Simultaneous Verification of Genuine Multipartite Nonlocality and Full Network Nonlocality

TL;DR

This paper introduces a novel method to simultaneously verify genuine multipartite nonlocality and full network nonlocality in quantum networks, demonstrated experimentally with photonic systems, advancing quantum nonlocality certification.

Contribution

The paper presents the first approach to verify both types of nonlocality simultaneously in a single experiment within a quantum network.

Findings

Quantum correlations cannot be simulated by certain biseparable and stronger-than-quantum sources.

Verification of genuine multipartite nonlocality in GHZ states.

Experimental demonstration of both nonlocalities via a single Bell inequality violation.

Abstract

Genuine multipartite nonlocality and nonlocality arising in networks composed of several independent sources have been separately investigated. While some genuinely entangled states cannot be verified by violating a single Bell-type inequality, a quantum network consisting of different sources allows for the certification of the non-classicality of all sources. In this paper, we propose the first method to verify both types of nonlocality simultaneously in a single experiment. We consider a quantum network comprising a bipartite source and a tripartite source. We demonstrate that there are quantum correlations cannot be simulated if the tripartite source distributes biseparable systems while the bipartite source distributes even stronger-than-quantum systems. These correlations can be used to verify both the genuine multipartite nonlocality of generalized Greenberger-Horne-Zeilinger states and the full network nonlocality that is stronger than all the existing results. Experimentally, we observe both types of nonlocality in a high fidelity photonic quantum network by violating a single network Bell inequality.