Robust entanglement of a micromechanical resonator with output optical fields

TL;DR

This paper demonstrates how to detect and enhance optomechanical entanglement between a vibrating mirror and output optical fields, revealing a tripartite-entangled system useful for quantum communication.

Contribution

It introduces a method to optimize optomechanical entanglement detection via detection bandwidth choice, and predicts all-optical entanglement between sidebands and a tripartite system.

Findings

Detection and enhancement of intracavity entanglement through bandwidth optimization

Prediction of all-optical entanglement between sidebands

Identification of a robust tripartite-entangled system for quantum communication

Abstract

We perform an analysis of the optomechanical entanglement between the experimentally detectable output field of an optical cavity and a vibrating cavity end-mirror. We show that by a proper choice of the readout (mainly by a proper choice of detection bandwidth) one can not only detect the already predicted intracavity entanglement but also optimize and increase it. This entanglement is explained as being generated by a scattering process owing to which strong quantum correlations between the mirror and the optical Stokes sideband are created. All-optical entanglement between scattered sidebands is also predicted and it is shown that the mechanical resonator and the two sideband modes form a fully tripartite-entangled system capable of providing practicable and robust solutions for continuous variable quantum communication protocols.