Dresden 2011 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 20: Ultra-cold atoms, ions and BEC V (with Q)

A 20.10: Vortrag

Donnerstag, 17. März 2011, 12:45–13:00, BAR 106

Large coordination number expansion for a lattice Bose gas — •Patrick Navez¹, Ralf Schützhold², and Konstantin Krutitsky² — ¹Institut für Theoretische Physik, TU Dresden, D-01062 Dresden, Germany — ²Fakultät für Physik, Universität Duisburg-Essen, Lotharstrasse 1, D-47057 Duisburg, Germany

We establish a set of hierarchy equations describing the time evolution of the N-points spatial correlation reduced density matrix in a lattice Bose gas. This set of equations is solved through a 1/z expansion where z is the coordination number i.e. number of interaction of a site with its nearest neighbors. The leading order of this expansion corresponds to the time-dependent Gutzwiller mean field approach that is used to describe the Bragg scattering in the superfluid regime. The next order contribution includes the correlations between sites. We illustrate how these correlations appear in the process of a ultra fast sweeping from a deep Mott regime to the superfluid regime.