Magnon blockade in spin-magnon systems with frequency detuning

Abstract: Magnon blockade is a physical mechanism for the preparation of a single-magnon source, which has important applications in quantum information processing. Here we propose a scheme for generating an optimal magnon blockade in the spin-magnon quantum system. By introducing frequency detuning between the magnon and the spin qubit of the NV center, the conventional magnon blockade and the unconventional magnon blockade can be obtained under both strong and weak coupling, relaxing the requirements for coupling strength. Moreover, the conventional and unconventional magnon blockade can occur simultaneously when both the magnon and the spin qubit are driven. This allows the equal-time second-order correlation function to reach $10^{-8}$, about five orders of magnitude lower than that in previous works. Additionally, the time-delayed second-order correlation function avoids oscillation. Our study demonstrates the impact of frequency detuning on the magnon blockade and proposes methods to enhance the magnon blockade and relax the requirements for coupling strength through frequency detuning.