A quantum algorithm that solves the time-dependent Dirac equation on a digital quantum computer is developed and analyzed. The time evolution is performed by an operator-splitting decomposition technique that allows for a mapping of the Dirac operator to a quantum walk supplemented by unitary rotati…

[Phys. Rev. A 95, 042343] Published Fri Apr 28, 2017

]]>In quantum private query (QPQ), a client obtains values corresponding to his or her query only, and nothing else from the server, and the server does not get any information about the queries. V. Giovannetti *et al.* [Phys. Rev. Lett. **100**, 230502 (2008)] gave the first QPQ protocol and since then qui…

[Phys. Rev. A 95, 042344] Published Fri Apr 28, 2017

]]>A scheme for fast measurements of geometrical phases in a superconducting qubit platform is demonstrated. The result might boost developments in quantum computation.

[Phys. Rev. A 95, 042345] Published Fri Apr 28, 2017

]]>A pair of neutral atoms separated by several microns and prepared in identical $s$ states of large principal quantum number experience a van der Waals interaction. If microwave fields are used to generate a superposition of $s$ states with different principal quantum numbers, a null point may be found a…

[Phys. Rev. A 95, 043429] Published Fri Apr 28, 2017

]]>Motivated by the recent realization of the Haldane model in a shaking optical lattice, we investigate the effects of attractive interaction and the BEC-BCS crossover in this model at and away from half-filling. We show that, contrary to the usual $s$-wave BEC-BCS crossover in the lattice, a topologica…

[Phys. Rev. A 95, 043640] Published Fri Apr 28, 2017

]]>The effect of atom losses on a homogeneous one-dimensional Bose gas lying within the quasicondensate regime is investigated using a Monte Carlo wave-function approach. The evolution of the system is calculated, conditioned by the loss sequence, namely, the times of individual losses and the position…

[Phys. Rev. A 95, 043641] Published Fri Apr 28, 2017

]]>In its simplest form, decoherence occurs when a quantum state is entangled with a second state, but the results of measurements made on the second state are not accessible. As the second state has effectively “measured” the first, in this paper we argue that the quantum Fisher information is the rel…

[Phys. Rev. A 95, 043642] Published Fri Apr 28, 2017

]]>We present a mixed-dimensional atomic gas system to unambiguously detect and systematically probe mediated interactions. In our scheme, fermionic atoms are confined in two parallel planes and interact via exchange of elementary excitations in a three-dimensional background gas. This interaction give…

[Phys. Rev. A 95, 043643] Published Fri Apr 28, 2017

]]>We are interested in dynamics of quantum many-body systems under continuous observation, and its physical realizations involving cold atoms in lattices. In the present work we focus on continuous measurement of atomic currents in lattice models, including the Hubbard model. We describe a Cavity QED …

[Phys. Rev. A 95, 043843] Published Fri Apr 28, 2017

]]>We provide a description of spontaneous emission in a dispersive and dissipative linear inhomogeneous medium based on the generalized Huttner-Barnett model [Phys. Rev. A **46**, 4306 (1992)]. Our discussion considers on an equal footing both the photonic and material fluctuations which are necessary to …

[Phys. Rev. A 95, 043844] Published Fri Apr 28, 2017

]]>We discuss the collective modes in an alkaline-earth-metal Fermi gas close to an orbital Feshbach resonance. Unlike the usual Feshbach resonance, the orbital Feshbach resonance in alkaline-earth-metal atoms realizes a two-band superfluid system where the fermionic nature of both the open and the clo…

[Phys. Rev. A 95, 041603(R)] Published Thu Apr 27, 2017

]]>We study the phase diagram of a Rashba spin-orbit-coupled Bose-Einstein condensate confined in a two-dimensional toroidal trap. In the immiscible regime we find an azimuthally periodic density distribution, with the periodicity highly tunable as a function of the spin-orbit-coupling strength and whi…

[Phys. Rev. A 95, 041604(R)] Published Thu Apr 27, 2017

]]>In practical applications, quantum systems work in a finite-temperature environment. Quantum entanglement is inevitably destroyed by the thermal noise. Here we experimentally demonstrate the protection of entanglement on the platform of linear optics. The finite-temperature thermal noise is describe…

