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A: Fachverband Atomphysik

A 40: Poster: Ultra-cold atoms, ions and BEC

A 40.12: Poster

Donnerstag, 15. März 2012, 16:30–19:00, Poster.V

Emergence of exotic condensates from a melting bosonic Mott insulator in a 2D optical lattice — •Ulrike Bornheimer, Julia Wernsdorfer, and Walter Hofstetter — Goethe Universität Frankfurt am Main, Institut für theoretische Physik, Max-von- Laue Str. 1, 60438 Frankfurt am Main, Germany

We investigate the expansion dynamics of a bosonic quantum gas initially prepared in the Mott insulating ground state of an optical lattice. Once released from harmonic confinement, the interacting many-body system is observed to develop coherence while simultaneously populating states with finite quasi-momentum. We demonstrate that for strong and intermediate interactions the emerging condensate fraction depends on the number of particles in the MI phase rather than on the particular interaction or tunneling strength. During expansion, the condensate is observed to develop a spiked structure breaking the initial spherical symmetry of the density distribution. The expanding spikes exhibit the maximal lattice velocity, independent of other system parameters. These dynamical properties of the system are obtained by means of Gutzwiller mean-field theory and confirmed analytically.