Thermalization in a coherently driven ensemble of two-level systems

TL;DR

This paper investigates how a driven chain of two-level quantum systems with van-der-Waals interactions thermalizes under certain conditions, providing insights into thermalization mechanisms in strongly interacting quantum systems.

Contribution

It demonstrates that coherent driving can induce thermalization in a mesoscopic quantum system with van-der-Waals interactions, linking quantum dynamics to classical thermal behavior.

Findings

System reaches thermal equilibrium for specific parameters

Thermalization characterized by classical observables like energy and particle distribution

Method to determine the effective temperature of the thermal state

Abstract

We study the coherent quantum evolution of a closed and driven mesoscopic chain of two-level systems that interact via the van-der-Waals interaction in their excited state. The Hamiltonian consists of a part corresponding to a classical lattice gas and an off-diagonal driving term without classical counterpart. We show that in a certain parameter range the latter leads to a thermalization of the system with respect to observables of the classical lattice gas such as the interaction energy and particle number distribution. We investigate the evolution of the system into this thermal state and discuss how to determine the corresponding temperature. Our findings can be applied to understand thermalization in strongly interacting systems of laser-driven Rydberg atoms, ions or polar molecules.