Activation of entanglement in teleportation

Abstract

We study the activation of entanglement in teleportation protocols. To this end, we present a derivation of the average fidelity of the teleportation process with a noisy classical channel for qudits. In our work, we do not make any assumptions about the entangled states shared by communicating parties. Our result allows us to specify the minimum amount of classical information required to beat the classical limit when the protocol is based on the Bell measurements. We also compare the average fidelity of teleportation obtained using a noisy and perfect classical channel with restricted capacity. The most important insight into the intricacies of quantum information theory that we gain is that, although entanglement is obviously a necessary resource for efficient teleportation, it requires a certain threshold amount of classical communication to be more useful than classical communication. Another interesting finding is that the amount of classical communication required to activate entanglement for teleportation purposes depends on the dimension d of the system being teleported but is not monotonic, reaching a maximum for d = 4.