Torque-induced dispersive readout in a weakly coupled hybrid system
Vahram L. Grigoryan, Ke Xia · Physical review. B./Physical review. B · 2020
We propose a quantum state readout mechanism of a weakly coupled qubit in a dispersive regime. The hybrid system consists of a ferromagnetic insulator and a weakly coupled quantum system, e.g., single electron spin, in a microwave cavity. The enhancement of the measurement sensitivity is achieved by exerting torque on the ferromagnetic insulator magnetization, which compensates the damping of the system leading to an exceptional point. The proposed mechanism allows us to measure the qubit state either via the transmission of the cavity or the FMR signal of the magnetic material.