We give a conceptually simple necessary condition such that a separable quantum operation can be implemented by local operations on subsystems and classical communication between parties (LOCC), a condition which follows from a novel approach to understanding LOCC. This necessary condition applies t...

[Phys. Rev. A 90, 012336] Published Tue Jul 29, 2014

]]>We present a protocol for quantum state transfer and remote state preparation across spin chains which operate in their antiferromagnetic mode. The proposed mechanism harnesses the inherent entanglement of the ground state of the strongly correlated many-body systems which naturally exists for free....

[Phys. Rev. A 90, 012337] Published Tue Jul 29, 2014

]]>We present a comprehensive implementation of the quantum trajectory theory for the description of the entanglement dynamics in a Markovian open quantum system made of two qubits. We introduce the average concurrence to characterize the entanglement in the system and derive a deterministic evolution ...

[Phys. Rev. A 90, 012338] Published Tue Jul 29, 2014

]]>We theoretically analyzed a scheme for optical trapping of neutral atoms by plasmonic nanotips. An analytic quasistatic model was developed for studying the requirements on geometry and material parameters needed for a successful trap generation. We then used the numerical solution of Maxwell's equa...

[Phys. Rev. A 90, 013421] Published Tue Jul 29, 2014

]]>The ground state of a homogeneous Bose gas of hard spheres is treated in self-consistent mean-field theory. It is shown that this approach provides an accurate description of the ground state of a Bose-Einstein condensed gas for arbitrarily strong interactions. The results are in good agreement with...

[Phys. Rev. A 90, 013627] Published Tue Jul 29, 2014

]]>The linear driving for a single-mode optical field in a cavity can result from the external driving of a classical field even when the coupling between the classical field and the cavity is weak. We revisit this well-known effect with a microscopic model where a classical field is applied to a wall ...

[Phys. Rev. A 90, 013836] Published Tue Jul 29, 2014

]]>The amplitude of two-photon transitions between hyperfine states in hydrogenlike ions is derived based on the relativistic Dirac equation and second-order perturbation theory. We study angular and linear polarization properties of the photon pair emitted in the decay of 2s states, where spin-flip an...

[Phys. Rev. A 90, 014502] Published Tue Jul 29, 2014

]]>We present a simple tomographic protocol, for two-qubit systems, that relies on a single discriminatory transition and no direct spatially selective imaging. This scheme exploits excess micromotion in the trap to realize all operations required to prepare all input states and analyze all output stat...

[Phys. Rev. A 90, 010103] Published Mon Jul 28, 2014

]]>We study informationally overcomplete measurements for quantum state estimation so as to clarify their tomographic significance as compared with minimal informationally complete measurements. We show that informationally overcomplete measurements can improve the tomographic efficiency significantly ...

[Phys. Rev. A 90, 012115] Published Mon Jul 28, 2014

]]>Recent attoclock experiments using the attosecond angular streaking technique enabled the measurement of the tunneling time delay during laser-induced strong-field ionization. One of the theoretical models for the tunneling time delay is the Wigner time delay, which is the asymptotic time difference...

[Phys. Rev. A 90, 012116] Published Mon Jul 28, 2014

]]>Starting with a set of conditions for bipartite separability of arbitrary quantum states in any dimension and expressed in terms of arbitrary operators whose commutator is a c-number, we derive a hierarchy of conditions for tripartite separability of continuous-variable three-mode quantum states. Th...

[Phys. Rev. A 90, 012334] Published Mon Jul 28, 2014

]]>We develop a theory for the interaction of multilevel atoms with multimode cavities yielding cavity-enhanced multiphoton resonances. The locations of the resonances are predicted from the use of effective two- and three-level Hamiltonians. As an application we show that quantum gates can be realized...

[Phys. Rev. A 90, 012335] Published Mon Jul 28, 2014

]]>The transformation design method of momentum for matter waves in a harmonic trap is proposed. As applications, we design (1) a momentum invisibility cloak to control the distribution of a wave function in momentum space, (2) a quantum localization cloak that localizes a matter wave around zero momen...

