>VITAE:
Rafal Demkowicz-Dobrzanski did his master thesis (“Cloning of quantum states”) in 2003 at the faculty of physics, Warsaw University, under supervision of Krzysztof Wodkiewicz.
Presently he is doing a PhD at the Center for theoretical physics, Warsaw, under supervision of Marek Kus. Main areas of interests: quantum cloning, state estimation, multipartite entanglement and entanglement production in chaotic systems.

Cloning of entangled two qubit states is analysed when only local operations and classical communication is allowed (LOCC). The optimal LOCC operation is found. Suprisingly, an entanglement threshold is discovered above which classical communication improves cloning fidelity, while below the threshold the classical communication doesn't help and the optimal cloning procedure is the independent application of two Buzek-Hillery cloners.