Spin waves in a one-dimensional spinor Bose gas

TL;DR

This paper investigates spin wave excitations in a one-dimensional spinor Bose gas with repulsive interactions, revealing suppressed spin transport at strong coupling and analyzing spin dynamics in trapped systems.

Contribution

It provides analytical and numerical analysis of spin wave properties and spin-charge separation in a 1D spinor Bose gas using Bethe Ansatz and hydrodynamics.

Findings

Spin waves have quadratic dispersion.

Spin transport is suppressed at strong coupling.

Maximal spin-charge separation occurs in the strong coupling regime.

Abstract

We study a one-dimensional (iso)spin 1/2 Bose gas with repulsive delta-function interaction by the Bethe Ansatz method and discuss the excitations above the polarized ground state. In addition to phonons the system features spin waves with a quadratic dispersion. We compute analytically and numerically the effective mass of the spin wave and show that the spin transport is greatly suppressed in the strong coupling regime, where the isospin-density (or ``spin-charge'') separation is maximal. Using a hydrodynamic approach, we study spin excitations in a harmonically trapped system and discuss prospects for future studies of two-component ultracold atomic gases.