A $L^{2}$ to $L^{\infty}$ approach for the Landau Equation

TL;DR

This paper introduces a novel $L^{2} o L^{ty}$ framework for the Landau equation with Coulomb potential, establishing global solutions near Maxwellian by combining $L^{2}$ estimates, De Giorgi's method, and $S_{p}$ space controls.

Contribution

It develops a new analytical approach linking $L^{2}$ and $L^{ty}$ estimates to prove global existence and uniqueness for the Landau equation with Coulomb potential.

Findings

Established global $L^{2}$ estimates with velocity weight and decay.

Controlled velocity derivatives using $S_{p}$ space estimates.

Proved uniqueness of solutions near Maxwellian.

Abstract

Consider the Landau equation with Coulomb potential in a periodic box. We develop a new $L^{2}\rightarrow L^{\infty }$ framework to construct global unique solutions near Maxwellian with small $L^{\infty }\ $norm. The first step is to establish global $L^{2}$ estimates with strong velocity weight and time decay, under the assumption of $L^{\infty }$ bound, which is further controlled by such $L^{2}$ estimates via De Giorgi's method \cite{golse2016harnack} and \cite{mouhot2015holder}. The second step is to employ estimates in $S_{p}$ spaces to control velocity derivatives to ensure uniqueness, which is based on Holder estimates via De Giorgi's method \cite{golse2016harnack}, \cite{golse2015holder}, and \cite{mouhot2015holder}.