No Bipartite-Nonlocal Causal Theory Can Explain Nature's Correlations

We show that some tripartite quantum correlations are inexplicable by any causal theory involving bipartite nonclassical common causes and unlimited shared randomness. This constitutes a device independent proof that nature's nonlocality is fundamentally at least tripartite in every conceivable physical theory-no matter how exotic. To formalize this claim, we are compelled to substitute Svetlichny's historical definition of genuine tripartite nonlocality with a novel theory-agnostic definition tied to the framework of local operations and shared randomness. A companion article by Coiteux-Roy et al. generalizes these concepts to any N >= 3 number of parties, providing experimentally amenable device independent inequality constraints along with quantum correlations violating them, thereby certifying that nature's nonlocality must be boundlessly multipartite.

Automated summary

The study proves that certain tripartite quantum correlations cannot be explained by a causal theory involving bipartite nonclassical common causes and unlimited shared randomness, demonstrating that nature's nonlocality is fundamentally tripartite in any physical theory. A new theory-agnostic definition tied to the framework of local operations and shared randomness is proposed, replacing Svetlichny's historical definition of genuine tripartite nonlocality. Another article extends these concepts to any N >= 3 number of parties, providing experimentally feasible device independent inequality constraints and certifying that nature's nonlocality must be infinitely multipartite.