The Ergotropy of Quantum Batteries under Unruh Effect

Abstract

We study the effects of uniform acceleration on the ergotropy of quantum batteries modeled as Unruh-DeWitt detectors, in both bipartite and tripartite setups. In the bipartite system, we systematically compare three scenarios: accelerating the battery, accelerating the charger, and accelerating both simultaneously. We find that only battery acceleration can induce a sudden emergence of ergotropy at a critical acceleration threshold, while the corresponding composite-system energy change may increase or decrease depending on the initial state at the onset of acceleration. Charger acceleration leaves the battery ergotropy constant within the perturbative regime, while simultaneous acceleration leads to monotonic decay due to coherent cancellation of the q-dependence. Extending to a tripartite system with one battery and two chargers, we find that battery acceleration again induces ergotropy emergence, whereas accelerating adjacent charger does not--consistent with the bipartite charger-acceleration case. These results reveal that the Unruh effect plays a dual role, both enhancing and degrading quantum battery performance, depending on which subsystem is accelerated and on the multipartite structure, bridging relativistic quantum field theory and quantum thermodynamics with relevance to experimentally accessible platforms.