Equilibrium solutions of immiscible two-species Bose-Einstein condensates in perturbed harmonic traps

TL;DR

This paper studies the equilibrium density structures of two-species immiscible Bose-Einstein condensates in perturbed harmonic traps, highlighting the importance of linear perturbations in matching experimental observations.

Contribution

It introduces a detailed analysis of how linear trap perturbations influence equilibrium configurations of two-species BECs, providing insights for interpreting experimental results.

Findings

Equilibrium density structures are highly sensitive to trap perturbations.

Linear perturbations are crucial to replicate experimental density profiles.

Sensitivity to perturbations affects interpretation of BEC experiments.

Abstract

We investigate the mean--field equilibrium solutions for a two--species immiscible Bose--Einstein condensate confined by a harmonic confinement with additional linear perturbations. We observe a range of equilibrium density structures, including `ball and shell' formations and axially/radially separated states, with a marked sensitivity to the potential perturbations and the relative atom number in each species. Incorporation of linear trap perturbations, albeit weak, are found to be essential to match the range of equilibrium density profiles observed in a recent Rb-87 - Cs-133 Bose-Einstein condensate experiment [D. J. McCarron et al., Phys. Rev. A, 84, 011603(R) (2011)]. Our analysis of this experiment demonstrates that sensitivity to linear trap perturbations is likely to be important factor in interpreting the results of similar experiments in the future.