Remote preparation of mixed states via noisy entanglement

We present a practical and general scheme of remote preparation for pure and mixed states, which is proposed with an auxiliary qubit and controlled-NOT gate. We discuss the remote state preparation (RSP) in two important types of decoherent channel (depolarizing and dephasing). We realize RSP in the dephasing channel in our experiment by using spontaneous parametric down-conversion, linear optical elements, and single photon detector. Our experimental results match the theoretical prediction well.