双模压缩态量子相干性演化的实验研究  

Experimental demonstration on quantum coherence evolution of two-mode squeezed state

作　　者：蔚娟 张岩 吴银花 杨文海 闫智辉[2,3] 贾晓军 Yu Juan;Zhang Yan;Wu Yin-Hua;Yang Wen-Hai;Yan Zhi-Hui;Jia Xiao-Jun(School of Optoelectronic Engineering,Xi’an Technological University,Xi’an 710021,China2;State Key Laboratory of Quantum Optics and Quantum Optics Devices,Institute of Opto-Electronics,Shanxi University,Taiyuan 030006,China;Collaborative Innovation Center of Extreme Optics,Shanxi University,Taiyuan 030006,China;China Academy of Space Technology(Xi’an),Xi’an 710000,China)

机构地区：[1]西安工业大学光电工程学院,西安710021 [2]山西大学光电研究所,量子光学与光量子器件国家重点实验室,太原030006 [3]山西大学,极端光学协同创新中心,太原030006 [4]中国空间技术研究院西安分院,西安710000

出　　处：《物理学报》2023年第3期77-84,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:62105256,62122044,61925503,11904218,12147215,11834010,62135008,62001374,12004276,12103039);陕西省教育厅自然科学研究项目(批准号:21JK0694,18JK0386,21JY016);山西省高等学校创新人才支持计划;山西省高等学校科技创新项目(批准号:2019L0794);山西青年三晋学者项目;山西省“1331工程”重点学科建设计划资助的课题;陕西省自然科学基础研究项目(批准号:2021JQ-640)资助的课题。

摘　　要：量子相干性作为量子力学一个最显著的特征,被认为是量子信息过程中很重要的一种量子资源.单模压缩态和双模压缩态(Einstein-Podolsky-Rosen纠缠态)均具有量子相干性,在制备和传输过程中的量子相干性对于实际应用具有重要意义.利用平衡零拍探测重构量子态的协方差矩阵,本文定量分析了量子态制备过程中的不完美以及信道传输损耗对单模和双模压缩态量子相干性的影响.实验证明量子态的压缩和纠缠特性及量子相干性对损耗均是鲁棒的.特别地,压缩和纠缠特性会随着量子态制备过程中热光子数的增大而减小,直至消失,而当压缩和纠缠均已消失时,量子相干性依然存在.实验结果为压缩态、纠缠态光场的量子相干性作为量子资源在量子信息过程中的应用提供了参考.As one of the most remarkable features of quantum mechanics,quantum coherence is regarded as an important quantum resource in the quantum information processing.The one-mode squeezed state and the twomode squeezed state(Einstein-Podolsky-Rosen(EPR)entangled states)as the most representative examples of nonclassical states both have quantum coherence.The squeezing property of the squeezed state is described by the variance of quadrature components,and the positive partial transposition(PPT)criterion is used to describe the entanglement of the EPR entangled states.The research of the quantum coherence of Gaussian states is also a bridge between the properties of squeezing and entanglement.It has been shown that the quantum coherence with infinite-dimensional systems can be quantified by relative entropy.One of the widely used effective methods to obtain the value of quantum coherence experimentally is the quantum tomography.The covariance matrices of the quantum states are reconstructed via balanced homodyne detection and then taken into quantum coherence expression to calculate the corresponding value.The main factors affecting quantum coherence are the classical and uncorrelated noise in the actual experimental generation processing and the decoherence effect caused by the coupling between quantum resources and the surrounding environment.And the quantum coherence evolution in the generation and transmission process of the quantum resources is essential for the practical applications.Therefore,we analyze in detail the influences of the impurity of quantum resource on squeezing,entanglement and quantum coherence.The evolutions of quantum coherence of these Gaussian states in the lossy channels are demonstrated experimentally.The quantum coherence is shown to be robust against the loss in the lossy channels,which is similar to the case of squeezing and entanglement.The quantum coherences of the squeezed states and the EPR entangled states are robust against the thermal photons in the actual experimental generation

关 键 词：压缩态 Einstein-Podolsky-Rosen纠缠态 量子态纯度 量子相干性 

分 类 号：O431.2[机械工程—光学工程]