Optimal probabilistic cloning and purification of quantum states

Journal Article · Wed Sep 01 04:00:00 EDT 2004 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.70.032308· OSTI ID:20646013

Fiurasek, Jaromir ^[1]

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1. QUIC, Ecole Polytechnique, CP 165, Universite Libre de Bruxelles, 1050 Brussels (Belgium)

We investigate the probabilistic cloning and purification of quantum states. The performance of these probabilistic operations is quantified by the average fidelity between the ideal and actual output states. We provide a simple formula for the maximal achievable average fidelity and we explicitly show how to construct a probabilistic operation that achieves this fidelity. We illustrate our method on several examples such as the phase covariant cloning of qubits, cloning of coherent states, and purification of qubits transmitted via depolarizing channel and amplitude damping channel. Our examples reveal that the probabilistic cloner may yield higher fidelity than the best deterministic cloner even when the states that should be cloned are linearly dependent and are drawn from a continuous set.

• OSTI ID: 20646013
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 3 Vol. 70; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
AMPLITUDES
ANNIHILATION OPERATORS
DAMPING
EIGENSTATES
INFORMATION THEORY
OPERATION
OPTIMIZATION
PERFORMANCE
PROBABILISTIC ESTIMATION
PROBABILITY
QUANTUM MECHANICS