Results in Engineering
Exact dynamics of a four-level quantum battery driven by an external field
Souha K. Badr, Hanaa Abu-Zinadah, Eied Mahmoud Khalil
Abstract
In this paper, we theoretically investigate the charging dynamics of a closed quantum battery embodied by a four-level atom in a diamond configuration, operating without dissipation. The system is coupled to a single-mode cavity field, which acts as the charger initially prepared in a coherent state, and is simultaneously manipulated by an external classical driving field. By solving the exact system dynamics, we provide a holistic analysis of key performance metrics, including stored energy, ergotropy, energy fluctuations, and von Neumann entropy, as a function of critical system parameters. Our investigation delineates a paramount trade-off; while larger initial charger amplitudes and optimized detunings substantially enhance the stored energy and extractable work, they concurrently amplify fluctuations and entropy, thereby diminishing the battery’s stability and quantum coherence. Crucially, we demonstrate that the coupling to the external drive exhibits a non-monotonic influence, revealing an optimal intermediate regime, specifically at a classical driving strength of λ 2 = 0.5 and detunings δ 1 = δ 3 = 1 ω f , that judiciously balances rapid energy uptake with stable, long-term storage. These results elucidate the complex interplay of coherent control and system parameters, offering critical insights for the rational design of efficient and robust quantum energy storage devices by effectively decoupling charging performance from operational instability.