Strong thermomechanical squeezing via weak measurement

TL;DR

This paper demonstrates experimentally surpassing the 3dB steady-state squeezing limit of a mechanical oscillator using optimal estimation and detuned parametric drive, paving the way for quantum squeezing below zero-point motion.

Contribution

It introduces a method to exceed the 3dB squeezing limit in mechanical oscillators using weak measurement and optimal estimation techniques.

Findings

Achieved up to 6.2 dB squeezing in one quadrature.

Surpassed the 3dB steady-state squeezing limit.

Potential to reach quantum squeezing below zero-point motion.

Abstract

We experimentally surpass the 3dB limit to steady state parametric squeezing of a mechanical oscillator. The localization of a AFM cantilever, achieved by optimal estimation, is enhanced by up to 6.2 dB in one position quadrature when a detuned parametric drive is used. This squeezing is, in principle, limited only by the oscillator Q-factor. Used on low temperature, high frequency oscillators, this technique provides a pathway to achieve robust quantum squeezing below the zero-point motion. Broadly, our results demonstrate that control systems engineering can overcome well established limits in applications of nonlinear processes. Conversely, by localizing the mechanical position to better than the measurement precision of our apparatus, they demonstrate the usefulness of nonlinearities in control applications.