Searcharxiv⌕ Search

arXiv · 2610.31493

Improved Bounds for the Entropic Central Limit Theorem in the Log-Concave Case

Abstract

Let $μ$ be a log-concave isotropic probability measure on $R^d$ , and let $μ^n$ denote the law of the normalized sum of $n$ independent random vectors with law $μ$. We prove that \[ H(μ^n|γ)\leq \frac{C}{n} \min\left\{1+\log(ed)^2H(μ|γ)\ ,\ d\right\}. \] Compared to the previous best known bound, our estimate replaces the polynomial dependence on the dimension by a polylogarithmic one. The proof relies on a new combination of the De Bruijn identity with Eldan's stochastic localization process.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Tom Maitre. 2026-10-22. Improved Bounds for the Entropic Central Limit Theorem in the Log-Concave Case. https://arxiv.org/abs/2610.31493

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Age Optimal Sampling and Routing under Intermittent Links and Energy Constraints

Links in practical systems, such as satellite--terrestrial integrated networks, exhibit distinct delay distributions, intermittent availability, and heterogeneous energy costs. These characteristics pose significant challenges to maintaining timely and energy-efficient status updates. While link availability restricts feasible transmission routes, routing decisions determine the actual delay and energy expenditure. This paper tackles these challenges by jointly optimizing sampling and routing decisions to minimize monotonic, non-linear Age of Information (AoI). The proposed formulation incorporates key system features, including multiple routes with correlated random delays, stochastic link availability, and route-dependent energy consumption. We model the problem as an infinite-horizon Constrained Semi-Markov Decision Process (CSMDP) with a hybrid state--action space and develop an efficient nested algorithm, termed Bisec-\textsc{ReaVI}, to solve this problem. We analyze the structural properties of the solution and reveal a well-defined jointly optimal policy structure: (i) For general monotonic penalty functions, the optimal sampling policy is a piecewise linear waiting policy with at most $N$ breakpoints given $N$ routes; and (ii) under a derived Expected Penalty Ordering condition, the optimal routing policy is a monotonic threshold-based handover policy characterized by at most $\binom{N}{2}$ thresholds. Numerical experiments in a \textit{satellite--terrestrial} integrated routing scenario demonstrate that the proposed scheme efficiently balances energy usage and information freshness, and reveal a counter-intuitive insight: \textit{even routes with higher average delay, higher delay variance or lower availability can still play a critical role in minimizing monotonic functions of AoI}.

cs.IT↗

Construction and Decoding of Convolutional Codes with optimal Column Distances

The construction of Maximum Distance Profile (MDP) convolutional codes in general requires the use of very large finite fields. In contrast convolutional codes with optimal column distances maximize the column distances for a given arbitrary finite field. In this paper, we present a construction of such convolutional codes. In addition, we prove that for the considered parameters the codes that we constructed are the only ones achieving optimal column distances. The structure of the presented convolutional codes with optimal column distances is strongly related to first order Reed-Muller block codes and we leverage this fact to develop a reduced complexity version of the Viterbi algorithm for these codes.

cs.IT↗

GRAND for Gaussian Intersymbol Interference Channels

Channel decoding is challenging in communication channels exhibiting memory effects. In this work, we extend the recently proposed decoding paradigm of guessing random additive noise decoding (GRAND) to channels with memory, focusing on linear Gaussian intersymbol interference (ISI) channels. To characterize error patterns (EPs) under channel memory, we introduce the concept of error bursts and define sequence reliability to quantify the likelihood of an EP. Based on sequence reliability, we develop soft GRAND for ISI channels, termed SGRAND-ISI, which generalizes SGRAND to linear Gaussian ISI channels and is equivalent to maximum-likelihood (ML) decoding. We then develop ordered reliability bit GRAND (ORBGRAND) variants based on SGRAND-ISI that replace exact sequence reliabilities with rank-based approximations to reduce online computation. The proposed framework is first established for binary-input first-order ISI channels and subsequently extended to higher-order channel memory and higher-order modulation. Numerical experiments over first- and second-order ISI channels show that the proposed algorithms achieve multiple-dB gains over GRAND algorithms that ignore channel memory and can operate within $0.1$-$0.2$ dB of the ML benchmark. Compared with the recently proposed ORBGRAND-Approximate Independence algorithm, CDF-ORBGRAND-ISI provides a gain of at least $0.5$ dB at a block error rate (BLER) of $10^{-3}$. We further evaluate the online decoding complexity of the proposed GRAND-ISI algorithms using a module-wise complexity analysis.

cs.IT↗