Quantum repeaters free of polarization disturbance and phase noise

Original quantum repeater protocols based on the single-photon interference suffer from the phase noise of the channel, which makes the long-distance quantum communication infeasible. Fortunately, two-photon interferencelike quantum repeaters can be immune to the phase noise of the channel. However, this type of quantum repeaters may still suffer from polarization disturbance of the channel. Here we propose a quantum repeaters protocol, which is free of the polarization disturbance of the channel based on the invariance of the antisymmetric Bell state |ψ^-⟩=(|H⟩|V⟩-|V⟩|H⟩)/√2 under collective noise. Our protocol is also immune to the phase noise with the Sagnac interferometer configuration. Through single-atom cavity-QED technology and linear optics, this scheme can be implemented easily.