Exotic quantum phase transitions in a Bose-Einstein condensate coupled to an optical cavity

TL;DR

This paper introduces an extended Dicke model for a Bose-Einstein condensate in an optical cavity, revealing novel phase transitions and a rich phase diagram, with potential for experimental observation of these quantum phenomena.

Contribution

It develops a new extended Dicke model including atom interactions and laser driving, predicting exotic phase transitions and a detailed phase diagram for BECs in optical cavities.

Findings

Prediction of a second-order superradiant-normal phase transition.

Discovery of a second-order transition from superradiant to Mott phase.

Proposal of an experimental setup to observe these transitions.

Abstract

A new extended Dicke model, which includes atom-atom interactions and a driving classical laser field, is established for a Bose-Einstein condensate inside an ultrahigh-finesse optical cavity. A feasible experimental setup with a strong atom-field coupling is proposed, where most parameters are easily controllable and thus the predicted second-order superradiant-normal phase transition may be detected by measuring the ground-state atomic population. More intriguingly, a novel second-order phase transition from the superradiant phase to the \textquotedblleft Mott" phase is also revealed. In addition, a rich and exotic phase diagram is presented.