Double-Quantum Spin Vortices in SU(3) Spin-Orbit Coupled Bose Gases

TL;DR

This paper demonstrates the existence of double-quantum spin vortices in the ground states of SU(3) spin-orbit coupled Bose gases, revealing new topological phenomena influenced by spin interactions and spin-orbit coupling.

Contribution

It introduces the concept of double-quantum spin vortices in SU(3) Bose gases and analyzes their emergence due to spin-orbit coupling and spin interactions.

Findings

Double-quantum spin vortices can exist in SU(3) spin-orbit coupled Bose gases.

SU(3) spin-orbit coupling induces a three-fold degeneracy in ferromagnetic cases.

Spontaneous emergence of double-quantum spin vortices occurs in antiferromagnetic cases.

Abstract

We show that double-quantum spin vortices, which are characterized by doubly quantized circulating spin currents and unmagnetized filled cores, can exist in the ground states of SU(3) spin-orbit coupled Bose gases. It is found that the SU(3) spin-orbit coupling and spin-exchange interaction play important roles in determining the ground-state phase diagram. In the case of effective ferromagnetic spin interaction, the SU(3) spin-orbit coupling induces a three-fold degeneracy to the magnetized ground state, while in the antiferromagnetic spin interaction case, the SU(3) spin-orbit coupling breaks the ordinary phase rule of spinor Bose gases, and allows the spontaneous emergence of double-quantum spin vortices. This exotic topological defect is in stark contrast to the singly quantized spin vortices observed in existing experiments, and can be readily observed by the current magnetization-sensitive phase-contrast imaging technique.