Multi-component quantum gases in optical lattices
Dr. Christoph Becker (Institut für Laserphysik, Univ. Hamburg)

Ultracold atoms in optical lattices have developed into a well established research field mainly due their versatility and the excellent degree of control over all system parameters.
I will present results on two distinct experiments underlining the importance of these systems to explore anticipated solid state models such as the Bose and Fermi Hubbard model or the simulation of frustrated magnetism.
<p> A detailed experimental study of the low lying excitations and tunneling properties of ultracold fermions in optical lattices will be given introducing a novel multi-band spectroscopy for fermionic atoms that allows to access the full band structure and tunneling energy with high accuracy.
<p> In the second part I will report on the realization of a large scale quantum simulator for classical geometrically frustrated magnetism. This is achieved by loading a BEC in a driven triangular optical lattice which allows us to dynamically control the tunneling along different directions independently. The resulting rich phase diagram which we have completely mapped experimentally include e.g. Neel phases and frustrated symmetry broken phases.