On the concentration of the Fourier coefficients for products of Laplace-Beltrami eigenfunctions on real-analytic manifolds

Fuente: arXiv
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Main Authors: Charron, Philippe, Pagano, François
Format: Preprint
Published: 2024
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author Charron, Philippe
Pagano, François
author_facet Charron, Philippe
Pagano, François
contents On a closed analytic manifold $(M,g)$, let $ϕ_i$ be the eigenfunctions of $Δ_g$ with eigenvalues $λ_i^2$ and let $f:=\prod ϕ_{k_j}$ be a finite product of Laplace-Beltrami eigenfunctions. We show that $\left\langle f, ϕ_i \right\rangle_{L^2(M)}$ decays exponentially as soon as $λ_i > C \sum λ_{k_j}$ for some constant $C$ depending only on $M$. Moreover, by using a lower bound on $\| f \|_{L^2(M)} $, we show that $99\%$ of the $L^2$-mass of $f$ can be recovered using only finitely many Fourier coefficients.
format Preprint
id arxiv_https___arxiv_org_abs_2403_18663
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On the concentration of the Fourier coefficients for products of Laplace-Beltrami eigenfunctions on real-analytic manifolds
Charron, Philippe
Pagano, François
Analysis of PDEs
Classical Analysis and ODEs
Spectral Theory
35C99, 35A10, 35P10
On a closed analytic manifold $(M,g)$, let $ϕ_i$ be the eigenfunctions of $Δ_g$ with eigenvalues $λ_i^2$ and let $f:=\prod ϕ_{k_j}$ be a finite product of Laplace-Beltrami eigenfunctions. We show that $\left\langle f, ϕ_i \right\rangle_{L^2(M)}$ decays exponentially as soon as $λ_i > C \sum λ_{k_j}$ for some constant $C$ depending only on $M$. Moreover, by using a lower bound on $\| f \|_{L^2(M)} $, we show that $99\%$ of the $L^2$-mass of $f$ can be recovered using only finitely many Fourier coefficients.
title On the concentration of the Fourier coefficients for products of Laplace-Beltrami eigenfunctions on real-analytic manifolds
topic Analysis of PDEs
Classical Analysis and ODEs
Spectral Theory
35C99, 35A10, 35P10
url https://arxiv.org/abs/2403.18663