Magnon-mediated quantum battery under systematic errors

Quantum battery is one of the most prominent micro-devices in the\nrapid-developing quantum thermodynamics. We propose a quantum charging protocol\nin which both battery and charger are consisted of a many-spin system. The\nbattery and charger are connected via the Kittle mode of the magnon system,\nthat serves as a charging wire and then enables a long-range charging protocol.\nCounter-intuitively, we find that the spin-spin couplings insider both battery\nand charger can be used to promote the charging performance in comparison to\nthe noninteracting condition. And a remarkable promotion is realized at a\n"sweet" spot in terms of the average coupling strength. Moreover, we apply the\nquantum-state-diffusion equation to test the robustness of our magnon-mediated\ncharging protocol to the systematic errors about the magnon frequency.\n