Classification of mixed three-qubit states

We introduce a classification of mixed three-qubit states, in which we define the classes of separable, biseparable, W, and Greenberger-Horne-Zeilinger states. These classes are successively embedded into each other. We show that contrary to pure W-type states, the mixed W class is not of measure ze...

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Bibliographic Details
Published inPhysical review letters Vol. 87; no. 4; p. 040401
Main Authors Acín, A, Bruss, D, Lewenstein, M, Sanpera, A
Format Journal Article
LanguageEnglish
Published United States 23.07.2001
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Summary:We introduce a classification of mixed three-qubit states, in which we define the classes of separable, biseparable, W, and Greenberger-Horne-Zeilinger states. These classes are successively embedded into each other. We show that contrary to pure W-type states, the mixed W class is not of measure zero. We construct witness operators that detect the class of a mixed state. We discuss the conjecture that all entangled states with positive partial transpose (PPTES) belong to the W class. Finally, we present a new family of PPTES "edge" states with maximal ranks.
ISSN:0031-9007
DOI:10.1103/PhysRevLett.87.040401