Multipartite product-state analogue of genuine nonlocality without entanglement

Determine whether an analogous phenomenon of two globally distinguishable but locally indistinguishable multipartite product states can occur for any number of states.

Background

The paper constructs pairs of multipartite product measurements that are globally perfectly distinguishable but remain indistinguishable by finite-round LOCC across every bipartition, even when the parties on either side may act jointly.

The authors contrast this result with multipartite product-state discrimination and state that, to their knowledge, the analogous phenomenon has not been demonstrated for any number of product states. This leaves unresolved whether such a state-based counterpart exists.

References

To the best of our knowledge, an analogous phenomenon has not yet been demonstrated for multipartite product-state discrimination, for any number of states.

— Nonlocality without entanglement for multipartite quantum measurements  (2610.02032 - Manna et al., 1 Oct 2026) in Section Discussion