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Autori principali: Germain, Pierre, Myerson, Simon L. Rydin, Pezzi, Daniel
Natura: Preprint
Pubblicazione: 2025
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Accesso online:https://arxiv.org/abs/2508.05573
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author Germain, Pierre
Myerson, Simon L. Rydin
Pezzi, Daniel
author_facet Germain, Pierre
Myerson, Simon L. Rydin
Pezzi, Daniel
contents We study $L^2$ to $L^p$ operator norms of spectral projectors for the Euclidean Laplacian on the torus in the case where the spectral window is narrow. With a window of constant size this is a classical result of Sogge; in the small-window limit we are left with $L^p$ norms of eigenfunctions of the Laplacian, as considered for instance by Bourgain. For the three-dimensional torus we prove new cases of a previous conjecture of the first two authors concerning the size of these norms; we also refine certain prior results to remove $ε$-losses in all dimensions. We use methods from number theory: the geometry of numbers, the circle method and exponential sum bounds due to Guo. We complement these techniques with height splitting and a bilinear argument to prove sharp results. We exposit on the various techniques used and their limitations.
format Preprint
id arxiv_https___arxiv_org_abs_2508_05573
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Bounds for spectral projectors on the three-dimensional torus
Germain, Pierre
Myerson, Simon L. Rydin
Pezzi, Daniel
Analysis of PDEs
Classical Analysis and ODEs
42A45, 42B15 (Primary), 11L07, 11H06, 11P21 (Secondary)
We study $L^2$ to $L^p$ operator norms of spectral projectors for the Euclidean Laplacian on the torus in the case where the spectral window is narrow. With a window of constant size this is a classical result of Sogge; in the small-window limit we are left with $L^p$ norms of eigenfunctions of the Laplacian, as considered for instance by Bourgain. For the three-dimensional torus we prove new cases of a previous conjecture of the first two authors concerning the size of these norms; we also refine certain prior results to remove $ε$-losses in all dimensions. We use methods from number theory: the geometry of numbers, the circle method and exponential sum bounds due to Guo. We complement these techniques with height splitting and a bilinear argument to prove sharp results. We exposit on the various techniques used and their limitations.
title Bounds for spectral projectors on the three-dimensional torus
topic Analysis of PDEs
Classical Analysis and ODEs
42A45, 42B15 (Primary), 11L07, 11H06, 11P21 (Secondary)
url https://arxiv.org/abs/2508.05573