title: Efficient decoherence-free entanglement distribution over lossy quantum channels.
abstract: We propose and demonstrate a scheme for boosting the efficiency of entanglement distribution based on a decoherence-free subspace over lossy quantum channels. By using backward propagation of a coherent light, our scheme achieves an entanglement-sharing rate that is proportional to the transmittance T of the quantum channel in spite of encoding qubits in multipartite systems for the decoherence-free subspace. We experimentally show that highly entangled states, which can violate the Clauser-Horne-Shimony-Holt inequality, are distributed at a rate proportional to T.
authors.affiliation: Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
authors.forename: Rikizo
authors.initials: R
authors.lastname: Ikuta
authors.forename: Yohei
authors.initials: Y
authors.lastname: Ono
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Tashima
authors.forename: Takashi
authors.initials: T
authors.lastname: Yamamoto
authors.forename: Masato
authors.initials: M
authors.lastname: Koashi
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Imoto