Vortex sheet in rotating two-component Bose-Einstein condensates

TL;DR

This paper explores vortex structures in rotating two-component Bose-Einstein condensates, revealing stable vortex sheets formed by phase-separated components and providing a phase diagram based on numerical simulations.

Contribution

It introduces a detailed analysis of vortex sheet formation and stability in immiscible two-component BECs under rotation, supported by a planar sheet model and numerical phase diagram.

Findings

Vortex sheets form instead of lattices in phase-separated BECs.

Vortex sheet stability depends on intracomponent parameter imbalance.

A phase diagram of vortex states is established based on length scale comparisons.

Abstract

We investigate vortex states of immiscible two-component Bose-Einstein condensates under rotation through numerical simulations of the coupled Gross-Pitaevskii equations. For strong intercomponent repulsion, the two components undergo phase separation to form several density domains of the same component. In the presence of the rotation, the nucleated vortices are aligned between the domains to make up winding chains of singly quantized vortices, a vortex sheet, instead of periodic vortex lattices. The vortices of one component are located at the region of the density domains of the other component, which results in the serpentine domain structure. The sheet configuration is stable as long as the imbalance of the intracomponent parameter is small. We employ a planar sheet model to estimate the distance between neighboring sheets, determined by the competition between the surface tension of the domain wall and the kinetic energy of the superflow via quantized vortices. By comparing the several length scales in this system, the phase diagram of the vortex state is obtained.