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Phys. Rev. A 78, 042316 (2008) [11 pages]

Tomography increases key rates of quantum-key-distribution protocols

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Shun Watanabe*, Ryutaroh Matsumoto, and Tomohiko Uyematsu
Department of Communications and Integrated Systems, Tokyo Institute of Technology, 2-12-1, Oookayama, Meguro-ku, Tokyo, 152-8552, Japan

Received 18 February 2008; revised 16 July 2008; published 17 October 2008

We construct a practically implementable classical processing for the Bennett-Brassard 1984 (BB84) protocol and the six-state protocol that fully utilizes the accurate channel estimation method, which is also known as the quantum tomography. Our proposed processing yields at least as high a key rate as the standard processing by Shor and Preskill. We show two examples of quantum channels over which the key rate of our proposed processing is strictly higher than the standard processing. In the second example, the BB84 protocol with our proposed processing yields a positive key rate even though the so-called error rate is higher than the 25% limit.

This article is available under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

© 2008 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevA.78.042316
DOI:
10.1103/PhysRevA.78.042316
PACS:
03.67.Dd, 89.70.−a, 03.65.Wj

*shun-wata@it.ss.titech.ac.jp

ryutaroh@rmatsumoto.org http:∕∕www.rmatsumoto.org∕research.html

uyematsu@ieee.org