Effects of Axial Vorticity in Elongated Mixtures of Bose-Einstein Condensates

TL;DR

This paper models the effects of axial vorticity on phase separation and mixing in elongated Bose-Einstein condensates confined in a pipe-shaped trap, revealing how vorticity influences the onset of mixing.

Contribution

It derives coupled 1D nonpolynomial Schrödinger equations for two-component BECs with vorticity and analyzes how vorticity affects phase behavior in a toroidal geometry.

Findings

Vorticity influences the onset of mixing in BECs.

Inter-atomic interaction strengths affect phase separation.

Vortex presence determines core filling behavior.

Abstract

We consider a meniscus between rotating and nonrotating species in the Bose-Einstein condensate (BEC) with repulsive inter-atomic interactions, confined to a pipe-shaped trap. In this setting, we derive a system of coupled one-dimensional (1D) nonpolynomial Schrodinger equations (NPSEs) for two mean-field wave functions. Using these equations, we analyze the phase separation/mixing in the pipe with periodic axial boundary conditions, i.e. in a toroidal configuration. We find that the onset of the mixing, in the form of suction, i.e., filling the empty core in the vortical component by its nonrotating counterpart, crucially depends on the vorticity of the first component, and on the strengths of the inter-atomic interactions.