Stuttgart 2012 – wissenschaftliches Programm

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Q: Fachverband Quantenoptik und Photonik

Q 7: Quantengase: Fermionen

Q 7.6: Vortrag

Montag, 12. März 2012, 15:15–15:30, V47.02

Ultracold Driven Fermigases: Population Trapping and Bloch Oscillations — •Regine Frank — Institut f\"ur Theoretische Festk\"orperphysik Wolfgang-G\"ade-Strasse 1, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany

Ultracold gases are quite perfect to study physical systems under various aspects in situations far off the thermodynamical equilibrium. The two major reasons are that the properties of ultracold gases in optical lattices can be experimentally controlled almost without restrictions and the pronounced lack of dissipative coupling to the environment. We consider a three dimensional optical lattice whith strength modulations in time and loaded with an interacting gas of fermionic atoms. The inter-atomic correlation strength is varied from weak to strong and the temporal lattice modulations are taken into account by means of an non-equilibrium dynamical mean field theory (DMFT) incorporating the Keldysh Green's function technique. The numerical results for both the fluid (conducting) and the insulating regime, include the spectral weight function, the non-equilibrium distribution function, the optical conductivity and the relaxation time aof the excited atoms. We show the effects of population trapping in gapstates and Bloch oscillations of the ultracold fermions.