[Phys. Rev. A 90, 012709] Published Mon Jul 28, 2014

]]>Floquet states are signatured by pseudoeigenvalues which are discretely separated by the photon energy. Similarly, the laser-assisted photoemission effect (LAPE) induces electron-photon energy exchange (with momentum change), and also results in a discrete energy distribution. Both effects result fr...

[Phys. Rev. A 90, 013420] Published Mon Jul 28, 2014

]]>We generate spin currents in an Rb87 spin-2 Bose-Einstein condensate by application of a magnetic field gradient. The spin current destroys the spin polarization, leading to a sudden onset of two-body collisions. In addition, the spin coherence, as measured by the fringe contrast using Ramsey interf...

[Phys. Rev. A 90, 013626] Published Mon Jul 28, 2014

]]>The resonant-state expansion (RSE), a rigorous perturbative method in electrodynamics, is developed for three-dimensional open optical systems. Results are presented using the analytically solvable homogeneous dielectric sphere as unperturbed system. Since any perturbation which breaks the spherical...

[Phys. Rev. A 90, 013834] Published Mon Jul 28, 2014

]]>We show that the propagation direction of the Dirac-cone modes of photonic-crystal slabs can be continuously controlled by the polarization of the incident wave. This property is realized by their isotropic dispersion relation and anisotropic mixture of two dipolar wave functions. To clarify these f...

[Phys. Rev. A 90, 013835] Published Mon Jul 28, 2014

]]>It has been shown in earlier works that the vertices of Platonic solids are good measurement choices for tests of Einstein-Podolsky-Rosen (EPR)-steering using isotropically entangled pairs of qubits. Such measurements are regularly spaced, and measurement diversity is a good feature for making EPR-s...

[Phys. Rev. A 90, 012114] Published Fri Jul 25, 2014

]]>In this paper, we have calculated parity nonconserving electric dipole amplitudes of the hyperfine components for the transitions between the ground and first excited states of 137Ba+ and 87Sr+ using sum-over-states technique. The results are presented to extract the constants associated with the nu...

[Phys. Rev. A 90, 012522] Published Fri Jul 25, 2014

]]>Neutral mercury is proposed to be an ideal atomic system for an optical clock based on two-photon E1-M1 transitions.

[Phys. Rev. A 90, 012523] Published Fri Jul 25, 2014

]]>We follow the alignment-assisted orientation technique proposed by Zhang et al. [Phys. Rev. A 83, 043410 (2011)PLRAAN10.1103/PhysRevA.83.043410] to experimentally demonstrate a substantial enhancement of the field-free orientation by using a combination of single- and two-color laser pulses. When a ...

[Phys. Rev. A 90, 013419] Published Fri Jul 25, 2014

]]>We present a general theory for calculating the damping rate of elementary density-wave excitations in a Bose-Einstein condensate strongly coupled to a single radiation field mode of an optical cavity. Thereby we give a detailed derivation of the huge resonant enhancement in the Beliaev damping of a...

[Phys. Rev. A 90, 013623] Published Fri Jul 25, 2014

]]>We analyze the Bose-Einstein condensation process and the Berezinskii-Kosterlitz-Thouless phase transition within the nonlinear Schrödinger model and their interplay with wave turbulence theory. By using numerical experiments we study how the condensate fraction and the first-order correlation funct...

[Phys. Rev. A 90, 013624] Published Fri Jul 25, 2014

]]>We obtain the complete quantum phase diagram of bosons on a two-leg ladder in the presence of attractive onsite and repulsive interchain nearest-neighbor interactions by imposing the onsite three-body constraint. We find three distinct phases; namely, the atomic superfluid (ASF), dimer superfluid (D...

[Phys. Rev. A 90, 013625] Published Fri Jul 25, 2014

]]>We consider a quantum emitter (“atom”) radiating in a one-dimensional photonic waveguide in the presence of a single mirror, resulting in a delay differential equation for the atomic amplitude. We carry out a systematic analysis of the non-Markovian (NM) character of the atomic dynamics in terms of ...

