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

Area of Science:

• Quantum Information Science
• Foundations of Physics
• Quantum Correlations

Background:

• Classical and quantum theories explain correlations through shared randomness and causal influences.
• Nonlocality in quantum mechanics challenges classical intuition, suggesting correlations stronger than classical physics allows.
• Previous definitions of multipartite nonlocality were often theory-dependent.

Purpose of the Study:

• To demonstrate that certain tripartite quantum correlations cannot be explained by theories relying solely on bipartite nonclassical common causes and unlimited shared randomness.
• To provide a device-independent proof of fundamental tripartite nonlocality in nature.
• To introduce a novel, theory-agnostic definition of genuine tripartite nonlocality.

Main Methods:

• Analysis of tripartite quantum correlations.
• Development of a theory-agnostic framework based on local operations and shared randomness.
• Comparison of quantum correlations with causal models based on bipartite nonclassical common causes.

Main Results:

• Identified specific tripartite quantum correlations that violate the constraints of causal theories involving bipartite nonclassical common causes and unlimited shared randomness.
• Established a device-independent proof that nature's nonlocality is fundamentally at least tripartite.
• Introduced a new definition for genuine tripartite nonlocality.

Conclusions:

• Nature's nonlocality is fundamentally tripartite, irrespective of the physical theory considered.
• The findings necessitate a re-evaluation of nonlocality beyond bipartite frameworks.
• The new definition and framework pave the way for certifying boundlessly multipartite nonlocality in future research.