Reliable quantum advantage in quantum battery charging

TL;DR

This paper demonstrates that preparing a quantum battery's charger in a non-Gaussian Fock state significantly enhances charging power and efficiency, showcasing a clear quantum advantage in energy storage and transfer.

Contribution

It introduces a model analyzing quantum battery charging with a flying qubit and optical cavity, revealing advantages of non-Gaussian initial states over classical or Gaussian states.

Findings

Non-Gaussian Fock states improve charging efficiency.

Quantum non-Gaussian states outperform classical states.

Measurable quantum advantage in charging power and fluctuations.

Abstract

Quantum batteries represent one of the most promising applications of quantum thermodynamics, whose goal is not only to store energy inside small quantum systems but also to potentially leverage genuine quantum effects to outperform classical counterparts. In this context, however, energy fluctuations become extremely relevant and have a significant impact on the charging efficiency. In our work, we consider a simple yet paradigmatic model in which a flying qubit (the battery) coherently interacts with a single mode optical cavity (the charger) through a number conserving Jaynes-Cummings interaction. By making use of full-counting statistics techniques, we fully characterize the average charging power, its fluctuations and the associated charging efficiency for several different choices of initial states of the optical cavity, demonstrating that preparing the latter in a genuinely quantum non-Gaussian Fock state (rather than a classical or even non-classical Gaussian state) leads to a definite and (in principle) measurable advantage in all these figures of merit.