Inhomogeneous spin domain induced by the quadratic Zeeman effect in spin-1 Bose-Einstein condensate

TL;DR

This paper investigates how positive and negative quadratic Zeeman effects induce distinct inhomogeneous spin domains with domain walls in spin-1 Bose-Einstein condensates, revealing different spin patterns and topological structures.

Contribution

It demonstrates the formation of inhomogeneous spin domains caused by the quadratic Zeeman effect and analyzes their properties and experimental implications.

Findings

Different spin patterns for positive and negative QZE

Presence of Nél-like domain walls in spin-1 BECs

Distinct topological structures depending on QZE sign

Abstract

We show two kinds of inhomogeneous spin domain possessing N\'{e}el-like domain walls in spin-1 Bose-Einstein condensate, which are induced by the positive and negative quadratic Zeeman effect (QZE) respectively. In both cases, the spin density distribution is inhomogeneous and has zeros where the magnetization vanishes. For positive and negative QZE, the spin patterns and topological structures are remarkably different. Such phenomena are due to the pointwise different axisymmetry-breaking caused by the pointwise different population exchange between the sublevels, arising uniquely from the QZE. We analyze in detail the inhomogeneous domain formation and related experimental observations for the spin-1 $^{87}$Rb and $^{23}$Na condensate.