Fundamental limits on anomalous energy flows in correlated quantum systems

TL;DR

This paper explores the fundamental limits of anomalous energy flow in correlated quantum systems, revealing how initial correlations and catalytic processes can reverse classical energy transfer directions.

Contribution

It establishes the maximum energy transfer possible under reversible quantum dynamics and demonstrates how catalysts enable surpassing these bounds using quantum correlations.

Findings

Optimal energy transfer bounds derived for correlated quantum systems

Catalytic processes enable exceeding fundamental energy flow limits

Experimental setup with atoms and optical cavity illustrates theoretical results

Abstract

In classical thermodynamics energy always flows from the hotter system to the colder one. However, if these systems are initially correlated, the energy flow can reverse, making the cold system colder and the hot system hotter. This intriguing phenomenon is called ``anomalous energy flow'' and shows the importance of initial correlations in determining physical properties of thermodynamic systems. Here we investigate the fundamental limits of this effect. Specifically, we find the optimal amount of energy that can be transferred between quantum systems under closed and reversible dynamics, which then allows us to characterize the anomalous energy flow. We then explore a more general scenario where the energy flow is mediated by an ancillary quantum system that acts as a catalyst. We show that this approach allows for exploiting previously inaccessible types of correlations, ultimately resulting in an energy transfer that surpasses our fundamental bound. To demonstrate these findings, we use a well-studied quantum optics setup involving two atoms coupled to an optical cavity.