title: Robust one-step catalytic machine for high fidelity anticloning and W-state generation in a multiqubit system.
abstract: We propose a physically realizable machine which can either generate multiparticle W-like states, or implement high-fidelity 1-->M (M=1,2,...infinity) anticloning of an arbitrary qubit state, in a single step. This universal machine acts as a catalyst in that it is unchanged after either procedure, effectively resetting itself for its next operation. It possesses an inherent immunity to decoherence. Most importantly in terms of practical multiparty quantum communication, the machine's robustness in the presence of decoherence actually increases as the number of qubits M increases.
authors.affiliation: Centre for Quantum Computation and Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, OX1 3PU, United Kingdom. a.olaya@physics.ox.ac.uk
authors.forename: Alexandra
authors.initials: A
authors.lastname: Olaya-Castro
authors.forename: Neil F
authors.initials: NF
authors.lastname: Johnson
authors.forename: Luis
authors.initials: L
authors.lastname: Quiroga