Effective quantum unique ergodicity for Hecke-Maass newforms and Landau-Siegel zeros

Analytic ranks of automorphic L-functions and Landau-Siegel zeros

We relate the study of Landau-Siegel zeros to the ranks of Jacobians $J_0(q)$ of modular curves for large primes $q$. By a conjecture of Brumer-Murty, the rank should be equal to half of the dimension. Equivalently, almost all newforms of weight two and level $q$ have analytic rank $\leq 1$. We show that either Landau-Siegel zeros do not exist, or that almost all such newforms have analytic rank $\leq 2$. In particular, almost all odd newforms have analytic rank equal to one. Additionally, for a sparse set of primes $q$ we show the rank of $J_0(q)$ is asymptotically equal to the rank predicted…

Schneider-Siegel theorem for a family of values of a harmonic weak Maass form at Hecke orbits

Let $j(z)$ be the modular $j$-invariant function. Let $τ$ be an algebraic number in the complex upper half plane $\mathbb{H}$. It was proved by Schneider and Siegel that if $τ$ is not a CM point, i.e., $[\mathbb{Q}(τ):\mathbb{Q}]\neq2$, then $j(τ)$ is transcendental. Let $f$ be a harmonic weak Maass form of weight $0$ on $Γ_0(N)$. In this paper, we consider an extension of the results of Schneider and Siegel to a family of values of $f$ on Hecke orbits of $τ$. For a positive integer $m$, let $T_m$ denote the $m$-th Hecke operator. Suppose that the coefficients of the principal part of $f$ at t…

On Hecke eigenvalues of Siegel modular forms in the Maass space

In this article, we prove an omega-result for the Hecke eigenvalues $λ_F(n)$ of Maass forms $F$ which are Hecke eigenforms in the space of Siegel modular forms of weight $k$, genus two for the Siegel modular group $Sp_2(\Z)$. In particular, we prove $$ λ_F(n)= Ω(n^{k-1}\text{exp} (c \frac{\sqrt{\log n}}{\log\log n})), $$ when $c>0$ is an absolute constant. This improves the earlier result $$ λ_F(n)= Ω(n^{k-1} (\frac{\sqrt{\log n}}{\log\log n})) $$ of Das and the third author. We also show that for any $n \ge 3$, one has $$ λ_F(n) \leq n^{k-1}\text{exp} \left(c_1\sqrt{\frac{\log n}{\log\log n}}…

Hecke-Maass cusp forms on PGL_n of large levels with non-vanishing L-values

We introduce a new trace formula of Kuznetsov type involving the central standard L-values and the Whittaker periods of cuspidal automorphic representations of PGL_n(Q) which are spherical at the archimedean place. As an application, we show a simultaneous non-vanishing of standard L-values at n-1 points on the critical strip for infinitely many Hecke-Maass cuspidal newforms.

Siegel Paramodular Forms of Weight 2 and Squarefree Level

We compute the space $S_2(K(N))$ of weight $2$ Siegel paramodular cusp forms of squarefree level $N<300$. In conformance with the paramodular conjecture of A. Brumer and K. Kramer, the space is only the additive (Gritsenko) lift space of the Jacobi cusp form space $J_{2,N}^{\text{cusp}}$ except for $N=249,295$, when it further contains one nonlift newform. For these two values of $N$, the Hasse-Weil $p$-Euler factors of a relevant abelian surface match the spin $p$-Euler factors of the nonlift newform for the first two primes $p\nmid N$.

On $p$-adic Siegel modular forms of non-real Nebentypus of degree 2

We show that all Siegel modular forms of non-real Nebentypus for $Γ_0^{(2)}(p)$ are $p$-adic Siegel modular forms by using a Maass lift.

