High-power collective charging of a solid-state quantum battery

TL;DR

This paper introduces a model of a solid-state quantum battery utilizing collective quantum effects to significantly enhance charging power, demonstrating a quantum advantage that scales with the square root of the number of units.

Contribution

It presents a solvable model of a quantum battery in solid-state architecture that exploits collective quantum resources for improved charging performance.

Findings

Dicke quantum batteries exhibit a charging power scaling as √N.

Exact diagonalization confirms quantum advantage in collective charging.

Comparison with separate cavity mode model highlights the role of entanglement.

Abstract

Quantum information theorems state that it is possible to exploit collective quantum resources to greatly enhance the charging power of quantum batteries (QBs) made of many identical elementary units. We here present and solve a model of a QB that can be engineered in solid-state architectures. It consists of $N$ two-level systems coupled to a single photonic mode in a cavity. We contrast this collective model ("Dicke QB"), whereby entanglement is genuinely created by the common photonic mode, to the one in which each two-level system is coupled to its own separate cavity mode ("Rabi QB"). By employing exact diagonalization, we demonstrate the emergence of a quantum advantage in the charging power of Dicke QBs, which scales like $\sqrt{N}$ for $N\gg 1$.