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Accueil du site > Publications > Publications 2008 > Role of interference in quantum cloning

Role of interference in quantum cloning

Benoit Roubert and Daniel Braun

par Daniel Braun - 17 mars 2009

We study the role of interference in the process of quantum cloning. We show that in order to achieve better than classical cloning of a qubit no interference is needed. In particular, a large class of symmetric universal 1→2 qubit cloners exists which achieve the optimal average fidelity 5/6 for such machines, without using any interference in the propagation of the original and copied qubits. We also obtain optimal average fidelities for interference-free cloning in asymmetric situations, and discuss the relation of the quantum cloners found to the Bužek-Hillery quantum cloner.