Instabilities of off-centered vortices in a Bose-Einstein condensate

TL;DR

This paper numerically investigates the stability and excitation modes of off-centered vortices in Bose-Einstein condensates, revealing persistent instability features and continuous deformation of excitation modes with vortex displacement.

Contribution

It provides a detailed numerical analysis of vortex excitations, highlighting the instability of off-centered vortices and their excitation mode behaviors.

Findings

Core-localized excitations indicate vortex instability.

Excitation modes deform continuously with vortex displacement.

Vortex separation affects excitation properties.

Abstract

We study numerically the excitations of off-centered vortices in a Bose-Einstein condensate. The displacement of a single vortex and the separation of a doubly quantized vortex are considered. We find that the core-localized excitations of the precessing vortices continue to feature the property which implies that the vortices are unstable. The core-localized, dipolar, and quadrupolar excitations are found to deform continuously as functions of vortex displacements and intervortex separation.