München 2004 – scientific programme

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A: Atomphysik

A 3: Kalte Atome in Fallen

A 3.5: Talk

Monday, March 22, 2004, 15:00–15:15, HS 132

N-component Bose-Einstein condensate in an optical lattice — •Christopher Moseley and Klaus Ziegler — Lehrstuhl für theoretische Physik II, Institut für Physik, Universität Augsburg, Universitätsstr. 1, 86135 Augsburg

We consider an N-component system of hard-core bosons in an optical lattice. On each lattice site a boson can occupy one of the N different states. Tunneling is possible between neighbouring lattice sites as well as between the states. In our model, the limit N→∞ can be solved exactly. This case represents a Bose-Einstein condensate where interactions play a minor role due to the large number of possible states.The influence of the hard-core interaction in a system with finite N can be investigated by means of a 1/N-expansion. This approach allows the determination of several physical quantities like the density of the condensate, the condensate fraction and the dispersion relation and density of states of quasi particles. The zero temperature phase diagram is investigated.