Toward an ion–photon quantum interface in an optical cavity

We demonstrate several building blocks for an ion–photon interface based on a trapped ⁴⁰Ca⁺ ion in an optical cavity. We identify a favorable experimental configuration and measure system parameters, including relative motion of the trapped ion and the resonator mode. A complete spectrum of cavity-assisted Raman transitions between the 4²S_1/2 and 3²D_5/2 manifolds is obtained. On two of these transitions, we generate orthogonally polarized cavity photons, and we demonstrate coherent manipulation of the corresponding pair of atomic states. Possible implementations of atom-photon entanglement and state mapping within the ion-cavity system are discussed.     

Nonreciprocal Phonon Laser in an Asymmetric Cavity with an Atomic Ensemble

Phonon lasers, as a novel kind of lasers for generating coherent sound oscillation, has attracted extensive attention. Here, we theoretically propose a nonreciprocal phonon laser in a hybrid optomechanical system, which is composed of an asymmetric Fabry–Pérot cavity, an ensemble of N identical two-level atoms, and a mechanical oscillator. The effective driving amplitude related to driving direction leads to an obvious difference in mechanical gain and threshold power, bringing about a nonrecipr...     

Suszeptibilitätsmessungen an Aluminiummischkristallen

Zeitschrift für Physik A Hadrons and nuclei - Reines Aluminium sowie Aluminiumlegierungen werden mit einer Gouyschen Waagemethode magnetisch gemessen und bei den Mischkristallen systematische...     

Can an electric field induce an antiferroelectric phase out of a ferroelectric phase?

It has been widely accepted that electric fields favor the ferroelectric phase with parallel electric dipoles over the antiferroelectric phase. With detailed measurements in polycrystalline ceramics of Pb(0.99)Nb(0.02[(Zr(0.57)Sn(0.43)(1-y)Ti(y)](0.98)O(3), we demonstrate in this Letter that electric fields can induce an antiferroelectric phase out of a ferroelectric phase, i.e., trigger an apparently unlikely ferroelectric-to-antiferroelectric phase transition. We suggest that it is caused by the volume contraction from the converse piezoelectric effect at the coercive field with a reversed polarity.     

Metastable π junction between an s(±)-wave and an s-wave superconductor

We examine a contact between a superconductor whose order parameter changes sign across the Brillioun zone, and an ordinary, uniform-sign superconductor. Within a Ginzburg-Landau-type model, we find that if the barrier between the two superconductors is not too high, the frustration of the Josephson coupling between different portions of the Fermi surface across the contact can lead to surprising consequences. These include time-reversal symmetry breaking at the interface and unusual energy-phase relations with multiple local minima. We propose this mechanism as a possible explanation for the half-integer flux quantum transitions in composite niobium-iron pnictide superconducting loops, which were discovered in recent experiments [C.-T. Chen et al., Nature Phys. 6, 260 (2010).].     

Dynamical Localization in an Asymmetric Two-Electron Quantum Dot Molecule by an Alternating-Current Electric Field

We investigate the dynamics of two interacting electrons in an asymmetric double coupled quantum dot under an ac electric field. The numerical results demonstrate that dynamical localization and Rabi oscillation still exist in such a system under the stronger electron correlation. The two electrons can be regarded as a quasiparticle, which move together between two dots similarly to a boson. The dynamics of two electrons in such a quantum system are mainly confined in a Q subspace, which is constructed by two double-occupied states.     

Quantum—Mechanical Simulation of an Atomic Beam Focused by an Optical Standing Wave

Recent experiments have demonstrated that the light pressure force from an optical standing wave (SW) focuses an atomic beajm to sub-micrometre dimensions.We start from a two-dimensional time-dependent Schrodinger equation and reduce in to a one-dimensional equation by a paraxial approximation.We calculate some theoretical limits on the focusing of an atomic beam by an SW optical field.It is found that two parameters,the atomic velocity and the intensity of the laser beam,play an important role in determining the deposition quality.     

Effect of an intermediate layer on the strength of an ice−substrate interface

The purpose of this investigation is quantitative determination of deformational changes in the ice structure immediately upon displacement under conditions of high hydrostatic pressure by the method of acoustic emission and estimation of the effect of the structure on the ice?substrate adhesive bond strength. The relation between the reciprocal acoustic compliance of ice, the size of mobile elements of its structure, their resonance eigenfrequency, and the density is established. The model is verified. The correlation of the amplitude?frequency spectra of the acoustic emission on the frictional contact with the acoustic spectra of eigenvibrations on glaciers from remote sources is confirmed. The results obtained can be used for distant study of the modes of motion of ice in glaciers.