[Phys. Rev. A 90, 012113] Published Thu Jul 24, 2014

]]>We show how two distrustful parties, “Bob” and “Charlie,” can share a secret key with the help of a mutually trusted “Alice” counterfactually; that is, with no information-carrying particles traveling between any of the three.

[Phys. Rev. A 90, 012333] Published Thu Jul 24, 2014

]]>The low-energy and weak-field limit of the Dirac equation can be obtained by an order-by-order block diagonalization approach to any desired order in the parameter π/mc (π is the kinetic momentum and m is the mass of the particle). In previous work, it has been shown that, up to the order of (π/mc)8...

[Phys. Rev. A 90, 012112] Published Wed Jul 23, 2014

]]>We consider a system composed of a qubit interacting with a quartic (undriven) nonlinear oscillator (NLO) through a conditional displacement Hamiltonian. We show that even a modest nonlinearity can enhance and stabilize the quantum entanglement dynamically generated between the qubit and the NLO. In...

[Phys. Rev. A 90, 013829] Published Wed Jul 23, 2014

]]>We put forward an operational degree of polarization that can be extended in a natural way to fields whose wave fronts are not necessarily planar. This measure appears as a distance from a state to the set of all of its polarization-transformed counterparts. By using the Hilbert-Schmidt metric, the ...

[Phys. Rev. A 90, 013830] Published Wed Jul 23, 2014

]]>Our theoretical examination of second- and third-harmonic generation from metal-based nanostructures predicts that nonlocal and quantum-tunneling phenomena can significantly exceed expectations based solely on local, classical electromagnetism. Mindful that the diameter of typical transition-metal a...

[Phys. Rev. A 90, 013831] Published Wed Jul 23, 2014

]]>Recent high-precision measurements in a three-slit diffraction experiment [Sinha et al., Science 329, 418 (2010)SCIEAS10.1126/science.1190545] have been performed as an explicit test of the validity of Born's rule for quantum probabilities. This experiment aims to establish an upper limit to the pos...

[Phys. Rev. A 90, 013832] Published Wed Jul 23, 2014

]]>We study the generation of propagation invariant photons with orbital angular momentum by spontaneous parametric down conversion (SPDC) using a Bessel-Gauss pump beam. The angular and conditional angular spectra are calculated for an uniaxial crystal optimized for type I SPDC with standard Gaussian ...

[Phys. Rev. A 90, 013833] Published Wed Jul 23, 2014

]]>A driven Fabry-Perot cavity with Kerr nonlinearity shows stable localized structures in a region far from modulational instability.

[Phys. Rev. A 90, 011806] Published Tue Jul 22, 2014

]]>We investigate entropic uncertainty relations for two or more binary measurements, for example, spin-12 or polarization measurements. We argue that the effective anticommutators of these measurements, i.e., the anticommutators evaluated on the state prior to measuring, are an expedient measure of me...

[Phys. Rev. A 90, 012332] Published Tue Jul 22, 2014

]]>The electron capture process for the Si3+(3s) + H(1s) collisions is investigated by the quantum-mechanical molecular orbital close-coupling (MOCC) method and by the two-center atomic orbital close-coupling (AOCC) method in the energy range of 10−5–10 keV/u and 0.8–200 keV/u, respectively. Total and ...

[Phys. Rev. A 90, 012708] Published Tue Jul 22, 2014

]]>We consider the process of atomic ionization driven by a laser pulse with varying ellipticity. We study the distribution of the momenta of the photoelectrons, ionized by a strong laser field, emitted in the direction perpendicular to the polarization plane (transverse distribution). We show that wit...

[Phys. Rev. A 90, 013418] Published Tue Jul 22, 2014

]]>Incoherent dispersive shock waves and collapselike singularities have been recently predicted to occur in the spectral evolution of an incoherent optical wave that propagates in a noninstantaneous nonlinear medium. Here we extend this work by considering the generalized nonlinear Schrödinger equatio...

[Phys. Rev. A 90, 013828] Published Tue Jul 22, 2014

]]>Noncommutative phase space plays an essential role in particle physics and quantum gravity at the Planck scale. However, direct experimental evidence or observation to demonstrate the existence of noncommutative phase space is still lacking. We study a quantum ring in noncommutative phase space base...

