Vortex stability in interacting Bose-Einstein condensates

TL;DR

This paper investigates the stability of vortices in binary Bose-Einstein condensates, analyzing how interatomic interactions and rotation influence vortex stability and identifying a new subphase within the miscible regime.

Contribution

It introduces an approximate energy expression and stability criteria for vortices in binary condensates, supported by numerical solutions, revealing complex vortex behavior due to nonlinear interactions.

Findings

Derived critical angular velocities for vortex stability

Identified a novel subphase within the miscible regime

Supported theoretical results with numerical simulations

Abstract

We study the stability of vortices in a binary system of Bose-Einstein condensates, with their wave functions modeled by a set of coupled, time-dependent Gross-Pitaevskii equations. Beginning with an effective two-dimensional system, we identify miscible and immiscible regimes characterized by the inter- and intra-atomic interactions and the initial configuration of the system. We then consider a binary system of Bose-Einstein condensates placed in a rotating harmonic trap and study the single vortex state in this system. We derive an approximate form for the energy of a single vortex in the binary system and the critical angular velocity for the global stability of a vortex at the center of the trap. We also compute the metastability onset angular velocity for the local stability of a vortex at the center of the trap. Numerical solutions to the Gross-Pitaevskii equations support these expressions. These rotational results inform us of a novel subphase within the miscible regime of the binary condensate system. We thus demonstrate the non-trivial aspects of vortex stability in interacting binary Bose-Einstein condensates as a result of their non-linear interactions.