Simpler scenarios witnessing LOSR-GMNL

Determine whether scenarios simpler than the five-party, two-setting, two-outcome configuration used by Brassard et al. can witness a separation between quantum behaviors and models based on at-most-bipartite nonclassical resources under the LOSR-GMNL definition.

Background

Prior work established a five-party pseudotelepathic game whose perfect quantum behavior is incompatible with a broad class of models built from bipartite nonclassical resources, but did not derive an explicit robustness bound. The paper notes that this result uses a relatively large outcome space for two of the parties and leaves unresolved whether a simpler experimental and conceptual scenario can demonstrate the same separation.

Resolving this problem would identify whether the strong LOSR-GMNL phenomenon can occur in a more elementary Bell scenario than the previously known construction. The present paper answers this question for the simplest nontrivial five-party (5,2,2) scenario, but the quoted open problem concerns scenarios simpler than the earlier construction in Ref. Brassard26.

References

This work also leaves open the question as to whether simpler scenarios can witness the separation, a question of both practical and conceptual significance.

— Minimal Scenarios Witnessing Genuine Multipartite Nonlocality Possibilistically  (2610.11377 - Patra et al., 8 Oct 2026) in Section 1, paragraph discussing Ref. Brassard26

While we do not know if there is a quantum-achievable 3-party strongly LOSR-GMNL behavior, we are able to construct $\epsilon$-close instances.

— Minimal Scenarios Witnessing Genuine Multipartite Nonlocality Possibilistically  (2610.11377 - Patra et al., 8 Oct 2026) in Section “A family of tripartite LOSR-GMNL games with ε-close-to-winning quantum strategies”