Global Existence for an Isotropic Landau Model

Abstract

Following the recent ideas of Guillen and Silvestre in $[9]$, we prove that the Fisher information is non-increasing along the flow of the isotropic Landau equation. We then use this fact to deduce global existence for the equation ${\partial }_{t}f=(-\Delta {)}^{-1}f\cdot \Delta f+f^2$ under a relatively lax set of conditions on the initial data. In particular, we remove the restrictive radially decreasing assumption of previous works.

arXiv comment35 pages, comments welcome