Characterization of a Two-Photon Quantum Battery: Initial Conditions, Stability and Work Extraction

TL;DR

This paper analyzes a two-photon quantum battery based on a two-level system coupled to a cavity, examining initial states, stability, and work extraction, and finds that Fock states perform best, but coherent states offer promising work extraction at short times.

Contribution

It introduces a detailed characterization of a two-photon quantum battery, comparing different initial cavity states and their effects on performance and work extraction capabilities.

Findings

Fock states lead to better battery performance.

Coherent states allow for nearly complete energy extraction at short times.

Energy fluctuations are higher in coherent states but still offer useful work extraction.

Abstract

We consider a quantum battery that is based on a two-level system coupled with a cavity radiation by means of a two-photon interaction. Various figures of merit, such as stored energy, average charging power, energy fluctuations, and extractable work are investigated, considering, as possible initial conditions for the cavity, a Fock state, a coherent state, and a squeezed state. We show that the first state leads to better performances for the battery. However, a coherent state with the same average number of photons, even if it is affected by stronger fluctuations in the stored energy, results in quite interesting performance, in particular since it allows for almost completely extracting the stored energy as usable work at short enough times.