Rotating Bose-Einstein condensate in an square optical lattice: vortex configuration for ground state in Josephson junction arrays regime

TL;DR

This paper investigates the vortex configurations of a rotating Bose-Einstein condensate in a square optical lattice, modeled as a Josephson junction array, and compares theoretical predictions with experimental data.

Contribution

It introduces a robust vortex configuration analysis for BECs in optical lattices mapped onto Josephson junction arrays, extending previous models to more realistic non-uniform couplings.

Findings

Vortex configurations are consistent with experimental observations.

The vortex pattern remains stable despite variations in coupling strengths.

The model aligns with the frustrated XY model results.

Abstract

We consider a rotating Bose-Einstein condensate in a square optical lattice in the regime in which the Hamiltonian of the system can be mapped onto a Josephson junction array. In an approximate scheme where the couplings are assumed uniform, the ground state energy is formulated in terms of the vortex configuration. The results are compared with experimental results and also previously reported results for frustrated XY model. We also show that vortex configuration is robust with respect to change of couplings and therefore the results remain valid when we consider more realistic model with non-uniform couplings.