Equidistribution of signs for Hilbert modular forms of half-integral weight

We prove an equidistribution of signs for the Fourier coefficients of Hilbert modular forms of half-integral weight. Our study focuses on certain subfamilies of coefficients that are accessible via the Shimura correspondence. This is a generalization of the result of Inam and Wiese to the setting of totally real number fieldsComment: To appear in Research in Number Theor

An Alternative Approach to Computing β(2k+1)\beta(2k+1)

This paper presents a new approach to evaluating the special values of the Dirichlet beta function, $\beta(2k+1)$, where $k$ is any nonnegative integer. Our approach relies on some properties of the Euler numbers and polynomials, and uses basic calculus and telescoping series. By a similar procedure, we also yield an integral representation of $\beta(2k)$. The idea of our proof adapts from a previous study by Ciaurri et al., where the authors introduced a new proof of Euler's formula for $\zeta(2k)$.Comment: 11 page

Notes on the arithmetic of Hilbert modular forms

The purpose of this semi-expository article is to give another proof of a classical theorem of Shimura on the critical values of the standard L-function attached to a Hilbert modular form. Our proof is along the lines of previous work of Harder and Hida (independently). What is different is an organizational principle based on the period relations proved by Raghuram and Shahidi for periods attached to regular algebraic cuspidal automorphic representations. The point of view taken in this article is that one need only prove an algebraicity theorem for the most interesting L-value, namely, the central critical value of the L-function of a sufficiently general type of a cuspidal automorphic representation. The period relations mentioned above then gives us a result for all critical values. To transcribe such a result into a more classical context we also discuss the arithmetic properties of the dictionary between holomorphic Hilbert modular forms and automorphic representations of GL(2) over a totally real number field F.Comment: To appear in the Journal of the Ramanujan Mathematical Societ

Arithmetic Properties of L-functions Attached to Hilbert Modular Forms

The goal of this thesis is to study some arithmetic properties of L-functions attached to Hilbert modular forms. We mainly use a representation theoretical point of view for the study, which can be done by associating Hilbert modular forms of our interests with automorphic representations of GL(2). Furthermore, their L-functions are deeply related. We use this realization to analyze the critical L-values for Hilbert modular forms, which reduces some technical difficulties. The thesis focuses on three main theorems which concern: Algebraicity theorem; Congruence property; and Non-vanishing property. The first theorem is completed by interpreting the Mellin transform cohomologically, and the second follows from analyzing it integrally. The third theorem is obtained by studying the completed L-functions of Hilbert modular forms.Department of Mathematic

Large Sums of Fourier Coefficients of Cusp Forms

Let $N$ be a fixed positive integer, and let $f\in S_k(N)$ be a primitive cusp form given by the Fourier expansion $f(z)=\sum_{n=1}^{\infty} \lambda_f(n)n^{\frac{k-1}{2}}e(nz)$. We consider the partial sum $S(x,f)=\sum_{n\leq x}\lambda_f(x)$. It is conjectured that $S(x,f)=o(x\log x)$ in the range $x\geq k^{\epsilon}$. Lamzouri proved in arXiv:1703.10582 [math.NT] that this is true under the assumption of the Generalized Riemann Hypothesis (GRH) for $L(s,f)$. In this paper, we prove that this conjecture holds under a weaker assumption than GRH. In particular, we prove that given $\epsilon>(\log k)^{-\frac{1}{8}}$ and $1\leq T\leq (\log k)^{\frac{1}{200}}$, we have $S(x,f)\ll \frac{x\log x}{T}$ in the range $x\geq k^{\epsilon}$ provided that $L(s,f)$ has no more than $\epsilon^2\log k/5000$ zeros in the region $\left\{s\,:\, \Re(s)\geq \frac34, \, |\Im(s)-\phi| \leq \frac14\right\}$ for every real number $\phi$ with $|\phi|\leq T$.Comment: 14 page