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Sequential Quantum Cloning

Y. Delgado·L. Lamata·J. Leon·D. Salgado·E. Solano
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Abstract

Not all unitary operations upon a set of qubits can be implemented by sequential interactions between each qubit and an ancillary system. We analyze the specific case of sequential quantum cloning 1->M and prove that the minimal dimension D of the ancilla grows linearly with the number of clones M. In particular, we obtain D = 2M for symmetric universal quantum cloning and D = M+1 for symmetric phase-covariant cloning. Furthermore, we provide a recipe for the required ancilla-qubit interactions in each step of the sequential procedure for both cases.

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Y. Delgado, L. Lamata, J. Leon, D. Salgado, E. Solano. 2007-03-08. Sequential Quantum Cloning. https://doi.org/10.1103/physrevlett.98.150502

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