Canonical ensemble of an interacting Bose gas: Stochastic matter fields and their coherence
Institut für Theoretische Physik, Technische Universität Dresden - D-01062 Dresden, Germany, EU
Received: 4 October 2012
Accepted: 4 March 2013
We present a novel quantum stochastic evolution equation for a matter field describing the canonical state of a weakly interacting ultracold Bose gas. In the ideal gas limit our approach is exact. This numerically very stable equation suppresses high-energy fluctuations exponentially, which enables us to describe condensed and thermal atoms within the same formalism. We present applications to ground-state occupation and fluctuations, density profile of ground-state and thermal cloud, and ground-state number statistics. Our main aim are spatial coherence properties which we investigate through the determination of interference contrast and spatial density correlations. Parameters are taken from actual experiments.
PACS: 05.30.Jp – Boson systems / 67.85.-d – Ultracold gases, trapped gases / 05.10.Gg – Stochastic analysis methods (Fokker-Planck, Langevin, etc.)
© EPLA, 2013