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. 
G. M. Kavoulakis (1), A. D. Jackson (2), Gordon Baym (3,4) ((1) LTH,   Lund (2) Niels Bohr Institute, (3) Urbana, Illinois (...