Dresden 2009 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 1: Focussed Session: The Mott Transition in Model Systems

TT 1.2: Topical Talk

Montag, 23. März 2009, 10:45–11:15, HSZ 03

Mott transition and metastable superconductivity of repulsive Fermions in optical lattices — •Achim Rosch — Institute of Theoretical Physics, University of Cologne, 50937 Cologne

Cold atoms in optical lattices can be used to realize and control strongly correlated states of matter with unprecedented flexibility and precision. One can, for example, study the physics of the fermionic Mott transition by measuring [1] to what extent an atomic cloud in the Mott regime can be compressed. The experiments are well described by the dynamical mean field theory [1].

With cold atoms one can also realize novel non-equilbrium states. We show theoretically [2] that one can prepare an s-wave superfluid state when a dense clould of atoms described by the strongly repulsive Hubbard model is slowly expanded. Here we use that doubly occupied sites have an exponential large lifetime in the limit of strong repulsion. These pairs condense at a finite momentum which allows for a reliable detection of this exotic state of matter.

[1] U. Schneider, L. Hackermuller, S. Will, Th. Best, I. Bloch, T. A. Costi, R. W. Helmes, D. Rasch, A. Rosch, preprint arXiv:0809.1464, accepted for publication in Science

[2] A. Rosch, D. Rasch, B. Binz, M. Vojta, preprint arXiv:0809.0505, accepted for publication in PRL