Inspired by a recent work [F. Reiter, D. Reeb, and A. S. Sørensen, Phys. Rev. Lett. **117**, 040501 (2016)], we present a simplified proposal for dissipatively preparing a Greenberger-Horne-Zeilinger (GHZ) state of three Rydberg atoms in a cavity. The $Z$ pumping is implemented under the action of the spo...

[Phys. Rev. A 96, 062315] Published Fri Dec 15, 2017

]]>We present visible spectra of Ag-like ($4{d}^{10}4f$) and Cd-like ($4{d}^{10}4{f}^{2}$) ions of Ho (atomic number $Z=67$), Er (68), and Tm (69) observed with a compact electron beam ion trap. For Ag-like ions, prominent emission corresponding to the M1 transitions between the ground state fine-structure splitting $4{f}_{5/2}\text{\u2212}\mathrm{...}$

[Phys. Rev. A 96, 062506] Published Fri Dec 15, 2017

]]>We study level crossings and spin flips in a system consisting of a spin-1 (an electron spin triplet) coupled to a nuclear spin of arbitrary size $K$, in the presence of a uniform magnetic field and the electron spin-spin interaction within the triplet. Through an analytical diagonalization based on t...

[Phys. Rev. A 96, 062507] Published Fri Dec 15, 2017

]]>We perform Feshbach spectroscopy in an ultracold mixture of ${}^{23}\mathrm{Na}$ and ${}^{40}\mathrm{K}$ with different spin-state combinations. We observed 24 new interspecies Feshbach resonances at magnetic fields up to 350 G. A full coupled-channel calculation is performed to assign these resonances. Among them, 12 resonances a...

[Phys. Rev. A 96, 062705] Published Fri Dec 15, 2017

]]>We report integral and differential cross sections for positron collisions with allene, calculated with the Schwinger multichannel method. The cross sections were computed in the static-polarization approximation for energies up to 7 eV. We have tested a series of single-particle basis sets and diff...

[Phys. Rev. A 96, 062706] Published Fri Dec 15, 2017

]]>We provide a nonperturbative theory for photoionization of transparent solids, which consistently accounts for the *selection rules* related to the parity of the number of absorbed photons (*odd* or *even*). We derive closed-form analytical expressions for the photoionization rate within the two-band stru...

[Phys. Rev. A 96, 063410] Published Fri Dec 15, 2017

]]>We present the prospects for photoassociation, optical control of interspecies scattering lengths, and, finally, the production of ultracold absolute ground-state molecules in the Rb+Hg system. We use the state-of-the-art *ab initio* methods for the calculations of ground- [CCSD(T)] and excited-state ...

[Phys. Rev. A 96, 063411] Published Fri Dec 15, 2017

]]>We propose a scheme to obtain the Heisenberg-limited parameter estimation precision by immersing atoms in a thermally equilibrated quasi-one-dimensional dipolar Bose-Einstein condensate reservoir. We show that the collisions between the dipolar atoms and the immersed atoms can result in a controllab...

[Phys. Rev. A 96, 063614] Published Fri Dec 15, 2017

]]>An unexplored nonperturbative deep strong coupling (npDSC) achieved in superconducting circuits has been studied in the anisotropic Rabi model by the generalized squeezing rotating-wave approximation. Energy levels are evaluated analytically from the reformulated Hamiltonian and agree well with nume...

[Phys. Rev. A 96, 063821] Published Fri Dec 15, 2017

]]>We study the phase diagram of fermionic polar molecules in a bilayer system, with an imbalance of molecular densities of the layers. For the imbalance exceeding a critical value, the system undergoes a transition from the uniform interlayer superfluid to the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) s...

[Phys. Rev. A 96, 061602(R)] Published Thu Dec 14, 2017

]]>A quantum random-number generator (QRNG) can produce true randomness by utilizing the inherent probabilistic nature of quantum mechanics. Recently, the spontaneous-emission quantum phase noise of the laser has been widely deployed for quantum random-number generation, due to its high rate, its low c...

[Phys. Rev. A 96, 062314] Published Thu Dec 14, 2017

]]>We consider Casimir-Polder and Casimir forces with finite dissipation by coupling heat baths to the dipoles introducing, this way, dissipation from first principles. We derive a representation of the free energy as an integral over real frequencies, which can be viewed as an generalization of the re...

