In quantum optimal control theory, kinematic bounds are the minimum and maximum values of the control objective achievable for any physically realizable system dynamics. For a given initial state of the system, these bounds depend on the nature and state of the controller. We consider a general situ...

[Phys. Rev. A 91, 042327] Published Thu Apr 23, 2015

]]>We study an asymmetric form of the two-mode entangled coherent state (ECS), where the two local amplitudes have different values, as a tool for testing the Bell-Clauser-Horne-Shimony-Holt (Bell-CHSH) inequality. We find that the asymmetric ECSs have obvious advantages over the symmetric form of ECSs...

[Phys. Rev. A 91, 042328] Published Thu Apr 23, 2015

]]> One of the promising systems to realize quantum computation is a hybrid system where a superconducting flux qubit plays the role of a quantum processor and the nitrogen-vacancy- (NV^{−}) center ensemble is used as a quantum memory. We have theoretically and experimentally studied the effect of magnetic...

[Phys. Rev. A 91, 042329] Published Thu Apr 23, 2015

]]>Nowadays, geometric tools are being used to treat a huge class of problems of quantum information science. By understanding the interplay between the geometry of the state space and information-theoretic quantities, it is possible to obtain less trivial and more robust physical constraints on quantu...

[Phys. Rev. A 91, 042330] Published Thu Apr 23, 2015

]]> We present a simple theoretical model for describing ultracold-atomic collision dynamics and Feshbach resonances (FRs) without onerous numerical computation. An effective quantum-defect phase shift δ_{Y}^{eff} is derived and the reference potentials are shown acting as an assistant tool in the calculation...

[Phys. Rev. A 91, 042708] Published Thu Apr 23, 2015

]]>By numerically solving the time-dependent Schrödinger equation in full dimensionality, we discuss the dependance of joint photoelectron angular distributions on the energy sharing of the emitted electrons for the double ionization of helium atoms by ultrashort pulses of extreme ultraviolet (XUV) rad...

[Phys. Rev. A 91, 043416] Published Thu Apr 23, 2015

]]>We demonstrate that a site-dependent driving of a periodic potential allows for the controlled manipulation of a quantum particle on length scales of the lattice spacing. Specifically we observe for distinct driving frequencies a near depletion of certain sites which is explained by a resonant mixin...

[Phys. Rev. A 91, 043628] Published Thu Apr 23, 2015

]]>While different ways to realize spin-orbit coupling in Bose-Einstein condensates exist, not all are currently experimentally implementable. Here we present a detailed study of gap solitons in a Bose-Einstein condensate with experimentally realizable spin-orbit coupling and discuss two cases relating...

[Phys. Rev. A 91, 043629] Published Thu Apr 23, 2015

]]>We present a detailed, realistic analysis of the implementation of a proposal for dipole-induced electromagnetic transparency (DIET) [R. Puthumpally-Joseph, M. Sukharev, O. Atabek, and E. Charron, Phys. Rev. Lett. 113, 163603 (2014)PRLTAO10.1103/PhysRevLett.113.163603] using an ensemble of cold atom...

[Phys. Rev. A 91, 043835] Published Thu Apr 23, 2015

]]>We study the dissociation of Feshbach molecules in ultracold Fermi gases with spin-orbit (SO) coupling. Since SO coupling can induce a quantum transition between Feshbach molecules and the fully polarized Fermi gas, the Feshbach molecules can be dissociated by the SO coupling. We experimentally real...

[Phys. Rev. A 91, 041604] Published Wed Apr 22, 2015

]]>The detection-efficiency loophole poses a significant problem for experimental tests of Bell inequalities. The recently discovered Pusey-Barrett-Rudolph (PBR) theorem suffers from the same vulnerability. In this paper we calculate the critical detection efficiency, below which the PBR argument for t...

[Phys. Rev. A 91, 042125] Published Wed Apr 22, 2015

]]>We study the occurrence of errors in a continuously decoupled two-qubit state during a √SWAP quantum operation under decoherence. We consider a realization of this quantum gate based on the Heisenberg exchange interaction, which alone suffices for achieving universal quantum computation. Furthermore...

