Dynamical phase transition in the open Dicke model

TL;DR

This paper investigates the dynamical phase transition in an open Dicke model realized with a Bose-Einstein condensate in an optical cavity, revealing hysteresis and scaling behavior during quenches across the phase boundary.

Contribution

It demonstrates the observation of hysteresis and power-law scaling in the dynamical phase transition of an open Dicke model, supported by mean field simulations, advancing understanding of nonequilibrium many-body physics.

Findings

Hysteresis observed during phase transition with power-law scaling.

Numerical mean field solutions reproduce experimental hysteresis.

Insights into nonequilibrium dynamics of open quantum systems.

Abstract

The Dicke model with a weak dissipation channel is realized by coupling a Bose-Einstein condensate to an optical cavity with ultra-narrow bandwidth. We explore the dynamical critical properties of the Hepp-Lieb-Dicke phase transition by performing quenches across the phase boundary. We observe hysteresis in the transition between a homogeneous phase and a self-organized collective phase with an enclosed loop area showing power law scaling with respect to the quench time, which suggests an interpretation within a general framework introduced by Kibble and Zurek. The observed hysteretic dynamics is well reproduced by numerically solving the mean field equation derived from a generalized Dicke Hamiltonian. Our work promotes the understanding of nonequilibrium physics in open many-body systems with infinite range interactions.