Magnon blockade induced by parametric amplification

We propose to achieve and enhance the magnon blockade effect in an optomechanical-magnetic system based on a quantum destructive interference mechanism between three indirect transition pathways. By introducing a degenerate parametric amplifier, we analytically obtain the optimal parametric gain and phase for achieving the magnon blockade. Under the optimized parameter conditions, the driving detunings of cavity and magnon modes can be flexibly controlled to achieve the smallest second-order magnon correlation function. Moreover, the magnon blockade can exhibit fascinating features by proper driving detuning and weaker driving strength. Our scheme combines the benefits of destructive interference-induced magnon blockade and energy-level anharmonicity-induced magnon blockade, which results in a reduction of equal-time second-order magnon correlation while simultaneously avoiding time-delay second-order magnon correlation with rapid oscillation. Our work provides an alternative and experimentally feasible platform for manipulating few-magnon states and generating single-magnon sources.