[Phys. Rev. A 91, 042325] Published Wed Apr 22, 2015

]]>Quantum state joining has been recently experimentally demonstrated [C. Vitelli et al., Nat. Photon. 7, 521 (2013)10.1038/nphoton.2013.107] which can transfer two input photonic qubits into a photonic ququart. Here, we revisit these processes from a hybrid point of view. By exploring the giant optic...

[Phys. Rev. A 91, 042326] Published Wed Apr 22, 2015

]]>We present theoretical studies on real-time probing of the electron density evolution of an atom in a strong infrared (IR) laser field with few-cycle near-infrared (NIR) and attosecond extreme-ultraviolet (XUV) pulses. Our results indicate that the electron density near the tunneling barrier is refl...

[Phys. Rev. A 91, 043414] Published Wed Apr 22, 2015

]]> We study dissociative photoionization of molecular oxygen in a kinematically complete XUV-IR pump-probe experiment. Detecting charged fragments and photoelectrons in coincidence using a reaction microscope, we observe a pump-probe delay-dependent yield of very low energetic O^{+} ions which oscillates ...

[Phys. Rev. A 91, 043415] Published Wed Apr 22, 2015

]]>We compute the spectral density in the normal phase of an interacting homogenous Fermi gas using a T-matrix approximation. We fit the quasiparticle peaks of the spectral density to BCS-like dispersion relations and extract estimates of a “pseudogap” energy scale and an effective Fermi wave vector as...

[Phys. Rev. A 91, 043627] Published Wed Apr 22, 2015

]]>The output incoherent spectrum and the photon blockade for the two-photon near-resonant excitation are numerically investigated by using the modified theories which are valid for an arbitrary degree of the qubit-cavity interaction. Owing to the effects of strong coupling of the system, the relaxatio...

[Phys. Rev. A 91, 043831] Published Wed Apr 22, 2015

]]>Using the variational method extended to dissipative systems and numerical simulations, an analytical stability criterion is established allowing the determination of stability domains of parameters for vortices with high topological charge S. Parameters from these domains are used as inputs for num...

[Phys. Rev. A 91, 043832] Published Wed Apr 22, 2015

]]>We propose a realistic physical scheme to produce one-dimensional and two-dimensional weak-light solitons in an atomic system with PT symmetry. The system we suggest is a cold three-level atomic gas with two species and is driven by control and probe laser fields. We show that by the interference of...

[Phys. Rev. A 91, 043833] Published Wed Apr 22, 2015

]]>We investigate theoretically quantum scattering of two distinguishable photon wave packets from a Ξ-type three-level atom in a one-dimensional waveguide. The quantum state of scattered photons is solved analytically, and the solution indicates how the two photons become strongly correlated after the...

[Phys. Rev. A 91, 043834] Published Wed Apr 22, 2015

]]>Nuclear structure corrections to energy levels of light muonic atoms are derived with particular attention to the nuclear mass dependence. The obtained result for the 2P-2S transition of 1.717(20) meV serves for determination of the nuclear charge radius from the spectroscopic measurement in muonic ...

[Phys. Rev. A 91, 040503] Published Tue Apr 21, 2015

]]>We study an ensemble of two-level quantum systems (qubits) interacting with a common electromagnetic field in the proximity of a dielectric slab whose temperature is held different from that of some far surrounding walls. We show that the dissipative dynamics of the qubits driven by this stationary ...

[Phys. Rev. A 91, 042124] Published Tue Apr 21, 2015

]]> We demonstrate the importance of electron correlation effects in the hyperfine structure constants of many low-lying states in ^{210}Fr and ^{212}Fr. This is achieved by calculating the magnetic dipole and electric quadrupole hyperfine structure constants using the Dirac-Fock approximation, second-order m...

[Phys. Rev. A 91, 042507] Published Tue Apr 21, 2015

]]> X rays originating from transitions from high Rydberg states to the M shell (here called Rydberg-to-M-shell x rays) have been measured in the interaction of Xe^{q+}(q=27–30) ions with aluminum, molybdenum, and beryllium surfaces in the energy range of 350–600 keV, by using a Si(Li) detector. The transi...

