Ad. Jackson et al., Weakly interacting Bose-Einstein condensates under rotation: Mean-field versus exact solutions, PHYS REV L, 86(6), 2001, pp. 945-949
We consider a weakly interacting, harmonically trapped Bose-Einstein conden
sed 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 s
cheme valid in the thermodynamic limit of many particles. Mean-field result
s are shown to emerge as the correct leading-order approximation to exact c
alculations in the same subspace.