Shimura 曲线上的特殊循环交集与Siegel Maass形式

Intersections of special cycles on Shimura curves and Siegel Maass forms

本文研究Shimura曲线上的特殊循环交集与Siegel Maass形式的关系，通过非全纯模形式和theta提升方法，推广了Rickards的计数结果，并给出了傅里叶系数的几何解释。

Maass relations in higher genus

For an arbitrary even genus $2n$ we show that the subspace of Siegel cusp forms of degree $2n$ generated by Ikeda lifts of elliptic cusp forms can be characterized by certain linear relations among Fourier coefficients. This generatizes the work of Kohnen and Kojima.

Maass relations for Saito-Kurokawa lifts of higher levels

It is known that among Siegel modular forms of degree $2$ and level $1$ the only functions that violate the Ramanujan conjecture are Saito-Kurokawa lifts of modular forms of level $1$. These are precisely the functions whose Fourier coefficients satisfy Maass relations. More generally, the Ramanujan conjecture for $\mathrm{GSp}_4$ is predicted to fail only in case of CAP representations. It is not known though whether the associated Siegel modular forms (of various levels) still satisfy a version of Maass relations. We show that this is indeed the case for the ones related to P-CAP representat…

Asymptotic densities of newforms

We define the counting function for non-analytic (Maass) newforms of Hecke congruence groups_Gamma_0(M)_. We then calculate the three main terms of this counting function and give necessary and sufficient conditions on M for this counting function to have the same shape as if it were counting eigenvalues related to a cocompact group.

Hybrid sup-norm bounds for Maass newforms of powerful level

Let $f$ be an $L^2$-normalized Hecke--Maass cuspidal newform of level $N$, character $χ$ and Laplace eigenvalue $λ$. Let $N_1$ denote the smallest integer such that $N|N_1^2$ and $N_0$ denote the largest integer such that $N_0^2 |N$. Let $M$ denote the conductor of $χ$ and define $M_1= M/\gcd(M,N_1)$. In this paper, we prove the bound $|f|_\infty$ $\ll_ε$ $N_0^{1/6 + ε} N_1^{1/3+ε} M_1^{1/2} λ^{5/24+ε}$, which generalizes and strengthens previously known upper bounds for $|f|_\infty$. This is the first time a hybrid bound (i.e., involving both $N$ and $λ$) has been established for $|f|_\infty$…

关于 Maass 形式的 Weil 逆定理及零点相消

Weil's converse theorem for Maass forms and cancellation of zeros

本文证明了允许亚纯扭曲的 Maass 形式 Weil 型逆定理，并据此推出 Maass 新形式对称平方 L-函数与 Riemann zeta 函数之商有无穷多个极点。

Differential operators for harmonic weak Maass forms and the vanishing of Hecke eigenvalues

For integers $k\geq 2$, we study two differential operators on harmonic weak Maass forms of weight $2-k$. The operator $ξ_{2-k}$ (resp. $D^{k-1}$) defines a map to the space of weight $k$ cusp forms (resp. weakly holomorphic modular forms). We leverage these operators to study coefficients of harmonic weak Maass forms. Although generic harmonic weak Maass forms are expected to have transcendental coefficients, we show that those forms which are "dual" under $ξ_{2-k}$ to newforms with vanishing Hecke eigenvalues (such as CM forms) have algebraic coefficients. Using regularized inner products, w…

Newforms and Spectral Multiplicities for $Γ_0(9)$

The goal of this paper is to explain certain experimentally observed properties of the (cuspidal) spectrum and its associated automorphic forms (Maass waveforms) on the congruence subgroup $Γ_{0}(9)$. The first property is that the spectrum possesses multiplicities in the so-called new part, where it was previously believed to be simple. The second property is that the spectrum does not contain any "genuinely new" eigenvalues, in the sense that all eigenvalues of $Γ_{0}(9)$ appear in the spectrum of some congruence subgroup of lower level. The main theorem in this paper gives a precise decompo…

Fourier coefficients of Eisenstein series for $O^+(2, n + 2)$

We derive the Fourier expansion of scalar-valued Eisenstein series for O(2, n+2) using classical methods of Siegel, Braun, Zagier, Bruinier and others. We assume that the underlying lattice splits two hyperbolic planes. Finally we prove for the Eisenstein series at the standard cusp that they belong to the Maass space for O(2, n + 2), an analogue of the "Spezialschar" for Siegel modular forms introduced by Maass, at least at all local places p, where the localization of the underlying lattice is maximal.