[Phys. Rev. A 91, 042707] Published Tue Apr 21, 2015

]]>We theoretically investigate the effects of strong couplings in resonant Auger processes under the combination of strong resonant x-ray and nearly resonant optical pulses. The x-ray field couples the ground state with a core-excited state, while the optical field couples the core-excited state with ...

[Phys. Rev. A 91, 043413] Published Tue Apr 21, 2015

]]> We quantify a limitation in the usual accounting of the finite-size effects, where the leading [(Zα)^{4}] and subleading [(Zα)^{5}] contributions to the Lamb shift are given by the mean-square radius and the third Zemach moment of the charge distribution. In the presence of any nonsmooth behavior of the n...

[Phys. Rev. A 91, 040502] Published Mon Apr 20, 2015

]]>The state of quantum systems, their energetics, and their time evolution is modeled by abstract operators. How can one visualize such operators for coupled spin systems? A general approach is presented that consists of several shapes representing linear combinations of spherical harmonics. It is app...

[Phys. Rev. A 91, 042122] Published Mon Apr 20, 2015

]]>The generalization of the concept of interaction-free evolutions (IFE) [Napoli et al., Phys. Rev. A 89, 062104 (2014)PLRAAN10.1103/PhysRevA.89.062104] to the case of time-dependent Hamiltonians is discussed. It turns out that the time-dependent case allows for much richer structures of interaction-f...

[Phys. Rev. A 91, 042123] Published Mon Apr 20, 2015

]]>We study the problem of witnessing entanglement among indistinguishable particles. For this purpose, we derive a set of equations which results in necessary and sufficient conditions for probing multipartite entanglement between arbitrary systems of bosons or fermions. The solution of these equation...

[Phys. Rev. A 91, 042324] Published Mon Apr 20, 2015

]]>Electromagnetic driving in a honeycomb lattice can induce gaps and topological edge states with a structure of increasing complexity as the frequency of the driving lowers. While the high-frequency case is the most simple to analyze we focus on the multiple photon processes allowed in the low-freque...

[Phys. Rev. A 91, 043625] Published Mon Apr 20, 2015

]]>We optimize a collision-induced cooling process for ultracold atoms in the nondegenerate regime. It makes use of a Feshbach resonance, instead of rf radiation in evaporative cooling, to selectively expel hot atoms from a trap. Using functional minimization we analytically show that for the optimal c...

[Phys. Rev. A 91, 043626] Published Mon Apr 20, 2015

]]>We demonstrate an effective control of nonlinear interactions of lasing modes in a semiconductor microdisk cavity by shaping the pump profile. A target mode is selected at the expense of its competing modes either by increasing their lasing thresholds or suppressing their power slopes above the lasi...

[Phys. Rev. A 91, 043828] Published Mon Apr 20, 2015

]]>We experimentally study the phase-space distribution (PSD) of a mechanical resonator that is simultaneously coupled to two electromagnetic cavities. The first one, operating in the microwave band, is employed for inducing either cooling or self-excited oscillation (SEO), whereas the second one, oper...

[Phys. Rev. A 91, 043829] Published Mon Apr 20, 2015

]]>We propose a method of measuring topological invariants of a photonic crystal through phase spectroscopy. We show how the Chern numbers can be deduced from the winding numbers of the reflection coefficient phase. An explicit proof of the existence of edge states in a system with a nonzero reflection...

[Phys. Rev. A 91, 043830] Published Mon Apr 20, 2015

]]> The branching fractions from the excited state 6P_{1/2} of singly charged barium ion has been measured with a precision 0.03% in an ion trap experiment. This measurement along with the known value of the upper state lifetime allowed the determination of the dipole matrix elements for the transitions P-...

[Phys. Rev. A 91, 040501] Published Fri Apr 17, 2015

]]>The principle of local distinguishability states that an arbitrary physical state of a bipartite system can be determined by the combined statistics of local measurements performed on the subsystems. A necessary and sufficient requirement for the local measurements is that each one must be able to d...

[Phys. Rev. A 91, 042121] Published Fri Apr 17, 2015

]]>The linear polarization of x rays produced by dielectronic recombination into highly charged xenon ions was measured at an electron beam ion trap using the Compton polarimetry technique. This opens numerous possibilities for diagnostics of anisotropies of hot plasmas. Moreover, it was observed that ...

