Economical Gaussian cloning of coherent states with known phase
Yuli Dong, Xu‐Bo Zou, Shangbin Li, Guang‐Can Guo · Physical Review A · 2007
We investigate the economical Gaussian cloning of coherent states with the known phase, which produces $M$ copies from $N$ input replica and can be implemented with degenerate parametric amplifiers and beam splitters.The achievable fidelity of single copy is given by $2M\sqrt{N}∕[\sqrt{N}(M\ensuremath{-}1)+\sqrt{(1+N)({M}^{2}+N)}]$, which is bigger than the optimal fidelity of the universal Gaussian cloning. The cloning machine presented here works without ancillary optical modes and can be regarded as the continuous variable generalization of the economical cloning machine for qudits.