[Phys. Rev. A 95, 042342] Published Thu Apr 27, 2017

]]>In this article, we investigate the role of the self-interaction error in the simulation of collisions using time-dependent density functional theory (TDDFT) and Ehrenfest dynamics. We compare many different approximations of the exchange and correlation potential, using as a test system the collisi…

[Phys. Rev. A 95, 042517] Published Thu Apr 27, 2017

]]>Semiclassical open-orbit theory (OOT), previously developed to study photoionization of hydrogenic atoms in a uniform electric field [L. B. Zhao and J. B. Delos, Phys. Rev. A **81**, 053417 (2010)], has been generalized to describe the propagation of outgoing electron waves to macroscopic distances from…

[Phys. Rev. A 95, 043428] Published Thu Apr 27, 2017

]]>In the present work, we explore the existence, stability, and dynamics of single- and multiple-vortex-ring states that can arise in Bose-Einstein condensates. Earlier works have illustrated the bifurcation of such states in the vicinity of the linear limit for isotropic or anisotropic three-dimensio…

[Phys. Rev. A 95, 043638] Published Thu Apr 27, 2017

]]>We demonstrate experimentally that an electric field can be used to control quantum reflection of matter waves off periodically microstructured surfaces. Applying a voltage of alternating polarity between neighboring grating bars induces an electric field which modifies the interaction between the s…

[Phys. Rev. A 95, 043639] Published Thu Apr 27, 2017

]]>We present a general model, based on a Hamiltonian approach, for the joint quantum state of photon pairs generated through pulsed spontaneous four-wave mixing, including nonlinear phase modulation and a finite material response time. For the case of a silica fiber, it is found that the pair-producti…

[Phys. Rev. A 95, 043842] Published Thu Apr 27, 2017

]]>We analyze theoretically the many-body dynamics of a dissipative Ising model in a transverse field using a variational approach. We find that the steady-state phase diagram is substantially modified compared to its equilibrium counterpart, including the appearance of a multicritical point belonging …

[Phys. Rev. A 95, 042133] Published Wed Apr 26, 2017

]]>We study the dependence of the fidelity of the surface code in the presence of a single finite-temperature massless bosonic environment after a quantum error correction cycle. The three standard types of environment are considered: super-Ohmic, Ohmic, and sub-Ohmic. Our results show that, for regime…

[Phys. Rev. A 95, 042339] Published Wed Apr 26, 2017

]]>Detection of entanglement in quantum networks consisting of many parties is one of the important steps toward building quantum communication and computation networks. We consider a scenario where the measurement devices used for this certification are uncharacterized. In this case, it is well known …

[Phys. Rev. A 95, 042340] Published Wed Apr 26, 2017

]]>Quantum search on the two-dimensional lattice with one marked vertex and cyclic boundary conditions is an important problem in the context of quantum algorithms with an interesting unfolding. It avails to test the ability of quantum walk models to provide efficient algorithms from the theoretical si…

[Phys. Rev. A 95, 042341] Published Wed Apr 26, 2017

]]>Rydberg molecules, often exemplified by long-range “trilobite” molecules, are a subject of much recent interest at high principal quantum number $n$. States that use the same bonding mechanism can exist at much lower $n$ and less-extreme internuclear separations that are still quite long range. We use a…

[Phys. Rev. A 95, 042516] Published Wed Apr 26, 2017

]]>We study the isotope effect on high-order-harmonic generation (HHG) of vibrating ${{\mathrm{H}}_{2}}^{+}$ and ${{\mathrm{D}}_{2}}^{+}$ molecular ions aligned parallel to the polarization of the laser field. The time-dependent Schrödinger equation is solved accurately and efficiently by the time-dependent generalized pseudospectral and Fouri…

[Phys. Rev. A 95, 043425] Published Wed Apr 26, 2017

]]>The photoelectron emission time delay $\tau $ associated with one-photon absorption, which coincides with half the Wigner delay ${\tau}_{{\scriptscriptstyle \mathrm{W}}}$ experienced by an electron scattered off the ionic potential, is a fundamental descriptor of the photoelectric effect. Although it is hard to access directly from experiment, …

[Phys. Rev. A 95, 043426] Published Wed Apr 26, 2017

]]>We used extreme ultraviolet (XUV) transient absorption spectroscopy to study the autoionizing Rydberg states of oxygen in an electronically- and vibrationally-resolved fashion. XUV pulse initiates molecular polarization and near-infrared pulse perturbs its evolution. Transient absorption spectra sho…

