Generation of robust optical entanglement in cavity optomagnonics

We propose a scheme to realize robust optical entanglement in cavity optomagnonics, where two optical whispering gallery modes (WGMs) couple to a magnon mode in a yttrium iron garnet (YIG) sphere. The beam-splitter-like and two-mode squeezing magnon-photon interactions can be realized simultaneously when the two optical WGMs are driven by external fields. Entanglement between the two optical modes is then generated via their coupling with magnons. By exploiting the destructive quantum interference between the bright modes of the interface, the effects of initial thermal occupations of magnons can be eliminated. Moreover, the excitation of the Bogoliubov dark mode is capable of protecting the optical entanglement from thermal heating effects. Therefore, the generated optical entanglement is robust against thermal noise and the requirement of cooling the magnon mode is relaxed. Our scheme may find applications in the study of magnon-based quantum information processing.

Automated summary

We propose a scheme to achieve robust optical entanglement in cavity optomagnonics by coupling two optical whispering gallery modes (WGMs) to a magnon mode in a yttrium iron garnet (YIG) sphere. The simultaneous realization of beam-splitter-like and two-mode squeezing magnon-photon interactions is possible when the two optical WGMs are driven by external fields. The entanglement between the optical modes is generated via their coupling with magnons, and the effects of initial thermal occupations of magnons can be eliminated by exploiting destructive quantum interference between bright modes at the interface. Additionally, the excitation of the Bogoliubov dark mode protects the optical entanglement from thermal heating effects, relaxing the requirement of cooling the magnon mode. Our scheme has potential applications in magnon-based quantum information processing.