Waveform Binarization in a Parametrically Driven Magnon-Cavity QED System

We theoretically study a parametrically driven hybrid magnon-cavity QED system with intrinsic magnon Kerr nonlinearity. We show that a cavity parametric drive qualitatively reshapes the nonlinear steady-state response, changing the conventional cubic bistability equation into a quintic one and thereby enabling external control of both bistability and multistability. This mechanism lowers the switching threshold of the effective signal drive to the milliwatt and sub-milliwatt regimes under suitable detuning and gain conditions. The resulting hysteresis provides a nonlinear threshold response that can convert analog microwave waveforms into binary square-wave signals with strong noise tolerance. In the strong coupling regime, the parametric control gives rise to three stable branches and the latching dynmaics that can protect the system from transient high-power perturbations. Our results identify parametric driving as an effective route to tunable nonlinear dynamics and low-power signal processing in cavity magnonics.