[Phys. Rev. A 91, 042705] Published Fri Apr 17, 2015

]]> The electronic structure of the (LiYb)^{+} molecular ion is investigated with two variants of the coupled cluster method restricted to single, double, and noniterative or linear triple excitations. Potential-energy curves for the ground and excited states, permanent and transition electric dipole momen...

[Phys. Rev. A 91, 042706] Published Fri Apr 17, 2015

]]>The triple differential cross section for laser-assisted ionization of a helium target by slow electrons is analyzed within the framework of the second Born approximation. We evaluate the S-matrix elements using Volkov and Coulomb-Volkov wave functions for describing the continuum states of the scat...

[Phys. Rev. A 91, 043411] Published Fri Apr 17, 2015

]]>The growing successes in performing quantum control experiments motivated the development of control landscape analysis as a basis to explain these findings. When a quantum system is controlled by an electromagnetic field, the observable as a functional of the control field forms a landscape. Theore...

[Phys. Rev. A 91, 043412] Published Fri Apr 17, 2015

]]>Motivated by the recent experiment performed by the Berkeley group [G. E. Marti et al., Phys. Rev. Lett. 113, 165301 (2014)PRLTAO10.1103/PhysRevLett.113.165301], we consider the dynamics of magnons in a spin-1 spinor-dipolar Bose-Einstein condensate, using mean-field theory. We show that the effecti...

[Phys. Rev. A 91, 041603] Published Thu Apr 16, 2015

]]>We investigate the fidelity of the quantum state transfer (QST) of two qubits by means of an arbitrary spin-1/2 network, on a lattice of any dimensionality. Under the assumptions that the network Hamiltonian preserves the magnetization and that a fully polarized initial state is taken for the lattic...

[Phys. Rev. A 91, 042321] Published Thu Apr 16, 2015

]]>We present a discussion of the continuous-time quantum error correction introduced by J. P. Paz and W. H. Zurek [Proc. R. Soc. A 454, 355 (1998)10.1098/rspa.1998.0165]. We study the general Lindbladian which describes the effects of both noise and error correction in the weak-noise (or strong-correc...

[Phys. Rev. A 91, 042322] Published Thu Apr 16, 2015

]]>For bipartite pure and mixed quantum states, in addition to the quantum mutual information, there is another measure of total correlation, namely, the entanglement of purification. We study the monogamy, polygamy, and additivity properties of the entanglement of purification for pure and mixed state...

[Phys. Rev. A 91, 042323] Published Thu Apr 16, 2015

]]>We analyze the influence of an external electric field on the ns and np Rydberg states. The impact of an electric field leads to a significant modification of the decay rate. Namely, the additional (linear and quadratic in the field) terms arise in the differential transition probabilities. In contr...

[Phys. Rev. A 91, 042506] Published Thu Apr 16, 2015

]]>Using the time-dependent density matrix renormalization-group method and exact diagonalization, we study the nonequilibrium dynamics of the one-dimensional Fermi-Hubbard model following a quantum quench or a ramp of the on-site interaction strength. We are particularly interested in the nonequilibri...

[Phys. Rev. A 91, 043623] Published Thu Apr 16, 2015

]]>Using a variational method, we derive an exact upper bound for one-magnon excitation energy in ferromagnetic spinor gases, which limits the quantum corrections to the effective mass of a magnon to be positive. We also derive an upper bound for one-magnon excitation energy in lattice systems. The res...

[Phys. Rev. A 91, 043624] Published Thu Apr 16, 2015

]]>The Levy-like steady-state distributions of emission intensities in random lasers are derived analytically, and it is shown that the Levy exponent alpha can act as a universal identifier of the lasing threshold.

[Phys. Rev. A 91, 043827] Published Thu Apr 16, 2015

]]>It is shown how quantum gas microscopy, in which atoms in an optical lattice are imaged with single-site resolution, can be greatly improved by using a bilayer trapping potential, thus overcoming the long-standing limitation of parity projection in the imaging procedure.

[Phys. Rev. A 91, 041602] Published Wed Apr 15, 2015

]]>We study the time evolution of a two-dimensional quantum particle exhibiting a two-band energy spectrum with two Dirac cones as, for example, in the honeycomb lattice. A force is applied such that the particle experiences two Landau-Zener transitions in succession in the vicinity of the Dirac cones....

