Nonreciprocal PT-symmetric magnon laser in spinning cavity optomagnonics

We propose a scheme to achieve nonreciprocal parity -time (PT) -symmetric magnon laser in a PT -symmetric cavity optomagnonical system. The system consists of active and passive optical spinning resonators. We demonstrate that the Fizeau light -dragging effect induced by the spinning of a resonator results in significant variations in magnon gain and stimulated emitted magnon numbers for different driving directions. We find that utilizing the Fizeau light -dragging effect allows the system to operate at ultra -low thresholds even without reaching gain -loss balance. A one-way magnon laser can also be realized across a range of parameters. High tunability of the magnon laser is achieved by changing the spinning speed of the resonators and driving direction. Our work provides a new way to explore various nonreciprocal effects in non -Hermitian magnonic systems, which may be applied to manipulate photons and magnons in multi -body non -Hermitian coupled systems.