Cloning a real d-dimensional quantum state on the edge of the no-signaling condition

@inproceedings{Navez2003CloningAR,
  title={Cloning a real d-dimensional quantum state on the edge of the no-signaling condition},
  author={Patrick Navez and Nicolas J. Cerf},
  year={2003}
}
We investigate the class of quantum cloning machines that equally duplicate all real states in a Hilbert space of arbitrary dimension. By using the no-signaling condition, namely, that cloning cannot make superluminal communication possible, we derive an upper bound on the fidelity of this class of quantum cloning machines. Then, for each dimension d, we construct an optimal symmetric cloner whose fidelity saturates this bound. Similar calculations can also be performed in order to recover the… CONTINUE READING