Cavity-mediated charging of scalable quantum battery based on superconducting flux qubits

Abstract

By utilizing superconducting flux qubits (FQs) embedded in a transmission line resonator cavity, we propose a scalable quantum battery (QB) and analyze its charging dynamics in the dispersive regime. The QB can be efficiently charged mediated by the cavity, which induces coherence among all FQs through a common photonic mode. Our results indicate that such coherence enhances the charging power. Furthermore, we identify a trade-off: increasing the battery size improves the charging power but reduces the storage capacity. By selecting an appropriate battery size, we achieve a practical QB that combines high power with large capacity. This optimal size can be moderately increased at the cost of a weaker coupling strength between the FQs and the cavity. This work, which integrates superconducting quantum circuits with energy storage technology, may pave the way for scalable and reliable quantum applications.