[Phys. Rev. A 95, 043427] Published Wed Apr 26, 2017

]]>The phenomenon of interference plays a crucial role in the field of precision measurement science. Wave-particle duality has expanded the well-known interference effects of electromagnetic waves to massive particles. The majority of the wave-particle interference experiments require a near monochrom…

[Phys. Rev. A 95, 043637] Published Wed Apr 26, 2017

]]>In this article, we demonstrate that the angles at which second-harmonic (SH) waves are generated at ferroelectric domain walls satisfy the Snell law for nonlinear media. Nonlinear reflection and refraction are observed experimentally and the relation is found to be in good agreement with theoretica…

[Phys. Rev. A 95, 043841] Published Wed Apr 26, 2017

]]>The one-clean qubit model (or the DQC1 model) is a restricted model of quantum computing where only a single qubit of the initial state is pure and others are maximally mixed. Although the model is not universal, it can efficiently solve several problems whose classical efficient solutions are not k…

[Phys. Rev. A 95, 042336] Published Tue Apr 25, 2017

]]>Quantifying coherence is a key task in both quantum-mechanical theory and practical applications. Here, a reliable quantum coherence measure is presented by utilizing the quantum skew information of the state of interest subject to a certain broken observable. This coherence measure is proven to ful…

[Phys. Rev. A 95, 042337] Published Tue Apr 25, 2017

]]>Quantum digital signatures (QDSs) provide a means for signing electronic communications with information-theoretic security. However, all previous demonstrations of quantum digital signatures assume trusted measurement devices. This renders them vulnerable against detector side-channel attacks, just…

[Phys. Rev. A 95, 042338] Published Tue Apr 25, 2017

]]>We present calculations of the one-loop vacuum polarization correction (Uehling potential) for the three-body problem in the NRQED formalism. The case of one-electron molecular systems is considered. Numerical results of the vacuum polarization contribution at $m{\alpha}^{7}$ and higher orders for the fundament…

[Phys. Rev. A 95, 042514] Published Tue Apr 25, 2017

]]>The interaction between a Rydberg electron and a neutral atom situated inside its extended orbit is described via contact interactions for each atom-electron scattering channel. In ultracold environments, these interactions lead to long-range molecules with binding energies typically ranging from 10…

[Phys. Rev. A 95, 042515] Published Tue Apr 25, 2017

]]>The coherent nuclear motion in photoexcited 2,4-difluorophenol (2,4-DFP) has been visualized in real time using femtosecond time-resolved ion-yield spectroscopy and time-resolved photoelectron imaging. A coherent vibrational packet is created by the simultaneous excitation of the out-of-plane bendin…

[Phys. Rev. A 95, 043421] Published Tue Apr 25, 2017

]]>By two-color photoassociation of ${}^{40}\mathrm{Ca}$ four weakly bound vibrational levels in the ${\mathrm{Ca}}_{2}X{\phantom{\rule{0.16em}{0ex}}}^{1}{\mathrm{\Sigma}}_{g}^{+}$ ground-state potential were measured, using highly spin-forbidden transitions to intermediate states of the coupled system ${{}^{3}\mathrm{\Pi}}_{u}$ and ${{}^{3}\mathrm{\Sigma}}_{u}^{+}$ near the ${{}^{3}P}_{1}+{{}^{1}S}_{0}$ asymptote. From the observed binding energies, includin…

[Phys. Rev. A 95, 043422] Published Tue Apr 25, 2017

]]>Streaked photoemission from nanostructured surfaces and nanoparticles by attosecond extreme ultraviolet pulses into an infrared (IR) or visible streaking pulse allows for sub-fs-resolution of the plasmonically enhanced streaking-pulse electric field. It thus holds promise for the time-resolved imagi…

[Phys. Rev. A 95, 043423] Published Tue Apr 25, 2017

]]>We show how to emulate a conventional pump-probe scheme using a single frequency-chirped ultrashort UV pulse to obtain a time-resolved image of molecular ultrafast dynamics. The chirp introduces a spectral phase in time that encodes the delay between the pump and the probe frequencies contained in t…

[Phys. Rev. A 95, 043424] Published Tue Apr 25, 2017

]]>We study the effects of synthetic spin-orbit coupling on the pairing physics in quasi-one-dimensional ultracold Fermi gases of alkaline-earth-metal-like atoms near an orbital Feshbach resonance (OFR). The interplay between spin-orbit coupling and pairing interactions near the OFR leads to an interes…

