Global optimality of hybrid entanglement-distribution protocols

Determine whether hybrid entanglement-distribution protocols more efficient than the proposed scalable hybrid protocol exist, including protocols that may sacrifice scalability.

Background

The paper develops a scalable hybrid entanglement-distribution scheme combining homodyne-based and majorization-based operations at DV–CV interfaces. The protocol is shown to outperform pairwise singlet conversion on series-parallel topologies, but the authors explicitly acknowledge that the optimization over the considered protocol family may not be globally optimal.

The unresolved issue is whether other hybrid protocols—potentially non-scalable—can achieve higher singlet-conversion probabilities or otherwise provide more efficient entanglement distribution. This question concerns protocol optimality beyond the specific operations and recursive framework analyzed in the paper.

References

While our proposed hybrid protocol offers clear advantages, it is likely not globally optimal. Determining whether more efficient (but potentially not scalable) hybrid protocols exist remains a valuable direction for investigation.

— A scalable entanglement distribution framework for hybrid quantum networks  (2609.25571 - Zhao et al., 22 Sep 2026) in Section 7, Conclusion and discussion, item 1

However, extending the advances to a unified framework for a large hybrid QN remains an open challenge.

— A scalable entanglement distribution framework for hybrid quantum networks  (2609.25571 - Zhao et al., 22 Sep 2026) in Section 1, Introduction