Gaussian distribution of short sums of trace functions over finite fields

TL;DR

This paper demonstrates that short sums of trace functions over finite fields tend to follow a normal distribution under certain conditions, extending classical results to a broader class of exponential sums.

Contribution

It generalizes previous central limit theorems for trace functions, applying to sums like Kloosterman and Birch sums through monodromy group analysis.

Findings

Short sums of trace functions are asymptotically normal.

The results apply to exponential sums from Fourier transforms.

A quantitative version based on moments of random matrices is provided.

Abstract

We show that under certain general conditions, short sums of $\ell$-adic trace functions over finite fields follow a normal distribution asymptotically when the origin varies, generalizing results of Erd\H{o}s-Davenport, Mak-Zaharescu and Lamzouri. In particular, this applies to exponential sums arising from Fourier transforms such as Kloosterman sums or Birch sums, as we can deduce from the works of Katz. By approximating the moments of traces of random matrices in monodromy groups, a quantitative version can be given as in Lamzouri's article, exhibiting a different phenomenon than the averaging from the central limit theorem.