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A simple quantum channel having superadditivity of channel capacity

Masahide Sasaki·Kentaro Kato·Masayuki Izutsu·Osamu Hirota
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Abstract

When classical information is sent through a quantum channel of nonorthogonal states, there is a possibility that transmittable classical information exceeds a channel capacity in a single use of the initial channel by extending it into multi-product channel. In this paper, it is shown that this remarkable feature of a quantum channel, so-called superadditivity, appears even in as low as the third extended coding of the simplest binary input channel. A physical implementation of this channel is indicated based on cavity QED techniques.

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Masahide Sasaki, Kentaro Kato, Masayuki Izutsu, Osamu Hirota. 1997-05-26. A simple quantum channel having superadditivity of channel capacity. https://doi.org/10.1016/s0375-9601(97)00740-8

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