关于大水平新形式在PGL(n)上的上范数问题

The sup-norm problem for newforms of large level on $\operatorname{PGL}(n)$

本文研究了大水平新形式在PGL(n)上的上范数问题，通过新的降维理论和Atkin-Lehner算子推广，证明了次下界并基于GRH条件扩展结果。

具有 Paramodular 级的 Siegel Eisenstein 级数

Siegel Eisenstein Series with Paramodular Level

本文由导子为 $N$ 的本原 Dirichlet 特征构造级 $N^2$、权 $k\geq4$ 的 paramodular Siegel Eisenstein 级数，计算其 Fourier 展开，并证明它是生成不可约自守表示的 paramodular 新形式。

分裂 $\mathrm{SO}(8)$ 上的四元数 Maass Spezialschar

The quaternionic Maass Spezialschar on split $\mathrm{SO}(8)$

定义分裂 $\mathrm{SO}(8)$ 上四元数模形式的 Spezialschar，通过 theta 提升与 $\mathrm{Sp}(4)$ 上 Siegel 模形式空间关联，并给出标准 $L$ 函数 Dirichlet 级数的猜想。

On the Spezialschar of Maass

Let $M_k^{(n)}$ be the space of Siegel modular forms of degree $n$ and even weight $k$. In this paper firstly a certain subspace $\mathsf{Spez}(M_k^{(2n)})$ the Spezialschar of $M_k^{(2n)}$ is introduced. In the setting of the Siegel three-fold it is proven that this Spezialschar is the Maass Spezialschar. Secondly an embedding of $M_k^{(2)}$ into a direct sum $\oplus_{ν= 0}^{\lfloor \frac{k}{10} \rfloor} \text{Sym}^2 M_{k + 2 ν}$ is given. This leads to a basic characterization of the Spezialschar property. The results of this paper are directly related to the non-vanishing of certain special…

$GL(2)\ imes GL(2)$ $L$-函数在谱方面的均匀次凸性界

Uniform subconvexity bounds for $GL(2)\times GL(2)$ $L$-functions in the spectral aspect

本文研究GL(2)×GL(2) L函数在谱方面的二次矩，得到均匀次凸性界，并应用于二面体Maass新形式的QUE收缩结果。

On the cuspidality of pullbacks of Siegel Eisenstein series and applications to the Bloch-Kato conjecture

Let $k > 3$ be an integer and $p$ a prime with $p > 2k-2$. Let $f$ be a newform of weight $2k-2$ and level 1 so that $f$ is ordinary at $p$ and $\barρ_{f}$ is irreducible. Under some additional hypotheses we prove that $ord_{p}(L_{alg}(k,f)) \leq ord_{p}(# S)$ where $S$ is the Pontryagin dual of the Selmer group associated to $ρ_{f} \otimes ε^{1-k}$ with $ε$ the $p$-adic cyclotomic character. We accomplish this by first constructing a congruence between the Saito-Kurokawa lift of $f$ and a non-CAP Siegel cusp form. Once this congruence is established, we use Galois representations to obtain th…

Pullbacks of Eisenstein series from GU(3,3) and critical L-values for GSp(4) X GL(2)

Let F be a genus two Siegel newform and g a classical newform, both of squarefree levels and of equal weight l. We prove a pullback formula for certain Eisenstein series -- thus generalizing a construction of Shimura -- and use this to derive an explicit integral representation for the degree eight L-function L(s, F X g). This integral representation involves the pullback of a simple Siegel-type Eisenstein series on the unitary group GU(3,3). As an application, we prove a reciprocity law -- predicted by Deligne's conjecture -- for the critical special values L(m, F X g) where m is an integer, …

