Coherent one-way quantum conference key agreement based on twin field

TL;DR

This paper introduces a new quantum conference key agreement protocol for three users that leverages coherent states and twin-field techniques to surpass traditional efficiency limits, simplifying experimental implementation.

Contribution

It presents a novel three-user quantum CKA protocol based on twin-field ideas that removes phase randomization and multiple intensity modulation requirements.

Findings

Protocol surpasses traditional efficiency limits.

Eliminates phase randomization requirement.

Simplifies experimental setup.

Abstract

Quantum conference key agreement (CKA) enables key sharing among multiple trusted users with information-theoretic security. Currently, the key rates of most quantum CKA protocols suffer from the limit of the total efficiency among quantum channels. Inspired by the coherent one-way and twin-field quantum key distribution (QKD) protocols, we propose a quantum CKA protocol of three users. Exploiting coherent states with intensity 0 and $\mu$ to encode logic bits, our protocol can break the limit. Additionally, the requirements of phase randomization and multiple intensity modulation are removed in our protocol, making its experimental demonstration simple.