A crucial goal for quantum key distribution (QKD) is to transmit unconditionally secure keys over long distances. Previous studies show that the key rate of point-to-point QKD is limited by a secret key rate capacity bound, and higher key rates would require quantum repeaters. In 2018, the seminal twin-field (TF) QKD protocol was proposed to provide a remarkable solution to overcoming the linear secret key capacity bound. This article presents an up-to-date survey on recent developments in this area, including the security proofs of phase-matching QKD and other TF-QKD type protocols, the theoretical examinations of these protocols under realistic conditions, and the recent experimental demonstrations.
@article{arxiv.2011.13092,
title = {Recent advances on quantum key distribution overcoming the linear secret key capacity bound},
author = {Yingqiu Mao and Pei Zeng and Teng-Yun Chen},
journal= {arXiv preprint arXiv:2011.13092},
year = {2020}
}