Dynamical symmetries and crossovers in a three-spin system with collective dissipation

TL;DR

This paper investigates the non-equilibrium behavior of a three-spin system with collective damping, revealing dynamical phase coexistence, symmetry properties, and the effects of additional damping through analytical and simulation methods.

Contribution

It introduces a detailed analysis of dynamical symmetries and phase crossovers in a three-spin system with collective dissipation, supported by large-deviation theory and Monte Carlo simulations.

Findings

Discovery of Gallavotti-Cohen symmetry in the system's dynamics

Identification of two coexisting dynamical phases with different activity levels

Additional damping smooths out phase coexistence effects

Abstract

We consider the non-equilibrium dynamics of a simple system consisting of interacting spin-$1/2$ particles subjected to a collective damping. The model is close to situations that can be engineered in hybrid electro/opto-mechanical settings. Making use of large-deviation theory, we find a Gallavotti-Cohen symmetry in the dynamics of the system as well as evidence for the coexistence of two dynamical phases with different activity levels. We show that additional damping processes smoothen out this behavior. Our analytical results are backed up by Monte Carlo simulations that reveal the nature of the trajectories contributing to the different dynamical phases.