Nonreciprocal Entanglement in Spinning Cavity Magnomechanical System with Coherent Feedback Loop

A scheme is proposed for generating and enhancing stable nonreciprocal entanglement in a spinning cavity magnomechanical system. The key components of this scheme include a ferromagnetic yttrium iron garnet sphere and a whispering gallery mode resonator supporting two counter-propagating modes. To further optimize the performance of the system, a coherent feedback loop is introduced to reinject the dissipated energy back into the system. This not only provides an additional coupling path for the system but also effectively avoids introducing additional noise caused by measurement. The design significantly enhances both bipartite entanglement and genuine tripartite entanglement. Meanwhile, by spinning the resonator, the cavity modes experience Fizeau drag due to the optical Sagnac effect, thereby achieving nonreciprocal entanglement, which is crucial for applications such as unidirectional quantum communication channels. Additionally, the research demonstrates that even in the presence of backscattering, the entangled state can still recover significantly, highlighting the robustness of entanglement under photon backscattering. This work provides an effective method to enhance and protect quantum resources and holds important application potential for applications in quantum information processing based on magnonics.