Single-atom dissipation and dephasing in Dicke and Tavis-Cummings quantum batteries

TL;DR

This paper investigates how single-atom dissipation and dephasing affect the transient charging performance of Dicke and Tavis-Cummings quantum batteries, revealing conditions for optimal energy extraction and the impact of system size and detuning.

Contribution

It provides a numerical and analytical study of dissipation effects on quantum batteries, highlighting the asymptotic free behavior and optimal detuning regimes for charging.

Findings

Maximum ergotropy occurs at specific transient times.

Dicke and Tavis-Cummings models become asymptotically free with increasing constituents.

Optimal charging in Dicke batteries is achieved off-resonance.

Abstract

We study the influence of single-atom dissipation and dephasing noise on the performance of Dicke and Tavis-Cummings quantum batteries, where the electromagnetic field of the cavity hosting the system acts as a charger. For these models a genuine charging process can only occur in the transient regime. Indeed, unless the interaction with the environment is cut off, the asymptotic energy of the battery is solely determined by the environment and does not depend on the initial energy of the electromagnetic field. We numerically estimate the fundamental figures of merit for the model, including the time at which the battery reaches its maximum ergotropy, the average energy, and the energy that needs to be used to switch the battery-charger interaction on and off. Depending on the scaling of the coupling between the battery and the charger, we show that the model can still exhibit a subextensive charging time. However, for the Dicke battery, this effect comes with a higher cost when switching the battery-charger interaction on and off. We also show that as the number of battery constituents increases, both the Dicke and Tavis-Cummings models become asymptotically free, meaning the amount of energy that is not unitarily extractable becomes negligible. We obtain this result numerically and demonstrate analytically that it is a consequence of the symmetry under permutation of the model. Finally, we perform simulations for different values of the detuning, showing that the optimal regime for the Dicke battery is off-resonance, in contrast to what is observed in the Tavis-Cummings case.