Phys. Rev. A 68, 054301 (2003) [4 pages]Quantum cloning of mixed states in symmetric subspacesReceived 1 May 2003; published 3 November 2003 Quantum-cloning machine for arbitrary mixed states in symmetric subspaces is proposed. This quantum-cloning machine can be used to copy part of the output state of another quantum-cloning machine and is useful in quantum computation and quantum information. The shrinking factor of this quantum cloning achieves the well-known upper bound. When the input is identical pure states, two different fidelities of this cloning machine are optimal. © 2003 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevA.68.054301
DOI:
10.1103/PhysRevA.68.054301
PACS:
03.67.-a, 03.65.Ta, 89.70.+c
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