English

Sums of Kloosterman sums over primes in an arithmetic progression

Number Theory 2018-06-08 v2

Abstract

For qq prime, X1X \geq 1 and coprime u,vNu,v \in \mathbb{N} we estimate the sums \begin{equation*} \sum_{\substack{p \leq X \substack p \equiv u \hspace{-0.25cm} \mod{v} p \text{ prime}}} \text{Kl}_2(p;q), \end{equation*} where Kl2(p;q)\text{Kl}_2(p;q) denotes a normalised Kloosterman sum with modulus qq. This is a sparse analogue of a recent theorem due to Blomer, Fouvry, Kowalski, Michel and Mili\'cevi\'c showing cancellation amongst sums of Kloosterman sums over primes in short intervals. We use an optimisation argument inspired by Fouvry, Kowalski and Michel. Our argument compares three different bounds for bilinear forms involving Kloosterman sums. The first input in this method is a bilinear bound we prove using uniform asymptotics for oscillatory integrals due to Kiral, Petrow and Young. In contrast with the case when the sum runs over all primes, we exploit cancellation over a sum of stationary phase integrals that result from a Voronoi type summation. The second and third inputs are deep bilinear bounds for Kloosterman sums due to Fouvry-Kowalski-Michel and Kowalski-Michel-Sawin.

Keywords

Cite

@article{arxiv.1801.05880,
  title  = {Sums of Kloosterman sums over primes in an arithmetic progression},
  author = {Alexander Dunn and Alexandru Zaharescu},
  journal= {arXiv preprint arXiv:1801.05880},
  year   = {2018}
}

Comments

19 pages. Minor corrections and improved exposition throughout