Maximal Privacy without Coherence
Name
PhysRevLett.113.030502.pdf
Size
183.58 KB
Format
Adobe PDF
Checksum (MD5)
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Author(s)
Leung, Debbie W.
Li, Ke
Smith, Graeme
Smolin, John A.
Date Issued
July 2014
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Leung, Debbie, Ke Li, Graeme Smith, and John A. Smolin. "Maximal Privacy without Coherence." Phys. Rev. Lett. 113, 030502 (July 2014). © 2014 American Physical Society
Version
Final published version
Abstract
Privacy is a fundamental feature of quantum mechanics. A coherently transmitted quantum state is inherently private. Remarkably, coherent quantum communication is not a prerequisite for privacy: there are quantum channels that are too noisy to transmit any quantum information reliably that can nevertheless send private classical information. Here, we ask how much private classical information a channel can transmit if it has little quantum capacity. We present a class of channels N[subscript d] with input dimension d[superscript 2], quantum capacity Q(N[subscript d]) ≤ 1, and private capacity P(N[subscript d])= log d. These channels asymptotically saturate an interesting inequality P(N) ≤ (1/2)[log d[subscript A] + Q(N)] for any channel N with input dimension d[subscript A] and capture the essence of privacy stripped of the confounding influence of coherence.
MIT Department
Massachusetts Institute of Technology. Center for Theoretical Physics
Massachusetts Institute of Technology. Laboratory for Nuclear Science
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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.113.030502
