Stability of excited states of a Bose-Einstein condensate in an anharmonic trap

Abstract

We analyze the stability of nonground nonlinear states of a Bose-Einstein condensate in the mean-field limit in effectively one-dimensional (``cigar-shape'') traps for various types of confining potentials. We find that nonlinear states become, in general, more stable when switching from a harmonic potential to an anharmonic one. We discuss the relation between this fact and the specifics of the harmonic potential which has an equidistant spectrum.