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Characterizing the Structure of Preserved Information in Quantum Processes

Blume-Kohout, Robin and Ng, Hui Khoon and Poulin, David and Viola, Lorenza (2008) Characterizing the Structure of Preserved Information in Quantum Processes. Physical Review Letters, 100 (3). Art. No. 030501. ISSN 0031-9007. doi:10.1103/PhysRevLett.100.030501.

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We introduce a general operational characterization of information-preserving structures—encompassing noiseless subsystems, decoherence-free subspaces, pointer bases, and error-correcting codes—by demonstrating that they are isometric to fixed points of unital quantum processes. Using this, we show that every information-preserving structure is a matrix algebra. We further establish a structure theorem for the fixed states and observables of an arbitrary process, which unifies the Schrödinger and Heisenberg pictures, places restrictions on physically allowed kinds of information, and provides an efficient algorithm for finding all noiseless and unitarily noiseless subsystems of the process.

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Additional Information:©2008 The American Physical Society. (Received 29 May 2007; published 22 January 2008) We thank H. Barnum, P. Hayden, M.-B. Ruskai, R. Spekkens, J. Yard, P. Zanardi, and W. Zurek for helpful discussions. This work was supported in part by the Gordon and Betty Moore Foundation, by the NSF under Grants No. PHY-0456720 and No. PHY-0555417, and by the NSERC.
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9492
Deposited By: Archive Administrator
Deposited On:26 Jan 2008
Last Modified:08 Nov 2021 20:59

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