Preparing Magnon–Photon Pairs in a Cavity–Magnon–Qubit System

Hybrid quantum states consisting of single photons and single magnons are valuable quantum resources for realizing multiple quantum information tasks. The blockade effects of magnons and photons in a cavity–magnon–qubit system are investigated, where an auxiliary microwave cavity is simultaneously coupled with an yttrium iron garnet sphere, a qubit, and another microwave cavity. The modes of the auxiliary cavity are adiabatically eliminated, and the virtual photons in the auxiliary cavity mediate the coupling between the magnon mode and photon mode. When the system parameters satisfy both conventional and unconventional blockade conditions, both the magnon/photon auto‐correlation and magnon–photon cross‐correlation are weak, indicating that magnons and photons tend to exist alone in the system. When the system parameters only satisfy unconventional blockade conditions, strong magnon–photon cross‐correlation can be exhibited, indicating that magnons and photons tend to exist simultaneously in the system. The proposal presents a method for preparing magnon–photon pairs, which may have potential applications in quantum information sciences and technologies.