Engineering Quantum Criticality for Quantum Dot Power Harvesting

Coupling of quantum-dot circuits to microwave photons enables us to investigate photon-assisted quantum transport. Here, we revisit this typical circuit quantum electrodynamical setup by introducing the Kerr nonlinearity of photons. By exploiting quantum critical behavior, we propose a powerful scheme to control the power-harvesting efficiency in the microwave regime, where the driven-dissipative optical system acts as an energy pump. It drives electron transport against a load in the quantum-dot circuit. The energy transfer and, consequently, the harvesting efficiency are enhanced near the critical point. As the critical point moves towards to low input power, high efficiency within experimental parameters is achieved. Our results complement fundamental studies of photon-to-electron conversion at the nanoscale and provide practical guidance for designs of integrated photoelectric devices through quantum criticality.