Optimized mechanical quadrature squeezing beyond the 3-dB limit via a gradient-descent algorithm

TL;DR

This paper introduces a gradient-descent algorithm-based method to generate mechanical quadrature squeezing in cavity optomechanics, surpassing the 3-dB limit and enabling rapid, high-quality squeezing even at high thermal phonon occupancy.

Contribution

It presents a novel optimal control scheme for mechanical squeezing that exceeds traditional limits and operates efficiently in realistic thermal conditions.

Findings

Achieves quadrature squeezing beyond 3-dB limit.

Creates mechanical squeezing within one oscillation period.

Identifies optimal pulsed drivings for enhanced squeezing.

Abstract

The preparation of mechanical quadrature-squeezed states holds significant importance in cavity optomechanics because the squeezed states have extensive applications in understanding fundamental quantum mechanics and exploiting modern quantum technology. Here, we propose a reliable scheme for generating mechanical quadrature squeezing in a typical cavity optomechanical system via seeking optimal cavity-field driving pulses using the gradient-descent algorithm. We realize strong quadrature squeezing in a mechanical resonator that exceeds the 3-dB steady-state limit, even with a thermal phonon occupancy of 100. Furthermore, the mechanical squeezing can be ultrarapidly created within one mechanical oscillation period. We also obtain the optimal pulsed drivings associated with the created mechanical squeezings and analyze the mechanism for mechanical squeezing generation. This paper will promote the application of optimal quantum control in quantum optics and quantum information science.