title: Consequence of superfluidity on the expansion of a rotating Bose-Einstein condensate.
abstract: We propose an easily detectable signature of superfluidity in rotating, vortex-free gaseous Bose-Einstein condensates. We have studied the time evolution of the expansion of such a condensate after it is released from the confining trap. We find that if such a condensate is not initially rotating, then at some moment it will instantaneously achieve a circular cross section. If the condensate is initially rotating its irrotational flow and the conservation of angular momentum prevent the released condensate from attaining a circular cross section, since the instantaneous moment of inertia is then proportional to the asymmetry of this cross section.
authors.affiliation: Department of Physics, Georgia Southern University, Statesboro, Georgia 30460-803, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Edwards
authors.forename: Charles W
authors.initials: CW
authors.lastname: Clark
authors.forename: P
authors.initials: P
authors.lastname: Pedri
authors.forename: L
authors.initials: L
authors.lastname: Pitaevskii
authors.forename: S
authors.initials: S
authors.lastname: Stringari