Multipartite nonlocality in photonic quantum networks

I will present two recent results in the realm of quantum networks from Quantum Optics and Information Laboratory at Griffith University. First, we show how multi-partite quantum networks enable the recovery of genuine nonlocal correlations from mixed entangles states that cannot demonstrate quantumness in the standard bi-partite scenario. We use a complex network that incorporates quantum sources, measurement nodes, and a quantum channel to observe nonlocal tri-partite correlations that do not have a local hidden variable description [1] using Bell-local missed entangled states. In our second work, we demonstrate a resource-efficient method of distributing loophole-free nonlocality between multiple parties. We implement a photonic three-party experiment where we verify nonlocal quantum correlations between two trusted and one untrusted node with the detection loophole closed. Our approach is easily scalable toward larger numbers of parties and more complex multi-partite network configurations. [1] L. Villegas-Aguilar et al. Nature Communications 15, 3112 (2024) [2] A. Pepper et al. AVS Quantum Science 6, 021401 (2024)