[Phys. Rev. A 90, 010102] Published Mon Jul 21, 2014

]]>A new technique employing Raman sideband cooling is used to detect and cool single atoms trapped in optical tweezers which may have a significant impact on neutral-atom quantum computing, quantum simulations, and quantum-gas microscope experiments.

[Phys. Rev. A 90, 011804] Published Mon Jul 21, 2014

]]>Multiplex two-photon excitation spectroscopy is demonstrated at Doppler-limited resolution. We describe first Fourier-transform two-photon spectroscopy of an atomic sample with two mode-locked laser oscillators in a dual-comb technique. Each transition is uniquely identified by the modulation impart...

[Phys. Rev. A 90, 011805] Published Mon Jul 21, 2014

]]>We propose a quantum algorithm in an embedding ion-trap quantum simulator for the efficient computation of N-qubit entanglement monotones without the necessity of full tomography. Moreover, we discuss possible realistic scenarios and study the associated decoherence mechanisms.

[Phys. Rev. A 90, 012327] Published Mon Jul 21, 2014

]]>Based on a microwave-photon quantum processor with two superconducting resonators coupled to one transmon qutrit, we construct the controlled-phase (c-phase) gate on microwave-photon-resonator qudits, by combination of the photon-number-dependent frequency-shift effect on the transmon qutrit by the ...

[Phys. Rev. A 90, 012328] Published Mon Jul 21, 2014

]]>We consider quantum-key-distribution implementations in which the receiver's apparatus is fixed and does not depend on his choice of basis at each qubit transmission. We show that, although theoretical quantum key distribution is proven secure, such implementations are totally insecure against a str...

[Phys. Rev. A 90, 012329] Published Mon Jul 21, 2014

]]>Finding optimal and noise robust probe states is a key problem in quantum metrology. In this paper we propose Markov dynamics as a possible mechanism for generating such states, and show how the Heisenberg scaling emerges for systems with multiple “dynamical phases” (stationary states), and noiseles...

[Phys. Rev. A 90, 012330] Published Mon Jul 21, 2014

]]>We show that a perfect state transfer of an arbitrary unknown two-qubit state can be achieved via a discrete-time quantum walk with various settings of coin flips and extend this method to the distribution of an arbitrary unknown multiqubit entangled state between every pair of sites in the multidim...

[Phys. Rev. A 90, 012331] Published Mon Jul 21, 2014

]]>The relativistic many-body perturbation theory (RMBPT), including the Breit interaction, is used to evaluate the multipole (E1,M1,E2,M2, and E3) matrix elements to determine the 3s3p3P2 lifetime and multipole polarizabilities in Mg-like ions. The electric multipole matrix elements are determined in ...

[Phys. Rev. A 90, 012519] Published Mon Jul 21, 2014

]]>On the basis of the quasipotential method in quantum electrodynamics we calculate corrections of orders α5 and α6 to the hyperfine structure of S-wave energy levels of muonic deuterium. Relativistic corrections, effects of vacuum polarization in first, second and third orders of perturbation theory,...

[Phys. Rev. A 90, 012520] Published Mon Jul 21, 2014

]]>We present two analytical methods, Taylor expansion and Gegenbauer expansion, to efficiently and accurately calculate the two-electron screened Coulomb potential matrix elements with Slater-type configuration-interaction basis functions. The former permits great advantages in fast computation of the...

[Phys. Rev. A 90, 012521] Published Mon Jul 21, 2014

]]>We present relativistic convergent close-coupling and Breit-Pauli R-matrix calculations for the polarization of the light emitted after electron-impact excitation of the (5s)2S1/2→(5p)2P3/2 transition in Cd+. While we find consistency between the theoretical predictions, a discrepancy persists with ...

[Phys. Rev. A 90, 012707] Published Mon Jul 21, 2014

]]>While the zero-temperature properties of harmonically trapped cold few-atom systems have been discussed fairly extensively over the past decade, much less is known about the finite-temperature properties. Working in the canonical ensemble, we characterize small harmonically trapped atomic systems as...