[Phys. Rev. A 96, 062504] Published Thu Dec 14, 2017

]]>Based on the theory of macroscopic quantum electrodynamics, we generalize the expression of the Casimir force for nonreciprocal media. The essential ingredient of this result is the Green's tensor between two nonreciprocal semi-infinite slabs, including a reflexion matrix with four coefficients that...

[Phys. Rev. A 96, 062505] Published Thu Dec 14, 2017

]]>We study the response of ${\mathrm{HeH}}^{+}$ to an intense, few-cycle laser pulse. Specifically, we present the carrier-envelope phase (CEP) dependence of the kinetic-energy-release spectrum, the spatial asymmetry, and the total dissociation probability in two-cycle pulses with an intensity of ${10}^{14}\phantom{\rule{0.28em}{0ex}}{\mathrm{W}/\mathrm{cm}}^{2}$ and wavele...

[Phys. Rev. A 96, 063409] Published Thu Dec 14, 2017

]]>We theoretically investigate the macroscopic quantum coherence and the mechanical squeezing of a mechanical oscillator in a hybrid optomechanical system consisting of a suspended graphene sheet and an ultracold atomic ensemble trapped inside a Fabry-Pérot cavity. In the study the vacuum is used to m...

[Phys. Rev. A 96, 063819] Published Thu Dec 14, 2017

]]>The coherent process that a single photon simultaneously excites two qubits has recently been theoretically predicted by Garziano *et al.* [L. Garziano, V. Macrì, R. Stassi, O. Di Stefano, F. Nori, and S. Savasta, One Photon Can Simultaneously Excite two or More Atoms, Phys. Rev. Lett. **117**, 043601 (20...

[Phys. Rev. A 96, 063820] Published Thu Dec 14, 2017

]]>[Phys. Rev. A 96, 069905] Published Thu Dec 14, 2017

]]>We propose a dissipative method for the preparation of many-body steady entangled states in spin and fermionic chains. The scheme is accomplished by means of an engineered set of Lindbladians acting over the eigenmodes of the system, whose spectrum is assumed to be resolvable. We apply this idea to ...

[Phys. Rev. A 96, 062313] Published Wed Dec 13, 2017

]]>Encoding quantum information in the photon temporal mode (TM) offers a robust platform for high-dimensional quantum protocols. The main practical challenge, however, is to design a device that operates on single photons in specific TMs and all coherent superpositions. The quantum pulse gate (QPG) is...

[Phys. Rev. A 96, 063817] Published Wed Dec 13, 2017

]]>We theoretically analyze the ground-state cooling of an optically levitated nanosphere in the unresolved-sideband regime by introducing a coupled high-quality-factor cavity. On account of the quantum interference stemming from the presence of the coupled cavity, the spectral density of the optical f...

[Phys. Rev. A 96, 063818] Published Wed Dec 13, 2017

]]>[Phys. Rev. A 96, 069904] Published Wed Dec 13, 2017

]]>We propose a protocol to simulate the evolution of a non-Markovian open quantum system by considering a collisional process with a many-body system, which plays the role of an environment. As a result of our protocol, the environment spatial correlations are mapped into the time correlations of a no...

[Phys. Rev. A 96, 062117] Published Tue Dec 12, 2017

]]>Calculating the degree of non-Markovianity of a quantum process, for a high-dimensional system, is a difficult task given complex maximization problems. Focusing on the entanglement-based measure of non-Markovianity we propose a numerically feasible quantifier for finite-dimensional systems. We defi...

[Phys. Rev. A 96, 062118] Published Tue Dec 12, 2017

]]>We study how the entanglement dynamics between two-level atoms is impacted by random fluctuations of the light cone. In our model the two-atom system is envisaged as an open system coupled with an electromagnetic field in the vacuum state. We employ the quantum master equation in the Born-Markov app...

[Phys. Rev. A 96, 062119] Published Tue Dec 12, 2017

]]>We present an analytical compact solution for the density matrix and all correlation functions of two collective-macroscopic spins evolving via an Ising-like Hamiltonian in the presence of particle losses. The losses introduce nonlocal phase noise which destroys highly entangled states arising in th...