[Phys. Rev. A 95, 043634] Published Tue Apr 25, 2017

]]>Recent experimental advances in the cooling and manipulation of bialkali-metal dimer molecules have enabled the production of gases of ultracold molecules that are not chemically reactive. It has been presumed in the literature that in the absence of an electric field the low-energy scattering of su…

[Phys. Rev. A 95, 043635] Published Tue Apr 25, 2017

]]>We calculate the parameters of the recently derived many-channel Hubbard model that is predicted to describe ultracold nonreactive molecules in an optical lattice, going beyond the approximations used by Doçaj *et al.* [A. Doçaj *et al.*, Phys. Rev. Lett. **116**, 135301 (2016)]. Although those approximatio…

[Phys. Rev. A 95, 043636] Published Tue Apr 25, 2017

]]>We consider the propagation of Gaussian spatiotemporal wave packets in arrays of parallel optical waveguides, assuming linear and nondispersive coupling between the adjacent guides. The numerical analysis is based on a discrete version of the modified Korteweg–de Vries equation that adequately descr…

[Phys. Rev. A 95, 043839] Published Tue Apr 25, 2017

]]>We theoretically investigate the spectral entanglement of a multiphoton source generated from the cascade emissions in cascaded cold atomic ensembles. This photon source is highly directional, which is guaranteed under the four-wave mixing condition, and is also highly frequency correlated due to fi…

[Phys. Rev. A 95, 043840] Published Tue Apr 25, 2017

]]>We analyze entanglement and nonlocal properties of the convex set of symmetric $N$-qubit states which are diagonal in the Dicke basis. First, we demonstrate that within this set, semidefinite positivity of partial transposition (PPT) is necessary and sufficient for separability—which has also been rep…

[Phys. Rev. A 95, 042128] Published Mon Apr 24, 2017

]]>In which-way double-slit experiments with perfect detectors, it is assumed that having a second detector at the slits is redundant because it will not change the interference pattern. We, however, show that if higher-order or nonclassical paths are accounted for, the presence of the second detector …

[Phys. Rev. A 95, 042129] Published Mon Apr 24, 2017

]]>We consider the problem of determining the presence of genuine tripartite entanglement through the violation of Mermin inequality. Although the violation of Mermin inequality cannot certify the presence of genuine nonlocality, it can certify the presence of genuine tripartite entanglement whenever t…

[Phys. Rev. A 95, 042130] Published Mon Apr 24, 2017

]]>We provide a large class of quantum evolutions governed by the memory kernel master equation. This class defines a quantum analog of so-called semi-Markov classical stochastic dynamics. In this paper we provide a precise definition of quantum semi-Markov evolution, and using the appropriate gauge fr…

[Phys. Rev. A 95, 042131] Published Mon Apr 24, 2017

]]>We investigate the quantum Zeno and anti-Zeno effects in quantum dissipative systems by employing a hierarchical equations of motion approach which is beyond the usual Markovian approximation, the rotating wave approximation, and the perturbative approximation. The quantum Zeno and anti-Zeno dynamic…

[Phys. Rev. A 95, 042132] Published Mon Apr 24, 2017

]]>Reliable quantum communication and/or processing links between modules are a necessary building block for various quantum processing architectures. Here we consider a spin-chain system with alternating strength couplings and containing three defects, which impose three domain walls between topologic…

[Phys. Rev. A 95, 042335] Published Mon Apr 24, 2017

]]>By theoretical calculation, we demonstrate the possibility to control and partially suppress the Coulomb explosion of ${\mathrm{N}}_{2}$ molecules after core-level photoionization by an x-ray laser and subsequent Auger decay. This is achieved by means of a femtosecond infrared laser pulse interacting with the ${\mathrm{N}}_{2}{}^{2+}$ …

[Phys. Rev. A 95, 043419] Published Mon Apr 24, 2017

]]>The photoionization of model neon atoms carrying different angular momenta in strong laser fields is studied using several different theoretical methods, such as the time-dependent Schrödinger simulation, classical trajectory Monte Carlo simulation, quantum trajectory Monte Carlo simulation, and bac…

