Quantum Optimal Control for Mixed State Squeezing in Cavity Optomechanics

TL;DR

This paper develops an optimal control framework for enhancing the squeezing of an optomechanical oscillator at finite temperature, significantly speeding up state preparation using shaped cavity drives compatible with current technology.

Contribution

It introduces a geometric measure for non-pure state optimization and applies it to achieve rapid, experimentally feasible squeezing in cavity optomechanics.

Findings

Shaping cavity drives speeds up squeezing by over two orders of magnitude.

The proposed method is compatible with existing experimental setups.

Optimized pulses improve state preparation efficiency at finite temperature.

Abstract

The performance of key tasks in quantum technology, such as accurate state preparation, can be maximized by utilizing external controls and deriving their shape with optimal control theory. For non-pure target states, the performance measure needs to match both angle and length of the generalized Bloch vector. We introduce a measure based on this simple geometric picture that separates angle and length mismatch into individual terms and apply the ensuing optimization framework to maximize squeezing of an optomechanical oscillator at finite temperature. Our results show that shaping the cavity drives can speed up squeezed state preparation by more than two orders of magnitude. Cooperativities and pulse shapes required to this end are fully compatible with current experimental technology.