算术量子遍历性的新变体

New variants of arithmetic quantum ergodicity

本文建立了算术量子遍历性的两个新变体，分别针对自对偶 $\mathrm{GL}_2$ Hecke-Maass 新形式在级与 Laplace 特征值联合变化时的情形，以及 Hilbert 或 Bianchi 尖点形式限制到模曲面上随特征值增长而耗散的非分裂类似情形。

Bounds for twisted symmetric square $L$-functions via half-integral weight periods

We establish the first moment bound $$ \sum_φ L(φ\otimes φ\otimes Ψ, \tfrac{1}{2}) \ll_{\varepsilon} p^{5/4+\varepsilon} $$ for triple product $L$-functions, where $Ψ$ is a fixed Hecke-Maass form on $\operatorname{SL}_2(\mathbb{Z})$ and $φ$ runs over the Hecke-Maass newforms on $Γ_0(p)$ of bounded eigenvalue. The proof is via the theta correspondence and analysis of periods of half-integral weight modular forms. This estimate is not expected to be optimal, but the exponent $5/4$ is the strongest obtained to date for a moment problem of this shape. We show that the expected upper bound follows …

On the subconvexity problem for $GL(3)\times GL(2)$ $L$-functions

Fix $g$ a self-dual Hecke-Maass form for $SL_3(\mathbb{Z})$. Let $f$ be a holomorphic newform of prime level $q$ and fixed weight. Conditional on a lower bound for a short sum of squares of Fourier coefficients of $f$, we prove a subconvexity bound in the $q$ aspect for $L(s, g\times f)$ at the central point.

Low-lying zeroes of Maass form $L$-functions

The Katz-Sarnak density conjecture states that the scaling limits of the distributions of zeros of families of automorphic $L$-functions agree with the scaling limits of eigenvalue distributions of classical subgroups of the unitary groups $U(N)$. This conjecture is often tested by way of computing particular statistics, such as the one-level density, which evaluates a test function with compactly supported Fourier transform at normalized zeros near the central point. Iwaniec, Luo, and Sarnak studied the one-level densities of cuspidal newforms of weight $k$ and level $N$. They showed in the l…

关于 Kleinian mock 模形式

On Kleinian mock modular forms

本文提出了一种显式且计算高效的构造方法，利用 Abelian 函数理论中 Kleinian $ζ$-函数的新非解析完备化，构建了在 $ξ$-算子下映射到权 $2$ 新形式的调和弱 Maass 形式。

Simultaneous non-vanishing of $GL(3)\times GL(2)$ and GL(2) $L$-functions

Fix $g$ a Hecke-Maass form for $SL_3(\mathbb{Z})$. Let $q$ be any large prime number. In the family of holomorphic newforms $f$ of level $q$ and fixed weight, we find the average value of the product $L(\half,g\times f)L(\half,f)$. From this we derive a result on the simultaneous non-vanishing of these $L$-functions at the central point.

The sup-norm problem for the Siegel modular space of rank two

Let F be a square integrable Maass form on the Siegel upper half space of rank 2 for the Siegel modular group Sp(4, Z) with Laplace eigenvalue lambda. If, in addition, F is a joint eigenfunction of the Hecke algebra, we show a power-saving sup-norm bound in terms of lambda (relative to the generic bound) for F restricted to a compact set. As an auxiliary result of independent interest we prove new uniform bounds for spherical functions on semisimple Lie groups.

