Properties of a nematic spin vortex in an antiferromagnetic spin-1 Bose-Einstein condensate

TL;DR

This paper investigates the properties, stability, and excitation spectrum of nematic spin vortices in a uniform antiferromagnetic spin-1 Bose-Einstein condensate, revealing conditions for their dynamical stability.

Contribution

It provides a detailed characterization of nematic spin vortices, including their core structure, excitation spectrum, and stability criteria, in a quasi-two-dimensional antiferromagnetic spin-1 BEC.

Findings

Nematic spin vortices have a $2 extpi$ winding of the nematic director.

A parameter regime exists where the vortex is dynamically stable.

Full dynamical simulations support the analytical results.

Abstract

A spin-1 condensate with antiferromagnetic interactions supports nematic spin vortices in the easy-plane polar phase. These vortices have a $2\pi$ winding of the nematic director, with a core structure that depends on the quadratic Zeeman energy. We characterize the properties of the nematic spin vortex in a uniform quasi-two-dimensional system. We also obtain the vortex excitation spectrum and use it to quantify its stability against dissociating into two half-quantum vortices, finding a parameter regime where the nematic spin vortex is dynamically stable. These results are supported by full dynamical simulations.