arXiv:1706.07137 · Physical Review A
Vortex precession dynamics in general radially symmetric potential traps in two-dimensional atomic Bose-Einstein condensates
P. G. Kevrekidis, Wenlong Wang, R. Carretero-González, D. J. Frantzeskakis, Shuangquan Xie
Abstract
We consider the motion of individual two-dimensional vortices in general radially symmetric potentials in Bose-Einstein condensates. We find that although in the special case of the parabolic trap there is a logarithmic correction in the dependence of the precession frequency $\ensuremath{\omega}$ on the chemical potential $\ensuremath{\mu}$, this is no longer true for a general potential $V(r)\ensuremath{\propto}{r}^{p}$. Our calculations suggest that for $p>2$, the precession frequency scales with $\ensuremath{\mu}$ as $\ensuremath{\omega}\ensuremath{\sim}{\ensuremath{\mu}}^{\ensuremath{-}2/p}$. This theoretical prediction is corroborated by numerical computations, not only at the level of spectral (Bogolyubov--de Gennes) stability analysis by identifying the relevant precession mode dependence on $\ensuremath{\mu}$ but also through direct numerical computations of the vortex evolution in the large-$\ensuremath{\mu}$, so-called Thomas-Fermi, limit. Additionally, the dependence of the precession frequency on the distance to the trap center of an initially displaced vortex is examined, and the corresponding predictions are tested against numerical results.