherently pumped exciton-polariton condensates. However, a brute force numerical simulation of the gGPE provides little physical insight into condensate formation under arbitrary pump…

[Phys. Rev. A 94, 053856] Published Wed Nov 30, 2016

]]>The one- and two-photon scattering matrix $S$ is obtained analytically for a one-dimensional waveguide and a pointlike scatterer with $N$ excited levels (generalized $\mathsf{\text{V}}\text{-type}$ atom). We argue that the two-photon scattering matrix contains sufficient information to distinguish between different level struct…

[Phys. Rev. A 94, 053857] Published Wed Nov 30, 2016

]]>Single-photon devices at microwave frequencies are important for applications in quantum information processing and communication in the microwave regime. In this work we describe a proposal of a multioutput single-photon device. We consider two superconducting resonators coupled to a gap-tunable qu…

[Phys. Rev. A 94, 053858] Published Wed Nov 30, 2016

]]>We describe how electromagnetically induced transparency may be used to construct a nontraditional near-ideal quantum heat engine as constrained by the second law. The engine is pumped by a thermal reservoir that may be either hotter or colder than that of an exhaust reservoir, and also by a monochr…

[Phys. Rev. A 94, 053859] Published Wed Nov 30, 2016

]]>[Phys. Rev. A 94, 059905] Published Wed Nov 30, 2016

]]>Wave functions and density matrices represent our knowledge about a quantum system and give probabilities for the outcomes of measurements. If the combined dynamics and measurements on a system lead to a density matrix $\rho \left(t\right)$ with only diagonal elements in a given basis $\left\{\right|n\rangle \}$, it may be treated as a c…

[Phys. Rev. A 94, 050102(R)] Published Tue Nov 29, 2016

]]>Gapless many-body quantum systems in one spatial dimension are universally described by the Luttinger liquid effective theory at low energies. Essentially, only two parameters enter the effective low-energy description, namely, the speed of sound and the Luttinger parameter. These are highly system …

[Phys. Rev. A 94, 051606(R)] Published Tue Nov 29, 2016

]]>It is well known that a state with complex energy cannot be the eigenstate of a self-adjoint operator, such as the Hamiltonian. Resonances, i.e., states with exponentially decaying observables, are not vectors belonging to the conventional Hilbert space. One can describe these resonances in an unusu…

[Phys. Rev. A 94, 052136] Published Tue Nov 29, 2016

]]>Quantum noise is ubiquitous to quantum systems as they incessantly interact with their surroundings and results in degrading useful resources such as coherence for single quantum systems and quantum correlations for multipartite systems. Given the importance of these resources in various quantum inf…

[Phys. Rev. A 94, 052335] Published Tue Nov 29, 2016

]]>We determine the frequency of the Yb I ${}^{1}S_{0}\text{\u2212}{}^{1}P_{1}$ transition at 399 nm using an optical frequency comb. Although this transition was measured previously using an optical transfer cavity [D. Das *et al.*, Phys. Rev. A **72**, 032506 (2005)], recent work has uncovered significant errors in that method. We com…

[Phys. Rev. A 94, 052511] Published Tue Nov 29, 2016

]]>We report direct laser spectroscopy of the ${}^{1}{S}_{0}$ to ${}^{3}{D}_{1}$ highly-forbidden M1 clock transition in ${}^{175}{\mathrm{Lu}}^{+}$. Clock operation is demonstrated on three pairs of Zeeman transitions, one pair from each hyperfine manifold of the ${}^{3}{D}_{1}$ term. We measure the hyperfine intervals of the ${}^{3}{D}_{1}$ to 10 ppb uncertainty and i…

[Phys. Rev. A 94, 052512] Published Tue Nov 29, 2016

]]>The effects of the lattice constant and electron affinity on the negative-ion conversion of a neutral atom undergoing grazing scattering on an ionic-crystal surface over the complete velocity range were investigated. Here, a comparison of negative-ion conversion of neutral ${\mathrm{O}}^{0}\text{\u2212}\mathrm{KCl}\left(100\right),{\mathrm{F}}^{0}\text{\u2212}\mathrm{KCl}\left(100\right)$, a…

