ATOM-INTERFEROMETRIC STUDY OF BOSE-EINSTEIN CONDENSATION

We investigate the influence of a Bose-Einstein condensate on the cohe rence properties of a traversing atomic beam. We derive a master equat ion describing the interaction between beam atoms and the condensate i n s-wave approximation. Scattering rates are calculated and compared w ith the case of an ordinary Boltzmann gas. Special attention is paid t o the decoherence of the beam, i.e., the decay of spatial coherence in the presence of the condensate. As an application, we explicitly calc ulate the visibility of the interference pattern in a double-slit expe riment and indicate signs for the onset of the condensation.