Characterization of eigenfunctions of Laplacian having exponential growth using Fourier multipliers

Fuente: arXiv
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Main Authors: Paul, Basil, Boggarapu, Pradeep
Format: Preprint
Published: 2026
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author Paul, Basil
Boggarapu, Pradeep
author_facet Paul, Basil
Boggarapu, Pradeep
contents In 1993, Robert Strichartz established a characterization for bounded eigenfunctions of the Laplacian on $\mathbb{R}^d$. Let $\left\{f_k \right\}_{k\in \mathbb{Z}}$ be a doubly infinite sequence of functions on $\mathbb{R}^d$ satisfying $Δf_k= f_{k+1}$ for all $k \in \mathbb{Z}$. If $\left\{f_k \right\}$'s are uniformly bounded, then Strichartz proved that $Δf_0= f_0$, thus generalizing a classical result of Roe on the real line. Recognizing that many physically significant eigenfunctions exhibit unbounded behavior, Howard and Reese extended this result to include functions of polynomial growth. Building upon a refined functional-analytic framework, we recently established a broader extension of Strichartz's theorem encompassing eigenfunctions of exponential growth. In the present article, we further investigate the spectral geometry of the Laplacian by replacing the differential operator with a broader class of Fourier multipliers. Specifically, we focus on radial convolution operators, including the spherical average, the ball average, and the heat operator. The central problem addressed is as follows: For a fixed multiplier $Θ$, we consider a doubly infinite sequence of exponentially growing functions $\{f_k\}_{k \in \mathbb{Z}}$ satisfying the recurrence relation $Θf_k = A f_{k+1}$ for a complex constant $A$. We demonstrate that under specific spectral conditions, the functions $f_k$ correspond precisely to the eigenfunctions of the Laplacian $Δ$ on $\mathbb{R}^d$. This result provides a unified approach to characterization theorems, linking the growth rate of eigenfunctions to the symbol of the associated multiplier.
format Preprint
id arxiv_https___arxiv_org_abs_2601_19572
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Characterization of eigenfunctions of Laplacian having exponential growth using Fourier multipliers
Paul, Basil
Boggarapu, Pradeep
Classical Analysis and ODEs
Primary: 42B10, Secondary: 46E10
In 1993, Robert Strichartz established a characterization for bounded eigenfunctions of the Laplacian on $\mathbb{R}^d$. Let $\left\{f_k \right\}_{k\in \mathbb{Z}}$ be a doubly infinite sequence of functions on $\mathbb{R}^d$ satisfying $Δf_k= f_{k+1}$ for all $k \in \mathbb{Z}$. If $\left\{f_k \right\}$'s are uniformly bounded, then Strichartz proved that $Δf_0= f_0$, thus generalizing a classical result of Roe on the real line. Recognizing that many physically significant eigenfunctions exhibit unbounded behavior, Howard and Reese extended this result to include functions of polynomial growth. Building upon a refined functional-analytic framework, we recently established a broader extension of Strichartz's theorem encompassing eigenfunctions of exponential growth. In the present article, we further investigate the spectral geometry of the Laplacian by replacing the differential operator with a broader class of Fourier multipliers. Specifically, we focus on radial convolution operators, including the spherical average, the ball average, and the heat operator. The central problem addressed is as follows: For a fixed multiplier $Θ$, we consider a doubly infinite sequence of exponentially growing functions $\{f_k\}_{k \in \mathbb{Z}}$ satisfying the recurrence relation $Θf_k = A f_{k+1}$ for a complex constant $A$. We demonstrate that under specific spectral conditions, the functions $f_k$ correspond precisely to the eigenfunctions of the Laplacian $Δ$ on $\mathbb{R}^d$. This result provides a unified approach to characterization theorems, linking the growth rate of eigenfunctions to the symbol of the associated multiplier.
title Characterization of eigenfunctions of Laplacian having exponential growth using Fourier multipliers
topic Classical Analysis and ODEs
Primary: 42B10, Secondary: 46E10
url https://arxiv.org/abs/2601.19572