量子纠缠及其度量
摘要：量子纠缠是首先被Einstein-Podolsky-Rosen(EPR)和薛定谔注意到的不同于经典物理最奇特、最不可思议的1种奇妙现象。它是微观量子系统内各子系统或各自由度之间关联的反映。在量子信息中，纠缠态扮演着极为重要的角色。可以说如果没有量子纠缠现象，就不会有现在所说的量子信息。由于纠缠态特殊的物理性质，使量子信息具有经典信息所没有的许多新的特征，同时纠缠态也为信息传输和信息处理提供了新的物理资源。本文对量子纠缠以及量子纠缠的度量（包含纯态和非纯态两种系统）的历史渊源和基本概念，以及近年来在理论实践研究方面的重要进展和在量子信息科学领域的应用前景，做1个系统、综合的介绍和讨论。
关键字：量子纠缠；纠缠的度量；EPR佯谬；薛定谔猫
Quantum entanglement and measurement
Abstract: Quantum entanglement, which is first revealed by Einstein-Podolsky-Rosen(EPR) and Schrodinger, is the unique phenomenon of quantum system. It is the most strange and unbelievable phenomenon which is different from classical physics. It reflects the correlation between different subsystems or freedom of degree in the microscopic quantized system. Quantum entanglement is the key role in the realism of quantum information. Due to the particular physical properties of quantum entanglement, there are some new properties which we cannot find in the classical information theory. Quantum entanglement also provides the key resource for quantum communication and quantum information processing. In this paper we review the concept and history of quantum entanglement, the progress in theory and experiment and the measurement of entanglement.
Keywords：Entanglement; Measurement of the entanglement; EPR-Paradox; Schrodingers Cat.
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