Quantum Correlations in Connected Multipartite Bell Experiments

TL;DR

This paper investigates quantum correlations in complex network structures beyond traditional Bell experiments, deriving tight inequalities for classical correlations and analyzing quantum violations.

Contribution

It introduces tight Bell-type inequalities for multipartite network configurations and examines their quantum violations, advancing understanding of quantum correlations in networked systems.

Findings

Derived tight Bell inequalities for networked quantum systems

Identified quantum violations of classical bounds in these networks

Enhanced understanding of quantum correlations beyond standard Bell experiments

Abstract

Quantum correlations arising in Bell experiments, involving a physical source that emits a quantum state to a number of observers, have been intensively studied over the last decades. Much less is known about the nature of quantum correlations arising in network structures beyond the Bell experiments. Such networks can involve many independent sources emitting states to observers in accordance with the network configuration. Here, we will study classical and quantum correlations in a family of networks which can be regarded as compositions of several independent multipartite Bell experiments connected together through a central node. For such networks we present tight Bell-type inequalities which are satisfied by all classical correlations. We study properties of the violations of our inequalities by probability distributions arising in quantum theory.