[Phys. Rev. A 91, 042119] Published Wed Apr 15, 2015

]]>We investigate the coherence measures induced by fidelity and trace norm, based on the coherence quantification recently proposed by Baumgratz et al. [T. Baumgratz, M. Cramer, and M. B. Plenio, Phys. Rev. Lett. 113, 140401 (2014)PRLTAO10.1103/PhysRevLett.113.140401]. We show that the fidelity of coh...

[Phys. Rev. A 91, 042120] Published Wed Apr 15, 2015

]]>We apply a version of the recently developed approach combining the correlation-potential, linearized singles-doubles coupled-cluster, and configuration-interaction methods to the spectra of the heavy alkaline earths barium, radium, and element 120. Quantum electrodynamics radiative corrections are ...

[Phys. Rev. A 91, 042505] Published Wed Apr 15, 2015

]]>We describe a procedure for the solution of the time-dependent Dirac equation. The procedure is based on the relativistic generalization of the matrix iteration method. We use this procedure to study electron-momentum distribution along the laser-beam propagation direction for the process of the tun...

[Phys. Rev. A 91, 043410] Published Wed Apr 15, 2015

]]>Traveling waves in two-component Bose-Einstein condensates whose dynamics is described by the Manakov limit of the Gross-Pitaevskii equations are considered in a general situation with relative motion of the components when their chemical potentials are not equal to each other. It is shown that in t...

[Phys. Rev. A 91, 043621] Published Wed Apr 15, 2015

]]>We theoretically study two atoms with p-wave interaction in a one-dimensional waveguide, investigating how the transverse anisotropy of the confinement affects the two-body state, especially the properties of the resonance. For a bound-state solution, we find there are a total of three two-body boun...

[Phys. Rev. A 91, 043622] Published Wed Apr 15, 2015

]]>Studies of the quasi-phase-matched harmonics generated in spatially modulated silver plasma are presented. We analyze the influence of the driving and heating pulse energies on the enhancement and spectral tuning of the quasi-phase-matched harmonics and show the tuning of those enhanced groups of ha...

[Phys. Rev. A 91, 043823] Published Wed Apr 15, 2015

]]> We demonstrate the manipulation of transmitted light through an optical Fabry-Pérot cavity, built around a spectroscopy cell containing enriched rubidium vapor. Light resonant with the ^{87}Rb D_{2} (F=2,F=1) ↔F^{′} manifold is controlled by the transverse intersection of the cavity mode by another resonant ...

[Phys. Rev. A 91, 043824] Published Wed Apr 15, 2015

]]>We demonstrate enhanced wavelike character of diffuse photon density waves (DPDW) in an amplifying random medium. The amplifying nature makes it necessary to choose the wave solution that grows inside the amplifying medium, and has a propagation vector pointing opposite to the growth direction. This...

[Phys. Rev. A 91, 043825] Published Wed Apr 15, 2015

]]>The analysis of wave propagation in linear, passive media is usually done by considering a single real frequency (the monochromatic limit) and also often a single plane-wave component (plane-wave limit). For gain media, we demonstrate that these two limits generally do not commute; for example, one ...

[Phys. Rev. A 91, 043826] Published Wed Apr 15, 2015

]]>The dynamics of a driven network of spin-1/2 systems coupled to chiral one-dimensional bosonic waveguides is studied, and the formation of pure, multipartite entangled states as steady states is demonstrated.

[Phys. Rev. A 91, 042116] Published Tue Apr 14, 2015

]]>Engineered dissipation can be employed to prepare interesting quantum many-body states in a nonequilibrium fashion. The basic idea is to obtain the state of interest as the unique steady state of a quantum master equation, irrespective of the initial state. Due to a fundamental competition of topolo...

[Phys. Rev. A 91, 042117] Published Tue Apr 14, 2015

]]>The present paper is the natural continuation of a recent paper [A. Di Piazza, Phys. Rev. Lett. 113, 040402 (2014)PRLTAO10.1103/PhysRevLett.113.040402], in which the electron wave functions in the presence of a background electromagnetic field of general space-time structure were constructed analyti...

