Magnon-mediated quantum battery under systematic errors

The quantum battery is one of the most prominent microdevices in the rapid-developing field of quantum thermodynamics. We propose a long-range charging protocol in which both battery and charger consist of a many-spin system. The battery and charger are indirectly connected via a quantum wire supported by the Kittle mode of a magnon system. Counterintuitively, we find that the undesired spin-spin couplings among both battery and charger can be used to promote the charging performance in comparison with the noninteracting condition. And a "sweet" spot of the average coupling strength allows the battery to store energy to the maximum possible value. Moreover, we apply the quantum-state-diffusion equation to estimate the robustness of our magnon-mediated charging protocol to the fluctuation in the magnon frequency.