[Phys. Rev. A 96, 062312] Published Tue Dec 12, 2017

]]>We have systematically investigated the ground-state hyperfine structure for alkali-metal atoms ${}^{87}\mathrm{Rb},{}^{133}\mathrm{Cs}$, and ${}^{211}\mathrm{Fr}$ and alkali-metal-like ions ${}^{135}\mathrm{Ba}^{+}$ and ${}^{225}\mathrm{Ra}^{+}$, which are of particular interest for parity violation studies. The quantum electrodynamic one-loop radiative corrections have been rigor...

[Phys. Rev. A 96, 062502] Published Tue Dec 12, 2017

]]>The effective Hamiltonian for the linear $E\otimes e$ Jahn-Teller model describes the coupling between two electronic states and two vibrational modes in molecules or bulk crystal impurities. While in the Born-Oppenheimer approximation the Berry curvature has a delta function singularity at the conical inter...

[Phys. Rev. A 96, 062503] Published Tue Dec 12, 2017

]]>We systematically studied the two-body loss in a two-component Fermi gas of ${}^{6}\mathrm{Li}$ atoms near a $p$-wave Feshbach resonance. The two-body loss rate constants were measured for various temperatures and magnetic fields using atoms trapped in three-dimensional and quasi-two-dimensional traps. Our results we...

[Phys. Rev. A 96, 062704] Published Tue Dec 12, 2017

]]>Kinetic-energy spectra of a single electron from strong-field nonsequential double ionization are investigated in a high-intensity regime with a quantum mechanical model. We find interference fringes with large energy spacings, which increases with the electron kinetic energy. These interference fri...

[Phys. Rev. A 96, 063408] Published Tue Dec 12, 2017

]]>We investigate universal properties of one-dimensional multicomponent systems composed of fermions, bosons, or an arbitrary mixture, with contact interactions and subjected to an external potential. The masses and the coupling strengths between different types of particles are allowed to be differen...

[Phys. Rev. A 96, 063612] Published Tue Dec 12, 2017

]]>Bloch oscillations in a tilted ladder lattice are studied in the presence of artificial magnetic flux. The oscillations exhibit chiral characteristics which may be used to distinguish the Meissner phase and the vortex phase. By incorporating the diagonal hopping into the ladder, the dynamical evolut...

[Phys. Rev. A 96, 063613] Published Tue Dec 12, 2017

]]>Anderson localization lasers exploit resonant cavities formed due to structural disorder. The inherent randomness in the structure of these cavities realizes a probability distribution in all cavity parameters such as quality factors, mode volumes, mode structures, and so on, implying resultant stat...

[Phys. Rev. A 96, 063816] Published Tue Dec 12, 2017

]]>It is demonstrated that the spectroscopy of a resonant transition can be altered by a nonvanishing population of the system in states away from the transition, so long as those states can radiatively decay into the states involved in the resonant transition. This finding identifies a systematic effect that can be important to precision measurements.

[Phys. Rev. A 96, 062111] Published Mon Dec 11, 2017

]]>We study the dynamics of quantum and classical correlations in a two-qutrit system coupled to independent reservoirs. In particular, we address the differences in the dynamics of Markovian and non-Markovian regimes and show that for specific initial states, classical correlations exhibit abrupt chan...

[Phys. Rev. A 96, 062112] Published Mon Dec 11, 2017

]]>Weakly nonlinear degrees of freedom in dissipative quantum systems tend to localize near manifolds of quasiclassical states. We present a family of analytical and computational methods for deriving optimal unitary model transformations that reduce the complexity of representing typical states. These...

[Phys. Rev. A 96, 062113] Published Mon Dec 11, 2017

]]>One of the fundamental issues in the field of open quantum systems is the classification and quantification of non-Markovianity. In the contest of quantity-based measures of non-Markovianity, the intuition of non-Markovianity in terms of information backflow is widely discussed. However, it is not e...

[Phys. Rev. A 96, 062114] Published Mon Dec 11, 2017

]]>We investigate under which conditions quantum nonlocal manifestations such as Einstein-Podolsky-Rosen steering or Bell nonlocality can manifest themselves even at the macroscopic level of two mechanical resonators in optomechanical systems. We adopt the powerful scheme of reservoir engineering, impl...