[Phys. Rev. A 95, 043420] Published Mon Apr 24, 2017

]]>We propose and study systems of coupled atomic wires in a perpendicular synthetic magnetic field as a platform to realize exotic phases of quantum matter. This includes (fractional) quantum Hall states in arrays of many wires inspired by the pioneering work [C. L. Kane *et al.*, Phys. Rev. Lett. **88**, …

[Phys. Rev. A 95, 043632] Published Mon Apr 24, 2017

]]>We report Dirac monopoles with a polar-core vortex induced by spin-orbit coupling in ferromagnetic Bose-Einstein condensates, which are attached to two nodal vortex lines along the vertical axis. These monopoles are more stable in the time scale of experiment and can be detected through directly ima…

[Phys. Rev. A 95, 043633] Published Mon Apr 24, 2017

]]>Motivated by the proposal to simulate para-Bose oscillators in a trapped-ion setup [C. Huerta Alderete and B. M. Rodríguez-Lara, Phys. Rev. A **95**, 013820 (2017)], we introduce an overcomplete, nonorthogonal basis for para-Bose Hilbert spaces. The states spanning these bases can be experimentally real…

[Phys. Rev. A 95, 043835] Published Mon Apr 24, 2017

]]>Iso-variance-matrix Laguerre-Gaussian superpositions corresponding to fundamental Laguerre-Gaussian modes are constructed and propagated numerically through atmospheric turbulence. The fact that these superpositions are iso-variance-matrix with the corresponding fundamental Laguerre-Gaussian mode en…

[Phys. Rev. A 95, 043836] Published Mon Apr 24, 2017

]]>By introducing loss to one sublattice of dimer chains described by the extended Aubry-André or Harper (AAH) model, we study the topological features including the winding number, the edge states, Chern number, and spectrum of the chain. We find that the parameter region for the system to have real b…

[Phys. Rev. A 95, 043837] Published Mon Apr 24, 2017

]]>We theoretically study the emission statistics of a weakly nonlinear photonic dimer during coherent oscillations. We show that the phase and population dynamics allow to periodically meet an optimal squeezing condition resulting in a strongly nonclassical emission statistics. By considering an excit…

[Phys. Rev. A 95, 043838] Published Mon Apr 24, 2017

]]>We study the fundamental limits of noise spectroscopy using estimation theory, Faraday rotation probing of an atomic spin system, and squeezed light. We find a simple and general expression for the Fisher information, which quantifies the sensitivity to spectral parameters such as resonance frequenc…

[Phys. Rev. A 95, 041803(R)] Published Fri Apr 21, 2017

]]>We examine optimal paths between initial and final states for diffusive quantum trajectories in continuously monitored pure-state qubits, obtained as extrema of a stochastic path integral. We demonstrate the possibility of “multipaths” in the dynamics of continuously monitored qubit systems, wherein…

[Phys. Rev. A 95, 042126] Published Fri Apr 21, 2017

]]>We present a comprehensive analysis of longitudinal particle drifting in a standing circularly polarized wave at extreme intensities when quantum radiation reaction (RR) effects should be accounted for. To get an insight into the physics of this phenomenon we made a comparative study considering the…

[Phys. Rev. A 95, 042127] Published Fri Apr 21, 2017

]]>Topological order is now being established as a central criterion for characterizing and classifying ground states of condensed matter systems and complements categorizations based on symmetries. Fractional quantum Hall systems and quantum spin liquids are receiving substantial interest because of t…

[Phys. Rev. A 95, 042330] Published Fri Apr 21, 2017

]]>An algorithm that initializes a quantum register to a state with a specified energy range is given, corresponding to a quantum implementation of the celebrated Feit-Fleck method. This is performed by introducing a nondeterministic quantum implementation of a standard spectral filtering procedure com…

[Phys. Rev. A 95, 042331] Published Fri Apr 21, 2017

]]>Quantum error correction is instrumental in protecting quantum systems from noise in quantum computing and communication settings. Pauli channels can be efficiently simulated and threshold values for Pauli error rates under a variety of error-correcting codes have been obtained. However, realistic q…

[Phys. Rev. A 95, 042332] Published Fri Apr 21, 2017

]]>The characterization of entanglement properties in mixed states is important from both a theoretical and a practical point of view. While the estimation of entanglement of bipartite pure states is well established, for mixed states it is a considerably much harder task. The key elements of the mixed…

