Quantum Noise Suppression Beyond the Standard Quantum Limit in a Hybrid Magnonic Optomechanical System

TL;DR

This paper proposes a hybrid magnonic optomechanical system that uses quantum noise engineering and coherent quantum noise cancellation to surpass the standard quantum limit in force sensing, with improved sensitivity and reduced power requirements.

Contribution

It introduces a novel hybrid platform with magnon-mediated dynamics and an internal OPA, enabling noise suppression and operation beyond the SQL in weak force detection.

Findings

Magnon-mediated dynamics reshape the noise spectrum for better sensitivity.

CQNC criterion allows complete suppression of radiation-pressure back-action.

Larger OPA gain enables surpassing SQL at lower laser power.

Abstract

We theoretically study how quantum measurement noise can be engineered in a hybrid cavitymagnomechanical platform for precision force sensing. The proposed configuration consists of a driven optomechanical cavity, with a movable mirror on one side plus a fixed semi-transparent mirror on the other side, coupled to a magnon mode, with an OPA placed inside the cavity. We show that the magnon mediated dynamics reshapes the added-noise spectrum leading to improved sensitivity compared to a conventional optomechanical sensor. In particular, by satisfying the coherent quantum noise cancellation (CQNC) criterion, radiation-pressure back-action can be fully suppressed. In addition, a larger OPA pump gain permits operation beyond the standard quantum limit at substantially reduced laser power, thereby mitigating power-related constraints without sacrificing performance. These combined advantages provide a practical pathway to below-SQL weak force detection and can outperform existing approaches based on squeezing in magnomechanics.