Mathematical Research Letters

Volume 14 (2007)

Number 2

Atkin-Serre Type Conjectures for Automorphic Representations on $GL(2)$

Pages: 189 – 204



Jeremy Rouse (University of Wisconsin)


Let $H(z)$ be a newform of weight $k \geq 4$ without complex multiplication on $\Gamma_{0}(N)$ with normalized $L$-function $L(H,s) = \prod_{p} (1 - \alpha_{p} p^{-s})^{-1} (1 - \beta_{p} p^{-s})^{-1}$. A conjecture of Atkin and Serre states that for sufficiently large primes $p$, \begin{equation} \label{atkinserre} |\alpha_{p} + \beta_{p}| \gg p^{-1-\epsilon} \end{equation} for all $\epsilon > 0$. Let $\pi$ a genuine cuspidal automorphic representation on $GL_{2}(\A_{F})$, where $F$ is a totally real number field. Assuming GRH for the symmetric power $L$-functions associated to $\pi$, we prove that \[ |\alpha_{v} + \beta_{v}| \geq q_{v}^{-\delta} \] for all but $O(x^{1 - \delta}/\log x)$ places $v$ with $q_{v} \leq x$ provided $\delta \leq 1/8$. This implies a strong form of \eqref{atkinserre} for almost all primes $p$.

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