Stable Skyrmions in SU(2) Gauged Bose-Einstein Condensates

TL;DR

This paper demonstrates the spontaneous formation of three-dimensional Skyrmions as the ground state in SU(2) symmetric Bose-Einstein condensates coupled with a non-Abelian gauge field, revealing new topological structures.

Contribution

It introduces the realization of 3D Skyrmions in BECs with non-Abelian gauge fields and explores their transformation under gauge field shape changes.

Findings

3D Skyrmions appear as ground states in SU(2) BECs with gauge fields.

Skyrmion dimensionality changes with gauge field shape, from 3D to 1D or 2D.

Skyrmions are characterized by winding numbers and helicity.

Abstract

We demonstrate that the three-dimensional Skyrmion, which has remained elusive so far, spontaneously appears as the ground state of $SU$(2) symmetric Bose-Einstein condensates coupled with a non-Abelian gauge field. The gauge field is a three-dimensional analogue of the Rashba spin-orbit coupling. Upon squashing the SO(3) symmetric gauge field to one- or two-dimensional shapes, we find that the ground state continuously undergoes a change from a three-dimensional to a one- or two-dimensional Skyrmion, which is identified by estimating winding numbers and helicity. All of the emerged Skyrmions are physically understandable with the concept of the helical modulation in a unified way. These topological objects might potentially be realizable in two-component BECs experimentally.