Signature of the existence of a coherently condensed state in a dilute gas above the Bose-Einstein-condensate transition temperature

摘要

We study quantum coherence properties of a dilute gas at temperatures above, but not much above, the transition temperature of Bose-Einstein condensation. In such a gas, a small proportion of the atoms may possess coherence lengths longer than the mean neighboring-atomic distance, implying the existence of quantum coherence greater than that expected for thermal atoms. Conjecturing that a part of this proportion of the atoms may lie in a coherently condensed state, some unexplained experimental results [ D. E. Miller et al., Phys. Rev. A 71, 043615 (2005)] can be explained.