报告人：何凌冰 教授（清华大学）

报告时间：2020年11月27日周五下午15:00 – 16:00

报告地点：腾讯会议ID：852 626 505

报告题目：Boltzmann equation with cutoff Rutherford cross section near Maxwellian

报告摘要：

The well-known Rutherford differential cross section corresponds to a two body interaction with Coulomb potential. It leads to the logarithmically divergence of the momentum transfer (or the transport cross section). In reality we assume that $\theta_{min}$ is the order of magnitude of the smallest angles for which the scattering can still be regarded as Coulomb scattering. Under ad hoc cutoff on the deviation angle, L. D. Landau derived a new equation for the weakly interacting gas which is now named after him. In this talk, we will present our results as follows:

(i). we prove global well-posedness of the Boltzmann equation with cutoff Rutherford scattering cross section near Maxwellian. As a result, we rigorously justify Landau's formal derivation globally in time;

(ii). we revisit Landau approximation problem and prove a global-in-time error estimate between solutions to Boltzmann and Landau equations with logarithm accuracy, which is consistent with the famous Coulomb logarithm. Key ingredients into the proofs of these results include a complete description of the linearized Boltzmann collision operator, a uniform spectral gap estimate and a novel linear-quasilinear method.

专家简介：

何凌冰教授，清华大学数学系，博士毕业于中科院，主要研究方向为Boltzmann方程及Landau方程解的正则性传播和渐进性行为。在Archive for Rational Mechanics and Analysis，Communications in Mathematical Physics，SIAM Journal on Mathematical Analysis、Journal of Functional Analysis，Journal of Differential Equations， J. Stat. Phys.等国际主流数学杂志发表多篇学术论文。