Regensburg 2010 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 37: MLT: Poster Session

TT 37.3: Poster

Donnerstag, 25. März 2010, 14:00–18:00, Poster A

Anomalous diffusion of strongly correlated fermions in an optical lattice — •Stephan Mandt¹, David Rasch¹, Theo Costi², and Achim Rosch¹ — ¹Institute of Theoretical Physics, Cologne, Germany — ²Forschungszentrum Jülich, Germany

We study the expansion of a cloud of strongly correlated fermionic atoms in an optical lattice. Initially, the cloud has a narrow Gaussian density profile but it spreads apart after being released from an additional confining potential. In experiment, it is observed that the particles at the edge of the cloud move ballistically. This ballistic motion is governed by the cubic symmetry of the lattice which is reflected in the characteristic shape of the expanding cloud. In contrast, the atoms at the center of the cloud are dominated by interparticle collisions and behave diffusively. Modelling the system in the framework of the Boltzmann equation, we describe the spatial crossover from ballistic to diffusive dynamics and recover the experimental observations made by the group of Immanuel Bloch.