Half-Quantum Vortex Molecules in a Binary Dipolar Bose Gas

TL;DR

This paper explores the complex ground state phases of a rotating binary dipolar Bose-Einstein condensate, revealing novel vortex structures like HQV chains and molecules due to dipolar interactions.

Contribution

It introduces the discovery of half-quantum vortex molecules in a dipolar BEC and explains their formation through the calculation of the adiabatic HQV interaction potential.

Findings

Identification of HQV chain and molecule phases

Calculation of the adiabatic HQV interaction potential

Demonstration of dipolar interactions leading to rich phase diagrams

Abstract

We study the ground state phases of a rotating two-component, or binary Bose-Einstein condensate, wherein one component possesses a large magnetic dipole moment. A variety of non-trivial phases emerge in this system, including a half-quantum vortex (HQV) chain phase and a HQV molecule phase, where HQVs of opposite charge bind at short distances. We attribute the emergence of these phases to the development of a minimum in the adiabatic HQV interaction potential, which we calculate explicitly. We thus show that the presence of dipolar interactions in this system leads to a rich phase diagram, and the formation of HQV molecules.