Exact JSD Contraction Coefficient for Tensorized Binary Symmetric Channels
Abstract
We derive an exact closed-form formula for the Jensen-Shannon divergence contraction coefficient of BSC(δ)^⊗n. The result expresses η_JSD(BSC^⊗n) as a finite sum over Hamming weights involving binomial distributions. The proof combines the equivalence η_JSD = η_χ² for operator convex f-divergences with explicit computation via S_n-reduction and tensor invariance of triangular discrimination.
Fields of Study & Subjects
Wireless Communication Security Techniques
Random Matrices and Applications
Statistical Mechanics and Entropy
Publication details
- Journal / source
- Zenodo (CERN European Organization for Nuclear Research)
- Publication date
- 3 January 2026
- Language
- EN
- Document type
- Preprint