Düsseldorf 2007 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 17: Quantengase (Bosonische Gitter I)
Q 17.1: Vortrag
Dienstag, 20. März 2007, 10:30–10:45, 6J
Sweeping from the Superfluid to the Mott Phase in the Bose-Hubbard Model — •Michael Uhlmann1, Ralf Schützhold1, Yan Xu1, and Uwe Fischer2 — 1Institut für Theoretische Physik, TU Dresden — 2Institut für Theoretische Physik, Eberhard-Karls-Universität Tübingen
We study the sweep through the quantum phase transition from the superfluid to the Mott state for the Bose-Hubbard model with a time-dependent tunneling rate J(t). In the experimentally relevant case of exponential decay J(t) ∝ e−γ t, an adapted mean-field expansion for large fillings n yields a scaling solution for the fluctuations. This enables us to analytically calculate the evolution of the number and phase variations (on-site) and correlations (off-site) for slow (γ ≪ µ), intermediate, and fast (non-adiabatic γ ≫ µ) sweeps, where µ is the chemical potential. Finally, we derive the dynamic decay of the off-diagonal long-range order as well as the temporal shrinkage of the superfluid fraction in a persistent ring-current setup.