[Phys. Rev. A 91, 042118] Published Tue Apr 14, 2015

]]> We give an explicit construction of d locally indistinguishable, orthogonal maximally entangled states in C^{d}⊗C^{d} for any d≥4. This gives an answer to the conjecture proposed by Bandyopadhyay et al. [New J. Phys. 13, 123013 (2011)NJOPFM10.1088/1367-2630/13/12/123013].

[Phys. Rev. A 91, 042318] Published Tue Apr 14, 2015

]]>An efficient scheme is proposed to implement a quantum cloning machine in separate cavities based on a hybrid interaction between electron-spin systems placed in the cavities and an optical coherent pulse. The coefficient of the output state for the present cloning machine is just the direct product...

[Phys. Rev. A 91, 042319] Published Tue Apr 14, 2015

]]>The unconditional security in the creation of cryptographic keys obtained by quantum key distribution (QKD) protocols will induce a quantum leap in free-space communication privacy in the same way that we are beginning to realize secure optical fiber connections. However, free-space channels, in par...

[Phys. Rev. A 91, 042320] Published Tue Apr 14, 2015

]]>We study the physics of interacting spin-1 bosons in an optical lattice using a variational Gutzwiller technique. We compute the mean-field ground state wave function and discuss the evolution of the condensate, spin, nematic, and singlet order parameters across the superfluid-Mott transition. We th...

[Phys. Rev. A 91, 043620] Published Tue Apr 14, 2015

]]>We consider the response of a nanomechanical resonator interacting with an electromagnetic cavity via a radiation-pressure coupling and a cross-Kerr coupling. Using a mean-field approach we solve the dynamics of the system and show the different corrections coming from the radiation pressure and the...

[Phys. Rev. A 91, 043822] Published Tue Apr 14, 2015

]]>[Phys. Rev. A 91, 049902] Published Tue Apr 14, 2015

]]> We present measurements of the motional heating rate of a trapped ion at different trap frequencies and temperatures between ∼0.6 and 1.5 MHz and ∼4 and 295 K. Additionally, we examine the possible effect of adsorbed surface contaminants with boiling points below ∼105 ^{∘}C by measuring the ion heating...

[Phys. Rev. A 91, 041402] Published Mon Apr 13, 2015

]]>The creation of tunable open quantum systems is becoming feasible in current experiments with ultracold atoms in low-dimensional traps. In particular, the high degree of experimental control over these systems allows detailed studies of tunneling dynamics, e.g., as a function of the trapping geometr...

[Phys. Rev. A 91, 041601] Published Mon Apr 13, 2015

]]>We address the question of how weak perturbations, which are quite ineffective in small many-body systems, can lead to decoherence and hence to irreversibility when they proliferate as the system size increases. This question is at the heart of solid-state NMR. There, an initially local polarization...

[Phys. Rev. A 91, 042112] Published Mon Apr 13, 2015

]]> We study violation of the Leggett-Garg inequality for the correlator K_{3} in two cases: (i) for a qubit weakly coupled to a thermal decohering (dissipative and/or dephasing) environment and (ii) for a pair of qubits with only one of them coupled to the environment. In the case of a single qubit, we id...

[Phys. Rev. A 91, 042113] Published Mon Apr 13, 2015

]]>Quantum mechanics allows only certain sets of experimental results (or “probabilistic models”) for Bell-type quantum nonlocality experiments. A derivation of this set from simple physical or information theoretic principles would represent an important step forward in our understanding of quantum me...

[Phys. Rev. A 91, 042114] Published Mon Apr 13, 2015

]]>We study a deformation of the counterdiabatic-driving Hamiltonian as a systematic strategy for an adiabatic control of quantum states. Using a unitary transformation, we design a convenient form of the driver Hamiltonian. We apply the method to a particle in a confining potential and discrete system...

[Phys. Rev. A 91, 042115] Published Mon Apr 13, 2015

]]>Recently the question of whether the D-Wave processors exhibit large-scale quantum behavior or can be described by a classical model has attracted significant interest. In this work we address this question by studying a 503-qubit D-Wave Two device in the “black box” model i.e., by studying its inpu...

