Phase-matching quantum key distribution based on heralded pair-coherent source

Twin-field quantum key distribution (TF-QKD) is known for its capacity of overcoming the fundamental rate-distance limit of QKD, and a variety of its variants have been derived. One of them, the phase-matching quantum key distribution (PM-QKD) not only inherits the high rate-distance capacity, but also outperforms the original TF-QKD. Moreover, the relatively less single-photon component of the most frequently used weak coherent source (WCS) makes it unable to meet the high-performance requirements of communication. In this paper, we propose a four-intensity decoy-state PM-QKD protocol based on heralded pair-coherent source to improve the secure key rate and the practicality. The simulations show that the secure key rate of our scheme is about an order of magnitude higher than that of four-intensity decoy-state PM-QKD protocol based on WCS. Meanwhile, the transmission distance is increased by more than 100 km. And the performance of our protocol has been greatly improved, in comparison with the better performance protocol known as 'new PM-QKD'. In addition, the proposed protocol also shows excellent performance when finite data size and statistical fluctuation are considered.