Bounds for state-dependent quantum cloning

Yong-Jian Han, Yong-Sheng Zhang, Guang-Can Guo
2002 Physical Review A. Atomic, Molecular, and Optical Physics  
Due to the no-cloning theorem, the unknown quantum state can only be cloned approximately or exactly with some probability. There are two types of cloners: universal and state-dependent cloner. The optimal universal cloner has been found and could be viewed as a special state-dependent quantum cloner which has no information about the states. In this paper, we investigate the state-dependent cloning when the state-set contains more than two states. We get some bounds of the global fidelity for
more » ... hese processes. This method is not dependent on the number of the states contained in the state-set. It is also independent of the numbers of copying.
doi:10.1103/physreva.66.052301 fatcat:26at5l7vcfdwzhm6gvgboihhge