Superadditivity of the Classical Capacity with Limited Entanglement Assistance
Name
PhysRevLett.119.040503.pdf
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396.54 KB
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Adobe PDF
Checksum (MD5)
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Author(s)
Zhu, Elton
Zhuang, Quntao
Shor, Peter Williston
Date Issued
July 2017
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Zhu, Elton Yechao, et al. "Superadditivity of the Classical Capacity with Limited Entanglement Assistance." Physical Review Letters 119, 4 (July 2017): 040503 © 2017 American Physical Society
Version
Final published version
Abstract
Finding the optimal encoding strategies can be challenging for communication using quantum channels, as classical and quantum capacities may be superadditive. Entanglement assistance can often simplify this task, as the entanglement-assisted classical capacity for any channel is additive, making entanglement across channel uses unnecessary. If the entanglement assistance is limited, the picture is much more unclear. Suppose the classical capacity is superadditive, then the classical capacity with limited entanglement assistance could retain superadditivity by continuity arguments. If the classical capacity is additive, it is unknown if superadditivity can still be developed with limited entanglement assistance. We show this is possible, by providing an example. We construct a channel for which the classical capacity is additive, but that with limited entanglement assistance can be superadditive. This shows entanglement plays a weird role in communication, and we still understand very little about it.
MIT Department
Massachusetts Institute of Technology. Center for Theoretical Physics
Massachusetts Institute of Technology. Department of Mathematics
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Research Laboratory of Electronics
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1103/PhysRevLett.119.040503
