Phys. Rev. Lett. 111, 050504 (2013)

The continuous-variable teleportation protocol is a fundamental and important element in many continuous-variable quantum information protocols, such as those used in quantum repeaters and measurement-induced quantum computation. This protocol has the advantages of permitting deterministic implementation and having a high efficiency. However, the teleportation fidelity is technically limited, as a fidelity of 100% would require infinitely squeezed light sources. Now, Ulrik Andersen from the Technical University of Denmark and Timothy Ralph from the University of Queensland in Australia have proposed a new scheme that can yield a teleportation fidelity close to 100% for continuous-variable states. The researchers proposed using an ensemble of maximally entangled single-photon states rather than squeezed states. In their scheme, the input state was divided into N modes, each of which was teleported with a qubit teleporter. The teleported outputs were recombined in an N splitter, and success was obtained if all photons exited from one port. A numerical calculation showed that the proposed teleporter outperformed the standard entanglement swapping protocol. A teleportation fidelity as high as 99.2% was achieved by using 100 single-photon states, even when the quantum transmission channel was lossy.