Non-Equilibrium Quantum Phases of Two-Atom Dicke Model

TL;DR

This paper explores the non-equilibrium quantum phases of a two-atom Dicke model in a cavity, revealing novel mixed phases and phase transitions influenced by atom-photon coupling tuning.

Contribution

It introduces a non-equilibrium mixed phase and predicts a new quantum phase transition mechanism in the two-atom Dicke model.

Findings

Identification of a non-equilibrium mixed phase combining normal and inverted phases.

Prediction of a new quantum phase transition from non-superradiant to superradiant phases.

Demonstration that certain atom-photon coupling values forbid specific phase transitions.

Abstract

In this paper, we investigate the non-equilibrium quantum phases of the two-atom Dicke model, which can be realized in a two species Bose-Einstein condensate interacting with a single light mode in an optical cavity. Apart from the usual non-equilibrium normal and inverted phases, a non-equilibrium mixed phase is possible which is a combination of normal and inverted phase. A new kind of quantum phase transition is predicted from non-superradiant mixed phase to the superradiant phase which can be achieved by tuning the two different atom-photon couplings. We also show that a quantum phase transition from the non-superradiant mixed phase to the superradiant phase is forbidden for certain values of the two atom-photon coupling strengths.