Energy-Invariant Catalysis of Stable Ergotropy in Strongly Coupled Spin-Chain Quantum Batteries

TL;DR

This paper demonstrates that an energy-invariant catalyst can stabilize ergotropy in strongly coupled spin-chain quantum batteries by suppressing non-Markovian oscillations and promoting steady energy output.

Contribution

It introduces a novel stabilization method using an energy-invariant auxiliary subsystem to control ergotropy in non-Markovian quantum batteries.

Findings

Catalyst reshapes the energy spectrum of the system.

It significantly suppresses non-Markovian oscillations.

The system reaches a quasi-stationary regime of extractable work.

Abstract

Quantum batteries (QBs) provide a platform for exploring quantum-scale energy storage, yet most existing analyses rely on weak-coupling and Markovian approximations. In realistic implementations operating in strongly coupled non-Markovian regimes, environmental memory effects induce pronounced oscillations of the maximum extractable work (ergotropy), hindering stable energy output. Here, we investigate the stabilization of ergotropy in a spin-chain QB assisted by an energy-invariant catalyst, namely an auxiliary subsystem whose average energy remains unchanged during the evolution. The dynamics are described by a Nakajima-Zwanzig master equation with a Gaussian memory kernel, enabling a systematic characterization of non-Markovian effects. Our results show that the memory-kernel parameters, the spin number, and the characteristic frequencies of both the cavity field and the local excitations jointly regulate the ergotropy dynamics. Compared with the uncatalyzed case, the catalyst effectively reshapes the system energy spectrum, markedly suppresses non-Markovian oscillations, and promotes a quasi-stationary regime of extractable work. These findings provide a practical strategy for stabilizing energy flows in strongly coupled open quantum systems, offering theoretical guidance for the development of robust quantum energy devices and contributing to ongoing research in quantum thermodynamics.