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Q: Quantenoptik und Photonik

Q 21: Poster Quantengase

Q 21.4: Poster

Tuesday, March 23, 2004, 14:00–16:00, Schellingstr. 3

Atomic Bose-Fermi mixtures in an optical lattice — •Fehrmann Henning, Maciej Lewenstein, Luis Santos und Mikhail Baranov — ITP Uni Hannover

A mixture of ultra-cold bosons and fermions placed in an optical lattice constitutes a novel kind of quantum gas and leads to phenomena, which so far have been discussed neither in atomic physics nor in condensed matter physics.

We discuss the phase diagram at low temperatures, and in the limit of strong atom-atom interactions. We predict the existence of quantum phases that involve pairing of fermions with one or more bosons, or bosonic holes respectively. The resulting composite fermions may form, depending on the system parameters, a normal Fermi liquid, a density wave, a super-fluid liquid, or an insulator with fermionic domains.

Furthermore we obtain the analytic form of the phase boundaries separating these composite fermion phases from the bosonic super-fluid which coexists with a Fermi liquid.

We compare the results with numerical simulations and discuss their validity and relevance for current experiments.