Efficient schemes of joint remote preparation with a passive receiver via EPR pairs*
Ma Song-Yaa), Gao Conga), Luo Ming-Xingb)
       
Quantum channel via four EPR pairs for two senders (Alice, Bob) to jointly prepare a general two-qubit state for the receiver Charlie. In this and all other figures, a qubit is represented by a dot and entangled qubits are connected by solid lines.