Tripartite quantum state violating the hidden-influence constraints

The possibility to explain quantum correlations via (possibly) unknown causal influences propagating gradually and continuously at a finite speed $v>c$ has attracted some 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.