Fully universal entanglement-assisted quantum Gel'fand–Pinsker coding

Develop an entanglement-assisted quantum Gel'fand–Pinsker channel coding protocol that is universal with respect to both the quantum channel and the shared channel-state information state, rather than depending on the description of the shared state.

Background

The paper constructs a universal Gel'fand–Pinsker coding scheme that does not require knowledge of the channel but does require knowledge of the state describing the correlation between the sender and the channel. The encoding and decoding operations depend on this shared state. Removing that dependence and obtaining a protocol universal over the shared state remains explicitly unresolved.

References

A fully universal protocol independent of the shared state $#1{\tau} remains an open problem.

— All you need is the universal correlation detector: A unified approach to universalize communication protocols over quantum channels  (2609.29954 - Watanabe et al., 24 Sep 2026) in Section 9, immediately following Theorem “Universal entanglement-assisted quantum Gel'fand-Pinsker channel coding”