Joint remote preparation of an arbitrary four-qubit |\c{hi}>-type   entangled state
  We present two schemes for joint remote preparation of an arbitrary four-qubit j\c{hi}i -type entangled state via three three- and (N+1)-qubit GHZ states as the quantum channel, respectively. In these schemes, two senders (or N senders) share the original state which they wish to help the receiver to remotely prepare. To complete the JRSP schemes, several novel sets of mutually orthogonal basis vectors are introduced. It is shown that, only if two senders (or N senders) collaborate with each other, and perform projective measurements under suitable measuring basis on their own qubits respectively, the receiver can reconstruct the original state by means of some appropriate unitary operations and suitable C-NOT gates. Compared with the previous schemes for the JRSP of four-qubit |\c{hi}>-type state, the advantages of the present schemes are that the total successful probability of JRSP can reach 1 and the entanglement resource can be reduced 
Hao Fu, Gui-Bin Chen, Xiao-Wei Li, Peng-Cheng Ma, You-Bang Zhan
quant-ph