Surpassing the currently achievable distance of quantum key distribution based on sending-or-not-sending approach

TL;DR

This paper introduces a new sending-or-not-sending phase-matching QKD protocol that enhances phase mismatch tolerance, enabling longer transmission distances for quantum key distribution compared to existing protocols.

Contribution

The paper proposes the SNS-PM-QKD protocol, improving phase mismatch tolerance and extending achievable transmission distances in quantum key distribution.

Findings

SNS-PM-QKD outperforms existing protocols in transmission distance

The protocol is secure under collective attacks in the asymptotic regime

Experimental results demonstrate distances over 1000 km

Abstract

Protocols based on the sending-or-not-sending (SNS) principle have been intensively studied in recent years and have been shown to enable the longest transmission distances in quantum key distribution (QKD). In this work, we propose a sending-or-not-sending phase-matching QKD protocol (SNS-PM-QKD) that improves tolerance to phase mismatch, thereby extending the achievable transmission distance. We present a security analysis of SNS-PM-QKD in the asymptotic (infinite-key) regime under collective attacks. The performance of the proposed protocol is compared with that of standard phase-matching QKD, theoretical SNS-type twin-field QKD protocols (SNS-TF-QKD), and an experimental SNS-TF-QKD operated over transmission distances of up to 1002km. Our results show that SNS-PM-QKD achieves greater transmission distances than these existing protocols, highlighting its potential for long-distance quantum communication.