Experimental Measurement-Device-Independent Quantum Cryptographic Conferencing

TL;DR

This paper demonstrates the experimental realization of measurement-device-independent quantum cryptographic conferencing with three users, employing decoy-state methods and GHZ state projection, advancing practical quantum network development.

Contribution

It presents the first experimental implementation of three-user MDIQCC using polarization encoding and GHZ state projection, enhancing secure multipartite quantum communication.

Findings

Successful three-user MDIQCC experiment

Use of four-intensity decoy-state method

Feasibility of multipartite quantum networks

Abstract

Quantum cryptographic conferencing (QCC) allows sharing secret keys among multiple distant users and plays a crucial role in quantum networks. Because of the fragility and low generation rate of genuine multipartite entangled states required in QCC, realizing and extending QCC with the entanglement-based protocol is challenging. Measurement-device-independent (MDI) QCC, which removes all detector side channels, is a feasible long-distance quantum communication scheme to practically generate multipartite correlation with multiphoton projection measurement. Here we experimentally realize the three-user MDIQCC protocol with four-intensity decoy-state method, in which we employ the polarization encoding and the Greenberger-Horne-Zeilinger state projection measurement. Our work demonstrates the experimental feasibility of the MDI QCC, which lays the foundation for the future realization of quantum networks with multipartite communication tasks.