A New $p$-adic Maass-Shimura operator and Supersingular Rankin-Selberg $p$-adic $L$-functions

We give a construction of a new $p$-adic Maass-Shimura operator defined on an affinoid subdomain of the preperfectoid $p$-adic universal cover $\mathcal{Y}$ of a modular curve $Y$. We define a new notion of $p$-adic modular forms as sections of a certain sheaf $\mathcal{O}_Δ$ of "nearly rigid functions" which transform under the action of subgroups of the Galois group $\mathrm{Gal}(\mathcal{Y}/Y)$ by $\mathcal{O}_Δ^{\times}$-valued weight characters. This extends Katz's notion of $p$-adic modular forms as functions on the Igusa tower $Y^{\mathrm{Ig}}$; indeed we may recover Katz's theory by re…

西格尔zeta函数的模性

The modularity of Siegel's zeta functions

本文利用新近的Maass形式Weil型逆定理证明了西格尔不定二次型zeta函数的模性，完成了西格尔1938年提出的研究设想，同时证明这类zeta函数的一半对应全纯模形式。

On the standard $L$-function for $GSp_{2n} \times GL_1$ and algebraicity of symmetric fourth $L$-values for $GL_2$

We prove an explicit integral representation -- involving the pullback of a suitable Siegel Eisenstein series -- for the twisted standard $L$-function associated to a holomorphic vector-valued Siegel cusp form of degree $n$ and arbitrary level. In contrast to all previously proved pullback formulas in this situation, our formula involves only scalar-valued functions despite being applicable to $L$-functions of vector-valued Siegel cusp forms. The key new ingredient in our method is a novel choice of local vectors at the archimedean place which allows us to exactly compute the archimedean local…

A Bessel $δ$-method and hybrid bounds for $\mathrm{GL}_2$

Let $g$ be a primitive holomorphic or Maass newform for $Γ_0(D)$. In this paper, by studying the Bessel integrals associated to $g$, we prove an asymptotic Bessel $δ$-identity associated to $g$. Among other applications, we prove the following hybrid subconvexity bound $$ L\left(1/2+it,g\otimes χ\right)\ll_{g,\varepsilon} (q(1+|t|))^{\varepsilon}q^{3/8}(1+|t|)^{1/3} $$ for any $\varepsilon>0$, where $χ\bmod q$ is a primitive Dirichlet character with $(q, D)=1$. This improves the previous known result.

Shifted convolution sums involving theta series

Let $f$ be a cuspidal newform (holomorphic or Maass) of arbitrary level and nebentypus and denote by $λ_f(n)$ its $n$-th Hecke eigenvalue. Let $$ r(n)=\#\left\{(n_1,n_2)\in \mathbb{Z}^2:n_1^2+n_2^2=n\right\}. $$ In this paper, we study the shifted convolution sum $$ \mathcal{S}_h(X)=\sum_{n\leq X}λ_f(n+h)r(n), \qquad 1\leq h\leq X, $$ and establish uniform bounds with respect to the shift $h$ for $\mathcal{S}_h(X)$.

On sup-norms of cusp forms of powerful level

Let f be an L^2-normalized Hecke--Maass cuspidal newform of level N and Laplace eigenvalue λ. It is shown that |f|_\infty <<_{λ, ε} N^{-1/12 + ε} for any ε>0. The exponent is further improved in the case when N is not divisible by "small squares". Our work extends and generalizes previously known results in the special case of N squarefree.

区分希格拉模形式

Distinguishing Siegel modular forms

本文通过研究海格尔特征值的多项式关系，证明了希格拉模形式之间的扭关系，扩展了强多重性一理论，并提供了一种统一区分椭圆和希格拉模形式的方法。

Stable Klingen Vectors and Paramodular Newforms

We introduce the family of stable Klingen congruence subgroups of GSp(4). We use these subgroups to study both local paramodular vectors and Siegel modular forms of degree $2$ with paramodular level. In the first part, when $F$ is a nonarchimedean local field of characteristic zero and $(π,V)$ is an irreducible, admissible representation of GSp(4,F) with trivial central character, we establish a basic connection between the subspaces $V_s(n)$ of $V$ fixed by the stable Klingen congruence subgroups and the spaces of paramodular vectors in $V$ and derive a fundamental partition of the set of par…

