Fluctuations in Extractable Work and Bounds on the Charging Power of Quantum Batteries

TL;DR

This paper critically examines the claim that free energy fluctuations limit quantum battery charging power, demonstrating that this does not hold for both closed and open quantum systems, and questions the free energy operator's validity as a work measure.

Contribution

The paper provides a critical analysis showing that fluctuations in the free energy operator do not bound charging power, challenging previous claims and highlighting limitations of the free energy operator.

Findings

The claim that free energy fluctuations bound charging power is invalid.

The free energy operator is not a reliable measure of work content.

The analysis applies to both closed and open quantum system dynamics.

Abstract

Motivated by a recent disagreement about the claim that fluctuations in the free energy operator bound the charging power of a quantum battery, we present a critical analysis of the original derivation. The analysis shows that the above claim does not hold for both closed- and open-system dynamics. Our results indicate that the free energy operator is not a consistent quantifying operator for the work content of a charging quantum battery.