What was already known
The 1999 Holevo–Werner thermal-input lower bound was the benchmark. The Gaussian threshold at ν=1 is η=0.8; antidegradability only forces zero capacity at η≤0.75.
AI involvement
Mele and coauthors credit ChatGPT 5.6 Sol with the non-Gaussian input families. They selected states, proved the Gaussian comparison and certified the finite witnesses.
The original paper expressly credits the model with the decisive non-Gaussian witness families while reserving the Gaussian theorem and certification to the authors.
Importance
The certified witnesses improve the one-use lower bound and establish positive communication in a previously unresolved high-noise range.
Limitations
The full quantum capacity remains unknown. The η=0.7818 point is numerical and lacks the rigorous interval certificate used for the two stated witnesses.
Technical verification
Appendices A and B report rigorous interval enclosures for the fixed eta=0.8 and eta=0.7841 witnesses. The certified fixed-parameter separation is complete within those inputs; the wider numerical scan is not included in this rating. The computation is source-reported.
Formal checking
Certified interval matrix entries, Gershgorin eigenvalue enclosures and outward-rounded entropy bounds
- Checker
- Mele, Catalano, Fanizza, Giovannetti and Lami's interval computation
- Scope
- Positive coherent information of explicit non-Gaussian witnesses at nu=1, eta=0.8 and eta=0.7841
- Basis
- Reported by the linked checker
Checking a formal statement does not establish that it matches the original problem.
Human understanding
The authors explain the witness construction, physical cutoff channel, coherent-information comparison and certification mechanism.
Correction and publication history
The certified witnesses improve the one-use lower bound and establish positive communication in a previously unresolved high-noise range.
Read this published revision