Experimental Quantum Cloning with Prior Partial Information
  When prior partial information about a state to be cloned is available, it can be cloned with a fidelity higher than that of universal quantum cloning. We experimentally verify this intriguing relationship between the cloning fidelity and the prior information by reporting the first experimental optimal quantum state-dependent cloning, using nuclear magnetic resonance techniques. Our experiments may further have important implications into many quantum information processing protocols. 
Jiangfeng Du, Thomas Durt, Ping Zou, Hui Li, L.C. Kwek, C.H. Lai, C.H.   Oh, Artur Ekert