于长水

个人信息Personal Information

教授

博士生导师

硕士生导师

主要任职:物理学院党委书记

其他任职:无

性别:男

毕业院校:大连理工大学

学位:博士

所在单位:物理学院

学科:理论物理

办公地点:313

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Dual roles of quantum discord in a nondemolition probing task

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论文类型:期刊论文

发表时间:2013-02-15

发表刊物:PHYSICAL REVIEW A

收录刊物:SCIE、EI、Scopus

卷号:87

期号:2

ISSN号:2469-9926

摘要:We present a nondemolition quantum information processing task of probing the information of a class of quantum state. In this task, the information is extracted by some unitary evolution with the introduced probing qubit assisted, but the probed quantum state (density matrix) is undisturbed at any time and independent of the choice of the initial probing state. We give a sufficient and necessary condition on the Hamiltonian that can lead to the successful realization of such a task. We prove that, for any feasible scheme, the probed plus probing system will always stay at a disentangled state with one side's quantum discord absent and the other side's inevitably produced in the probing process. An explicit example is given for the demonstration, which shows that the ratio of quantum discord to the total correlation will have to reduce to zero for the maximal accessible information. In this sense, we say that quantum discord plays a dual role in this case. DOI: 10.1103/PhysRevA.87.022113