Charging a quantum battery with linear feedback control

TL;DR

This paper demonstrates how linear quantum feedback control can effectively stabilize and optimize energy transfer in a quantum battery system, even under realistic noise and measurement imperfections.

Contribution

It introduces a feedback control scheme for quantum batteries that stabilizes energy deposition and maintains performance despite environmental noise and control imperfections.

Findings

Linear feedback stabilizes quantum battery charging.

Performance persists with measurement inefficiencies.

Control remains effective with small feedback delays.

Abstract

Energy storage is a basic physical process with many applications. When considering this task at the quantum scale, it becomes important to optimise the non-equilibrium dynamics of energy transfer to the storage device or battery. Here, we tackle this problem using the methods of quantum feedback control. Specifically, we study the deposition of energy into a quantum battery via an auxiliary charger. The latter is a driven-dissipative two-level system subjected to a homodyne measurement whose output signal is fed back linearly into the driving field amplitude. We explore two different control strategies, aiming to stabilise either populations or quantum coherences in the state of the charger. In both cases, linear feedback is shown to counteract the randomising influence of environmental noise and allow for stable and effective battery charging. We analyse the effect of realistic control imprecisions, demonstrating that this good performance survives inefficient measurements and small feedback delays. Our results highlight the potential of continuous feedback for the control of energetic quantities in the quantum regime.