The geometric size of the fundamental gap

Fuente: arXiv
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Autori principali: Amato, Vincenzo, Bucur, Dorin, Fragalà, Ilaria
Natura: Preprint
Pubblicazione: 2024
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author Amato, Vincenzo
Bucur, Dorin
Fragalà, Ilaria
author_facet Amato, Vincenzo
Bucur, Dorin
Fragalà, Ilaria
contents The fundamental gap conjecture proved by Andrews and Clutterbuck in 2011 provides the sharp lower bound for the difference between the first two Dirichlet Laplacian eigenvalues in terms of the diameter of a convex set in $\mathbb{R}^N$. The question concerning the rigidity of the inequality, raised by Yau in 1990, was left open. Going beyond rigidity, our main result strengthens Andrews-Clutterbuck inequality, by quantifying geometrically the excess of the gap compared to the diameter in terms of flatness. The proof relies on a localized, variational interpretation of the fundamental gap, allowing a dimension reduction via the use of convex partitions à la Payne-Weinberger: the result stems by combining a new sharp result for one dimensional Schrödinger eigenvalues with measure potentials, with a thorough analysis of the geometry of the partition into convex cells. As a by-product of our approach, we obtain a quantitative form of Payne-Weinberger inequality for the first nontrivial Neumann eigenvalue of a convex set in $\mathbb{R}^N$, thus proving, in a stronger version, a conjecture from 2007 by Hang-Wang.
format Preprint
id arxiv_https___arxiv_org_abs_2407_01341
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The geometric size of the fundamental gap
Amato, Vincenzo
Bucur, Dorin
Fragalà, Ilaria
Spectral Theory
Analysis of PDEs
35P15, 49R05
The fundamental gap conjecture proved by Andrews and Clutterbuck in 2011 provides the sharp lower bound for the difference between the first two Dirichlet Laplacian eigenvalues in terms of the diameter of a convex set in $\mathbb{R}^N$. The question concerning the rigidity of the inequality, raised by Yau in 1990, was left open. Going beyond rigidity, our main result strengthens Andrews-Clutterbuck inequality, by quantifying geometrically the excess of the gap compared to the diameter in terms of flatness. The proof relies on a localized, variational interpretation of the fundamental gap, allowing a dimension reduction via the use of convex partitions à la Payne-Weinberger: the result stems by combining a new sharp result for one dimensional Schrödinger eigenvalues with measure potentials, with a thorough analysis of the geometry of the partition into convex cells. As a by-product of our approach, we obtain a quantitative form of Payne-Weinberger inequality for the first nontrivial Neumann eigenvalue of a convex set in $\mathbb{R}^N$, thus proving, in a stronger version, a conjecture from 2007 by Hang-Wang.
title The geometric size of the fundamental gap
topic Spectral Theory
Analysis of PDEs
35P15, 49R05
url https://arxiv.org/abs/2407.01341