[Phys. Rev. A 95, 042333] Published Fri Apr 21, 2017

]]>Entanglement criteria for an $n$-partite quantum system with continuous variables are formulated in terms of Rényi entropies. Rényi entropies are widely used as a good information measure due to many nice properties. Derived entanglement criteria are based on several mathematical results such as the H…

[Phys. Rev. A 95, 042334] Published Fri Apr 21, 2017

]]>Mercury monohalides are promising candidates for electron electric dipole moment searches. This is due to their extremely large values of effective electric fields, besides other attractive experimental features. We have elucidated the theoretical reasons of our previous work. We have also presented…

[Phys. Rev. A 95, 042513] Published Fri Apr 21, 2017

]]>There are major discrepancies between recent $B$-spline $R$-matrix (BSR) and Dirac atomic $R$-matrix code (DARC) calculations regarding electron-impact excitation rates for transitions in ${\mathrm{Mg}}^{4+}$, with claims that the DARC calculations are much more accurate. To identify possible reasons for these discrepanc…

[Phys. Rev. A 95, 042709] Published Fri Apr 21, 2017

]]>The effects of weak electric fields on resonant energy transfer between ${\mathrm{NH}}_{3}$ in the $X$ ${{}^{1}A}_{1}$ ground electronic state and Rydberg He atoms in triplet states with principal quantum numbers $n=36$–41 have been studied in a crossed-beam apparatus. For these values of $n$, electric dipole transitions between the…

[Phys. Rev. A 95, 042710] Published Fri Apr 21, 2017

]]>Strongly interacting one-dimensional (1D) Bose–Fermi mixtures form a tunable $XXZ$ spin chain. Within the spin-chain model developed here, all properties of these systems can be calculated from states representing the ordering of the bosons and fermions within the atom chain and from the ground-state …

[Phys. Rev. A 95, 043630] Published Fri Apr 21, 2017

]]>We investigate the superfluid behavior of a two-dimensional (2D) Bose gas of ${}^{87}\mathrm{Rb}$ atoms using classical field dynamics. In the experiment by R. Desbuquois *et al.* [Nat. Phys. **8**, 645 (2012)], a 2D quasicondensate in a trap is stirred with a blue-detuned laser beam along a circular path around the trap…

[Phys. Rev. A 95, 043631] Published Fri Apr 21, 2017

]]>A detailed experimental investigation of classical and quantum noises in the LIGO gravitational-wave detector is performed. As a result, an estimate of the quantum radiation pressure noise is given and the sensitivity for the next run of astrophysical experiments is established.

[Phys. Rev. A 95, 043831] Published Fri Apr 21, 2017

]]>A recent experiment reveals the linear scaling property of the superradiant emission rate for a trapped atom cloud that is excited by weak and short light pulses. We adopt a real-space approach to numerically demonstrate that such a linear scaling law can be interpreted as single-photon superradianc…

[Phys. Rev. A 95, 043832] Published Fri Apr 21, 2017

]]>We examine theoretically the driven-dissipative Bose-Hubbard dimer in the optical bistable regime. Various approximation schemes based on a Gutzwiller mean-field decoupling are applied and compared. Depending on the system parameters, we show that a decoupling with respect to the real space or to th…

[Phys. Rev. A 95, 043833] Published Fri Apr 21, 2017

]]>We propose an efficient method to selectively enhance the spontaneous emission rate of a quantum system by changing the polarization of an incident control field, and exploiting the polarization dependence of the system's spontaneous emission rate. This differs from the usual Purcell enhancement of …

[Phys. Rev. A 95, 043834] Published Fri Apr 21, 2017

]]>Electron spin dynamics in counterpropagating, bichromatic laser fields are studied by solving the Dirac equation with different laser polarization configurations. It is found that the spin-dependent Kapitza-Dirac effect in the dynamical processes may be used to design spin filters for free electrons.

