Darmstadt 2008 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 60: Quantengase (Gemische / Tunneleffekte)
Q 60.2: Talk
Friday, March 14, 2008, 11:15–11:30, 3G/H
Self-Trapping of Bosons and Fermions in Optical Lattices — •Dirk-Sören Lühmann1, Kai Bongs2,3, Klaus Sengstock2, and Daniela Pfannkuche1 — 1I. Institut für Theoretische Physik, Universität Hamburg, Jungiusstr. 9, 20355 Hamburg, Germany — 2Institut für Laser-Physik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany — 3Midlands Centre for Ultracold Atoms, School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
The superfluid to Mott insulator transition is one of the paradigms of solid state physics that maps onto ultra cold atomic systems. The interaction between different kinds of atoms adds an additional degree of freedom to two-component atomic systems not present in the solid state counterpart.
We numerically investigate the enhanced localisation of bosonic 87Rb by fermionic 40K atoms in three-dimensional optical lattices and find a self-trapping of bosons and fermions. Due to the mutual interaction the fermion orbitals are substantially squeezed which results in a strong deformation of the bosonic effective potential. We show that orbital effects in attractively interacting atomic mixtures are non-negligible as they lead to a large shift of the critical point of the transition from a superfluid to a Mott-insulator, which is of direct relevance to recent experiments with 87Rb and 40K atoms.