Witnessing the quantumness of a single system: From anticommutators to interference and discord

Rosario Fazio, Kavan Modi, Saverio Pascazio, Vlatko Vedral, Kazuya Yuasa

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    We introduce a method to witness the quantumness of a system. The method relies on the fact that the anticommutator of two classical states is always positive. By contrast, we show that there is always a nonpositive anticommutator due to any two quantum states. We notice that interference depends on the trace of the anticommutator of two states, and it is therefore operationally more suitable to detect quantumness by looking at anticommutators of states rather than their commutators.

    Original languageEnglish
    Article number052132
    JournalPhysical Review A - Atomic, Molecular, and Optical Physics
    Issue number5
    Publication statusPublished - 2013 May 23


    ASJC Scopus subject areas

    • Atomic and Molecular Physics, and Optics

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