title: Quantum instability of a Bose-Einstein condensate with attractive interaction.
abstract: We study the quantum and the mean-field Gross-Pitaevskii (GP) dynamics of a Bose-Einstein condensate gas confined in a toroidal trap. According to GP, if the interatomic interaction is attractive, the rotational states of the system can be dynamically stable or unstable depending on the strength of the mean-field energy. The full quantum analysis, however, reveals that the condensate is always unstable. Quantum fluctuations are particularly important close to the GP stability borderline, even for systems with a relatively large number of condensate atoms.
authors.affiliation: Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA.
authors.forename: G P
authors.initials: GP
authors.lastname: Berman
authors.forename: A
authors.initials: A
authors.lastname: Smerzi
authors.forename: A R
authors.initials: AR
authors.lastname: Bishop