Vortices in a toroidal Bose-Einstein condensate with a rotating weak link

TL;DR

This paper studies how vortex excitations cause quantized circulation jumps in a toroidal Bose-Einstein condensate with a rotating weak link, revealing complex vortex dynamics through 3D simulations.

Contribution

It provides a detailed analysis of vortex-induced phase slips and their stability in a toroidal BEC with a rotating barrier, extending understanding beyond experimental conditions.

Findings

Vortex excitations induce quantized circulation jumps.

Density depletion and superflows affect vortex stability.

Complex vortex dynamics emerge beyond experimental parameters.

Abstract

Motivated by a recent experiment [K.C. Wright et. al. Phys. Rev. Lett. 110, 025302 (2013)], we investigate deterministic discontinuous jumps between quantized circulation states in a toroidally trapped Bose-Einstein condensate. These phase slips are induced by vortex excitations created by a rotating weak link. We analyze influence of a localized condensate density depletion and atomic superflows, governed by the rotating barrier, on the energetic and dynamical stability of the vortices in the ring-shaped condensate. We simulate in a three-dimensional dissipative mean field model the dynamics of the condensate using parameters similar to the experimental conditions. Moreover, we consider the dynamics of the stirred condensate far beyond the experimentally explored region and reveal surprising manifestations of complex vortex dynamics.