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Q: Fachverband Quantenoptik und Photonik

Q 60: Quantengase (Gemische / Tunneleffekte)

Q 60.5: Talk

Friday, March 14, 2008, 12:00–12:15, 3G/H

Do mixtures of bosonic and fermionic atoms adiabatically heat up in optical lattices? — •Marcus Cramer¹, Silke Ospelkaus², Christian Ospelkaus², Kai Bongs², Klaus Sengstock², and Jens Eisert¹ — ¹Blackett Laboratory, Imperial College London — ²Institut für Laser-Physik, Universität Hamburg

Mixtures of bosonic and fermionic atoms in optical lattices provide a promising arena to study strongly correlated systems. In experiments realizing such mixtures in the quantum degenerate regime the temperature is a key parameter. We investigate the intrinsic heating and cooling effects due to an entropy-preserving raising of the optical lattice, identify the generic behavior valid for a wide range of parameters and discuss it quantitatively for the recent experiments with ⁸⁷Rb and ⁴⁰K atoms. In the absence of a lattice, we treat the bosons in the Hartree-Fock-Bogoliubov-Popov approximation, including the fermions in a self-consistent mean field interaction. In the presence of the full three-dimensional lattice, we use a strong coupling expansion. We find the temperature of the mixture in the lattice to be always higher than for the pure bosonic case, shedding light onto a key point in the analysis of recent experiments.