Vortex Stability and Persistent Currents in Trapped Bose Gases

Abstract

We consider the stability of vortices in trapped dilute Bose gases. For weak coupling the vortex is unstable to single-particle excitations: the Bose condensate cannot support persistent currents, and the gas is not superfluid. For stronger coupling the azimuthal symmetry of the rotating condensate is spontaneously broken, resulting in an off-center vortex that eventually spirals out of the trap.