[Phys. Rev. A 96, 062115] Published Mon Dec 11, 2017

]]>The impossibility of an indeterministic evolution for standard relativistic quantum field theories, that is, theories in which all fields satisfy the condition that the generators of space-time translation have spectra in the forward light-cone, is demonstrated. The demonstration proceeds by arguing...

[Phys. Rev. A 96, 062116] Published Mon Dec 11, 2017

]]>We show how the presence of entanglement in a bipartite Gaussian state can be detected by the amount of work extracted by a continuous-variable Szilard-like device, where the bipartite state serves as the working medium of the engine. We provide an expression for the work extracted in such a process...

[Phys. Rev. A 96, 062311] Published Mon Dec 11, 2017

]]>We theoretically study cooling of flexural modes of a mechanical oscillator by Bose-Einstein-condensate (BEC) atoms (Rb87) trapped in a magnetic trap. The mechanical oscillator with a tiny magnet attached on one of its free ends produces an oscillating magnetic field. When its oscillating frequency ...

[Phys. Rev. A 96, 063813] Published Mon Dec 11, 2017

]]>We investigate laser-induced quantum interference phenomena in superradiance processes evolving in an ensemble of initially excited $\mathrm{\Lambda}$-type closely packed three-level emitters. The lower doublet levels are pumped with a coherent laser field. Due to constructive quantum interference effects, the super...

[Phys. Rev. A 96, 063814] Published Mon Dec 11, 2017

]]>The induced transparency was proposed recently in X. Guo *et al.* [Phys. Rev. Lett. **117**, 123902 (2016)] based on a three-wave mixing system. In this paper, we find the double- and multitransparency window can also be observed in this system. The zero-absorption point and profile of the transparency wi...

[Phys. Rev. A 96, 063815] Published Mon Dec 11, 2017

]]>Understanding the fundamental limits on the precision to which an optical phase can be estimated is of key interest for many investigative techniques utilized across science and technology. We study the estimation of a fixed optical phase shift due to a sample which has an associated optical loss, a...

[Phys. Rev. A 96, 062109] Published Fri Dec 08, 2017

]]>The role of intrinsic postselection is analyzed for individual stochastic quantum measurement records of a continuously monitored observable. The measurement operators and linearized limits of the past collected measurement are outlined, linking together smoothing, weak measurements, and the information contained in the noisy record with simple formulas.

[Phys. Rev. A 96, 062110] Published Fri Dec 08, 2017

]]>For pure symmetric three-qubit states there are only three algebraically independent entanglement measures; one choice is the pairwise concurrence $\mathcal{C}$, the three-tangle $\tau $, and the Kempe invariant $\kappa $. Using a canonical form for symmetric $n$-qubit states derived from their Majorana representation, we deri...

[Phys. Rev. A 96, 062310] Published Fri Dec 08, 2017

]]>The Lieb-Liniger equation of state accurately describes the zero-temperature universal properties of a dilute one-dimensional Bose gas in terms of the $s$-wave scattering length. For weakly interacting bosons we derive nonuniversal corrections to this equation of state taking into account finite-range...

[Phys. Rev. A 96, 063610] Published Fri Dec 08, 2017

]]>We study the effects of repulsive on-site interactions on the broadening of the localized Wannier functions used for calculating the parameters to describe ultracold atoms in optical lattices. For this, we replace the common single-particle Wannier functions, which do not contain any information abo...

[Phys. Rev. A 96, 063611] Published Fri Dec 08, 2017

]]>A scheme to achieve strong quantum squeezing of a mechanical resonator in a membrane-in-the-middle optomechanical system is developed. To this end, simultaneous linear and nonlinear coupling between the mechanical resonator and the cavity modes is applied. A two-tone driving light field, comprising ...

[Phys. Rev. A 96, 063811] Published Fri Dec 08, 2017

]]>A two-level quantum emitter with broken inversion symmetry simultaneously driven by an optical field and a microwave field that couples to the permanent dipole's moment is presented. We focus to a situation where the angular frequency of the microwave field is chosen such that it closely matches the...

[Phys. Rev. A 96, 063812] Published Fri Dec 08, 2017

]]>We establish the multiparameter quantum Cramér-Rao bound for simultaneously estimating the centroid, the separation, and the relative intensities of two incoherent optical point sources using a linear imaging system. For equally bright sources, the Cramér-Rao bound is independent of their separation...

