On rates of convergence in central limit theorems of Selberg and Bourgade
Po-Han Hsu, Peng-Jie Wong
TL;DR
This work provides explicit rates of convergence in central limit theorems for vectors formed from logarithms of shifted Dirichlet L-functions. Building on Selberg’s CLT and Bourgade’s zeta-function framework, the authors derive a quantitative Dudley-distance bound between the random vector of normalized log-L-values and a limiting N-variate normal with covariance determined by shift interactions, under precise control of shift gaps. The core method propagates through a chain of approximations (from the original X_T to a Gaussian process) and carefully tracks moments and covariance matching, revealing that dependence among components can dramatically affect the rate, and that multidimensional independence cases admit sharper bounds (valid up to N=3). The results extend prior work on Dirichlet L-functions and connect number-theoretic CLTs with multivariate Gaussian-process techniques, with further implications for Dedekind zeta functions and the probabilistic interpretation of log-correlated structures. Overall, the paper provides both a unified framework for high-dimensional CLTs in this setting and concrete rates that quantify how shift structure governs convergence.
Abstract
Based on the recent works of Radziwill-Soundararajan and Roberts, we establish a rate of convergence in Bourgade's central limit theorem for shifted Dirichlet $L$-functions. Our results also indicate that the dependence structure in the components of a random vector could have a dramatic impact on the rate of convergence in such a multivariate central limit theorem.
