Berry phase in a composite system

The Berry phase in a composite system with only one subsystem being driven has been studied in this Letter. We choose two spin-$\frac 1 2$ systems with spin-spin couplings as the composite system, one of the subsystems is driven by a time-dependent magnetic field. We show how the Berry phases depend on the coupling between the two subsystems, and what is the relation between these Berry phases of the whole system and those of the subsystems.Comment: 4 pages, 6 figure

Actinopolymorpha alba sp. nov., isolated from a rhizosphere soil

A Gram-positive, milk-white coloured, aerobic strain, YIM 48868(T), was isolated from the rhizosphere soil of Maytenus hookeri Loes in Xishuangbanna, China. 16S rRNA gene sequence similarity studies showed that strain YIM 48868(T) was a member of the genus Actinopolymorpha, showing 96.8% sequence similarity to Actinopolymorpha singaporensis IM 7744(T) and 97.0% similarity to Actinopolymorpha rutila YIM 45725(T). Chemotaxonomic data (peptidoglycan type 1, LL-diaminopimelic acid; sugar pattern C, glucose, rhamnose and ribose; polar lipids PI, diphosphatidylglycerol, phosphaticlylglycerol, phosphatidylinositol mannosides and phosphatidylinositol) were characteristic of the genus Actinopolymorpha. A phylogenetic tree based on 16S rRNA gene sequences showed that strain YIM 48868(T) formed a distinct phylogenetic lineage within the genus Actinopolymorpha. Strain YIM 48868(T) could be differentiated from recognized species by means of phenotypic properties and the predominant menaquinones [MK-9(H(6)), MK-9(H(8)), MK-10(H(6)), MK-10(H(8))]. The DNA G+C content was 66.6 mol%. The DNA-DNA relatedness values between strain YIM 48868(T) and the type strains of A. singaporensis and A. rutila were 48.7% and 53.1%, respectively. These data, in combination with phenotypic and chemotaxonomic data, demonstrate that strain YIM 48868(T) represents a novel species in the genus Actinopolymorpha, for which the name Actinopolymorpha alba sp. nov. is proposed. The type strain is YIM 48868(T) (=CCTCC AA 208030(T) =DSM 45243(T))

Entangled two atoms through different couplings and the thermal noise

The entanglement of two atoms is studied when the two atoms are coupled to a single-mode thermal field with different couplings. The different couplings of two atoms are in favor of entanglement preparation: it not only makes the case of absence entanglement with same coupling appear entanglement, but also enhances the entanglement with the increasing of the relative difference of two couplings. We also show that the diversity of coupling can improved the critical temperature. If the optical cavity is leaky during the time evolution, the dissipative thermal environment is benefit to produce the entanglement.Comment: 4 pages, 4 figure

Dynamical mean-field equations for strongly interacting fermionic atoms in a potential trap

We derive a set of dynamical mean-field equations for strongly interacting fermionic atoms in a potential trap across a Feshbach resonance. Our derivation is based on a variational ansatz, which generalizes the crossover wavefunction to the inhomogeneous case, and the assumption that the order parameter is slowly varying over the size of the Cooper pairs. The equations reduce to a generalized time-dependent Gross-Pitaevskii equation on the BEC side of the resonance. We discuss an iterative method to solve these mean-field equations, and present the solution for a harmonic trap as an illustrating example to self-consistently verify the approximations made in our derivation.Comment: replaced with the published versio

Fire responses and resistance of concrete-filled steel tubular frame structures

This paper presents the results of dynamic responses and fire resistance of concretefilled steel tubular (CFST) frame structures in fire conditions by using non-linear finite element method. Both strength and stability criteria are considered in the collapse analysis. The frame structures are constructed with circular CFST columns and steel beams of I-sections. In order to validate the finite element solutions, the numerical results are compared with those from a fire resistance test on CFST columns. The finite element model is then adopted to simulate the behaviour of frame structures in fire. The structural responses of the frames, including critical temperature and fire-resisting limit time, are obtained for the ISO-834 standard fire. Parametric studies are carried out to show their influence on the load capacity of the frame structures in fire. Suggestions and recommendations are presented for possible adoption in future construction and design of these structures