Generalized asymmetric quantum cloning machines
S. Iblisdir, A. Acín, Nicolas Gisin · Quantum Information and Computation · 2006
We study machines that take N identical replicas of a pure qudit state as input and output a set of M_A clones of a given fidelity and another set of M_B clones of another fidelity. The trade-off between these two fidelities is investigated, and numerous examples of optimal N \to M_A+M_B cloning machines are exhibited using a generic method. A generalisation to more than two sets of clones is also discussed. Finally, an optical implementation of some such machines is proposed. This paper is an extended version of Phys. Rev. A 72, 042328 (2005).