[Phys. Rev. A 95, 042124] Published Thu Apr 20, 2017

]]>The attainability of the quantum Cramér-Rao bound (QCR), the ultimate limit in the precision of the estimation of a physical parameter, requires the saturation of the quantum information bound (QIB). This occurs when the Fisher information associated to a given measurement on the quantum state of a …

[Phys. Rev. A 95, 042125] Published Thu Apr 20, 2017

]]>The definition of accessible coherence is proposed. Through local measurement on the other subsystem and one-way classical communication, a subsystem can access more coherence than the coherence of its density matrix. Based on the local accessible coherence, the part that cannot be locally accessed …

[Phys. Rev. A 95, 042328] Published Thu Apr 20, 2017

]]>We have performed an experiment demonstrating that loop state-preparation-and-measurement tomography [Jackson and van Enk, Phys. Rev. A **92**, 042312 (2015)] is capable of detecting correlated errors between the preparation and the measurement of a quantum system. Specifically, we have prepared pure an…

[Phys. Rev. A 95, 042329] Published Thu Apr 20, 2017

]]>The probability of the $E$0 transition between the ground state and the unusually low-lying 3/2${}^{+}$ state of the thorium nucleus is calculated, and the mean-square charge radius of the latter state is estimated. Possible applications include a high-precision nuclear clock that is highly insensitive to its environment, and a nuclear laser.

[Phys. Rev. A 95, 042512] Published Thu Apr 20, 2017

]]>The collision cross sections for alkali-metal–rare-gas spin orbit mixing between the ${n}^{2}{P}_{3/2}\to {n}^{2}{P}_{1/2}$ levels trend strongly with the Massey parameter, or adiabaticity of the collisions. The strength of the interaction, as characterized by the ${C}_{6}$ dispersion coefficient, is a secondary influence on the r…

[Phys. Rev. A 95, 042708] Published Thu Apr 20, 2017

]]>We analyze photoionization of hydrogen in the presence of a strong static electric field $F\sim 0.1$ a.u. Such a field essentially modifies the spectrum of the unperturbed atom. Even the ground $n=1$ state acquires a non-negligible width, while the higher field-free bound states become overlapping resonance…

[Phys. Rev. A 95, 043417] Published Thu Apr 20, 2017

]]>The spectrum of a high-repetition train of laser pulses consists of many equally spaced lines, forming an optical frequency comb which is useful for high-precision spectroscopy. By exposing atoms to a train of strong pulses, frequency combs reaching into the extreme ultraviolet may be produced via h…

[Phys. Rev. A 95, 043418] Published Thu Apr 20, 2017

]]>Momentum-resolved Raman spectra of a spin-polarized Fermi gas of ytterbium atoms are measured, and it is found that double resonances of first- and second-order Raman transitions can occur at certain magnetic fields. This implies that the conventional Raman laser dressing scheme provides two ways of spin-orbit coupling, and intrinsically generates a spinful band structure without the aid of an additional rf field.

[Phys. Rev. A 95, 043627] Published Thu Apr 20, 2017

]]>We consider a one-dimensional trapped gas of strongly interacting few spin-1 atoms which can be described by an effective spin chain Hamiltonian. Away from the $\text{SU}\left(3\right)$ integrable point, where the energy spectrum is highly degenerate, the rules of ordering and crossing of the energy levels and the symm…

[Phys. Rev. A 95, 043628] Published Thu Apr 20, 2017

]]>We introduce and study a photonic analog of the Kondo model. The model is defined as a far-detuned regime of photonic scattering off a three-level emitter in a $\mathrm{\Lambda}$-type configuration coupled to a one-dimensional waveguide with linear dispersion. We study dynamics of this local emitter driven by a cohe…

[Phys. Rev. A 95, 043829] Published Thu Apr 20, 2017

]]>The Heisenberg uncertainty principle suggests that it is impossible to determine the trajectory of a quantum particle in the same way as a classical particle. However, we may still yield insight into novel behavior of photons based on the average photon trajectories (APTs). Here we explore the APTs …

[Phys. Rev. A 95, 043830] Published Thu Apr 20, 2017

]]>Adopting concurrence as entanglement measure, we study entanglement and quantum phase transition of the Ising spin systems on the triangular lattice and Sierpiński fractal lattices by using the quantum renormalization-group method. It is found that the ground-state entanglement between two spins (or…

[Phys. Rev. A 95, 042327] Published Wed Apr 19, 2017

]]>A three-dimensional harmonic oscillator consisting of $N\ge 2$ Coulomb-interacting charged particles, often called a (many-electron) Hooke atom, is a popular model in computational physics for, e.g., semiconductor quantum dots and ultracold ions. Starting from Thomas-Fermi theory, we show that the ground…

[Phys. Rev. A 95, 042511] Published Wed Apr 19, 2017

]]>In two recent papers [Blum and Lohmann, Phys. Rev. Lett. **116**, 033201 (2016); Lohmann *et al.*, Phys. Rev. A **94**, 032331 (2016)], the possibility of continuously varying the degree of entanglement between an elastically scattered electron and the valence electron of an alkali-metal target was discussed.…

