A noisy channel less entangled than a pure can improve teleportation

TL;DR

This paper demonstrates that using a less entangled mixed X-state channel with a higher entanglement measurement basis can outperform a pure maximally entangled channel in quantum teleportation fidelity.

Contribution

It reveals that the entanglement of the measurement basis is as crucial as the entanglement of the channel for optimal teleportation.

Findings

X-state channels can surpass pure channels in fidelity

Entanglement of measurement basis impacts teleportation quality

Werner state channels can outperform Bell states

Abstract

In our work we consider the following problem in the context of teleportation: an unknown pure state have to be teleported and there are two laboratories which can perform the task. One laboratory uses a pure non maximally entangled channel but has a capability of performing the joint measurement on bases with a constrained degree of entanglement; the other lab makes use of a mixed X-state channel but can perform a joint measurement on bases with higher entanglement degrees. We compare the average teleportation fidelity achieved in both cases, finding that the fidelity achieved with the X-state can surpass the obtained with a pure channel, even though the X-state is less entangled than the latter. We find the conditions under which this effect occurs. Our results evidence that the entanglement of the joint measurement plays a role as important as the entanglement of the channel in order to optimize the teleportation process. We include an example showing that the average fidelity of teleportation obtained with a Werner state channel can be grater than that obtained with a Bell state channel.