title: Weakly interacting Bose-Einstein condensates under rotation: mean-field versus exact solutions.
abstract: We consider a weakly interacting, harmonically trapped Bose-Einstein condensed gas under rotation and investigate the connection between the energies obtained from mean-field calculations and from exact diagonalizations in a subspace of degenerate states. From the latter we derive an approximation scheme valid in the thermodynamic limit of many particles. Mean-field results are shown to emerge as the correct leading-order approximation to exact calculations in the same subspace.
authors.affiliation: Niels Bohr Institute, Copenhagen, Denmark.
authors.forename: A D
authors.initials: AD
authors.lastname: Jackson
authors.forename: G M
authors.initials: GM
authors.lastname: Kavoulakis
authors.forename: B
authors.initials: B
authors.lastname: Mottelson
authors.forename: S M
authors.initials: SM
authors.lastname: Reimann