Rosen-Zener interferometry with Ultracold Atoms

We propose a time-domain "interferometer" based on ultracold Bose atoms loaded on a double well potential. By the adiabatic Rosen-Zener process, the barrier between two wells is ramped down slowly, held for a while, then ramped back. Starting with a coherent state of double well system, the final occupations on one well show interesting interference fringes in the time-domain. The fringe pattern is sensitive to the initial state, the interatomic interaction, and the external forces such as gravity which can change the shape of the double well. In this sense, this interferometric scheme has the potentials for precision measurements with ultracold atoms. The underlying mechanism is revealed and possible applications are discussed.Comment: 4 pages, 5 figure

Isolation and characterization of cDNA encoding stilbene synthases from Chinese wild Vitis pseudoreticulata

mRNA differential display was employed to study powdery mildew disease resistance gene expression in Chinese wild Vitis pseudoreticulata 'Baihe-35-1' inoculated with Erysiphe necator (syn. Uncinula necator) under natural field conditions. A cDNA fragment T11AC/B0320-723 showing homology to stilbene synthase (STS) gene expressed more strongly at 1, 3, 5, 7 and 9 days after inoculation of leaves than in controls was found. The full cDNA length was cloned by rapid amplification of cDNA ends (RACE). Sequencing of the full length cDNA revealed cDNA sequences, sized 1288, 1411, 1468, 1492, 1506 and 1556 base pairs encoding 6 homologous polypeptides with 392 amino acid residues each, that were designated as VpSTS1, VpSTS2, VpSTS3, VpSTS4, VpSTS5 and VpSTS6 respectively. The deduced amino acid sequences shared identity of 65 %, 77 % and more than 94 % with Pinus strobus STS, Vitis vinifera chalcone synthase (CHS), and Vitis riparia, Vitis labrusca, Parthenocissus henryana, Cissus rhombifolia, Parthenocissus quinquefolia and Vitis vinifera STS, respectively.

Calculations of Chern number: equivalence of real-space and twisted-boundary-condition formulae

Chern number is a crucial invariant for characterizing topological feature of two-dimensional quantum systems. Real-space Chern number allows us to extract topological properties of systems without involving translational symmetry, and hence plays an important role in investigating topological systems with disorder or impurity. On the other hand, the twisted boundary condition (TBC) can also be used to define the Chern number in the absence of translational symmetry. Here we study the relation between these different definitions of Chern number. Through analyzing the TBC formula and two real-space formulae (the non-commutative Chern number and the Bott index formula), we show that these approaches are equivalent in the thermodynamic limit. The equivalence is also numerically confirmed via the Haldane model.Comment: 16 pages, 6 figure