Explicit expressions for the topological defects of spinor Bose-Einstein condensates

TL;DR

This paper develops a general method to derive explicit expressions for topological defects like vortices and monopoles in spinor Bose-Einstein condensates, enhancing understanding of their structure and stability.

Contribution

It introduces a novel method for constructing order-parameters for topological defects in spinor BECs, including cases with stable vortices and monopoles, and analyzes effects of magnetic fields.

Findings

Vortices in ferromagnetic condensates can exist without superfluid flow.

The order-parameter space of the cyclic phase in F=2 condensates has two disconnected sets.

External magnetic fields influence vortex structures and their experimental realization.

Abstract

In this paper we first derive a general method which enables one to create expressions for vortices and monopoles. By using this method we construct several order-parameters describing the vortices and monopoles of Bose-Einstein condensates with hyperfine spin F=1 and F=2. We concentrate on defects which are topologically stable in the absence of an external magnetic field. In particular we show that in a ferromagnetic condensate there can be a vortex which does not produce any superfluid flow. We also point out that the order-parameter space of the cyclic phase of F=2 condensate consists of two disconnected sets. Finally we examine the effect of an external magnetic field on the vortices of a ferromagnetic F=1 condensate and discuss the experimental preparation of a vortex in this system.