Superfluidity of pure spin current in ultracold Bose gases

TL;DR

This paper investigates the superfluidity of pure spin currents in ultracold spin-1 Bose gases, demonstrating stability conditions, generation methods, and potential for experimental realization.

Contribution

It introduces the concept of superfluid pure spin currents, analyzes their stability, and proposes experimental schemes for their realization and detection.

Findings

Circular pure spin current can be the ground state at weak spin-orbit coupling.

Quadratic Zeeman effect stabilizes planar pure spin currents.

Pure spin currents exhibit superfluid behavior in ultracold Bose gases.

Abstract

We study the superfluidity of a pure spin current that is a spin current without mass current. We examine two types of pure spin currents, planar and circular, in spin-1 Bose gas. For the planar current, it is usually unstable, but can be stabilized by the quadratic Zeeman effect. The circular current can be generated with spin-orbit coupling. When the spin-orbit coupling strength is weak, we find that the circular pure spin current is the ground state of the system and thus a super-flow. We discuss the experimental schemes to realize and detect a pure spin current.