Breaking the Rate-Loss Bound of Quantum Key Distribution with Asynchronous Two-Photon Interference

Twin-field quantum key distribution can overcome the secret key capacity of repeaterless quantum key distribution via single-photon interference. However, to compensate for the channel fluctuations and lock the laser fluctuations, the techniques of phase tracking and phase locking are indispensable in experiment, which drastically increase experimental complexity and hinder free-space realization. We herein present an asynchronous measurement-device-independent quantum key distribution protocol that can surpass the secret key capacity even without phase tracking and phase locking. Leveraging the concept of time multiplexing, asynchronous two-photon Bell-state measurement is realized by postmatching two…

• NN
  National Natural Science Foundation of China

  Award: 61801420
• CP
  China Postdoctoral Science Foundation

  Award: 2021M691536
• GO
  Government of Jiangsu Province
• NS
  Natural Science Foundation of Jiangsu Province

  Awards: 020414380182, BK20211145, ZDYD20210101
• FR
  Fundamental Research Funds for the Central Universities

  Award: 020414380182