[Phys. Rev. A 90, 013620] Published Mon Jul 21, 2014

]]>Motivated by recent experimental observations [Parker, Hua, and Chin, Nat. Phys. 9, 769 (2013)10.1038/nphys2789], we analyze the stability of a Bose-Einstein condensate (BEC) in a one-dimensional lattice subjected to periodic shaking. In such a system there is no thermodynamic ground state, but ther...

[Phys. Rev. A 90, 013621] Published Mon Jul 21, 2014

]]>We theoretically investigate collective modes of a one-dimensional (1D) interacting Bose gas in a harmonic tras at finite temperatures, by using a variational approach and the local density approximation. We find that the temperature dependence of collective mode frequencies is notably different in ...

[Phys. Rev. A 90, 013622] Published Mon Jul 21, 2014

]]>A method for ground-state cooling of a mechanical mode in the unresolved sideband regime of dispersive optomechanics is proposed using an auxiliary mechanical mode and optomechanically induced transparency effects.

[Phys. Rev. A 90, 013824] Published Mon Jul 21, 2014

]]>The absolute calibration of optical tweezers has been demonstrated by including the aberration effects of the optical system into the theoretical framework, thereby opening the door to an improved instrument design, reliable force measurements, and a better control over experiments.

[Phys. Rev. A 90, 013825] Published Mon Jul 21, 2014

]]>The ac Stark shift (or light shift) of the 62S1/2(F=3↔4) transition in 133Cs, as observed through coherent population trapping under pulsed excitation, is measured using a 133Cs gas cell and the D1-line vertical-cavity surface-emitting laser. This light shift can be calculated using density-matrix a...

[Phys. Rev. A 90, 013826] Published Mon Jul 21, 2014

]]>We revisit the scheme of single-photon weak-coupling optomechanics using postselection, proposed by Pepper, Ghobadi, Jeffrey, Simon, and Bouwmeester [Phys. Rev. Lett. 109, 023601 (2012)PRLTAO10.1103/PhysRevLett.109.023601], by analyzing the exact solution of the dynamical evolution. Positive and neg...

[Phys. Rev. A 90, 013827] Published Mon Jul 21, 2014

]]>We apply the classical data-processing inequality to quantum metrology to show that manipulating the classical information from a quantum measurement cannot aid in the estimation of parameters encoded in quantum states. We further derive a quantum data-processing inequality to show that coherent man...

[Phys. Rev. A 90, 014101] Published Mon Jul 21, 2014

]]>The effect of an electric quadrupole moment Q is studied for positron-atom bound systems. It is demonstrated that for Q>50 a.u. the electric quadrupole potential is sufficiently strong to bind a positron (or an electron) even in the absence of the dipole polarization potential. Such large values ...

[Phys. Rev. A 90, 014501] Published Mon Jul 21, 2014

]]>[Phys. Rev. A 90, 019903] Published Mon Jul 21, 2014

]]>We show that violation of genuine multipartite Bell inequalities can be obtained with sampled, probabilistic phase-space methods. These genuine Bell violations cannot be replicated if any part of the system is described by a local hidden variable theory. The Bell violations are simulated probabilist...

[Phys. Rev. A 90, 012111] Published Fri Jul 18, 2014

]]>We develop a complete resource theory of charge-parity-time (CPT) inversion symmetry for both massive and massless relativistic particles of arbitrary spin. We show that a unitary representation of CPT can be consistently constructed for all spins and develop the resource theory associated with CPT ...

[Phys. Rev. A 90, 012326] Published Fri Jul 18, 2014

]]>A version of the method of accurate calculations for few-valence-electron atoms which combines linearized single-double–coupled-cluster method with the configuration-interaction technique is presented. The use of the method is illustrated by calculations of the energy levels for Ba, Ba+, Lu, Lu+, an...

[Phys. Rev. A 90, 012517] Published Fri Jul 18, 2014

]]>Natural orbital theory is a computationally useful approach to the few- and many-body quantum problems. While natural orbitals have been known and applied for many years in electronic structure applications, their potential for time-dependent problems started being investigated only recently. Correl...

