Motion of vortices in inhomogeneous Bose-Einstein condensates

T. I. Zueva

Nicholas G. Parker, B. Jackson, A. Martin +1 more

Peter Mason

The mechanisms behind the motion of vortices has recently been re-examined. The findings have given a more detailed and complete view as to how vortices move in Bose-Einstein condensation. Specifically, vortex propagation is not seen as purely the result of a density gradient which would arise because of the gradient of the trapping potential, but is also made up of a contribution from the boundary eects. I will consider the motion of vortices in an asymptotically inhomogeneous condensate under various trapping potentials. By first considering a linear potential trap and then a semi-infinite quadratic trap, the eects that govern the motion can be separated. It will be shown that for large density gradient backgrounds the motion can be analysed from the energy-momentum dispersion relationship, whereas for low density gradient backgrounds the motion is dominated by an eective shift in the image term caused by the eects of the boundary. Finally, a separate case of the motion of vortices in an infinitely long two-dimensional channel will be presented where the interaction strength plays a key role in the dynamics.

Alexander L. Fetter

T. I. Zueva

A dissipative model of vortex motion within a two-dimensional Gross-Pitaevskii equation is studied. With the asymptotic coordination method of solutions, a system of ordinary first-order differential equations describing vortex motion in rotating Bose-Einstein condensate was derived. The model takes into account the effect of various external factors: magnetic trap frequencies, number of particles in the condensate, angular rotational velocity of the condensate, dissipation parameter, etc. In special cases of dissipation-free motion, the results are coordinated with the known results of other authors. The addition of dissipation generalizes the known equations and makes it possible to see the vortex motion to the equilibrium points and to define the equilibrium configurations of any number of vortices. The model is illustrated by a large number of examples.

Frédéric Chevy