Double square moments and bounds for resonance sums for cusp forms
Date: Thu, Jul 28, 2022
Location: PIMS, University of Northern British Columbia
Conference: Moments of L-functions Workshop
Subject: Mathematics, Number Theory
Class: Scientific
CRG: L-Functions in Analytic Number Theory
Abstract:
Let f and g be holomorphic cusp forms for the modular group SL2(Z) of weight k1 and k2 with
Fourier coefficients λf(n) and λg(n), respectively. For real α≠0 and 0<β≤1, consider a smooth resonance sum SX(f,g;α,β) of λf(n)λg(n) against e(αnβ) over X≤n≤2X. Double square moments of SX(f,g;α,β) over both f and g are nontrivially bounded when their weights k1 and k2 tend to infinity together. By allowing both f and g to move, these double moments are indeed square moments associated with automorphic forms for GL(4). These bounds reveal insights into the size and oscillation of the resonance sums and their potential resonance for GL(4) forms when k1 and k2 are large.