Fluctuational susceptibility of ultracold bosons in the vicinity of condensation
Abstract
We study the behaviour of ultracold bosonic gas in the critical region above the Bose-Einstein condensation in the presence of an artificial magnetic field, Bart. We show that the condensate fluctuations above the critical temperature Tc cause the fluctuational susceptibility, fl, of a uniform gas to have a stronger power-law divergence than in an analogous superconducting system. Measuring such a divergence opens new ways of exploring critical properties of the ultracold gas and an opportunity of an accurate determination of Tc. We describe a method of measuring fl which requires a constant gradient in Bart and suggest a way of creating such a field in experiment.
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