Double-Layer Bose-Einstein Condensates with Large Number of Vortices

TL;DR

This paper explores the phase diagram of double-layer vortex lattices in rotating Bose-Einstein condensates, revealing a novel phase transition driven by the competition between inter-layer interactions and tunneling.

Contribution

It introduces a systematic study of the double-layer vortex lattice model, identifying a new phase transition and comparing two mean field approaches for analyzing the system.

Findings

Identification of a novel phase transition due to inter-layer interactions.

Discovery of two distinct vortex lattice configurations in different phases.

Analysis of sliding mode excitations in the system.

Abstract

In this paper we systematically study the double layer vortex lattice model, which is proposed to illustrate the interplay between the physics of a fast rotating Bose-Einstein condensate and the macroscopic quantum tunnelling. The phase diagram of the system is obtained. We find that under certain conditions the system will exhibit one novel phase transition, which is consequence of competition between inter-layer coherent hopping and inter-layer density-density interaction. In one phase the vortices in one layer coincide with those in the other layer. And in another phase two sets of vortex lattices are staggered, and as a result the quantum tunnelling between two layers is suppressed. To obtain the phase diagram we use two kinds of mean field theories which are quantum Hall mean field and Thomas-Fermi mean field. Two different criteria for the transition taking place are obtained respectively, which reveals some fundamental differences between these two mean field states. The sliding mode excitation is also discussed.