2000/03/31 by Piotr Deuar, P. Deuar, William J. Munro +1
Computer Science · Physics and Astronomy · #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum Mechanics and Applications #quant-ph
paper · pdf · doi:10.1103/physreva.61.062304
published as Phys. Rev. A. 61, 062304 (2000) · 14 pages, 3 Figures, REVTeX. Accepted Physical Review A. Corrected minor grammatical errors
arxiv created 2000/04/12 · openalex publication_date 2000/05/12 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We find that very different quantum copying machines are optimal depending on the indicator used to assess their performance. Several quantum copying machine models acting on nonorthogonal input states are investigated, and assessed according to two types of criteria: transfer of (Shannon) information encoded in the initial states to the copies, and fidelity between the copies and the initial states. Transformations that optimize information transfer for messages encoded in qubits are found for three situations: (1) when the message is decoded one state at a time; (2) with simple schemes that allow the message to be encoded using block-coding schemes; and (3) when the copier produces independent copies. If the message is decoded one symbol at a time, information is best copied by a Wootters-Zurek copier.