On some Siegel threefold related to the tangent cone of the Fermat quartic surface

Let $Z$ be the quotient of the Siegel modular threefold $\mathcal{A}^{\rm sa}(2,4,8)$ which has been studied by van Geemen and Nygaard. They gave an implication that some 6-tuple $F_Z$ of theta constants which is in turn known to be a Klingen type Eisenstein series of weight 3 should be related to a holomorphic differential $(2,0)$-form on $Z$. The variety $Z$ is birationally equivalent to the tangent cone of Fermat quartic surface in the title. In this paper we first compute the L-function of two smooth resolutions of $Z$. One of these, denoted by $W$, is a kind of Igusa compactification such…

L-functions for holomorphic forms on GSp(4) x GL(2) and their special values

We provide an explicit integral representation for L-functions of pairs (F,g) where F is a holomorphic genus 2 Siegel newform and g a holomorphic elliptic newform, both of squarefree levels and of equal weights. When F,g have level one, this was earlier known by the work of Furusawa. The extension is not straightforward. Our methods involve precise double-coset and volume computations as well as an explicit formula for the Bessel model for GSp(4) in the Steinberg case; the latter is possibly of independent interest. We apply our integral representation to prove an algebraicity result for a cri…

大质量Theta提升

Massive Theta Lifts

本文利用大质量Maass-Jacobi形式的Poincare级数定义了“大质量theta提升”，以Siegel-Narain theta函数为积分核应用于常数函数与模不变j函数，发现其指数衰减特性使部分Rankin-Selberg积分无需Zagier重整化即为有限。

On the exceptional zeros of Rankin-Selberg L-functions

The main objects of study in this article are two classes of Rankin-Selberg L-unctions, namely L(s, f \times g) and L(s, sym^2(g) \times sym^2(g)), where f, g are newforms, holomorphic or of Maass type, on the upper half plane, and sym^2(g) denotes the symmetric square lift of g to GL(3). We prove that in general, i.e., when these L-functions are not divisible by L-functions of quadratic characters (such divisibility happening rarely), they do not admit any Landau-Siegel zeros. These zeros, which are real and close to s=1, are highly mysterious and are not expected to occur. There are corollar…

Zeros of Rankin-Selberg $L$-functions at the edge of the critical strip

Let $π$ and $π_0$ be unitary cuspidal automorphic representations. We prove log-free zero density estimates for Rankin-Selberg $L$-functions of the form $L(s,π\timesπ_0)$, where $π$ varies in a given family and $π_0$ is fixed. These estimates are unconditional in many cases of interest; they hold in full generality assuming an average form of the generalized Ramanujan conjecture. We consider applications of these estimates related to mass equidistribution for Hecke-Maass forms, the rarity of Landau-Siegel zeros of Rankin-Selberg $L$-functions, the Chebotarev density theorem, and $\ell$-torsion…

关于特殊点上Rankin–Selberg $L$-函数有效非零性的研究

On the Effective Non-vanishing of Rankin--Selberg $L$-functions at Special Points

本文研究Rankin–Selberg特殊$L$-值的非零性问题，证明了存在由Euler乘积给出的常数$γ(Q)$，使得在长区间和短区间上分别有至少$γ(Q)/11$和$γ(Q)\cdot(4μ-3)/(4μ+7)$的非零比例。

Motohashi公式在单个Dirichlet L函数四阶矩中的应用

Motohashi's Formula for the Fourth Moment of Individual Dirichlet $L$-Functions and Applications

本文建立了Dirichlet L函数的新互反公式，将单个Dirichlet L函数四阶矩与Hecke-Maass新形式中心L值三阶矩关联，推广了Iwaniec、Jutila和Heath-Brown的结果，是Petrow-Young工作的逆版本。