# Towards device-independent information processing on general quantum networks

## TL;DR

This paper demonstrates that polynomial Bell inequalities can be violated in multi-source quantum networks, enabling device-independent information processing that is secure against non-signalling eavesdroppers, thus extending Bell-based security to larger, more practical quantum networks.

## Contribution

It introduces the use of polynomial Bell inequalities for device-independence in multi-source quantum networks, expanding the scope of secure quantum communication.

## Key findings

- Polynomial Bell inequalities can be violated in multi-source networks.
- Violation of these inequalities enables device-independent security.
- Results extend Bell-based security to large-scale quantum networks.

## Abstract

The violation of certain Bell inequalities allows for device-independent information processing secure against non-signalling eavesdroppers. However, this only holds for the Bell network, in which two or more agents perform local measurements on a single shared source of entanglement. To overcome the practical constraint that entangled systems can only be transmitted over relatively short distances, large-scale multi-source networks have been employed. Do there exist analogues of Bell inequalities for such networks, whose violation is a resource for device-independence? In this paper, the violation of recently derived polynomial Bell inequalities will be shown to allow for device-independence on multi-source networks, secure against non-signalling eavesdroppers.