Benchmarking a quantum teleportation protocol in superconducting circuits using tomography and an entanglement witness

Teleportation of a quantum state may be used for distributing entanglement between distant qubits in quantum communication and for quantum computation. In this publication, the group of Andreas Wallraff at ETH Zurich demonstrated the implementation of a teleportation protocol, up to the single-shot measurement step, with superconducting qubits coupled to a microwave resonator. Using full quantum state tomography and evaluating an entanglement witness, they show that the protocol generates a genuine tripartite entangled state of all three qubits. Calculating the projection of the measured density matrix onto the basis states of two qubits allows them to reconstruct the teleported state. Repeating this procedure for a complete set of input states they find an average output state fidelity of the teleportation process of 86%.

Full article:
http://prl.aps.org/abstract/PRL/v108/i4/e040502, or arXiv:1107.4774