Nonreciprocal optical–microwave entanglement in a spinning magnetic resonator

We propose a nonreciprocal optical-microwave entanglement in a hybrid system composed of a spinning magnetic resonator and a microwave resonator. The optical Sagnac effect caused by the spinning of the magnetic resonator leads to a significant difference in the quantum entanglement for driving the magnetic resonator from opposite directions, which results in the nonreciprocal optical-microwave entanglement. Remarkably, the nonreciprocal optical-microwave entanglement determined by the spinning speed, driving direction, and driving frequency has a high tunability, so it can be turned on or off on demand. Our work opens up a new, to the best of our knowledge, route to achieve nonreciprocal entanglement between microwave and optical domains, which may have potential applications in chiral quantum networking.