[Phys. Rev. A 90, 012518] Published Fri Jul 18, 2014

]]>A series of computations based on multichannel quantum defect theory have been performed in order to produce the cross sections of rotational transitions (excitations Ni+−2→ Ni+, deexcitations Ni+ → Ni+−2, with Ni+=2 to 10) and of their competitive process, the dissociative recombination, induced by...

[Phys. Rev. A 90, 012706] Published Fri Jul 18, 2014

]]>The avalanche mechanism has been used to relate Efimov trimer states to certain enhanced atom loss features observed in ultracold-atom-gas experiments. These atom loss features are argued to be a signature of resonant atom-molecule scattering that occurs when an Efimov trimer is degenerate with the ...

[Phys. Rev. A 90, 013619] Published Fri Jul 18, 2014

]]>The fundamental mechanism underlying harmonic emission in the strong-field regime is governed by tunnel ionization of the atom, followed by the motion of the electron wave packet in the continuum, and finally by its recollision with the atomic core. Due to the quantum nature of the process, the prop...

[Phys. Rev. A 90, 013822] Published Fri Jul 18, 2014

]]>Experimental data of femtosecond thick-crystal second-harmonic generation show that when tuning away from phase matching, a dominating narrow spectral peak appears in the second harmonic that can be tuned over hundreds of nanometers by changing the phase-mismatch parameter. Traditional theory explai...

[Phys. Rev. A 90, 013823] Published Fri Jul 18, 2014

]]>[Phys. Rev. A 90, 019901] Published Fri Jul 18, 2014

]]>[Phys. Rev. A 90, 019902] Published Fri Jul 18, 2014

]]>Optical measurements of a nanoscale silicon optomechanical crystal cavity with a mechanical resonance frequency of 3.6 GHz are performed at subkelvin temperatures. We infer optical-absorption-induced heating and damping of the mechanical resonator from measurements of phonon occupancy and motional s...

[Phys. Rev. A 90, 011803] Published Thu Jul 17, 2014

]]>We study quantum process tomography given the prior information that the map is a unitary or close to a unitary process. We show that a unitary map on a d-level system is completely characterized by a minimal set of d2+d elements associated with a collection of POVMs, in contrast to the d4−d2 elemen...

[Phys. Rev. A 90, 012110] Published Thu Jul 17, 2014

]]>Numerical calculations for Majorana zero modes on finite chains are performed using the technique of block diagonalization. It is found that Majorana zero modes occur near the ends of the chain and decay exponentially away from the ends. The phase diagrams show that Majorana zero modes of a sufficie...

[Phys. Rev. A 90, 012323] Published Thu Jul 17, 2014

]]>We describe an adiabatic state-transfer mechanism that allows for high-fidelity transfer of a microwave quantum state from one cavity to another through an optical fiber. The conversion from microwave frequency to optical frequency is enabled by an optomechanical transducer. The transfer process uti...

[Phys. Rev. A 90, 012324] Published Thu Jul 17, 2014

]]>We present a system for the simulation of Heisenberg models with spins s=1/2 and s=1 with a linear crystal of trapped ions. We show that the laser-ion interaction induces a Jaynes-Cummings-Hubbard interaction between the atomic V-type level structure and the two phonon species. In the strong-couplin...

[Phys. Rev. A 90, 012325] Published Thu Jul 17, 2014

]]>Angular distributions of photoionization differential rates for an atom in arbitrary excited states ionized by intense laser fields with arbitrary polarization are reported. Relativistic effects are incorporated into the Keldysh theory, yielding semi-analytical expressions of ionization rates for hy...

[Phys. Rev. A 90, 013417] Published Thu Jul 17, 2014

]]>The Landau-Zener (LZ) transition is one of the most fundamental phenomena in quantum dynamics. It describes nonadiabatic transitions between quantum states near an avoided crossing that can occur in diverse physical systems. Here we report experimental measurements and tuning of LZ transitions betwe...

