Berlin 2008 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 7: Matter at Low Temperature: Poster Session

TT 7.20: Poster

Monday, February 25, 2008, 14:00–18:00, Poster B

Hubbard Model for Imbalanced Fermi-Mixtures on Optical Lattices — •Tobias Gottwald and Peter G. J. van Dongen — KOMET 337, Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, 55099 Mainz, Germany

In order to understand the properties of imbalanced ultracold fermionic quantum gases on optical lattices, we analyze a Hubbard model with attractive interaction strength, spin-dependent hopping amplitudes and/or a Zeeman-term at low temperatures in the weak-coupling (mean-field) approximation. In experiment, interactions can be tuned via Feshbach resonances, different hopping amplitudes arise from different atomic masses or different hyperfine states, and the Zeeman-term is used to control the population imbalance. We investigate this generalized Hubbard model between two extremes, on the one hand the Falicov-Kimball model, where charge density wave phases are dominating, and on the other the standard Hubbard model with equal hopping amplitudes for each pseudo-spin species, where superfluid phases occur.