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Phase-Conjugated Inputs Quantum Cloning Machines

N. J. Cerf·S. Iblisdir
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Abstract

A quantum cloning machine is introduced that yields $M$ identical optimal clones from $N$ replicas of a coherent state and $N'$ replicas of its phase conjugate. It also optimally produces $M'=M+N'-N$ phase-conjugated clones at no cost. For well chosen input asymmetries $N'/(N+N')$, this machine is shown to provide better cloning fidelities than the standard $(N+N') \to M$ cloner. The special cases of the optimal balanced cloner ($N=N'$) and the optimal measurement ($M=\infty$) are investigated.

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N. J. Cerf, S. Iblisdir. 2001-02-15. Phase-Conjugated Inputs Quantum Cloning Machines. https://doi.org/10.1103/physrevlett.87.247903

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