[Phys. Rev. A 96, 062107] Published Thu Dec 07, 2017

]]>The reliability of the Born and Markov approximations is studied within the framework of quantum Brownian motion described by a mechanical oscillator coupled to a bath of oscillators in thermal equilibrium. It is found that the conditions for the validity of the Born approximation with or without the Markov approximation are more stringent than the usual condition with a weak coupling.

[Phys. Rev. A 96, 062108] Published Thu Dec 07, 2017

]]>We address side-channel leakage in a trusted preparation station of continuous-variable quantum key distribution with coherent and squeezed states. We consider two different scenarios: multimode Gaussian modulation, directly accessible to an eavesdropper, or side-channel loss of the signal states pr...

[Phys. Rev. A 96, 062309] Published Thu Dec 07, 2017

]]>The isotopic effects in reactions of ${\mathrm{O}}^{-}$ ions with ${\mathrm{H}}_{2}$ and ${\mathrm{D}}_{2}$ have been studied experimentally using a cryogenic 22-pole radio-frequency ion trap. The rate coefficients for associative detachment leading to ${\mathrm{H}}_{2}\mathrm{O}+{e}^{-}$ and to ${\mathrm{D}}_{2}\mathrm{O}+{e}^{-}$ and for atom transfer reactions leading to formation of ${\mathrm{OH}}^{-}$ and ${\mathrm{OD}}^{-}$ ions w...

[Phys. Rev. A 96, 062703] Published Thu Dec 07, 2017

]]>We theoretically investigate a scattering configuration in Compton scattering, in which the orientation of the electron spin is reversed and, simultaneously, the photon polarization changes from linear polarization into circular polarization. The intrinsic angular momentum of electron and photon are...

[Phys. Rev. A 96, 063407] Published Thu Dec 07, 2017

]]>We study theoretically the creation of knot structures in the polar phase of spin-1 Bose-Einstein condensates using the counterdiabatic protocol in an unusual fashion. We provide an analytic solution to the evolution of the external magnetic field that is used to imprint the knots. As confirmed by o...

[Phys. Rev. A 96, 063609] Published Thu Dec 07, 2017

]]>A scheme for strong coupling between a single atomic spin and the rotational mode of levitating nanoparticles is proposed. The idea is based on spin readout of nitrogen-vacancy centers embedded in aspherical nanodiamonds levitating in an ion trap. We show that the asymmetry of the diamond induces a ...

[Phys. Rev. A 96, 063810] Published Thu Dec 07, 2017

]]>The Smith-Purcell effect, observed when an electron beam passes in the vicinity of a periodic structure, is a promising platform for the generation of electromagnetic radiation in previously unreachable spectral ranges. However, most of the studies of this radiation were performed on simple periodic...

[Phys. Rev. A 96, 061801(R)] Published Wed Dec 06, 2017

]]>The method of analytic continuation is applied to estimate eigenvalues of linear operators from finite order results of perturbation theory even in cases when the latter is divergent. Given a finite number of terms ${E}^{\left(k\right)},k=1,2,\cdots M$ resulting from a Rayleigh-Schrödinger perturbation calculation, scaling...

[Phys. Rev. A 96, 062106] Published Wed Dec 06, 2017

]]>We provide detailed proofs of triangle inequalities in coherence measures and entanglement concurrence. If a rank-2 state $\varrho $ can be expressed as a convex combination of two pure states, i.e., $\varrho ={p}_{1}|{\psi}_{1}\rangle \langle {\psi}_{1}|+{p}_{2}|{\psi}_{2}\rangle \langle {\psi}_{2}|$, a triangle inequality can be established as $|E\left(\right|{\mathrm{\Psi}}_{1}\rangle )-E\left(\right|{\mathrm{\Psi}}_{2}\rangle \left)\right|\le E\left(\varrho \right)\le E\left(\right|{\mathrm{\Psi}}_{1}\rangle )+E\left(\right|{\mathrm{\Psi}}_{2}\rangle )$, ...

[Phys. Rev. A 96, 062308] Published Wed Dec 06, 2017

]]>Low-lying rovibrational levels of Yb${}_{2}$ molecules are measured by photoassociation to an accuracy of about 500 Hz. The measurements, in combination with a potential model that includes some beyond-Born-Oppenheimer effects, produce a determination of the $s$-wave scattering lengths with error bars which are over two orders of magnitude better than previous determinations.

