Structure of quantum and broadcasting nonlocal correlations

TL;DR

This paper investigates the complex structure of tripartite nonlocal correlations, introducing inequalities that distinguish between bilocal, broadcasting, and quantum correlations, and reveals new quantum correlations in GHZ-like states.

Contribution

The paper proposes new inequalities for tripartite correlations, generalizes broadcasting inequalities to multipartite systems, and uncovers novel quantum correlations in GHZ-like states.

Findings

Broadcasting inequalities are violated by quantum states.

GHZ-like states exhibit strong, new quantum correlations.

Generalized inequalities distinguish different nonlocal correlation types.

Abstract

The multipartite setting offers much more complexity of nonlocality than the bipartite one. We analyze the structure of tripartite nonlocal correlations by proposing inequalities satisfied by each type: bilocal, broadcasting and quantum, but violated by the other two. One of the inequalities satisfied by broadcasting correlations is generalized for multipartite systems. The study of its quantum mechanical violation reveals that Greenberger-Horne-Zeilinger-like states exhibit new, powerful correlations.