Quantum discord: A measure of the quantumness of correlations
Quantum discord: A measure of the quantumness of correlations
复制标题
DOI：
10.1103/physrevlett.88.017901
复制
发表时间：
2002-01-07
影响因子：
8.6
通讯作者：
Zurek, WH
中科院分区：
文献类型：
--
作者：
Ollivier, H;Zurek, WH
当所涉及的系统是量子系统时，互信息的两个经典相同的表达式通常不同。这种差异定义了量子不和谐。它可以用来衡量关联的量化程度。描述一对系统的密度矩阵的可分性并不保证不协调的消失，从而表明没有纠缠并不意味着经典。我们将这与量子叠加原理联系起来，并将不协调的消失作为系统首选的有效经典态，即指针态的判据。
Two classically identical expressions for the mutual information generally differ when the systems involved are quantum. This difference defines the quantum discord. It can be used as a measure of the quantumness of correlations. Separability of the density matrix describing a pair of systems does not guarantee vanishing of the discord, thus showing that absence of entanglement does not imply classicality. We relate this to the quantum superposition principle, and consider the vanishing of discord as a criterion for the preferred effectively classical states of a system, i.e., the pointer states.