On the expected number of roots of a random Dirichlet polynomial

Fuente: arXiv
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Main Authors: Aymone, Marco, Bueno, Caio
Format: Preprint
Published: 2024
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author Aymone, Marco
Bueno, Caio
author_facet Aymone, Marco
Bueno, Caio
contents Let $T>0$ and consider the random Dirichlet polynomial $S_T(t)=Re\, \sum_{n\leq T} X_n n^{-1/2-it}$, where $(X_n)_{n}$ are i.i.d. Gaussian random variables with mean $0$ and variance $1$. We prove that the expected number of roots of $S_T(t)$ in the dyadic interval $[T,2T]$, say $\mathbb{E} N(T)$, is approximately $2/\sqrt{3}$ times the number of zeros of the Riemann $ζ$ function in the critical strip up to height $T$. Moreover, we also compute the expected number of zeros in the same dyadic interval of the $k$-th derivative of $S_T(t)$. Our proof requires the best upper bounds for the Riemann $ζ$ function known up to date, and also estimates for the $L^2$ averages of certain Dirichlet polynomials.
format Preprint
id arxiv_https___arxiv_org_abs_2401_07375
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On the expected number of roots of a random Dirichlet polynomial
Aymone, Marco
Bueno, Caio
Number Theory
Probability
Let $T>0$ and consider the random Dirichlet polynomial $S_T(t)=Re\, \sum_{n\leq T} X_n n^{-1/2-it}$, where $(X_n)_{n}$ are i.i.d. Gaussian random variables with mean $0$ and variance $1$. We prove that the expected number of roots of $S_T(t)$ in the dyadic interval $[T,2T]$, say $\mathbb{E} N(T)$, is approximately $2/\sqrt{3}$ times the number of zeros of the Riemann $ζ$ function in the critical strip up to height $T$. Moreover, we also compute the expected number of zeros in the same dyadic interval of the $k$-th derivative of $S_T(t)$. Our proof requires the best upper bounds for the Riemann $ζ$ function known up to date, and also estimates for the $L^2$ averages of certain Dirichlet polynomials.
title On the expected number of roots of a random Dirichlet polynomial
topic Number Theory
Probability
url https://arxiv.org/abs/2401.07375