Local cloning of genuinely entangled states of three qubits
Sujit K. Choudhary, Guruprasad Kar, Samir Kunkri, Ramij Rahaman, Anirban Roy · Physical Review A · 2007
We discuss the (im)possibility of the exact cloning of orthogonal but genuinely entangled three qubit states aided with entangled ancilla under local operation and classical communication. Whereas any two orthogonal Greenberger-Horne-Zeilinger (GHZ) states taken from the canonical GHZ basis can be cloned with the help of a known GHZ state, surprisingly we find that no two $W$ states can be cloned by using any known three qubit (possibly entangled) state as a blank copy.