title: Phase-fluctuating 3D Bose-Einstein condensates in elongated traps.
abstract: We find that in very elongated 3D trapped Bose gases, even at temperatures far below the BEC transition temperature T(c), the equilibrium state will be a 3D condensate with fluctuating phase (quasicondensate). At sufficiently low temperatures the phase fluctuations are suppressed and the quasicondensate turns into a true condensate. The presence of the phase fluctuations allows for extending thermometry of Bose-condensed gases well below those established in current experiments.
authors.affiliation: FOM Institute for Atomic and Molecular Physics, Kruislaan 407, 1098 SJ Amsterdam, The Netherlands.
authors.forename: D S
authors.initials: DS
authors.lastname: Petrov
authors.forename: G V
authors.initials: GV
authors.lastname: Shlyapnikov
authors.forename: J T
authors.initials: JT
authors.lastname: Walraven