Skip to Main Content


AMS eBook CollectionsOne of the world's most respected mathematical collections, available in digital format for your library or institution


The Second Moment Theory of Families of $L$-Functions–The Case of Twisted Hecke $L$-Functions

About this Title

Valentin Blomer, Étienne Fouvry, Emmanuel Kowalski, Philippe Michel, Djordje Milićević and Will Sawin

Publication: Memoirs of the American Mathematical Society
Publication Year: 2023; Volume 282, Number 1394
ISBNs: 978-1-4704-5678-8 (print); 978-1-4704-7350-1 (online)
DOI: https://doi.org/10.1090/memo/1394
Published electronically: January 3, 2023
Keywords: $L$-functions, modular forms, special values of $L$-functions, moments, mollification, analytic rank, shifted convolution sums, root number, Kloosterman sums, resonator method

PDF View full volume as PDF

View other years and numbers:

Table of Contents

Chapters

  • 1. The second moment theory of families of $L$-functions
  • 2. Preliminaries
  • 3. Algebraic exponential sums
  • 4. Computation of the first twisted moment
  • 5. Computation of the second twisted moment
  • 6. Non-vanishing at the central point
  • 7. Extreme values of twisted $L$-functions
  • 8. Upper bounds for the analytic rank
  • 9. A conjecture of Mazur-Rubin concerning modular symbols
  • Notation index

Abstract

For a fairly general family of $L$-functions, we survey the known consequences of the existence of asymptotic formulas with power-saving error term for the (twisted) first and second moments of the central values in the family.

We then consider in detail the important special case of the family of twists of a fixed cusp form by primitive Dirichlet characters modulo a prime $q$, and prove that it satisfies such formulas. We derive arithmetic consequences:

  • a positive proportion of central values $L(f\otimes \chi ,1/2)$ are non-zero, and indeed bounded from below;
  • there exist many characters $\chi$ for which the central $L$-value is very large;
  • the probability of a large analytic rank decays exponentially fast.
  • We finally show how the second moment estimate establishes a special case of a conjecture of Mazur and Rubin concerning the distribution of modular symbols.

    References [Enhancements On Off] (What's this?)

    References