Quantum Entropy Contraction and Factorization from Hypercontractivity — E8 Intelligence Research

We prove that hypercontractivity implies entropy contraction for a single quantum channel, without a detailed balance condition. For primitive quantum Markov semigroups that are KMS-symmetric with respect to a faithful invariant state \(σ\), we obtain the modified Log-Sobolev bound α₁≥ λ(2+log\|σ⁻¹\|_∞) where $λ$ is the spectral gap. This removes the assumption of \(L_p\)-regularity for the comparison through the log-Sobolev constant. As an application, we show that the hypercontractivity of an average of two conditional expectations implies the approximate tensorization of relative entropy. Source: http://arxiv.org/abs/2609.20753v1 (arXiv:2609.20753v1) Author: Andrew Stewart Caldin, Independent Researcher, UK. Part of the E8 Intelligence Research series. Platform: e8intelligence.com