English

Joint cubic moment of Eisenstein series and Hecke-Maass cusp forms

Number Theory 2025-09-24 v3

Abstract

Let ψ\psi be a smooth compactly supported function on X=SL(2,Z)\H\mathbb{X} = SL(2,\mathbb{Z})\backslash\mathbb{H}. In this paper, we are interested in the joint cubic moments of automorphic forms when the spectral parameters go to infinity. We show that the diagonal case for Eisenstein series Xψ(z)E(z,1/2+it)3dμz=Oψ(t1/3+ε)\int_{\mathbb{X}}\psi(z)E(z,1/2+it)^{3} d\mu z = \mathcal{O}_{\psi}(t^{-1/3+\varepsilon}). In off-diagonal case we prove 12logtXψ(z)E(z,1/2+it)2g(z)dμz=o(1)\frac{1}{2\log t}\int_{\mathbb{X}}\psi(z)|E(z,1/2+it)|^{2}g(z)d\mu z = o(1) as long as min{t,tg}\min\{t , t_{g}\} \rightarrow \infty. Finally we show Xψ(z)f2(z)g(z)dμz=o(1)\int_{\mathbb{X}}\psi(z)f^{2}(z)g(z)d\mu z = o(1) in the range tftgtf2/3ε|t_{f} - t_{g}| \leq t_{f}^{2/3-\varepsilon} where f,gf,g are two Hecke-Maass cusp forms.

Keywords

Cite

@article{arxiv.2410.04448,
  title  = {Joint cubic moment of Eisenstein series and Hecke-Maass cusp forms},
  author = {Chengliang Guo},
  journal= {arXiv preprint arXiv:2410.04448},
  year   = {2025}
}

Comments

29 pages, completely rewrite and polish. All results are unconditional. Final version, to appear in Journal of Number theory