Spin and mass currents near a moving magnetic obstacle in a two-component Bose-Einstein condensate

TL;DR

This paper analyzes how a moving magnetic obstacle influences spin and mass currents in a two-component Bose-Einstein condensate, revealing characteristic spatial structures and the impact of obstacle velocity and potential strength.

Contribution

It provides an analytical description of current distributions and investigates the critical velocity dependence on obstacle potential in a two-component BEC.

Findings

Spin and mass currents form electromagnetic-like dipole structures.

Increasing obstacle velocity enhances spin polarization and spin current.

Critical velocity decreases linearly with obstacle potential.

Abstract

We study the spatial distributions of the spin and mass currents generated by a moving Gaussian magnetic obstacle in a symmetric, two-component Bose-Einstein condensate in two dimensions. We analytically describe the current distributions for a slow obstacle and show that the spin and the mass currents exhibit characteristic spatial structures resembling those of electromagnetic fields around dipole moments. When the obstacle's velocity increases, we numerically observe that the flow pattern maintains its overall structure while the spin polarization induced by the obstacle is enhanced with an increased spin current. We investigate the critical velocity of the magnetic obstacle based on the local criterion of Landau energetic instability and find that it decreases almost linearly as the magnitude of the obstacle's potential increases, which can be directly tested in current experiments.