Rotating Bose-Einstein condensates with attractive interactions

We examine the phase diagram of a Bose-Einstein condensate of atoms, interacting with an attractive pseudopotential, in a quadratic-plus-quartic potential trap rotating at a given rate. Investigating the behavior of the gas as a function of interaction strength and rotational frequency of the trap, we find that the phase diagram has three distinct phases: one with vortex excitation, one with center-of-mass excitation, and an unstable phase in which the gas collapses.