Regensburg 2007 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 21: Solids at Low Temperature - Poster Session

TT 21.4: Poster

Mittwoch, 28. März 2007, 14:00–17:45, Poster A

Fermionic Hubbard model with spin-dependent hopping amplitudes for ultracold quantum gases — •Tobias Gottwald and Peter G. J. van Dongen — KOMET 337, Institut für Physik, Universität Mainz, Staudingerweg 7, 55099 Mainz

In order to understand the properties of fermionic ultracold quantum gases in optical lattices, we analyze a Hubbard model with spin-dependent hopping amplitudes at low temperatures in the limits of weak and strong coupling. In both cases we consider attractive as well as repulsive interactions, for which we find suprafluidity and (generalized) antiferromagnetism, respectively. In experiment, interactions can be tuned via Feshbach resonances, and different hopping amplitudes arise from different atomic masses or different hyperfine states. We investigate this generalized Hubbard model between two extremes, on the one hand the Falicov-Kimball model and on the other the standard Hubbard model with equal hopping amplitudes for each pseudo-spin species.