Active teleportation and entanglement swapping of a vacuum-one photon qubit



We report the experimental realization of the “active” quantum teleportation (QST) of a one-particle entangled qubit. The qubit is physically implemented by a two-dimensional subspace of states of a mode of the electromagnetic field, specifically, the space spanned by the vacuum and the one photon state. This demonstration completes the original QST protocol and renders it available for actual implementation in quantum computation networks. It is accomplished by implementing a 8 m optical delay line and a single-photon triggered fast Electro-Optic Pockels cell. A large value of teleportation “fidelity” was attained: Fa = 90 ∓ 2)%. Furthermore we present a scheme for delayed-entanglement swapping by applying the same quantum optical method.