Composite structure of vortices in two-component Bose-Einstein condensate

TL;DR

This paper investigates the complex vortex structures in two-component Bose-Einstein condensates, revealing their dependence on interaction parameters and identifying novel vortex types with unique density and rotational properties.

Contribution

It introduces a three-parameter description of vortices in two-component condensates and explores new vortex types, including super-density vortices and those with opposite rotation directions.

Findings

Vortex structure depends on three dimensionless parameters.

Super-density vortices can exist with positive interaction constants.

Vortices with opposite rotation directions near and far from the axis are possible.

Abstract

In contrast to one-component Bose-Einstein condensate case, the vortices in two-component condensate can have various complicated structures. The vortices in a space-homogeneous Bose-Einstein condensate have been studied in this paper. It is shown that the vortex structure is described by three dimensionless parameters. This is totally different from the usual one-component condensate case, where an isolated vortex is described by a parameter-less dimensionless equation. The two-component vortex structure strongly depends on the sign of "interaction" constant of the components. A few types of vortices with different qualitative structure are explored. We show that the super-density vortices can exist, when the "interaction" constant is positive. The super-density vortices have the near-axis density greater than the equilibrium density of a homogeneous space Bose-Einstein condensate. We also show that the vortices with opposite direction of the condensate component rotation near the axis and far off the axis can exist.