Dissipative Dicke time crystals: an atoms' point of view

TL;DR

This paper presents an atom-only theoretical framework for analyzing dissipative Dicke models with periodic driving, predicting the emergence of dissipative time crystals characterized by subharmonic responses and elucidating their relaxation dynamics.

Contribution

It introduces a novel atom-only description of the driven dissipative Dicke model, enabling precise phase boundary determination and understanding of time crystal formation.

Findings

Prediction of dissipative time crystals with subharmonic response

Atom-only theory accurately describes relaxation into time crystals

Damping rate explained as a cooling mechanism

Abstract

We develop and study an atom-only description of the Dicke model with time-periodic couplings between atoms and a dissipative cavity mode. The cavity mode is eliminated giving rise to effective atom-atom interactions and dissipation. We use this effective description to analyze the dynamics of the atoms that undergo a transition to a dynamical superradiant phase with macroscopic coherences in the atomic medium and the light field. Using Floquet theory in combination with the atom-only description we provide a precise determination of the phase boundaries and of the dynamical response of the atoms. From this we can predict the existence of dissipative time crystals that show a subharmonic response with respect to the driving frequency. We show that the atom-only theory can describe the relaxation into such a dissipative time crystal and that the damping rate can be understood in terms of a cooling mechanism.