We study the stability of a quasi-one-dimensional dipolar Bose-Einstein condensate that is perturbed by a weak lattice potential along its axis. Our numerical simulations demonstrate that systems exhibiting a roton-maxon structure destabilize readily when the lattice wavelength equals either half th...

[Phys. Rev. A 87, 051605] Published Tue May 21, 2013

We numerically simulate strongly correlated ultracold bosons coupled to a high-finesse cavity field, pumped by a laser beam in the transverse direction. Assuming a weak classical optical lattice added in the cavity direction, we model this system by a generalized Bose-Hubbard model, which is solved ...

[Phys. Rev. A 87, 051604] Published Mon May 20, 2013

Self-testing is a device-independent approach to estimate the state and measurement operators without the need to assume the dimension of our quantum system. In this paper, we show that one can self-test black boxes into any pure entangled two-qubit state by performing simple Bell-type experiments. ...

[Phys. Rev. A 87, 050102] Published Mon May 20, 2013

The spontaneous nucleation and dynamics of topological kink defects have been studied in trapped arrays of 41–43 Yb ions. The number of kinks formed as a function of quench rate across the linear-zigzag transition is measured in the underdamped regime of the inhomogeneous Kibble-Zurek theory. The ex...

[Phys. Rev. A 87, 051401] Published Fri May 17, 2013

We address binary optical communication channels based on phase-shift-keyed coherent signals in the presence of phase diffusion. We prove theoretically and demonstrate experimentally that a discrimination strategy based on homodyne detection is robust against this kind of noise for any value of the ...

[Phys. Rev. A 87, 050303] Published Fri May 17, 2013

It is well known that classical information can be cloned, but nonorthogonal quantum states cannot be cloned, and noncommuting quantum states cannot be broadcast. We conceive a scenario in which the object we want to broadcast is the statistical distinguishability, as quantified by quantum Fisher in...

[Phys. Rev. A 87, 050302] Published Thu May 16, 2013

Spin squeezed states are a class of entangled states of spins that have practical applications to precision measurements. In recent years spin squeezing with one-axis twisting (OAT) has been demonstrated experimentally with spinor Bose-Einstein condensates (BECs) with more than 10³ atoms. Although t...

[Phys. Rev. A 87, 051801] Published Tue May 14, 2013

We calculate the condensate fraction and the condensate and noncondensate spatial and momentum distribution of the Bose-Hubbard model in a trap. From our results, it is evident that using approximate distributions can lead to erroneous experimental estimates of the condensate. Strong interactions ca...

[Phys. Rev. A 87, 051603] Published Mon May 13, 2013

In Rydberg dressed ultracold gases, ground-state atoms inherit properties of a weakly admixed Rydberg state, such as sensitivity to long-range interactions. We show that through hyperfine-state-dependent interactions, a pair of atom clouds can evolve into a spin and subsequently into a spatial mesos...

[Phys. Rev. A 87, 051602] Published Mon May 13, 2013

The (e,2e) process is analyzed for the case of an ultrafast electron pulse incident upon a target prepared in a time-varying, coherent superposition of states. Conditions under which time-resolved target momentum densities can be obtained from experimental measurements are discussed. Results for coh...

[Phys. Rev. A 87, 050701] Published Fri May 10, 2013

A PT-symmetric Bose-Einstein condensate can be theoretically described using a complex optical potential; however, the experimental realization of such an optical potential describing the coherent in- and outcoupling of particles is a nontrivial task. We propose an experiment for a quantum mechanica...

[Phys. Rev. A 87, 051601] Published Tue May 07, 2013

The testability of the Kochen-Specker theorem is a subject of ongoing controversy. A central issue is that experimental implementations relying on sequential measurements cannot achieve perfect compatibility between the measurements and that therefore the notion of noncontextuality does not apply. W...

[Phys. Rev. A 87, 050101] Published Mon May 06, 2013

We propose a scheme to achieve controllable self-pulsing operation in a semiconductor photonic-crystal nanolaser. The scheme is based on coupling two asymmetric nanocavities and pumping only one of them. As a result, either periodic or chaotic subnanosecond Q-switched pulses can emerge. A coupled-mo...

[Phys. Rev. A 87, 041804] Published Tue Apr 30, 2013

We study a strongly interacting array of Bose-Einstein condensates trapped in a one-dimensional (1D) optical lattice. The system is described by a nonstandard 1D Bose-Hubbard model in which both the tunneling matrix element and the on-site atomic interaction depend on the lattice site due to the int...

[Phys. Rev. A 87, 041604] Published Mon Apr 29, 2013

We present a theoretical framework to tackle quantum non-Markovian dynamics based on a microscopic collision model (CM), where the bath consists of a large collection of initially uncorrelated ancillas. Unlike standard memoryless CMs, we endow the bath with memory by introducing interancillary colli...