[Phys. Rev. A 96, 063405] Published Wed Dec 06, 2017

]]>We theoretically investigate the resonant Auger process via multiple core-excited states. The presence of multiple core-excited states sets off interference into the common final continuum, and we show that the degree of interference depends on the various parameters such as the intensity of the emp...

[Phys. Rev. A 96, 063406] Published Wed Dec 06, 2017

]]>Superfluid vortex dynamics on an infinite cylinder differs significantly from that on a plane. The requirement that a condensate wave function be single valued upon once encircling the cylinder means that such a single vortex cannot remain stationary. Instead, it acquires one of a series of quantize...

[Phys. Rev. A 96, 063608] Published Wed Dec 06, 2017

]]>In this paper, we study the stochastic resonance (SR) effect in a driven dissipative Jaynes-Cummings model. The SR effect is systematically investigated in the semiclassical and full quantum frameworks, and in both cases we find that SRs simultaneously occur for optical and atomic degrees of freedom...

[Phys. Rev. A 96, 063808] Published Wed Dec 06, 2017

]]>We present the concept of a realization of three-photon interference based on the procedure of light storage and release. Three probe photons are stored in an atomic medium in the tetrapod configuration. The medium irradiated by three control fields is shown to act as a flexible tritter. By changing...

[Phys. Rev. A 96, 063809] Published Wed Dec 06, 2017

]]>[Phys. Rev. A 96, 069902] Published Wed Dec 06, 2017

]]>[Phys. Rev. A 96, 069903] Published Wed Dec 06, 2017

]]>Quantum Darwinism extends the traditional formalism of decoherence to explain the emergence of classicality in a quantum universe. A classical description emerges when the environment tends to redundantly acquire information about the pointer states of an open system. In light of recent interest, we...

[Phys. Rev. A 96, 062105] Published Tue Dec 05, 2017

]]>We introduce a family of quantum circuits in continuous variables and we show that, relying on the widely accepted conjecture that the polynomial hierarchy of complexity classes does not collapse, their output probability distribution cannot be efficiently simulated by a classical computer. These ci...

[Phys. Rev. A 96, 062307] Published Tue Dec 05, 2017

]]>Generation of circularly polarized high-order harmonics is studied with the targets of diatomic molecules subject to bichromatic counter-rotating circularly polarized laser fields. It is also found that with the driving field polarized perpendicular to the molecular axis, even-order harmonics polarized along the molecular axis can be generated by heteronuclear molecules, even if the permanent dipole moment of the molecules is very small.

[Phys. Rev. A 96, 063404] Published Tue Dec 05, 2017

]]>An atom interferometer serves as a sensitive tiltmeter that can measure Earth’s tidal deformations.

[Phys. Rev. A 96, 063606] Published Tue Dec 05, 2017

]]>We study the small frequency behavior of the bulk viscosity spectral function using stochastic fluid dynamics. We obtain a number of model independent results, including the long-time tail of the bulk stress correlation function and the leading nonanalyticity of the spectral function at small freque...

[Phys. Rev. A 96, 063607] Published Tue Dec 05, 2017

]]>A system of two-level noninteracting atoms driven by superposition of two Glauber coherent photonic states (a cat state) is studied. The field state is continuously restored by a source explicitly incorporated into the model. Due to its nature, the cat state changes phase by $\pi $ upon stimulated excita...

[Phys. Rev. A 96, 063805] Published Tue Dec 05, 2017

]]>We study the statistics of the lasing output from a single-atom quantum heat engine, which was originally proposed by Scovil and Schulz-DuBois [H. E. D. Scovil and E. O. Schulz-DuBois, Phys. Rev. Lett. **2**, 262 (1959)]. In this heat engine model, a single three-level atom is coupled with an optical ca...

[Phys. Rev. A 96, 063806] Published Tue Dec 05, 2017

]]>In this paper we studied the shaping and evolution of singular beams bearing optical vortices with fractional topological charges both in uniform and nonuniform anisotropic media. Starting from representation of the fractional-order vortex states as a superposition of an infinite number of integer-o...

