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arXiv · 1103.2615

Information capacity of quantum observable

A. S. Holevo
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Abstract

In this paper we consider the classical capacities of quantum-classical channels corresponding to measurement of observables. Special attention is paid to the case of continuous observables. We give the formulas for unassisted and entanglement-assisted classical capacities $C,C_{ea}$ and consider some explicitly solvable cases which give simple examples of entanglement-breaking channels with $C<C_{ea}.$ We also elaborate on the ensemble-observable duality to show that $C_{ea}$ for the measurement channel is related to the $χ$-quantity for the dual ensemble in the same way as $C$ is related to the accessible information. This provides both accessible information and the $χ$-quantity for the quantum ensembles dual to our examples.

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A. S. Holevo. 2011-04-18. Information capacity of quantum observable. https://doi.org/10.1134/s0032946012010012

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