Computing the Laplace eigenvalue and level of Maass cusp forms

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• 作者：Paul Savala ^{psavala@whittier.edu}
• 关键词：11L07 ; 11Y35
• 刊名：Journal of Number Theory
• 出版年：2017
• 出版时间：April 2017
• 年：2017
• 卷：173
• 期：Complete
• 页码：1-22
• 全文大小：717 K
• 卷排序：173

文摘

Let f   be a primitive Maass cusp form for a congruence subgroup Γ0(D)⊂SL(2,Z)Γ0(D)⊂SL(2,Z) and λf(n)λf(n) its n  -th Fourier coefficient. In this paper it is shown that with knowledge of only finitely many λf(n)λf(n) one can often solve for the level D  , and in some cases, estimate the Laplace eigenvalue to arbitrarily high precision. This is done by analyzing the resonance and rapid decay of smoothly weighted sums of λf(n)e(αnβ)λf(n)e(αnβ) for X≤n≤2XX≤n≤2X and any choice of α∈Rα∈R, and β>0β>0. The methods include the Voronoi summation formula, asymptotic expansions of Bessel functions, weighted stationary phase, and computational software. These algorithms manifest the belief that the resonance and rapid decay nature uniquely characterizes the underlying cusp form. They also demonstrate that the Fourier coefficients of a cusp form contain all arithmetic information of the form.