Bistability-assisted Mechanical Squeezing and Entanglement

TL;DR

This paper introduces a scheme leveraging optical bistability in optomechanical systems to significantly enhance mechanical squeezing and entanglement, with potential applications in quantum technologies.

Contribution

It demonstrates how bistability can be used to amplify quantum effects like squeezing and entanglement in optomechanical systems, a novel approach compared to prior methods.

Findings

Entanglement can be enhanced by three orders of magnitude in the upper bistable branch.

Mechanical squeezing reaches the standard quantum limit in the upper branch.

Giant entanglement is fragile against decoherence and thermal noise.

Abstract

We propose a scheme to squeeze mechanical motion and to entangle optical field with mechanical motion in an optomechanical system containing a parametric amplification. The scheme is based on optical bistability which emerges in the system for a strong enough driving field. By considering the steady state's lower branch of the bistability, the system shows weak entanglement and almost no mechanical squeezing. When the steady state is on the upper branch of the bistable shape, both squeezing and entanglement are greatly enhanced. Specifically, the entanglement shows three degrees of magnitude enhancement. However, this giant entanglement is fragile against decoherence and thermal fluctuation. Regarding the mechanical squeezing, it reaches the standard quantum limit (SQL) in the upper branch of the bistability. Our proposal provides a way to improve quantum effects in optomechanical systems by taking advantage of nonlinearities. This scheme can be realized in similar systems such as superconducting microwave, and hybrid optomechanical systems.