Curvature and sharp growth rates of log-quasimodes on compact manifolds

Fuente: arXiv
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Autori principali: Huang, Xiaoqi, Sogge, Christopher D.
Natura: Preprint
Pubblicazione: 2024
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author Huang, Xiaoqi
Sogge, Christopher D.
author_facet Huang, Xiaoqi
Sogge, Christopher D.
contents We obtain new optimal estimates for the $L^2(M)\to L^q(M)$, $q\in (2,q_c]$, $q_c=2(n+1)/(n-1)$, operator norms of spectral projection operators associated with spectral windows $[λ,λ+δ(λ)]$, with $δ(λ)=O((\logλ)^{-1})$ on compact Riemannian manifolds $(M,g)$ of dimension $n\ge2$ all of whose sectional curvatures are nonpositive or negative. We show that these two different types of estimates are saturated on flat manifolds or manifolds all of whose sectional curvatures are negative. This allows us to classify compact space forms in terms of the size of $L^q$-norms of quasimodes for each Lebesgue exponent $q\in (2,q_c]$, even though it is impossible to distinguish between ones of negative or zero curvature sectional curvature for any $q>q_c$.
format Preprint
id arxiv_https___arxiv_org_abs_2404_13734
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Curvature and sharp growth rates of log-quasimodes on compact manifolds
Huang, Xiaoqi
Sogge, Christopher D.
Analysis of PDEs
Classical Analysis and ODEs
Differential Geometry
58J50, 35P15
We obtain new optimal estimates for the $L^2(M)\to L^q(M)$, $q\in (2,q_c]$, $q_c=2(n+1)/(n-1)$, operator norms of spectral projection operators associated with spectral windows $[λ,λ+δ(λ)]$, with $δ(λ)=O((\logλ)^{-1})$ on compact Riemannian manifolds $(M,g)$ of dimension $n\ge2$ all of whose sectional curvatures are nonpositive or negative. We show that these two different types of estimates are saturated on flat manifolds or manifolds all of whose sectional curvatures are negative. This allows us to classify compact space forms in terms of the size of $L^q$-norms of quasimodes for each Lebesgue exponent $q\in (2,q_c]$, even though it is impossible to distinguish between ones of negative or zero curvature sectional curvature for any $q>q_c$.
title Curvature and sharp growth rates of log-quasimodes on compact manifolds
topic Analysis of PDEs
Classical Analysis and ODEs
Differential Geometry
58J50, 35P15
url https://arxiv.org/abs/2404.13734