Entanglement enhances cooling in microscopic quantum fridges

TL;DR

This paper investigates how entanglement affects the performance of small quantum refrigerators, showing it can hinder efficiency near the Carnot limit but enhance cooling away from it, making quantum devices potentially outperform classical ones.

Contribution

It demonstrates that entanglement can both be detrimental and beneficial in quantum refrigerators, depending on the operating regime, and quantifies entanglement's role in cooling enhancement.

Findings

Entanglement is absent in high-efficiency, near-Carnot refrigerators.

Entanglement enhances cooling and energy transport away from the Carnot regime.

The degree of entanglement correlates with cooling performance.

Abstract

Small self-contained quantum thermal machines function without external source of work or control, but using only incoherent interactions with thermal baths. Here we investigate the role of entanglement in a small self-contained quantum refrigerator. We first show that entanglement is detrimental as far as efficiency is concerned---fridges operating at efficiencies close to the Carnot limit do not feature any entanglement. Moving away from the Carnot regime, we show that entanglement can enhance cooling and energy transport. Hence a truly quantum refrigerator can outperform a classical one. Furthermore, the amount of entanglement alone quantifies the enhancement in cooling.