English

Pseudomoments of the Riemann zeta function

Functional Analysis 2018-12-05 v3 Complex Variables Number Theory

Abstract

The 22kth pseudomoments of the Riemann zeta function ζ(s)\zeta(s) are, following Conrey and Gamburd, the 2k2kth integral moments of the partial sums of ζ(s)\zeta(s) on the critical line. For fixed k>1/2k>1/2, these moments are known to grow like (logN)k2(\log N)^{k^2}, where NN is the length of the partial sum, but the true order of magnitude remains unknown when k1/2k\le 1/2. We deduce new Hardy--Littlewood inequalities and apply one of them to improve on an earlier asymptotic estimate when kk\to\infty. In the case k<1/2k<1/2, we consider pseudomoments of ζα(s)\zeta^{\alpha}(s) for α>1\alpha>1 and the question of whether the lower bound (logN)k2α2(\log N)^{k^2\alpha^2} known from earlier work yields the true growth rate. Using ideas from recent work of Harper, Nikeghbali, and Radziwi{\l\l} and some probabilistic estimates of Harper, we obtain the somewhat unexpected result that these pseudomements are bounded below by logN\log N to a power larger than k2α2k^2\alpha^2 when k<1/ek<1/e and NN is sufficiently large.

Keywords

Cite

@article{arxiv.1701.06842,
  title  = {Pseudomoments of the Riemann zeta function},
  author = {Andriy Bondarenko and Ole Fredrik Brevig and Eero Saksman and Kristian Seip and Jing Zhao},
  journal= {arXiv preprint arXiv:1701.06842},
  year   = {2018}
}

Comments

This paper has been accepted for publication in Bulletin of the LMS