[Phys. Rev. A 96, 063807] Published Tue Dec 05, 2017

]]>[Phys. Rev. A 96, 069901] Published Tue Dec 05, 2017

]]>Experiments with ultracold atoms provide a highly controllable laboratory setting with many unique opportunities for precision exploration of quantum many-body phenomena. The nature of such systems, with strong interaction and quantum entanglement, makes reliable theoretical calculations challenging...

[Phys. Rev. A 96, 061601(R)] Published Mon Dec 04, 2017

]]>We consider the problem of estimating the temperature $T$ of a very cold equilibrium sample. The temperature estimates are drawn from measurements performed on a quantum Brownian probe *strongly* coupled to it. We model this scenario by resorting to the canonical Caldeira-Leggett Hamiltonian and find an...

[Phys. Rev. A 96, 062103] Published Mon Dec 04, 2017

]]>General higher-order stochastic processes that correspond to any diffusion-type tensor of higher than second order are obtained. The relationship of multivariate higher-order stochastic differential equations with tensor decomposition theory and tensor rank is explained. Techniques for generating th...

[Phys. Rev. A 96, 062104] Published Mon Dec 04, 2017

]]>We study the sensitivity of phase estimation in a lossy Mach-Zehnder interferometer (MZI) using two general, and practical, resources generated by a laser and a nonlinear optical medium with passive optimal elements, which are readily available in the laboratory: One is a two-mode separable coherent...

[Phys. Rev. A 96, 062304] Published Mon Dec 04, 2017

]]>An operational approach to the study of computation based on correlations considers black boxes with one-bit inputs and outputs, controlled by a limited classical computer capable only of performing sums modulo-two. In this setting, it was shown that noncontextual correlations do not provide any ext...

[Phys. Rev. A 96, 062305] Published Mon Dec 04, 2017

]]>We consider the problem of estimating an unknown but constant carrier phase modulation $\theta $ using a general, possibly entangled, $n$-mode optical probe through $n$ independent and identical uses of a lossy bosonic channel with additive thermal noise. We find an upper bound to the quantum Fisher information...

[Phys. Rev. A 96, 062306] Published Mon Dec 04, 2017

]]>It is well known that the lanthanide and actinide elements are formed by the filling of $4f$ and $5f$ subshells which occurs after the filling of $5d$ and $6d$ subshells, respectively, has begun. With increasing ionization one expects the energy levels to eventually regroup to their hydrogenic ordering, i.e...

[Phys. Rev. A 96, 062501] Published Mon Dec 04, 2017

]]>We use paramagnetic Faraday rotation to study spin noise spectrum from unpolarized Rb vapor in a tightly focused probe beam in the presence of ${\mathrm{N}}_{2}$ buffer gas. We derive an analytical form for the diffusion component of the spin noise time-correlation function in a Gaussian probe beam. We also obtain ...

[Phys. Rev. A 96, 062702] Published Mon Dec 04, 2017

]]>The Talbot-Lau interferometer is a proven tool to perform measurements in the near-field regime. It has been extensively used for investigating the wave nature of electrons, atoms, and complex organic molecules. However, when designing devices with high geometrical acceptances, which would be desira...

[Phys. Rev. A 96, 063604] Published Mon Dec 04, 2017

]]>The Kondo effect describes the spin-exchange interaction between localized impurities and itinerant fermions. The ultracold alkaline-earth atomic gas provides a natural platform for quantum simulation of the Kondo model, utilizing its long-lived clock state and the nuclear-spin exchange interaction ...

[Phys. Rev. A 96, 063605] Published Mon Dec 04, 2017

]]>A general approach for the calculation of photonic band structures in generic two-dimensional atomic lattices is developed. The framework can be used to design topologically protected photonic quantum systems.

[Phys. Rev. A 96, 063801] Published Mon Dec 04, 2017

]]>Simple joint measurements of pairs of observables reveal that states considered universally as classical-like, such as SU(2) spin coherent states, Glauber coherent states, and thermal states, are actually nonclassical. We show that this holds because we can find a joint measurement the statistics of...

[Phys. Rev. A 96, 063802] Published Mon Dec 04, 2017

]]>We present a study of optical quantum states generated by subtraction of photons from the thermal state. Some aspects of their photon number and quadrature distributions are discussed and checked experimentally. We demonstrate an original method of up to ten photon subtracted state preparation with ...

