Driven–Dissipative Quantum Battery with Non-equilibrium Reservoirs

Going beyond traditional chemical batteries, we investigate a quantum battery system under both external driving and dissipation. The system consists of a coupled two-level charger and battery immersed in non-equilibrium fermionic reservoirs. By considering the changes in the energy spectrum induced by external driving and charger-battery coupling in a non-perturbative manner, we go beyond the secular approximation to derive the Redfield master equation. In the non-equilibrium scenario, both charging efficiency and power of the quantum battery can be optimized through a compensation mechanism. When the charger and battery are off-resonance, a significant chemical potential difference between the reservoirs, which characterizes the degree of non-equilibrium, plays a crucial role. Specifically, the charger's frequency should be higher (lower) than that of the battery when the average chemical potential is negative (positive) to achieve enhanced charging efficiency and power under strong non-equilibrium conditions. Remarkably, the efficiency in the non-equilibrium case can surpass that in the equilibrium setup. Moreover, we find no positive correlation between entanglement and efficiency; therefore, entanglement is not necessary to enhance the performance of quantum devices. Our results provide insights into the design and optimization of quantum batteries in non-equilibrium open systems.