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Title: Do almost-quantum correlations satisfy information causality?
Plain: The almost-quantum set is a slightly larger family than the quantum correlations that obeys nearly every principle proposed so far. If it also obeys information causality, that principle cannot single out quantum theory.
Precise: Determine whether every behavior in the almost-quantum set (level 1+AB of the Navascues-Pironio-Acin hierarchy, Navascues et al., Nature Communications 2015) satisfies information causality, in its original form and its generalized correlated-input form, for any number of copies and any wiring. An answer is a proof or an explicit almost-quantum box with a violating protocol.
Settled by: A proof that the almost-quantum set obeys information causality, or an almost-quantum box with an information-causality-violating protocol.
Kind: well-posed
Answer type: yes-no
References: (empty)
Literature status: open
Status note: Stated as unresolved in arXiv:2609.10508 (September 2026).
Posed since: 2015