Time Reversal and Exchange Symmetries of Unitary Gate Capacities
Name
Harrow-2010-Time Reversal and Exchange Symmetries of Unitary Gate Capacities.pdf
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381.79 KB
Format
Adobe PDF
Checksum (MD5)
db0d9e6ed058c906312f97bbf8a3a525
Author(s)
Harrow, Aram W.
Shor, Peter W.
Date Issued
January 2010
Journal
Transactions on Information Theory
Publisher
Institute of Electrical and Electronics Engineers (IEEE)
Citation
Harrow, Aram W., and Peter W. Shor. “Time Reversal and Exchange Symmetries of Unitary Gate Capacities.” IEEE Transactions on Information Theory 56.1 (2010): 462–475. Web. 12 Apr. 2012. © 2010 Institute of Electrical and Electronics Engineers
Version
Final published version
Abstract
Unitary gates are interesting resources for quantum communication in part because they are always invertible and are intrinsically bidirectional. This paper explores these two symmetries: time-reversal and exchange of Alice and Bob. We present examples of unitary gates that exhibit dramatic separations between forward and backward capacities (even when the back communication is assisted by free entanglement) and between entanglement-assisted and unassisted capacities, among many others. Along the way, we will give a general time-reversal rule for relating the capacities of a unitary gate and its inverse that will explain why previous attempts at finding asymmetric capacities failed. Finally, we will see how the ability to erase quantum information and destroy entanglement can be a valuable resource for quantum communication.
MIT Department
Massachusetts Institute of Technology. Department of Mathematics
Terms of Use
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/10.1109/tit.2009.2034899
