The Boltzmann equation in the homogeneous critical regularity framework

Fuente: arXiv
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Main Authors: Liu, Jing, Shou, Ling-Yun, Xu, Jiang
Format: Preprint
Published: 2024
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author Liu, Jing
Shou, Ling-Yun
Xu, Jiang
author_facet Liu, Jing
Shou, Ling-Yun
Xu, Jiang
contents We construct a unique global solution to the Cauchy problem of the 3D Boltzmann equation for initial data around the Maxwellian in the spatially critical homogeneous Besov space $\widetilde{L}^2_ξ(\dot{B}_{2,1}^{1/2}\cap\dot{B}_{2,1}^{3/2})$. In addition, under the condition that the low-frequency part of initial perturbation is bounded in $\widetilde{L}^2_ξ(\dot{B}_{2,\infty}^{σ_{0}})$ with $-3/2\leqσ_{0}<1/2$, it is shown that the solution converges to its equilibrium in large times with the optimal rate of $\mathcal{O}(t^{-(σ-σ_{0})/2})$ in $\widetilde{L}^2_ξ(\dot{B}_{2,1}^σ)$ with some $σ>σ_0$, and the microscopic part decays at an enhanced rate of $\mathcal{O}(t^{-(σ-σ_{0})/2-1/2})$. In contrast to [19], the usual $L^2$ estimates are not necessary in our approach, which provides a new understanding of hypocoercivity theory for the Boltzmann equation allowing to construct the Lyapunov functional with different dissipation rates at low and high frequencies. Furthermore, a time-weighted Lyapunov energy argument can be developed to deduce the optimal time-decay estimates.
format Preprint
id arxiv_https___arxiv_org_abs_2408_13610
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The Boltzmann equation in the homogeneous critical regularity framework
Liu, Jing
Shou, Ling-Yun
Xu, Jiang
Analysis of PDEs
35Q20, 76N10
We construct a unique global solution to the Cauchy problem of the 3D Boltzmann equation for initial data around the Maxwellian in the spatially critical homogeneous Besov space $\widetilde{L}^2_ξ(\dot{B}_{2,1}^{1/2}\cap\dot{B}_{2,1}^{3/2})$. In addition, under the condition that the low-frequency part of initial perturbation is bounded in $\widetilde{L}^2_ξ(\dot{B}_{2,\infty}^{σ_{0}})$ with $-3/2\leqσ_{0}<1/2$, it is shown that the solution converges to its equilibrium in large times with the optimal rate of $\mathcal{O}(t^{-(σ-σ_{0})/2})$ in $\widetilde{L}^2_ξ(\dot{B}_{2,1}^σ)$ with some $σ>σ_0$, and the microscopic part decays at an enhanced rate of $\mathcal{O}(t^{-(σ-σ_{0})/2-1/2})$. In contrast to [19], the usual $L^2$ estimates are not necessary in our approach, which provides a new understanding of hypocoercivity theory for the Boltzmann equation allowing to construct the Lyapunov functional with different dissipation rates at low and high frequencies. Furthermore, a time-weighted Lyapunov energy argument can be developed to deduce the optimal time-decay estimates.
title The Boltzmann equation in the homogeneous critical regularity framework
topic Analysis of PDEs
35Q20, 76N10
url https://arxiv.org/abs/2408.13610