Convolution estimates for the Boltzmann gain operator with hard spheres

Fuente: arXiv
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Auteurs principaux: Ampatzoglou, Ioakeim, Léger, Tristan
Format: Preprint
Publié: 2025
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author Ampatzoglou, Ioakeim
Léger, Tristan
author_facet Ampatzoglou, Ioakeim
Léger, Tristan
contents We prove new moment-preserving polynomially weighted convolution estimates for the gain operator of the Boltzmann equation with hard potentials, including the critical case of hard-spheres. Our approach relies crucially on a novel cancellation mechanism dealing with the pathological case of energy-absorbing collisions (that is, collisions that accumulate energy to only one of the outgoing particles). This difficulty is specific to hard potentials, and is not present for Maxwell molecules. Our method quantifies the heuristic that, while energy-absorbing collisions occur with non-trivial probability, they are statistically rare, and therefore do not affect the overall averaging behavior of the gain operator. At the technical level, our proof relies solely on tools from kinetic theory, such as geometric identities and angular averaging.
format Preprint
id arxiv_https___arxiv_org_abs_2505_09554
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Convolution estimates for the Boltzmann gain operator with hard spheres
Ampatzoglou, Ioakeim
Léger, Tristan
Analysis of PDEs
We prove new moment-preserving polynomially weighted convolution estimates for the gain operator of the Boltzmann equation with hard potentials, including the critical case of hard-spheres. Our approach relies crucially on a novel cancellation mechanism dealing with the pathological case of energy-absorbing collisions (that is, collisions that accumulate energy to only one of the outgoing particles). This difficulty is specific to hard potentials, and is not present for Maxwell molecules. Our method quantifies the heuristic that, while energy-absorbing collisions occur with non-trivial probability, they are statistically rare, and therefore do not affect the overall averaging behavior of the gain operator. At the technical level, our proof relies solely on tools from kinetic theory, such as geometric identities and angular averaging.
title Convolution estimates for the Boltzmann gain operator with hard spheres
topic Analysis of PDEs
url https://arxiv.org/abs/2505.09554