München 2004 – wissenschaftliches Programm
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Q: Quantenoptik und Photonik
Q 21: Poster Quantengase
Q 21.8: Poster
Dienstag, 23. März 2004, 14:00–16:00, Schellingstr. 3
Beyond Gutzwiller: Corrections to mean-field expansion patterns of interacting bosonic atoms in optical lattices. — •Christian Schroll1, Florian Marquardt2, and Christoph Bruder1 — 1Universität Basel, Departement für Physik und Astronomie, Klingelbergstr. 82, CH-4056 Basel, Schweiz — 2Yale University, Dept. of Physics, New Haven, USA
We consider the Mott-insulator transition in optical lattices, studying in particular short-range correlations that determine the momentum distribution and the experimentally observed expansion patterns. Based on the mean-field Gutzwiller ansatz, which is a good approximation for small and large ratio of the hopping to onsite energy J/U, we use perturbation theory to improve the results for intermediate values of J/U. We discuss the resulting substantial modifications of the density fluctuations and the density matrix, and we compare to other approaches.