[Phys. Rev. A 96, 063803] Published Mon Dec 04, 2017

]]>Recently, an approach to tomography with extended anisotropic radiation sources has been introduced, which helps to overcome the challenges resulting from the low brilliance typical for x-ray laboratory sources. The method is based on the three-dimensional Radon transform (3DRT) which uses planar in...

[Phys. Rev. A 96, 063804] Published Mon Dec 04, 2017

]]>We present a thorough classification of the isotropic quantum walks on lattices of dimension $d=1,2,3$ with a coin system of dimension $s=2$. For $d=3$ there exist two isotropic walks, namely, the Weyl quantum walks presented in the work of D'Ariano and Perinotti [G. M. D'Ariano and P. Perinotti, Phys. Re...

[Phys. Rev. A 96, 062101] Published Fri Dec 01, 2017

]]>Conditional von Neumann entropy is an intriguing concept in quantum information theory. In the present work, we examine the effect of global unitary operations on the conditional entropy of the system. We start with a set containing states with a non-negative conditional entropy and find that some s...

[Phys. Rev. A 96, 062102] Published Fri Dec 01, 2017

]]>Hybrid quantum circuits combining advantages of each individual system have provided a promising platform for quantum information processing. Here we propose an experimental scheme to directly couple a transmon qubit to an individual spin in the nitrogen-vacancy (NV) center, with a coupling strength...

[Phys. Rev. A 96, 062301] Published Fri Dec 01, 2017

]]>Usual metrics, such as the fidelity, used to characterize the success of implementing superconducting qubit-based quantum gates are analyzed. By numerically solving time-dependent Schrödinger equations for a transmon system, it is found that such metrics are not reliable to predict the performance of a quantum algorithm when the gates are used repeatedly.

[Phys. Rev. A 96, 062302] Published Fri Dec 01, 2017

]]>We propose and experimentally demonstrate an efficient framework for the quantum simulation of quantum channels in nuclear magnetic resonance (NMR). Our approach relies on the suitable decomposition of nonunitary operators in a linear combination of $d$ unitary ones, which can be then experimentally i...

[Phys. Rev. A 96, 062303] Published Fri Dec 01, 2017

]]>In this work we introduce modifications to the wave-packet method proposed by Kaneko to calculate the energy-loss moments of a projectile traversing a target which is represented in terms of Gaussian functions for the momentum distributions of electrons in the atomic shells. These modifications are ...

[Phys. Rev. A 96, 062701] Published Fri Dec 01, 2017

]]>High-order harmonic generation with bicircular fields—the combination of counter-rotating circularly polarized pulses at different frequencies—results in a series of short-wavelength XUV harmonics with alternating circular polarizations, and experiments show that there is an asymmetry in the emissio...

[Phys. Rev. A 96, 063401] Published Fri Dec 01, 2017

]]>We describe a dispersive Faraday optical probe of atomic spin which performs a weak measurement of spin projection of a quantum gas continuously for more than one second. To date, focusing bright far-off-resonance probes onto quantum gases has proved invasive due to strong scalar and vector light sh...

[Phys. Rev. A 96, 063402] Published Fri Dec 01, 2017

]]>We present an all-electron, *ab initio* calculation of time-resolved photoelectron momentum distributions (PMDs) induced by resonant two-color, two- or three-photon ionization of helium and neon atoms, as recently measured by Villeneuve *et al.* [Science **356**, 1150 (2017)] using a femtosecond infrared (I...

[Phys. Rev. A 96, 063403] Published Fri Dec 01, 2017

]]>A theoretical analysis is performed to explain the nonexponential decay of the macroscopic quantum tunneling of a Bose-Einstein condensate, where it is found that the self-interaction is responsible for the macroscopic decaying behavior.

[Phys. Rev. A 96, 063601] Published Fri Dec 01, 2017

]]>Recently, a cooling scheme for ultracold atoms in a bilayer optical lattice has been proposed (A. Kantian *et al.*, arXiv:1609.03579). In their scheme, the energy offset between the two layers is increased dynamically such that the entropy of one layer is transferred to the other layer. Using the ful...

[Phys. Rev. A 96, 063602] Published Fri Dec 01, 2017

]]>