Nonzero Classical Discord.
Nonzero Classical Discord.
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DOI：
10.1103/physrevlett.115.030403
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发表时间：
2014-07
影响因子：
8.6
通讯作者：
Vlad Gheorghiu;M. C. de Oliveira;B. Sanders
中科院分区：
文献类型：
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作者：
Vlad Gheorghiu;M. C. de Oliveira;B. Sanders
量子不和谐是由条件熵的两个不同定义分别给出的二部互信息的两个可选表达式之间的数量差异。通过构建共享态的随机模型，可以类似地定义经典不和谐，量化测量过程中某些随机性的存在。因此，不和谐通常可以理解为由于局部测量引起的系统状态扰动的量化，无论是量子的还是经典的。我们在状态合并与噪声测量的背景下建立了经典不和谐的操作意义，从而用负条件熵的方式展示了量子-经典分离。
Quantum discord is the quantitative difference between two alternative expressions for bipartite mutual information, given respectively in terms of two distinct definitions for the conditional entropy. By constructing a stochastic model of shared states, classical discord can be similarly defined, quantifying the presence of some stochasticity in the measurement process. Therefore, discord can generally be understood as a quantification of the system's state disturbance due to local measurements, be it quantum or classical. We establish an operational meaning of classical discord in the context of state merging with noisy measurement and thereby show the quantum-classical separation in terms of a negative conditional entropy.