Topological defects in spinor condensates

TL;DR

This paper analyzes the types and structures of topological defects in spinor Bose-Einstein condensates, showing how external magnetic fields influence defect configurations through homotopy group calculations.

Contribution

It provides a systematic classification of topological defects in spinor condensates by calculating homotopy groups, considering effects of external magnetic fields.

Findings

Defects differ significantly between zero and non-zero magnetic fields.

The structure of ground states determines the types of topological defects.

Homotopy groups classify possible defect configurations.

Abstract

We investigate the structure of topological defects in the ground states of spinor Bose-Einstein condensates with spin F=1 or F=2. The type and number of defects are determined by calculating the first and second homotopy groups of the order-parameter space. The order-parameter space is identified with a set of degenerate ground state spinors. Because the structure of the ground state depends on whether or not there is an external magnetic field applied to the system, defects are sensitive to the magnetic field. We study both cases and find that the defects in zero and non-zero field are different.