Extractable work from ensembles of quantum batteries. Entanglement helps

TL;DR

This paper investigates the maximum reversible work extractable from quantum batteries, demonstrating that entanglement enhances work extraction and can approach thermodynamic limits as system size grows.

Contribution

It introduces the role of entanglement in optimizing work extraction from quantum systems, surpassing independent control strategies.

Findings

Entangling unitaries extract more work than independent ones.

As the number of copies increases, work extraction approaches thermodynamic bounds.

Entanglement enables reaching the free energy limit in quantum thermodynamics.

Abstract

Motivated by the recent interest in thermodynamics of micro- and mesoscopic quantum systems we study the maximal amount of work that can be reversibly extracted from a quantum system used to store temporarily energy. Guided by the notion of passivity of a quantum state we show that entangling unitary controls extract in general more work than independent ones. In the limit of large number of copies one can reach the thermodynamical bound given by the variational principle for free energy.