Reduced dynamics of two oscillators collectively coupled to a thermal bath

TL;DR

This paper investigates the dynamics of two coupled oscillators interacting with a thermal bath, revealing non-Gaussian equilibrium states and metastability due to nonlinear interactions.

Contribution

It introduces a model linking collective coupling of oscillators to a thermal bath with nonlinear interactions leading to unique equilibrium states.

Findings

Non-Gaussian equilibrium states with Bose-Einstein distribution

Metastability before linear coupling dominates

Time evolution illustrates diverse system behaviors

Abstract

We study the reduced dynamics of a pair of non-degenerate oscillators coupled collectively to a thermal bath. The model is related to the trilinear boson model where the idler mode is promoted to a field. Due to nonlinear coupling, the Markovian master equation for the pair of oscillators admits non-Gaussian equilibrium states, where the modes distribute according to the Bose-Einstein statistics. These states are metastable before the nonlinear coupling is taken over by linear coupling between the individual oscillators and the field. The Gibbs state for the individual modes lies in the subspace with infinite occupation quantum number. We present the time evolution of a few states to illustrate the behaviors of the system.