Quantum Heat Baths satisfying the eigenstate thermalization hypothesis

TL;DR

This paper proposes a class of autonomous quantum heat baths satisfying ETH, demonstrating their ability to induce thermalization and decoherence in small quantum systems through local observable fluctuations.

Contribution

It introduces a new class of ETH-compliant quantum heat baths and analyzes their thermalization effects on coupled quantum systems both theoretically and numerically.

Findings

ETH baths cause thermal relaxation of small quantum systems.

Local observable fluctuations lead to decoherence.

Numerical simulations confirm theoretical predictions.

Abstract

A class of autonomous quantum heat baths satisfying the eigenstate thermalization hypothesis (ETH) criteria is proposed. We show that such systems are expected to cause thermal relaxation of much smaller quantum systems coupled to one of the baths local observables. The process of thermalization is examined through residual fluctuations of local observables of the bath around their thermal values predicted by ETH. It is shown that such fluctuations perturb the small quantum system causing its decoherence to the thermal state. As an example, we investigate theoretically and numerically thermalization of a qubit coupled to a realistic ETH quantum heat bath.