Self-similarity and diffusive limits for linear kinetic equations: a Wild sum approach

Fuente: arXiv
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Main Authors: Cañizo, José A., Mischler, Stéphane, Tassi, Niccolò
Format: Preprint
Published: 2026
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author Cañizo, José A.
Mischler, Stéphane
Tassi, Niccolò
author_facet Cañizo, José A.
Mischler, Stéphane
Tassi, Niccolò
contents We prove that linear collisional kinetic equations in the whole space without confinement mechanism display a long-time self-similar behaviour. This drastically improves the recently known results (decay estimates) about the solutions in such a context, providing the first result regarding this self-similar behaviour. As a consequence, we also establish a uniform-in-time convergence of the suitably rescaled solutions to their diffusion limit, which is also new. The class of equations considered includes some BGK type equations, some kinetic nonlocal Fokker--Planck-type equations and some kinetic (possibly fractional) Fokker--Planck equations, for which we are able to write explicitly solutions through a Wild sum (or Dyson series) or we can manage some accurate computations on the Fourier side.
format Preprint
id arxiv_https___arxiv_org_abs_2605_24685
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Self-similarity and diffusive limits for linear kinetic equations: a Wild sum approach
Cañizo, José A.
Mischler, Stéphane
Tassi, Niccolò
Analysis of PDEs
Probability
35B40 (Primary) 82C40, 35R11, 45M05, 60E15, 60K35 (Secondary)
We prove that linear collisional kinetic equations in the whole space without confinement mechanism display a long-time self-similar behaviour. This drastically improves the recently known results (decay estimates) about the solutions in such a context, providing the first result regarding this self-similar behaviour. As a consequence, we also establish a uniform-in-time convergence of the suitably rescaled solutions to their diffusion limit, which is also new. The class of equations considered includes some BGK type equations, some kinetic nonlocal Fokker--Planck-type equations and some kinetic (possibly fractional) Fokker--Planck equations, for which we are able to write explicitly solutions through a Wild sum (or Dyson series) or we can manage some accurate computations on the Fourier side.
title Self-similarity and diffusive limits for linear kinetic equations: a Wild sum approach
topic Analysis of PDEs
Probability
35B40 (Primary) 82C40, 35R11, 45M05, 60E15, 60K35 (Secondary)
url https://arxiv.org/abs/2605.24685