[Phys. Rev. A 87, 040103] Published Thu Apr 25, 2013

We investigate the effect of anharmonicity and interactions on the dynamics of an initially Gaussian wave packet in a weakly anharmonic potential. We note that, depending on the strength and sign of interactions and anharmonicity, the quantum state can be either localized or delocalized in the poten...

[Phys. Rev. A 87, 041603] Published Mon Apr 22, 2013

Partitioning of photon momenta between the ion and electron in photoionization and the involved subcycle dynamics are investigated using an extended semiclassical model, where momentum transfer from the photon to the electron-ion system via the (magnetic) Lorentz force is taken into account. It is f...

[Phys. Rev. A 87, 041403] Published Mon Apr 22, 2013

A method is suggested for the fabrication of three-dimensional photonic crystals operating in the visible by rolling patterned prestressed membranes. A variety of architectures accessible using this fabrication scheme, including 〈111〉 and 〈100〉 diamond structures, were theoretically examined and opt...

[Phys. Rev. A 87, 041803] Published Thu Apr 18, 2013

We consider spin-relaxation dynamics in cold Fermi gases with a pure-gauge spin-orbit coupling corresponding to recent experiments. We show that such experiments can give direct access to the collisional spin drag rate, and establish conditions for the observation of spin drag effects. In recent exp...

[Phys. Rev. A 87, 041602] Published Tue Apr 16, 2013

We perform an experimental time-domain mapping of nonlinear pulse propagation through a two-dimensional photonic-crystal waveguide. Our optical gating method allows for the complete reconstruction of the peculiar propagation behavior in this highly dispersive structure. Temporal soliton formation is...

[Phys. Rev. A 87, 041802] Published Fri Apr 12, 2013

In port-based teleportation, Alice teleports an unknown quantum state |ψ〉 to one of N ports at Bob's site. Alice applies a measurement and sends Bob the outcome k. Bob only needs to select the kth port in order to obtain |ψ〉. We present a theorem in the spirit of the no-cloning theorem, which says t...

[Phys. Rev. A 87, 040303] Published Fri Apr 12, 2013

The pairing and superfluid phenomena in a two-component Fermi gas can be strongly affected by the population and mass imbalances. Here we present phase diagrams of an atomic Fermi-Fermi mixture as they undergo BCS–Bose-Einstein condensation (BEC) crossover using a pairing fluctuation theory. We focu...

[Phys. Rev. A 87, 041601] Published Thu Apr 11, 2013

We present theoretical investigations of high-order-harmonic generation (HHG) resulting from the interaction of noble gases with localized surface plasmons. These plasmonic near-fields are produced when a metal nanoparticle is subject to a few-cycle laser pulse. The enhanced field, which largely dep...

[Phys. Rev. A 87, 041402] Published Thu Apr 11, 2013

We study theoretically light focusing at subwavelength scale inside a disordered strongly scattering open medium. We show that broadband time reversal at a single point antenna, in conjunction with near-field interactions and multiple scattering, produces spatial focusing with a quality comparable t...

[Phys. Rev. A 87, 041801] Published Tue Apr 09, 2013

We show that the observable rate of tunneling ionization of a molecule in an intense low-frequency laser field is affected by nuclear motion and can essentially differ from a bare electronic characteristic calculated for fixed nuclei. Both the absolute value of the rate and the shape of its orientat...

[Phys. Rev. A 87, 041401] Published Tue Apr 09, 2013

We propose a quantum computer architecture that is robust against decoherence and scalable. As a qubit we adopt rotational states of a nonpolar ionic molecule trapped in an ion trap. It is revealed that the rotational-state qubits are much more immune to decoherence than the conventional electronic-...

[Phys. Rev. A 87, 040302] Published Thu Apr 04, 2013

We introduce the term Majoranon to describe particles that obey the Majorana equation, which are different from the Majorana fermions widely studied in various physical systems. A general procedure to simulate the corresponding Majoranon dynamics, based on a decomposition of the Majorana equation in...

[Phys. Rev. A 87, 040102] Published Wed Apr 03, 2013

Topological quantum error-correction codes are extremely practical, typically requiring only a two-dimensional lattice of qubits with tunable nearest-neighbor interactions yet tolerating high physical error rates p. It is computationally expensive to simulate the performance of such codes at low p, ...

[Phys. Rev. A 87, 040301] Published Tue Apr 02, 2013

We examine the feasibility of a parity nonconserving (PNC) optical rotation experiment for the ²P_3/2→ ²P_1/2 transition of atomic iodine at 1315 nm. The calculated E1_PNC to M1 amplitude ratio is R=0.80(16)×10⁻⁸. We show that very large PNC rotations (greater than 10 μrad) are obtained for iodine-atom...

[Phys. Rev. A 87, 040101] Published Mon Apr 01, 2013

We present a real-time observation of electron motion in the ground state of the carbon atom. A wave packet is created in the ground triplet state of the atom via photodetachment of its negative ion in a strong laser field. Its dynamics is probed using the selectivity of strong-field ionization to o...

[Phys. Rev. A 87, 031404] Published Fri Mar 29, 2013