Still more on norms of completely positive maps

Stanislaw J. Szarek

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arXiv · quant-ph/0603110

Still more on norms of completely positive maps

Stanislaw J. Szarek

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Abstract

King and Ruskai asked whether the norm of a completely positive map acting between Schatten classes of operators is equal to that of its restriction to the real subspace of self-adjoint operators. Proofs have been promptly supplied by Watrous and Audenaert. Here we provide one more proof, in fact of a slightly more general fact, under the (slightly weaker) assumption of 2-positivity. The argument is elementary and self-contained.

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Stanislaw J. Szarek. 2006-03-13. Still more on norms of completely positive maps. https://arxiv.org/abs/quant-ph/0603110

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