Number Theory

Moments of large families of Dirichlet $L$-functions

Speaker: 
Vorrapan Chandee
Date: 
Wed, Jul 27, 2022
Location: 
PIMS, University of Northern British Columbia
Conference: 
Moments of L-functions Workshop
Abstract: 

Sixth and higher moments of $L$-functions are important and challenging problems in analytic number theory. In this talk, I will discuss my recent joint works with Xiannan Li, Kaisa Matom\"aki, and Maksym Radziwi\l\l~on an asymptotic formula of the sixth and the eighth moment of Dirichlet $L$-functions averaged over primitive characters mod~$q$ over all moduli $q \leq Q$ (and with a short average over critical line for the eighth moment). Unlike the previous works, we do not need to include an average on the critical line for the sixth moment, and we can obtain the eighth moment result without the Generalized Riemann Hypothesis.

Class: 

Discrete Moments

Speaker: 
Fatma Cicek
Date: 
Wed, Jul 27, 2022
Location: 
PIMS, University of Northern British Columbia
Conference: 
Moments of L-functions Workshop
Abstract: 

This talk aims to provide an overview of discrete moment computations, specifically, moments of objects related to the Riemann zeta-function when they are sampled at the nontrivial zeros of the zeta-function. We will discuss methods that have been used to do such calculations and will mention their applications.

Class: 

Limitations to equidistribution in arithmetic progressions

Speaker: 
Aditi Savalia
Date: 
Wed, Jul 27, 2022
Location: 
PIMS, University of Northern British Columbia
Conference: 
Moments of L-functions Workshop
Abstract: 

It is well known that the prime numbers are equidistributed in arithmetic progressions. Such a phenomenon is also observed more generally for a class of arithmetic functions. A key result in this context is the Bombieri--Vinogradov theorem which establishes that the primes are equidistributed in arithmetic progressions ``on average" for moduli $q$ in the range $q\leq x^{1/2-\epsilon}$ for any $\epsilon > 0 $. Building on an idea of Maier, Friedlander--Granville showed that such equidistribution results fail if the range of the moduli $q$ is extended to $q\leq x/(\log x)^B$ for any $B>1$. We discuss variants of this result and give some applications. This is joint work with my supervisor Akshaa Vatwani

Class: 

Quantum variance for automorphic forms

Speaker: 
Bingrong Huang,
Date: 
Wed, Jul 27, 2022
Location: 
PIMS, University of Northern British Columbia
Conference: 
Moments of L-functions Workshop
Abstract: 

In this talk, I will discuss the quantum variances for families of automorphic forms on modular surfaces. The resulting quadratic forms are compared with the classical variance. The proofs depend on moments of central $L$-values and estimates of the shifted convolution sums/non-split sums. (Based on joint work with Stephen Lester.)

Class: 

Logging of the zeta-function, but only for a few moments!

Speaker: 
Tim Trudgian
Date: 
Tue, Jul 26, 2022
Location: 
PIMS, University of Northern British Columbia
Conference: 
Moments of L-functions Workshop
Abstract: 

When we're between friends, we often throw in an $\epsilon$ here or there, and why not? Whether something grows like $(\log T)^{100}$ or just $T^{\epsilon}$ doesn?t often make much difference. I shall outline some current work, with Aleks Simoni\v{c}, on the error term in the fourth-moment of the Riemann zeta-function. We know that the $T^{\epsilon}$ in this problem can be replaced by a power of $\log T$ ? but which power? Tune in to find out.

Class: 

The generalised Shanks's conjecture

Speaker: 
Andrew Pearce-Crump
Date: 
Mon, Jul 25, 2022 to Tue, Jul 26, 2022
Location: 
PIMS, University of Northern British Columbia
Conference: 
Moments of L-functions Workshop
Abstract: 
Shanks's conjecture states that for $\rho$ a non-trivial zero of the Riemann zeta function $\zeta (s)$, we have that $\zeta ' (\rho)$ is real and positive in the mean. We show that this generalises to all order derivatives, with a natural pattern that comes from the leading order of the asymptotic result. We give an idea of the proof, and a discussion on the error term.
Class: 

Asymptotic mean square of product of higher derivatives of the zeta-function and Dirichlet polynomials

Speaker: 
Mithun Das
Date: 
Tue, Jul 26, 2022
Location: 
PIMS, University of Northern British Columbia
Conference: 
Moments of L-functions Workshop
Abstract: 

We discuss the asymptotic behavior of the mean square of higher derivatives of the Riemann zeta function or Hardy's $Z$-function product with a Dirichlet polynomial in a short interval. As an application, we obtain a refinement of some results by Levinson--Montgomery as well as Ki--Lee on zero density estimates of higher derivatives of the Riemann zeta function near the critical line. Also, we obtain a zero distribution result for Matsumoto--Tanigawa's $\eta_k$-function. This is joint work with S. Pujahari.

Class: 

Lambert series of logarithm and a mean value theorem for $\zeta(\frac{1}{2}-it)\zeta'(\frac{1}{2}+it)$

Speaker: 
Atul Dixit
Date: 
Tue, Jul 26, 2022
Location: 
PIMS, University of Northern British Columbia
Conference: 
Moments of L-functions Workshop
Abstract: 
An explicit transformation for the series $\sum_{n=1}^{\infty}d(n)\log(n)e^{-ny},$ Re$(y)>0$, which takes $y$ to~$\frac1y$, is obtained. This series transforms into a series containing $\psi_1(z)$, the derivative of~$R(z)$. The latter is a function studied by Christopher Deninger while obtaining an analogue of the famous Chowla--Selberg formula for real quadratic fields. In the course of obtaining the transformation, new important properties of $\psi_1(z)$ are derived, as is a new representation for the second derivative of the two-variable Mittag-Leffler function $E_{2, b}(z)$ evaluated at $b=1$. Our transformation readily gives the complete asymptotic expansion of $\sum_{n=1}^{\infty}d(n)\log(n)e^{-ny}$ as $y\to0$. This, in turn, gives the asymptotic expansion of $\int_{0}^{\infty}\zeta\left(\frac{1}{2}-it\right)\zeta'\left(\frac{1}{2}+it\right)e^{-\delta t}\, dt$ as $\delta\to0$. This is joint work with Soumyarup Banerjee and Shivajee Gupta.
Class: 

Negative moments of the Riemann zeta function

Speaker: 
Alexandra Florea
Date: 
Mon, Jul 25, 2022
Location: 
PIMS, University of Northern British Columbia
Conference: 
Moments of L-functions Workshop
Abstract: 
I will talk about recent work towards a conjecture of Gonek regarding negative shifted moments of the Riemann zeta function. I will explain how to obtain asymptotic formulas when the shift in the Riemann zeta function is big enough, and how we can obtain non-trivial upper bounds for smaller shifts. This is joint work with H. Bui.
Class: 

The recipe for moments of $L$-functions

Speaker: 
Siegfried Baluyot
Date: 
Mon, Jul 25, 2022
Location: 
PIMS, University of Northern British Columbia
Conference: 
Moments of L-functions Workshop
Abstract: 

In 2005, Conrey, Farmer, Keating, Rubinstein, and Snaith formulated a `recipe' that leads to detailed conjectures for the asymptotic behavior of moments of various families of $L$-functions. In this talk, we will survey recent progress towards their conjectures and explore connections with different subjects.

Class: 

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