We propose and demonstrate a scheme for boosting up the efficiency of entanglement distribution based on a decoherence-free subspace (DFS) 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 DFS. We experimentally show that highly entangled states, which can violate the Clauser-Horne-Shimony-Holt inequality, are distributed at a rate proportional to T.
@article{arxiv.1012.5584,
title = {Efficient decoherence-free entanglement distribution over lossy quantum channels},
author = {Rikizo Ikuta and Yohei Ono and Toshiyuki Tashima and Takashi Yamamoto and Masato Koashi and Nobuyuki Imoto},
journal= {arXiv preprint arXiv:1012.5584},
year = {2011}
}