Quantum Optimal Control of Squeezing in Cavity Optomechanics

TL;DR

This paper develops optimal control strategies to maximize quantum squeezing in an optomechanical system, revealing fundamental limits and practical protocols for faster squeezing using two-stage cooling and control simplification.

Contribution

It introduces a novel optimal control approach for squeezing in cavity optomechanics and identifies a two-stage cooling and squeezing protocol that simplifies experimental implementation.

Findings

Inverse cavity decay bounds protocol duration

Two-stage control enhances squeezing efficiency

Simplified drive profiles facilitate experimental application

Abstract

Squeezing is a non-classical feature of quantum states that is a useful resource, for example in quantum sensing of mechanical forces. Here, we show how to use optimal control theory to maximize squeezing in an optomechanical setup with two external drives and determine how fast the mechanical mode can be squeezed. For the autonomous drives considered here, we find the inverse cavity decay to lower-bound the protocol duration. At and above this limit, we identify a family of protocols leveraging a two-stage control strategy, where the mechanical mode is cooled before it is squeezed. Identification of the control strategy allows for two important insights - to determine the factors that limit squeezing and to simplify the time-dependence of the external drives, making our protocol readily applicable in experiments.