Generating quantum entanglement between macroscopic objects with continuous measurement and feedback control

TL;DR

This paper explores how continuous measurement and feedback control can generate quantum entanglement between macroscopic mechanical mirrors, demonstrating the feasibility of entangling 7 mg mirrors in optomechanical systems.

Contribution

It derives a covariance matrix for steady-state mechanical mirrors and shows entanglement can be achieved through asymmetric squeezing of modes.

Findings

Entanglement is generated when common and differential modes are highly pure and asymmetrically squeezed.

Quantum entanglement between 7 mg mirrors is feasible in the short term.

The approach employs Kalman filtering to analyze the system's steady state.

Abstract

This study is aimed at investigating the feasibility of generating quantum entanglement between macroscopic mechanical mirrors in optomechanical systems while under continuous measurement and feedback control. We carefully derive a covariance matrix for mechanical mirrors in a steady state, employing the Kalman filtering problem with an assumed dominant cavity photon dissipation, such that the common and differential modes of the mirrors are squeezed by the action of measuring the output light beams. We demonstrate that entanglement between the mechanical mirrors is generated when the states of the common and differential modes are squeezed with high purity in an asymmetric manner. Our results also show that quantum entanglement between $7$ mg mirrors is achievable in the short term.