Tripartite quantum state violating the hidden influence constraints

TL;DR

This paper demonstrates that a specific three-party quantum state can produce correlations incompatible with hidden influence models that assume finite-speed causal influences, challenging classical explanations of quantum nonlocality.

Contribution

It introduces a three-party quantum state that violates constraints of hidden influence models, extending previous bipartite and four-party results.

Findings

The three-party state enables superluminal correlation explanations.

Hidden influence models cannot account for the observed correlations.

The results challenge classical causal explanations of quantum nonlocality.

Abstract

The possibility to explain quantum correlations via (possibly) unknown causal influences propagating gradually and continuously at a finite speed v > c has attracted a lot of attention recently. In particular, it could be shown that this assumption leads to correlations that can be exploited for superluminal communication. This was achieved studying the set of possible correlations that are allowed within such a model and comparing them to correlations produced by local measurements on a four-party entangled quantum state. Here, we report on a quantum state that allows for the same conclusion involving only three parties.