Coherence Length for a Trapped Bose Gas

Stephen M. Barnett, Sonja Franke-Arnold, Aidan S. Arnold, Colin Baxter

Journal of Physics B, 33, 4177 (2000)

Matter waves can be assigned a coherence length analogous to the corresponding quantity in optics. We show that there is a dramatic increase in coherence length associated with the appearance of Bose-Einstein condensation in a trapped ideal Bose gas. The large increase in coherence length occurs even for temperatures just below the critical temperature at which only a small proportion of the trapped atoms is to be found in the ground state.