Multi-copy entanglement purification with practical spontaneous parametric down conversion sources

Zhang Shuai-Shuai^{1, 3}, Shu Qi^{1, 3}, Zhou Lan², Sheng Yu-Bo^{1, †}

(color online) The entanglement purification protocol (EPP) with two copies of mixed states using two SPDC sources. PBSs are polarization beam splitters. PBSs can fully transmit the polarized photon and reflect the polarized photon, respectively.