Experimental demonstration of non-bilocal quantum correlations

TL;DR

This paper experimentally demonstrates non-bilocal quantum correlations in a three-node photonic network, showing violations of a Bell-like inequality and greater noise tolerance compared to standard Bell non-locality.

Contribution

It provides the first experimental demonstration of non-bilocal correlations in a quantum network with independent entanglement sources.

Findings

Successfully violated a Bell-like inequality for bilocal models

Demonstrated non-bilocal correlations with photonic qubits

Showed increased noise tolerance over standard Bell non-locality

Abstract

Quantum mechanics admits correlations that cannot be explained by local realistic models. Those most studied are the standard local hidden variable models, which satisfy the well-known Bell inequalities. To date, most works have focused on bipartite entangled systems. Here, we consider correlations between three parties connected via two independent entangled states. We investigate the new type of so-called "bilocal" models, which correspondingly involve two independent hidden variables. Such models describe scenarios that naturally arise in quantum networks, where several independent entanglement sources are employed. Using photonic qubits, we build such a linear three-node quantum network and demonstrate non-bilocal correlations by violating a Bell-like inequality tailored for bilocal models. Furthermore, we show that the demonstration of non-bilocality is more noise-tolerant than that of standard Bell non-locality in our three-party quantum network.