Optimal entanglement generation for efficient hybrid quantum repeaters
  We propose a realistic protocol to generate entanglement between quantum memories at neighboring nodes in hybrid quantum repeaters. Generated entanglement includes only one type of error, which enables efficient entanglement distillation. In contrast to the known protocols with such a property, our protocol with ideal detectors achieves the theoretical limit of the success probability and the fidelity to a Bell state, promising higher efficiencies in the repeaters. We also show that the advantage of our protocol remains even with realistic threshold detectors. 
Naoya Sota, Koji Azuma, Ryo Namiki, Sahin Kaya Ozdemir, Takashi   Yamamoto, Masato Koashi, Nobuyuki Imoto