[Phys. Rev. A 91, 042314] Published Mon Apr 13, 2015

]]>A scheme to combine the two steps of fault-tolerant quantum computing into a single step is presented, which may dramatically reduce the overhead associated with realizing certain quantum gates.

[Phys. Rev. A 91, 042315] Published Mon Apr 13, 2015

]]>Implementation of exact BosonSampling via optical interferometry is considered, and a proof is given that significantly simplifies the requirements for this model by showing that a constant number of beam-splitter layers suffices as the numbers of interferometric channels and photons increase.

[Phys. Rev. A 91, 042316] Published Mon Apr 13, 2015

]]>The non-Markovianity is a prominent concept of the dynamics of open quantum systems, which is of fundamental importance in quantum mechanics and quantum information. Despite lots of efforts, the experimental measurement of non-Markovianity of an open system is still limited to very small systems. Pr...

[Phys. Rev. A 91, 042317] Published Mon Apr 13, 2015

]]>We study the ionization of Rydberg atoms in a single-cycle-pulse electric field based on both classical and quantum calculations. The ionization-probability curve exhibits a “ripple” structure as a function of the pulse duration and the field amplitude. These ripple structures are found to be depend...

[Phys. Rev. A 91, 043407] Published Mon Apr 13, 2015

]]>We investigate the characteristic effects of nuclear motion on attosecond transient-absorption spectra in molecules by calculating the spectrum for different model systems. Two models of the hydrogen molecular ion are considered: one where the internuclear separation is fixed, and one where the nucl...

[Phys. Rev. A 91, 043408] Published Mon Apr 13, 2015

]]>We report on quantum revivals and classical periodicities of wave packets centered around the ground state within the Lipkin-Meshkov-Glick model. Special attention is paid to the behavior at first- and second-order phase transitions. In line with previous studies, we find that away from criticality,...

[Phys. Rev. A 91, 043409] Published Mon Apr 13, 2015

]]>Polar molecules in geometrically frustrated lattices may result in a very rich landscape of quantum phases, due to the nontrivial interplay between frustration, and two- and possibly three-body intersite interactions. In this paper we illustrate this intriguing physics for the case of hard-core pola...

[Phys. Rev. A 91, 043614] Published Mon Apr 13, 2015

]]>We show the emergence of a third Goldstone mode in binary condensates at phase separation in quasi-one-dimensional (quasi-1D) optical lattices. We develop the coupled discrete nonlinear Schrödinger equations using Hartree-Fock-Bogoliubov theory with the Popov approximation in the Bose-Hubbard model ...

[Phys. Rev. A 91, 043615] Published Mon Apr 13, 2015

]]>Searching for novel topological objects is always an intriguing task for scientists in various fields. We study a three-dimensional (3D) topological structure called a 3D dimeron in trapped two-component Bose-Einstein condensates. The 3D dimeron differs from the conventional 3D skyrmion for the cond...

[Phys. Rev. A 91, 043616] Published Mon Apr 13, 2015

]]>Interactions are known to have dramatic effects on bosonic gases in one dimension (1D). Not only does the ground state transform from a condensate like state to an effective Fermi sea, but new fundamental excitations, which do not have any higher-dimensional equivalents, are predicted to appear. In ...

[Phys. Rev. A 91, 043617] Published Mon Apr 13, 2015

]]>We calculated the phase diagram of a continuous system of hard spheres loaded in a quasi-one-dimensional bichromatic optical lattice. The wavelengths of both lattice-defining lasers were chosen to model an incommensurate arrangement. Densities of one particle and half a particle per potential well w...

[Phys. Rev. A 91, 043618] Published Mon Apr 13, 2015

]]>Whenever the value of an unknown parameter θ is extracted from a series of experiments, the result is inevitably burdened by the uncertainty Δθ. If the system that is the subject of measurement consists of unentangled particles, this uncertainty is bounded by the shot-noise limit. To overcome this l...

[Phys. Rev. A 91, 043619] Published Mon Apr 13, 2015

]]> Tm:YAlO_{3} lasers suffer from self-pulsing. A four-level rate equation analysis suggested that the self-pulsing could be due to excited-state absorption. We report a measurement of the cross section for this absorption and show that it is too small to be the sole cause of the self-pulsing. We propose ...

