The fundamental solution of a nonlinear kinetic Fokker-Planck equation

Fuente: arXiv
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Main Authors: Brigati, Giovanni, Carlier, Guillaume, Dolbeault, Jean
Format: Preprint
Published: 2026
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_version_ 1866911548511879168
author Brigati, Giovanni
Carlier, Guillaume
Dolbeault, Jean
author_facet Brigati, Giovanni
Carlier, Guillaume
Dolbeault, Jean
contents This paper is devoted to a fundamental solution of a nonlinear kinetic equation involving a porous medium or fast diffusion operator acting on velocities. Such a nonlinearity has interesting scaling properties, which result in a self-similar behaviour of the fundamental solution. Here fundamental solution means a Dirac distribution initial datum which moreover governs the large time asymptotics of a large class of solutions. Using a self-similar change of variables, the equation becomes a nonlinear kinetic Fokker-Planck equation with harmonic confinement and the intermediate asymptotics regime is transformed into a stability property of a special stationary solution, which attracts the solutions for large times. In the homogeneous case (pure nonlinear diffusion), the problem is reduced to a classical nonlinear diffusion equation with Barenblatt-Pattle self-similar profiles. Unexpectedly, this beautiful structure is preserved at kinetic level, with remarkable consequences for relative entropy estimates, detailed intermediate asymptotics and nonlinear diffusion limits in adapted functional spaces.
format Preprint
id arxiv_https___arxiv_org_abs_2603_26650
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle The fundamental solution of a nonlinear kinetic Fokker-Planck equation
Brigati, Giovanni
Carlier, Guillaume
Dolbeault, Jean
Analysis of PDEs
35B40, 35A08, 35K65, 35Q84, 82C40
This paper is devoted to a fundamental solution of a nonlinear kinetic equation involving a porous medium or fast diffusion operator acting on velocities. Such a nonlinearity has interesting scaling properties, which result in a self-similar behaviour of the fundamental solution. Here fundamental solution means a Dirac distribution initial datum which moreover governs the large time asymptotics of a large class of solutions. Using a self-similar change of variables, the equation becomes a nonlinear kinetic Fokker-Planck equation with harmonic confinement and the intermediate asymptotics regime is transformed into a stability property of a special stationary solution, which attracts the solutions for large times. In the homogeneous case (pure nonlinear diffusion), the problem is reduced to a classical nonlinear diffusion equation with Barenblatt-Pattle self-similar profiles. Unexpectedly, this beautiful structure is preserved at kinetic level, with remarkable consequences for relative entropy estimates, detailed intermediate asymptotics and nonlinear diffusion limits in adapted functional spaces.
title The fundamental solution of a nonlinear kinetic Fokker-Planck equation
topic Analysis of PDEs
35B40, 35A08, 35K65, 35Q84, 82C40
url https://arxiv.org/abs/2603.26650