Exploring vortex dynamics in the presence of dissipation: Analytical and numerical results

In this paper, we examine the dynamical properties of vortices in atomic Bose-Einstein condensates in the presence of phenomenological dissipation, used as a basic model for the effect of finite temperatures. In the context of this so-called dissipative Gross-Pitaevskii model, we derive analytical results for the motion of single vortices and, importantly, for vortex dipoles, which have become very relevant experimentally. Our analytical results are shown to compare favorably to the full numerical solution of the dissipative Gross-Pitaevskii equation where appropriate. We also present results on the stability of vortices and vortex dipoles, revealing good agreement between numerical and analytical results for the internal excitation eigenfrequencies, which extends even beyond the regime of validity of this equation for cold atoms.