Quantum enhancement of a single quantum battery by repeated interactions with large spins

TL;DR

This paper introduces a generalized collision model for coherently charging a quantum battery via repeated interactions with large spins, demonstrating that phase coherence enhances charging speed and power, with analytical and numerical validation.

Contribution

It develops an analytical framework for quantum battery charging using large spins and shows phase coherence significantly improves charging performance.

Findings

Coherent interactions lead to faster charging.

Phase coherence increases the charging power.

Ergotropy closely matches analytical predictions in short-time limit.

Abstract

A generalized collision model is developed to investigate coherent charging a single quantum battery by repeated interactions with many-atom large spins, where collective atom operators are adopted and the battery is modeled by a uniform energy ladder. For an initially empty battery, we derive analytical results of the average number of excitations and hence the charging power in the short-time limit. Our analytical results show that a faster charging and an increased amount of the power in the coherent protocol uniquely arise from the phase coherence of the atoms. Finally, we show that the charging power defined by the so-called ergotropy almost follows our analytical result, due to a nearly pure state of the battery in the short-time limit.