Hybrid Optomechanical Cooling with Kerr Magnons and Squeezed Vacuum

TL;DR

This paper introduces a hybrid optomechanical cooling method using Kerr magnons and squeezed vacuum to achieve ground-state cooling even in the unresolved-sideband regime, surpassing quantum backaction limits.

Contribution

It proposes a novel cooling strategy leveraging magnon-induced two-photon processes and squeezed vacuum, enabling complete suppression of heating in challenging regimes.

Findings

Achieves cooling beyond quantum backaction limit in unresolved-sideband regime

Enhanced cooling rates with squeezed vacuum injection

Outperforms existing schemes without Kerr magnons

Abstract

Ground-state cooling is essential for accessing the quantum regime and enabling quantum control of macroscopic systems. However, achieving optomechanical cooling in the unresolved-sideband regime ($\omega_b < \kappa$) remains challenging. In this Letter, we propose an efficient cooling strategy based on a hybrid optomechanical system incorporating a yttrium iron garnet (YIG) sphere embedded in an optomechanical cavity. Under strong cavity driving, the Kerr nonlinearity of the magnons hosted in the YIG sphere gives rise to a two-magnon process. Adiabatic elimination of the magnons yields an effective two-photon process in the cavity, which destructively interferes with all dissipative channels, surpassing the quantum backaction limit and enabling \textit{complete suppression} of heating under optimal conditions, even in the deeply unresolved sideband regime (DUSR: $\omega_b \ll \kappa$). Moreover, injecting squeezed vacuum noise into the cavity not only preserves these advantages but also delivers additional enhancements, including higher net cooling rates, reduced optomechanical coupling requirements, and improved noise robustness. Comparative analysis shows that our approach outperforms existing schemes without Kerr magnons, underscoring the potential of integrating nonlinear magnonics with optomechanics for quantum control of macroscopic mechanical systems.