[Phys. Rev. A 90, 013616] Published Thu Jul 17, 2014

]]>We study the dynamics of two strongly interacting bosons with an additional impurity atom trapped in a harmonic potential. Using exact numerical diagonalization we are able to fully explore the dynamical evolution when the interaction between the two distinct species is suddenly switched on (quenche...

[Phys. Rev. A 90, 013617] Published Thu Jul 17, 2014

]]>We use a class of variational wave functions to study the properties of an impurity in a Bose-Einstein condensate, i.e., the Bose polaron. The impurity interacts with the condensate through a contact interaction, which can be tuned by a Feshbach resonance. We find a stable attractive polaron branch ...

[Phys. Rev. A 90, 013618] Published Thu Jul 17, 2014

]]>The nonequilibrium dynamics of a gas of cold atoms in which Rydberg states are off-resonantly excited is studied in the presence of noise. The interplay between interaction and off-resonant excitation leads to an initial dynamics where aggregates of excited Rydberg atoms slowly nucleate and grow, ev...

[Phys. Rev. A 90, 011603] Published Wed Jul 16, 2014

]]>We find a sufficient set of equations between quantum circuits from which we can derive any other equation between stabilizer quantum circuits. To establish this result, we rely upon existing work on the completeness of the graphical ZX language for quantum processes, a two-coloured logical calculus...

[Phys. Rev. A 90, 012109] Published Wed Jul 16, 2014

]]>We investigate the dynamics of information among the parties of tripartite systems. We start by proving two results concerning the monogamy of mutual information. The first one states that mutual information is monogamous for generic tripartite pure states. The second shows that, in general, mutual ...

[Phys. Rev. A 90, 012322] Published Wed Jul 16, 2014

]]>A rotating object is shown to exhibit a quantum instability by dissipating its mechanical energy via spontaneous emission, thereby dragging nearby bodies and making them spin parallel to its axis of rotation while the object itself undergoes a quantum stochastic motion.

[Phys. Rev. A 90, 012515] Published Wed Jul 16, 2014

]]>We develop a formalism to calculate the fluctuation-induced interactions in periodic systems. The formalism, which combines the scattering theory with the C method borrowed from electromagnetic gratings studies, is suitable and efficient for the calculation of the Casimir forces involving surface-re...

[Phys. Rev. A 90, 012516] Published Wed Jul 16, 2014

]]>We demonstrate that when two polar molecules as those of water, ammonia, and hydrogen sulfide encounter each other at a distance much larger than their dimensions they engage a synchronous motion that promotes the transformation of free rotations into coupled pendular states. This discovery has been...

[Phys. Rev. A 90, 012705] Published Wed Jul 16, 2014

]]>Angular distributions of the N2O+(X) and N2O+(A) photoelectrons were measured as functions of the exciting-photon energy with small bandwidth in the vicinity of the resonant Nt(1s→π*), Nt(1s→σ*), and Nc(1s→π*) core excitations of N2O. For selected exciting-photon energies in this range, angular dist...

[Phys. Rev. A 90, 013416] Published Wed Jul 16, 2014

]]>It is shown using numerical simulations that flow patterns around an obstacle potential moving in a superfluid exhibit hysteresis. In a certain velocity region, there is a bistability between stationary laminar flow and periodic vortex shedding. The bistability exists in two- and three-dimensional s...

[Phys. Rev. A 90, 013612] Published Wed Jul 16, 2014

]]>Two-component mixtures in optical lattices reveal a rich variety of different phases. We employ an exact diagonalization method to obtain the relevant correlation functions in hexagonal optical lattices which characterize those phases. We relate the occupation difference of the two species to the ma...

[Phys. Rev. A 90, 013613] Published Wed Jul 16, 2014

]]>We study the ground-state properties of ultracold bosonic atoms in a state-dependent graphenelike honeycomb optical lattice, where the degeneracy between the two triangular sublattices A and B can be lifted. We discuss the various geometries accessible with this lattice setup and present a scheme to...

[Phys. Rev. A 90, 013614] Published Wed Jul 16, 2014

]]>We have measured the two-particle correlation function of atoms from a Bose-Einstein condensate participating in a superradiance process, which directly reflects the second-order coherence of the emitted light. We compare this correlation function with that of atoms undergoing stimulated emission. W...

