New chaos decomposition of Gaussian nodal volumes

Fuente: arXiv
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Autori principali: Stecconi, Michele, Todino, Anna Paola
Natura: Preprint
Pubblicazione: 2025
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_version_ 1866909682318180352
author Stecconi, Michele
Todino, Anna Paola
author_facet Stecconi, Michele
Todino, Anna Paola
contents We investigate the random variable defined by the volume of the zero set of a smooth Gaussian field, on a general Riemannian manifold possibly with boundary, a fundamental object in probability and geometry. We prove a new explicit formula for its Wiener-Itô chaos decomposition that is notably simpler than existing alternatives and which holds in greater generality, without requiring the field to be compatible with the geometry of the manifold. A key advantage of our formulation is a significant reduction in the complexity of computing the variance of the nodal volume. Unlike the standard Hermite expansion, which requires evaluating the expectation of products of $2+2n$ Hermite polynomials, our approach reduces this task--in any dimension $n$--to computing the expectation of a product of just four Hermite polynomials. As a consequence, we establish a new exact formula for the variance, together with lower and upper bounds. Importantly, in contrast to previous results, our approach applies to highly non-isotropic situations, allowing the study of Riemannian random waves on arbitrary manifolds. By introducing two parameters associated to any Gaussian field: the frequency and the eccentricity, we quantify the deviation from the standard settings (e.g., spheres) and establish a quantitative version of Berry's cancellation phenomenon valid on all manifolds.
format Preprint
id arxiv_https___arxiv_org_abs_2505_22350
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle New chaos decomposition of Gaussian nodal volumes
Stecconi, Michele
Todino, Anna Paola
Probability
Differential Geometry
60G15 (Primary) 60D05, 58C35, 60G57 (Secondary)
We investigate the random variable defined by the volume of the zero set of a smooth Gaussian field, on a general Riemannian manifold possibly with boundary, a fundamental object in probability and geometry. We prove a new explicit formula for its Wiener-Itô chaos decomposition that is notably simpler than existing alternatives and which holds in greater generality, without requiring the field to be compatible with the geometry of the manifold. A key advantage of our formulation is a significant reduction in the complexity of computing the variance of the nodal volume. Unlike the standard Hermite expansion, which requires evaluating the expectation of products of $2+2n$ Hermite polynomials, our approach reduces this task--in any dimension $n$--to computing the expectation of a product of just four Hermite polynomials. As a consequence, we establish a new exact formula for the variance, together with lower and upper bounds. Importantly, in contrast to previous results, our approach applies to highly non-isotropic situations, allowing the study of Riemannian random waves on arbitrary manifolds. By introducing two parameters associated to any Gaussian field: the frequency and the eccentricity, we quantify the deviation from the standard settings (e.g., spheres) and establish a quantitative version of Berry's cancellation phenomenon valid on all manifolds.
title New chaos decomposition of Gaussian nodal volumes
topic Probability
Differential Geometry
60G15 (Primary) 60D05, 58C35, 60G57 (Secondary)
url https://arxiv.org/abs/2505.22350