Figure 1: Schemes to transfer one qubit.
(a) Quantum teleportation layout. Charles prepares a state for Alice, who performs a Bell measurement between her state and Charles’. She then transmits the outcome to Bob, who is able to transform his photon into the state Charles had chosen. (b) Remote state preparation (RSP) layout. Charles performs a unitary transformation on one photon and sends it to Alice, who makes a positive-operator valued measure (POVM) measurement on the state. She then sends the outcome to Bob, who transforms his state into the state Charles chose. (c) The required number of transmitted classical bits for quantum teleportation (QT), RSP and superdense teleportation (SDT) as a function of the number of parameters teleported; for a large number of parameters, the ratio of classical bits needed for QT and RSP to bits needed for SDT approaches 2.
