Fermionic atoms in optical lattices are ideal model systems to explore the physics of strongly correlated quantum systems. Experiments of the Bloch group on the compressibility of atomar clouds in the Mott regime allow for a quantitative comparison of theory and experiments . Qualitatively new effects arise out of equilibrium. We investigate theoretically the physics of atoms expanding within an optical lattice and show that it is governed by a surprisingly complex interplay of diffusive and ballistic behavior. In recent experiments this physics is tracked by observing the shape of the atomar cloud which remains spherical in the diffusive regime but becomes cubic in its ballistic tails.
 U. Schneider, L. Hackermuller, S. Will, Th. Best, I. Bloch, T. A. Costi, R. W. Helmes, D. Rasch, A. Rosch, Science 322, 1520 (2008)
I did my PhD in 1998 at the University of Karlsruhe in Germany. After a postdoc at Rutgers University in 1998-2000, NJ, I came back to Karlsruhe as a head of a junior research group. In 2004 I became full professor at the University of Cologne. My main research interest are in the area of strongly correlated quantum systems including quantum dots, low-dimensional electron systems, quantum phase transitions and cold atoms.