Verifying Hierarchic Multipartite and Network Nonlocalities with a Unified Method

TL;DR

This paper introduces a unified method for verifying hierarchic multipartite and network nonlocalities, enabling comprehensive analysis of quantum correlations beyond fully separable states, with applications to quantum networks.

Contribution

It presents a novel, unified approach that verifies all quantum characteristics of multipartite systems, including hierarchic nonlocalities, using a chained Bell inequality construction.

Findings

The method can verify nonlocal correlations beyond fully separable states.

It applies to quantum networks, confirming quantum correlations.

Provides a straightforward way to lift partial nonlocal correlations.

Abstract

The multipartite nonlocality provides deep insights into the fundamental feature of quantum mechanics and guarantees different degrees of cryptography security for potential applications in the quantum internet. Verifying multipartite nonlocal correlations is a difficult task. We propose a unified approach that encompasses all the quantum characteristics of the multipartite correlated system beyond from fully separable to biseparable no-signaling correlations. We offer a straightforward method to verify general systems by lifting partial nonlocal correlations. This allows to construct a chained Bell inequality, facilitating the unified verification of hierarchic multipartite nonlocalities. We finally apply the lifting method to verify the correlations derived from quantum networks.