The driven Dicke Model: time-dependent mean field and quantum fluctuations in a non-equilibrium quantum many-body system

TL;DR

This paper develops a time-dependent mean field framework to analyze the non-equilibrium dynamics of the driven Dicke model, revealing complex phenomena like symmetry breaking, vacuum fluctuation amplification, and photon production.

Contribution

It introduces a novel theoretical approach combining mean fields and quantum fluctuations to study driven quantum many-body systems.

Findings

Identification of stable and unstable dynamical regimes.

Observation of vacuum fluctuation amplification and symmetry breaking.

Characterization of photon production related to driving and entanglement.

Abstract

We establish a new theoretical framework, based on a time-dependent mean field approach, to address the dynamics of the driven Dicke model. The joint evolution of both mean fields and quantum fluctuations gives rise to a rich and generally non-linear dynamics, featuring a normal (stable) regime and an unstable, super-radiant one. Various dynamical phenomena emerge, such as the spontaneous amplification of vacuum fluctuations, or the appearance of special points around which the mean-field amplitudes rotate during driven time evolution, signalling a dynamical symmetry breaking. We also provide a characterization of the driving-induced photon production in terms of the work done by the driving agent, of the non-adiabaticity of the process and of the entanglement generated between the atomic system and the cavity mode.