[Phys. Rev. A 90, 013615] Published Wed Jul 16, 2014

]]>Spectral singularities are spectral points of non-Hermitian Hamiltonians with the real energies, that annihilate the completeness of the eigenfunctions. The complex PT-symmetric potentials with real spectrum have such Hamiltonians. It was identified that the spectral singularities of complex potenti...

[Phys. Rev. A 90, 013820] Published Wed Jul 16, 2014

]]>Photon-subtracted and photon-added Gaussian states are amongst the simplest non-Gaussian states that are experimentally available. It is generally believed that they are some of the best candidates to enhance sensitivity in parameter extraction. We derive here the quantum Cramér-Rao bound for such s...

[Phys. Rev. A 90, 013821] Published Wed Jul 16, 2014

]]>In Phys. Rev. A 88, 062313 (2013)PLRAAN10.1103/PhysRevA.88.062313 we proposed and studied a model for a self-correcting quantum memory in which the energetic cost for introducing a defect in the memory grows without bounds as a function of system size. This positive behavior is due to attractive lon...

[Phys. Rev. A 90, 012321] Published Tue Jul 15, 2014

]]>We discuss the formalism of Balian and Duplantier [Balian and Duplantier, Ann. Phys. (NY) 104, 300 (1977)APNYA610.1016/0003-4916(77)90334-7; Balian and Duplantier, Ann. Phys. (NY) 112, 165 (1978)APNYA610.1016/0003-4916(78)90083-0] for the calculation of the Casimir energy for an arbitrary smooth com...

[Phys. Rev. A 90, 012514] Published Tue Jul 15, 2014

]]>Pulse-amplitude and fluence-specified optimal control simulation with linear (dipole) and nonlinear (polarizability) interactions is applied to find the best way to orient CO molecules with a combination of THz and laser pulses. The optimal pulses are numerically designed with a specified maximum am...

[Phys. Rev. A 90, 013415] Published Tue Jul 15, 2014

]]>We investigate the steady-state cooling dynamics of vibrational degrees of freedom related to a nanomechanical oscillator coupled with a laser-pumped quantum dot in an optical resonator. Correlations between phonon-cooling and quantum-dot photon emission processes occur, respectively, when a photon ...

[Phys. Rev. A 90, 013817] Published Tue Jul 15, 2014

]]>We present a theoretical investigation on the saturation of stimulated Raman scattering (SRS) and propose an application of it to break the diffraction limit in SRS microscopy. In our proposed scheme, a donut-shaped Stokes beam is used to saturate SRS at the rim of a focused Gaussian pump beam; thus...

[Phys. Rev. A 90, 013818] Published Tue Jul 15, 2014

]]>The propagation of a step pulse through a thick resonant absorber with a homogeneously broadened absorption line is considered. It is shown that a specific subradiant state is naturally developed in the absorber due to the formation of the spatial domains of the atomic coherence with opposite phases...

[Phys. Rev. A 90, 013819] Published Tue Jul 15, 2014

]]>In measurement-based quantum computing, there is a natural “causal cone” among qubits of the resource state, since the measurement angle on a qubit has to depend on previous measurement results in order to correct the effect of by-product operators. If we respect the no-signaling principle, by-produ...

[Phys. Rev. A 90, 010101] Published Mon Jul 14, 2014

]]>We show that the synthetic spin-orbit coupling created in current ultracold atom experiments provides physicists a unique tool to control the Luttinger liquid parameter K of weakly interacting bosons in one dimension. At a critical value of the Raman coupling strength Ωc, K is suppressed down to zer...

[Phys. Rev. A 90, 011602] Published Mon Jul 14, 2014

]]>The quantum reality problem is that of finding a mathematically precise definition of a sample space of configurations of beables, events, histories, paths, or other mathematical objects, and a corresponding probability distribution, for any given closed quantum system. Given a solution, we can post...

[Phys. Rev. A 90, 012107] Published Mon Jul 14, 2014

]]>