[Phys. Rev. A 91, 043819] Published Mon Apr 13, 2015

]]>We demonstrate the generation of narrowband biphotons with polarization-frequency-coupled entanglement from spontaneous four-wave mixing in cold atoms. The coupling between polarization and frequency is realized through a frequency shifter and linear optics. When the polarization-frequency degrees o...

[Phys. Rev. A 91, 043820] Published Mon Apr 13, 2015

]]>A combined theoretical and experimental study shows that it is possible to prepare an optical field that exhibits rotational acceleration as it propagates, which may lead to possibilities for unique forms of particle control.

[Phys. Rev. A 91, 043821] Published Mon Apr 13, 2015

]]> Field-grade atomic clocks capable of primary standard performance in compact physics packages would be of significant value in applications ranging from network synchronization to inertial navigation. A coherent-population-trapping clock featuring laser-cooled ^{87}Rb atoms and pulsed Ramsey interrogat...

[Phys. Rev. A 91, 041401] Published Fri Apr 10, 2015

]]> Highly charged states created through multiple ionization of gases are shown to enhance terahertz (THz) generation by intense, single- or two-color femtosecond laser pulses. A one-dimensional, nonpropagating fluid model reveals the main conversion processes up to 10^{17} W cm^{−2} laser intensities, namel...

[Phys. Rev. A 91, 041801] Published Fri Apr 10, 2015

]]>With the development of quantum-information theory, there has been a flurry of investigations of quantum non-Markovian dynamics, and several significant measures for such dynamics have been proposed from various perspectives, such as the breakdown of dynamical divisibility, increase in the distingui...

[Phys. Rev. A 91, 042110] Published Fri Apr 10, 2015

]]>We study the geometric phase of a two-level system under the presence of a structured environment, particularly analyzing its correction with the ohmicity parameter s and the onset of non-Markovianity. We first examine the system coupled to a set of harmonic oscillators and study the decoherence fac...

[Phys. Rev. A 91, 042111] Published Fri Apr 10, 2015

]]>We theoretically study operations with a four-level superconducting circuit as a two-qubit system. Using a mapping on a two-qubit system, we show how to implement iswap gates and Hadamard gates through pulses on transitions between particular pairs of energy levels. Our approach allows one to prepar...

[Phys. Rev. A 91, 042312] Published Fri Apr 10, 2015

]]>The k-nonseparability is a kind of multipartite quantum correlation which can be used to characterize some aspects of multipartite entanglement. In this paper, we discuss the detection of k-nonseparability of n-partite quantum states from an information perspective and obtain some k-nonseparability ...

[Phys. Rev. A 91, 042313] Published Fri Apr 10, 2015

]]> We observe the microwave transitions of calcium from the 4snf states to the 4s(n+1)d,4sng,4snh,4sni, and 4snk states for 18≤n≤23 using delayed field ionization as the state selective detection technique. The observed intervals between the ℓ≥5 states can be analyzed to extract the Ca^{+} ionic dipole (α_{...}

[Phys. Rev. A 91, 042503] Published Fri Apr 10, 2015

]]> We report the results of a theoretical investigation of the electronic structure of the ThF^{+} cation, which is one of the most interesting systems to search for the electron electric dipole moment (eEDM) [H. Loh, K. C. Cossel, M. C. Grau, K.-K. Ni, E. R. Meyer, J. L. Bohn, J. Ye, and E. A. Cornell, S...

[Phys. Rev. A 91, 042504] Published Fri Apr 10, 2015

]]>The Coulomb explosion of small cluster beams can be used to measure the dwell time of fragments traversing amorphous films. Therefore, the thickness of thin films can be obtained with the so-called Coulomb depth profiling technique using relatively high cluster energies where the fragments are fully...

[Phys. Rev. A 91, 042704] Published Fri Apr 10, 2015

]]>Wave-function microscopy images for Stark resonance states of H atoms are simulated using the quantum-mechanical formalism developed previously. Spatial distributions of ejected electron current densities are compared with experiment, and a good agreement is shown. The nonzero values of minima in th...

[Phys. Rev. A 91, 043405] Published Fri Apr 10, 2015

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