Modular network for high-rate quantum conferencing

Carlo Ottaviani,Riccardo Laurenza,Stefano Pirandola,Cosmo Lupo

doi:10.1038/s42005-019-0209-6

Abstract

One of the main open problems in quantum communication is the design of efficient quantum-secured networks. This is a challenging goal, because it requires protocols that guarantee both unconditional security and high communication rates, while increasing the number of users. In this scenario, continuous-variable systems provide an ideal platform where high rates can be achieved by using off-the-shelf optical components. At the same time, the measurement-device independent architecture is also appealing for its feature of removing a substantial portion of practical weaknesses. Driven by these ideas, here we introduce a modular design of continuous-variable network where each individual module is a measurement-device-independent star network. In each module, the users send modulated coherent states to an untrusted relay, creating multipartite secret correlations via a generalized Bell detection. Using one-time pad between different modules, the network users may share a quantum-secure conference key over arbitrary distances at constant rate.

Highlights

One of the main open problems in quantum communication is the design of efficient quantum-secured networks
The first steps in this direction were moved in 2012 with the introduction of a swapping protocol based on an untrusted relay[39,40], a technique that became known as “measurement-device independence” (MDI), and recently extended to continuous variables (CV)-QKD41–46
In our modular architecture, each individual module is a star network running a multipartite MDI-quantum key distribution (QKD) quantum conferencing protocol based on the generalization of symmetric CV-MDI-QKD43

Summary

Introduction

One of the main open problems in quantum communication is the design of efficient quantum-secured networks. Each module consists of a central (untrusted) relay performing a general N-mode Bell detection that allows an arbitrary number of users to share the same quantum conference key. In our modular architecture (see Fig. 1), each individual module is a star network running a multipartite MDI-QKD quantum conferencing protocol based on the generalization of symmetric CV-MDI-QKD43.

Results

Conclusion