Certification of non-classicality in all links of a photonic star network without assuming quantum mechanics

TL;DR

This paper demonstrates full network nonlocality in a star-shaped photonic network with three sources, providing the first experimental evidence of nonlocality beyond bilocal networks without assuming quantum mechanics.

Contribution

It reports the first experimental certification of full network nonlocality in a star-shaped network with three independent sources, without assuming quantum mechanics.

Findings

Observed full network nonlocality in a three-source photonic network

First demonstration of nonlocality beyond bilocal networks

Validates the non-classical nature of all links in the network

Abstract

Networks composed of independent sources of entangled particles that connect distant users are a rapidly developing quantum technology and an increasingly promising test-bed for fundamental physics. Here we address the certification of their post-classical properties through demonstrations of full network nonlocality. Full network nonlocality goes beyond standard nonlocality in networks by falsifying any model in which at least one source is classical, even if all the other sources are limited only by the no-signaling principle. We report on the observation of full network nonlocality in a star-shaped network featuring three independent sources of photonic qubits and joint three-qubit entanglement-swapping measurements. Our results constitute the first experimental demonstration of full network nonlocality beyond the bilocal network.