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arXiv · 2512.15656

All Entangled States are Nonlocal and Self-Testable in the Broadcast Scenario

Pavel Sekatski·Jef Pauwels
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Abstract

Entanglement and Bell nonlocality are known to be inequivalent: there exist entangled states that admit a local hidden-variable model for all local measurements. Here we show that this gap disappears in a minimal broadcast extension of the Bell scenario. Assuming only the validity of quantum theory, we prove that for every entangled state $\rho_{AB}$ there exist local broadcasting maps and local measurements such that the resulting four--partite correlations cannot be reproduced by any broadcast network whose source is separable across the $A|B$ cut. Thus, all entangled states are broadcast nonlocal in quantum theory. In addition, we show that all (also mixed) multipartite states can be broadcast-self-tested, according to a natural operational definition.

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Pavel Sekatski, Jef Pauwels. 2025-12-17. All Entangled States are Nonlocal and Self-Testable in the Broadcast Scenario. https://arxiv.org/abs/2512.15656

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