[Phys. Rev. A 95, 042707] Published Wed Apr 19, 2017

]]>We present a concept for a multistage Zeeman decelerator that is optimized particularly for applications in molecular beam scattering experiments. The decelerator consists of a series of alternating hexapoles and solenoids, that effectively decouple the transverse focusing and longitudinal decelerat…

[Phys. Rev. A 95, 043415] Published Wed Apr 19, 2017

]]>We theoretically study high-order-harmonic generation (HHG) from solids driven by intense laser pulses using a one-dimensional model periodic crystal. By numerically solving the time-dependent Schrödinger equation directly on a real-space grid, we successfully reproduce experimentally observed uniqu…

[Phys. Rev. A 95, 043416] Published Wed Apr 19, 2017

]]>We study the single-particle dispersion of a spin-orbit-coupled (SOC) Bose-Einstein condensate (BEC) under the periodical modulation of the Raman coupling. This modulation introduces a further coupling of the SOC dressed eigenlevels, thus creating a second generation of modulation-dressed eigenlevel…

[Phys. Rev. A 95, 043623] Published Wed Apr 19, 2017

]]>We introduce shaken lattice interferometry with atoms trapped in a one-dimensional optical lattice. By phase modulating (shaking) the lattice, we control the momentum state of the atoms. Through a sequence of shaking functions, the atoms undergo an interferometer sequence of splitting, propagation, …

[Phys. Rev. A 95, 043624] Published Wed Apr 19, 2017

]]>We theoretically present an economical and convenient way to study ground-state properties of a strongly interacting superfluid Fermi gas. Our strategy is that complicated strong-coupling calculations are used only to evaluate quantum fluctuation corrections to the chemical potential $\mu $. Then, withou…

[Phys. Rev. A 95, 043625] Published Wed Apr 19, 2017

]]>We propose and analyze an experimental scheme using the quantum kicked rotor to observe the newly predicted coherent forward-scattering peak together with its long-known twin brother, the coherent backscattering peak. Contrary to coherent backscattering, which arises already under weak-localization …

[Phys. Rev. A 95, 043626] Published Wed Apr 19, 2017

]]>A rigorous description of volume and surface spontaneous parametric down-conversion in one-dimensional nonlinear layered structures is developed considering exact continuity relations for the fields' amplitudes at the boundaries. The nonlinear process is described by the quantum momentum operator th…

[Phys. Rev. A 95, 043828] Published Wed Apr 19, 2017

]]>A century after its conception, quantum mechanics still hold surprises that contradict many “common sense” notions. The contradiction is especially sharp in case one consider trajectories of truly quantum objects such as single photons. From a classical point of view, trajectories are well defined f…

[Phys. Rev. A 95, 042121] Published Tue Apr 18, 2017

]]>During recent developments in quantum theory it has been clarified that observable quantities (such as energy and position) may be represented by operators $\mathrm{\Lambda}$ (with real spectra) that are manifestly non-Hermitian in a preselected friendly Hilbert space ${\mathcal{H}}^{\left(F\right)}$. The consistency of these models is known t…

[Phys. Rev. A 95, 042122] Published Tue Apr 18, 2017

]]>The existence of Greenberger-Horne-Zeilinger (GHZ) contradictions in many-qutrit systems was a long-standing theoretical question until its (affirmative) resolution in 2013. To enable experimental tests, we derive Mermin inequalities from concurrent observable sets identified in those proofs. These …

[Phys. Rev. A 95, 042123] Published Tue Apr 18, 2017

]]>We study local-realistic inequalities, Bell-type inequalities, for bipartite pure states of finite dimensional quantum systems—qudits. There are a number of proposed Bell-type inequalities for such systems. Our interest is in relating the value of the Bell-type inequality function with a measure of …

[Phys. Rev. A 95, 042323] Published Tue Apr 18, 2017

]]>Oblivious transfer (OT) is an important tool in cryptography. It serves as a subroutine to other complex procedures of both theoretical and practical significance. A common attribute of OT protocols is that one party (Alice) has to send a message to another party (Bob) and has to stay oblivious to w…

[Phys. Rev. A 95, 042324] Published Tue Apr 18, 2017

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