Remote state preparation - art. no. 077902

Quantum teleportation uses prior entanglement and forward classical communi cation to transmit one instance of an unknown quantum state. Remote state p reparation (RSP) has the same goal, but the sender knows classically what s tate is to be transmitted. We show that the asymptotic classical communicat ion cost of RSP is one bit per qubit-half that of teleportation-and even le ss when transmitting part of a known entangled state. We explore the tradeo ff between entanglement and classical communication required for RSP, and d iscuss RSP capacities of general quantum channels.