From quantum coherence to quantum correlations
From quantum coherence to quantum correlations
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DOI：
10.1209/0295-5075/118/60007
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发表时间：
2017-09
期刊：
影响因子：
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通讯作者：
Yuan Sun;Y. Mao;S. Luo
中科院分区：
文献类型：
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作者：
Yuan Sun;Y. Mao;S. Luo
在量子力学中，相对于量子测量的状态的量子相干性可以用测量必须破坏的量子性来识别。特别是，二分态相对于局部量子测量的量子相干性编码了该态中的量子相关性。如果我们对局部测量进行最小化，那么我们就会得到从相干性角度捕获量子相关性的量词。在这种情况下，量子不和谐（量化必须通过量子测量破坏的最小相关性）可以被识别为最小相干性，而相干性是通过相干性的相对熵来测量的。为了在一般背景下倡导和阐述这一想法，我们首先回顾相对于吕德斯测量的相干性，它扩展了相对于冯·诺依曼测量（或等效的正交基）的相干性概念，并通过两个典型例子强调了量子不和谐作为最小相干性出现的观察结果。然后，我们在相干性方面介绍了一些量子相关性的新颖度量，通过示例进行说明，研究它们的基本属性和含义，并指出它们在量子计量学中的应用。
In quantum mechanics, quantum coherence of a state relative to a quantum measurement can be identified with the quantumness that has to be destroyed by the measurement. In particular, quantum coherence of a bipartite state relative to a local quantum measurement encodes quantum correlations in the state. If one takes minimization with respect to the local measurements, then one is led to quantifiers which capture quantum correlations from the perspective of coherence. In this vein, quantum discord, which quantifies the minimal correlations that have to be destroyed by quantum measurements, can be identified as the minimal coherence, with the coherence measured by the relative entropy of coherence. To advocate and formulate this idea in a general context, we first review coherence relative to Lüders measurements which extends the notion of coherence relative to von Neumann measurements (or equivalently, orthonomal bases), and highlight the observation that quantum discord arises as minimal coherence through two prototypical examples. Then, we introduce some novel measures of quantum correlations in terms of coherence, illustrate them through examples, investigate their fundamental properties and implications, and indicate their applications to quantum metrology.