2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/216161Based on a recent $L^{2}{-}L^{\infty}$ framework, we establish the acoustic limit of the Boltzmann equation for general collision kernels. The scaling of the fluctuations with respect to Knudsen number is optimal. Our approach is based on a new analysis of the compressible Euler limit of the Boltzmann equation, as well as refined estimates of Euler and acoustic solutions.Analysis of PDEsMathematical Physics76P05text