[Phys. Rev. A 94, 052708] Published Tue Nov 29, 2016

]]>The theoretical $\gamma $-ray spectra from positron-electron annihilation process in a wide variety of atoms and molecules are studied. The theoretical Doppler broadened $\gamma $-ray spectra for core, inner valence, and outer valence electrons of these molecules are studied systematically. The present results show…

[Phys. Rev. A 94, 052709] Published Tue Nov 29, 2016

]]>Double ionization of a model helium system by intense extreme ultraviolet laser pulses is investigated by solving the time-dependent Schrödinger equation and extracting the photoelectron spectra. Considering a frequency regime where the nonsequential two-photon double ionization is expected to domin…

[Phys. Rev. A 94, 053424] Published Tue Nov 29, 2016

]]>We calculate the reflection and transmission probabilities in a one-dimensional Fermi gas with an equal mixing of the Rashba and Dresselhaus spin-orbit coupling (RD-SOC) produced by an external Raman laser field. These probabilities are computed over multiple relevant energy ranges within the pseudo…

[Phys. Rev. A 94, 053635] Published Tue Nov 29, 2016

]]>Tightly confined modes of light, as in optical nanofibers or photonic crystal waveguides, can lead to large optical coupling in atomic systems, which mediates long-range interactions between atoms. These one-dimensional systems can naturally possess couplings that are asymmetric between modes propag…

[Phys. Rev. A 94, 053855] Published Tue Nov 29, 2016

]]>[Phys. Rev. A 94, 059904] Published Tue Nov 29, 2016

]]>An additive and semidefinite programming (SDP) computable entanglement measure is introduced to upper bound the amount of distillable entanglement in bipartite quantum states by operations completely preserving the positivity of partial transpose (PPT). This quantity is always smaller than or equal …

[Phys. Rev. A 94, 050301(R)] Published Mon Nov 28, 2016

]]>Efimov physics is renowned for the self-similar spectrum featuring the universal ratio of one eigenenergy to its neighbor. Even more esoteric is the numerically unveiled fact that every Efimov trimer is accompanied by a pair of tetramers. Here we demonstrate that this hierarchy of universal few-body…

[Phys. Rev. A 94, 050702(R)] Published Mon Nov 28, 2016

]]>We develop a theory of optomechanical cooling with a squeezed input light field. We show that Stokes heating transitions can be *fully* suppressed when the driving field is squeezed below the vacuum noise level at an appropriately selected squeezing phase and for a finite amount of squeezing. The quan…

[Phys. Rev. A 94, 051801(R)] Published Mon Nov 28, 2016

]]>Dynamical reduction models propose a solution to the measurement problem in quantum mechanics: the collapse of the wave function becomes a physical process. We compute the predictions to decaying and flavor-oscillating neutral mesons for the two most promising collapse models, the QMUPL (quantum mec…

[Phys. Rev. A 94, 052128] Published Mon Nov 28, 2016

]]>Considering stationary states of continuous-variable systems undergoing an open dynamics, we unveil the connection between properties and symmetries of the latter and the dynamical parameters. In particular, we explore the relation between the Lyapunov equation for dynamical systems and the steady-s…

[Phys. Rev. A 94, 052129] Published Mon Nov 28, 2016

]]>Brassard *et al.* [Phys. Rev. Lett. **96**, 250401 (2006)] showed that shared nonlocal boxes with a CHSH (Clauser, Horne, Shimony, and Holt) probability greater than $\frac{3+\sqrt{6}}{6}$ yield trivial communication complexity. There still exists a gap with the maximum CHSH probability $\frac{2+\sqrt{2}}{4}$ achievable by quantum mechanics…

[Phys. Rev. A 94, 052130] Published Mon Nov 28, 2016

]]>We consider two protocols for the measurement of the temporal correlation functions of a dichotomic variable $Q$ appearing in Leggett-Garg-type inequalities. The protocols measure solely whether $Q$ has the same or a different sign at the end of a given time interval, thereby measuring no more than is r…

[Phys. Rev. A 94, 052131] Published Mon Nov 28, 2016

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