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arXiv · 1201.6077

Region of fidelities for a 1 -> N universal qubit quantum cloner

Piotr Ćwikliński·Michał Horodecki·Michał Studziński
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Abstract

We analyze a region of fidelities for qubit which is obtained after an application of a 1 -> N universal quantum cloner. We express the allowed region for fidelities in terms of overlaps of pure states with irreps of S(n) (n = N+1) showing that the pure states can be taken with real coefficients only. Subsequently, the case n = 4, corresponding to a 1 -> 3 cloner is studied in more detail as an illustrative example. To obtain the main result, we make a convex hull of possible ranges of fidelities related to a given irrep. The formalism allows to construct the state giving rise to a given N-tuple of fidelities.

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Piotr Ćwikliński, Michał Horodecki, Michał Studziński. 2012-01-29. Region of fidelities for a 1 -> N universal qubit quantum cloner. https://doi.org/10.1016/j.physleta.2012.05.039

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