The optimal cloning of quantum coherent states is non-Gaussian

@inproceedings{Cerf2004TheOC,
  title={The optimal cloning of quantum coherent states is non-Gaussian},
  author={N. Cerf and O. Krueger and P. Navez and R. Werner and M. Wolf},
  year={2004}
}
We consider the optimal cloning of quantum coherent states with single-clone and joint fidelity as figures of merit. Both optimal fidelities are attained for phase space translation covariant cloners. Remarkably, the joint fidelity is maximized by a Gaussian cloner, whereas the single-clone fidelity can be enhanced by non-Gaussian operations: a symmetric non-Gaussian 1-to-2 cloner can achieve a single-clone fidelity of approximately 0.6826, perceivably higher than the optimal fidelity of 2/3 in… Expand