量子纠缠起源于Einstein-Podolsky-Rosen佯谬, 其本质来自于对物质之间的相互作用的定域性的认识。在量子尺度下, 当两个系统各自的 Einstein-Podolsky-Rosen 算符的总起伏低于标准量子极限时, 称这两个系统是不可分的, 即这两个系统是连续变量纠缠的。量子纠缠按照其违背测不准原理的程度分为三个类别, 分别是量子不可分、量子导引和贝尔非定域性。分别介绍了这三种不同类别的量子纠缠的概念及其相关的判据, 介绍了这几种量子纠缠的潜在应用, 并给出了基于量子导引型纠缠态的未来量子通信和量子计算可能的发展方向。

The study of the quantum entanglement origins from the Einstein-Podolsky-Rosen paradox, and the essence of the entanglement lies on the localization of the interactions between matters. In the quantum scale, two systems are inseparable if the total variance of a pair of EinsteinPodolsky-Rosen-like operators is below the standard quantum limit. This is known as the continuous variable entanglement. According to the violation of the uncertainty relation, the quantum entanglement is divided into three different categories, quantum inseparable, quantum steering and bell nonlocality. A brief review of all three types of quantum entanglement and their criteria is given. Furthermore, some potential applications of quantum entanglement, especially the quantum steering in both quantum communication and quantum computing are provided.