title: Critical rotation of a harmonically trapped Bose gas.
abstract: We study experimentally and theoretically a cold trapped Bose gas under critical rotation, i.e., with a rotation frequency close to the frequency of the radial confinement. We identify two regimes: the regime of explosion where the cloud expands to infinity in one direction, and the regime where the condensate spirals out of the trap as a rigid body. The former is realized for a dilute cloud, and the latter for a condensate with the interparticle interaction exceeding a critical value. This constitutes a novel system in which repulsive interactions help in maintaining particles together.
authors.affiliation: Laboratoire Kastler Brossel, 24 rue Lhomond, 75005 Paris, France.
authors.forename: P
authors.initials: P
authors.lastname: Rosenbusch
authors.forename: D S
authors.initials: DS
authors.lastname: Petrov
authors.forename: S
authors.initials: S
authors.lastname: Sinha
authors.forename: F
authors.initials: F
authors.lastname: Chevy
authors.forename: V
authors.initials: V
authors.lastname: Bretin
authors.forename: Y
authors.initials: Y
authors.lastname: Castin
authors.forename: G
authors.initials: G
authors.lastname: Shlyapnikov
authors.forename: J
authors.initials: J
authors.lastname: Dalibard