近日，日本九州大学Kazuhiro Yamamoto课题组与庆应义塾大学的Naoki Yamamoto以及学习院大学的Nobuyuki Matsumoto合作，通过连续测量和反馈控制，成功在宏观物体之间生成了量子纠缠。相关成果已于2023年3月13日在国际学术期刊《物理评论A》上发表。

研究人员通过测量Fabry-Pérot-Michelson干涉仪的公共和差分输出光束，压缩机械共振模态和反射镜的差分运动。他们利用耗散谐振腔的卡尔曼滤波问题，精确地推导出机械反射镜稳态下的协方差矩阵。研究发现，当反射镜的机械共振模态和微分模态以非对称方式被高纯度压缩时，会生成机械发射镜之间的高斯纠缠。他们的结果还表明，7毫克的反射镜之间的量子纠缠在短期内是可以实现的。

据悉，该研究旨在探索在光机械系统中利用连续测量和反馈控制，在宏观机械反射镜之间生成量子条件纠缠的可行性。

附：英文原文

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

Author: Daisuke Miki,Nobuyuki Matsumoto, Akira Matsumura, Tomoya Shichijo, Yuuki Sugiyama, Kazuhiro Yamamoto, Naoki Yamamoto

Issue&Volume: 2023/03/13

Abstract: This paper is aimed at investigating the feasibility of generating quantum conditional entanglement between macroscopic mechanical mirrors in optomechanical systems while under continuous measurement and feedback control. We consider the squeezing of the states of the mechanical common and the differential motions of the mirrors by the action of measuring the common and the differential output light beams in the Fabry-Pérot-Michelson interferometer. We carefully derive a covariance matrix for the mechanical mirrors in a steady state, employing the Kalman filtering problem with dissipative cavities. We demonstrate that Gaussian entanglement between the mechanical mirrors is generated when the states of the mechanical common and differential modes of the mirrors 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.

DOI: 10.1103/PhysRevA.107.032410

Source: https://journals.aps.org/pra/abstract/10.1103/PhysRevA.107.032410