Large-scale quantum networks based on graphs

TL;DR

This paper introduces a graph-based framework for designing and optimizing large-scale quantum networks that enable secure, long-distance entanglement distribution and error protection, advancing quantum communication infrastructure.

Contribution

It generalizes the quantum repeater concept to multipartite networks using graph states, providing a unified approach for entanglement distribution and error correction.

Findings

Unified graph-based model for quantum networks

Enhanced multipartite entanglement distribution methods

Tools for optimizing quantum network architectures

Abstract

Society relies and depends increasingly on information exchange and communication. In the quantum world, security and privacy is a built-in feature for information processing. The essential ingredient for exploiting these quantum advantages is the resource of entanglement, which can be shared between two or more parties. The distribution of entanglement over large distances constitutes a key challenge for current research and development. Due to losses of the transmitted quantum particles, which typically scale exponentially with the distance, intermediate quantum repeater stations are needed. Here we show how to generalise the quantum repeater concept to the multipartite case, by fully describing large-scale quantum networks, i.e. network nodes and their long-distance links, in the language of graphs and graph states. This unifying approach comprises both the distribution of multipartite entanglement across the network, and the protection against errors via encoding. The correspondence to graph states also provides a tool for optimising the architecture of quantum networks.