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arXiv · 1510.01366

On the complementary quantum capacity of the depolarizing channel

Debbie Leung·John Watrous
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Abstract

The qubit depolarizing channel with noise parameter $\eta$ transmits an input qubit perfectly with probability $1-\eta$, and outputs the completely mixed state with probability $\eta$. We show that its complementary channel has positive quantum capacity for all $\eta>0$. Thus, we find that there exists a single parameter family of channels having the peculiar property of having positive quantum capacity even when the outputs of these channels approach a fixed state independent of the input. Comparisons with other related channels, and implications on the difficulty of studying the quantum capacity of the depolarizing channel are discussed.

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Debbie Leung, John Watrous. 2015-10-05. On the complementary quantum capacity of the depolarizing channel. https://doi.org/10.22331/q-2017-09-19-28

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