Squeezing-enhanced dual-channel interference for ground-state cooling of a levitated micromagnet with a low quality...

Cooling the center-of-mass (CM) motion of a macroscopic oscillator to its quantum ground state is a fundamental prerequisite for testing quantum mechanics at macroscopic scales. However, achieving this goal is currently hindered by the stringent requirement for an ultrahigh mechanical quality factor (Q_c). Here, we propose a dual-channel cooling scheme based on squeezing-enhanced quantum interference within a hybrid levitated cavity-magnomechanical system to overcome this limitation. By synergizing squeezing effects with quantum interference between the magnon-CM and cavity-CM channels, our scheme simultaneously suppresses Stokes (heating) scattering while enhancing anti-Stokes (cooling) scattering. We demonstrate that this cooling mechanism reduces the critical Q_c required for ground-state cooling by two orders of magnitude, making it achievable in the experimentally accessible regime of Q_c ∼ 10⁶. Furthermore, the net cooling rate is enhanced by nearly 40-fold compared to that of conventional single-channel cooling. This improvement is accompanied by a one-order-of-magnitude reduction in both the steady-state CM occupancy. Importantly, this enhanced performance remains robust even deep within the unresolved-sideband regime. Our results provide a feasible path toward preparing macroscopic quantum states by actively controlling the cooling dynamics, thereby relaxing the constraints on intrinsic material properties.