QUROPE Quantum Information Processing and Communication in Europe

S. Takeda, T. Mizuta, M. Fuwa, P. van Loock and A. Furusawa
Nature 500, 315 (2013)

Quantum teleportation allows for the transfer of arbitrary, in principle, unknown quantum states from a
sender to a spatially distant receiver, who share an entangled state and can communicate classically. It is the
essence of many sophisticated protocols for quantum communication and computation. The natural choice of
flying qubits in these schemes is given by photons. However, teleporting a photonic qubit has to face several
challenges, related to the fundamentally probabilistic nature of linear-optics Bell measurements as well as the
need for either destroying the teleported qubit or attenuating the input qubit when the detectors do not
resolve photon numbers.

In their work, Takeda and colleagues experimentally realize fully deterministic, unconditional quantum
teleportation of photonic qubits. In order to attain this result, they implement a "hybrid" technique:
continuous-variable (CV) teleportation of a discrete-variable, photonic qubit. This allows for a faithful qubit
transfer even with imperfect CV entangled states: the overall transfer fidelities exceed the classical limit of
teleportation. Furthermore, even for a relatively low level of the entanglement, qubits are teleported much
more efficiently than in previous experiments, albeit post-selectively.