  We consider the intrinsic stability of the vortex states of a pure
Bose-Einstein condensate confined in a harmonic potential under the effects of
coherent atom-atom interaction. We find that stable vortices can be supported,
and that vortex stability can be controlled by changing the inter-particle
interaction strength. At unstable regimes, a vortex will spontaneously
disintegrate into states with different angular momenta even without external
perturbations, with the lifetime determined by its imaginary excitation
frequencies.

Statistical Mechanics