Quantum extension of conditional probability

Abstract

We analyze properties of the quantum conditional amplitude operator @Phys. Rev. Lett. 79, 5194 ~1997!#, which plays a role similar to that of the conditional probability in classical information theory. The spectrum of the conditional operator that characterizes a quantum bipartite system is shown to be invariant under local unitary transformations and reflects its inseparability. More specifically, it is proven that the conditional amplitude operator of a separable state cannot have an eigenvalue exceeding 1, which results in a necessary condition for separability. A related separability criterion based on the non-negativity of the von Neumann conditional entropy is also exhibited. @S1050-2947~99!00608-3#

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Cite this paper

@inproceedings{Cerf1999QuantumEO, title={Quantum extension of conditional probability}, author={Nicolas J. Cerf and C. Adami}, year={1999} }