2025/11/25 by Hongxu Chen, Renjun Duan, Chen, Hongxu +3
Engineering · Mathematics · #Analysis of PDEs (math.AP) #FOS: Mathematics #Gas Dynamics and Kinetic Theory #Spectral Theory in Mathematical Physics #Thermoelastic and Magnetoelastic Phenomena
paper · pdf · doi:10.48550/arxiv.2511.19950
openalex publication_date 2025/11/25 · openalex created_date 2025/11/28 · openalex updated_date 2026/07/28
In the paper, we develop spectral theory to analyze the sharp asymptotic behavior of solutions to the Boltzmann equation around global Maxwellians in a three-dimensional infinite layer ℝ2× (-1,1). The isothermal diffuse reflection boundary condition is imposed on two parallel infinite planes at x3=± 1. The main difficulties lie in the fact that the direct Fourier transform is not applicable to the vertical x3-variable, and the linear collision operator K loses its compactness on L2((-1,1)× \R3v) although it is compact on L2(\R3v). By introducing a regularization operator Kn via the finite-dimensional Fourier series truncation in L2(-1,1), we study the spectrum of the linearized initial-boundary value approximation problem, establish the resolvent estimates, and identify the leading diffusive eigenvalue. This spectral structure governs the sharp asymptotic dynamics of the original linear problem as n→ ∞, enabling us to construct the large-time behavior for the nonlinear problem and rigorously prove that the solution converges with a faster rate toward that of the two-dimensional heat equation in the horizontal direction.