量子纯态与混合态中力学量测量研究  

Measurement of mechanical quantity in quantum pure state and mixed state

作　　者：张登玉[1] 郭萍[2] 高峰[1] 

机构地区：[1]衡阳师范学院物理与电子信息科学系,湖南衡阳421008 [2]南华大学数理学院,湖南衡阳421001

出　　处：《量子电子学报》2008年第4期423-429,共7页Chinese Journal of Quantum Electronics

基　　金：湖南省自然科学基金(06JJ50118);湖南省教育厅重点科研基金(04A006)资助项目

摘　　要：量子纯态和混合态是量子信息中最重要的两种量子态,是研究密度算符、量子纠缠态和量子消相干的基础。量子纯态与混合态具有本质区别。量子干涉的一个最重要的特征是量子纯态的相对位相有可以观测的效应。利用量子力学的方法,通过测定特定力学量■_x,■_x和■_n的取值来分析从纯态到混合态的转变。结果表明:量子纯态中的测量是各向异性的,而对于混合态则是各向同性的。The quantum pure state and mixed state are the most important quantum states in quantum information. They are the foundation of studying density operator, quantum entanglement and quantum decoherence. The two states＇ definition and innate differences are given in quantum theory. The observable effect for quantum pure states＇ mutually phase is the most important characteristics in quantum interference. The transformation from quantum pure state to mixed state is analyzed through measurement of mechanic quantity σ^z, σ^x and σ^n by quantum mechanics methods. The result shows that the measurement of mechanical quantity is anisotropic in the quantum pure state but for quantum mixed state is isotropic.

关 键 词：量子光学 量子信息 力学量 Pauli算子 纯态 混合态 

分 类 号：O431.2[机械工程—光学工程]