Analysis Seminar

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Coarse-graining, renormalization, and anomalous diffusion

Speaker: Scott Armstrong, CNRS at Sorbonne Université, LJLL

Location: Warren Weaver Hall 1302

Date: Thursday, October 30, 2025, 11 a.m.

Synopsis:

I will talk about coarse-graining of elliptic divergence-form operators, and how it relates to infrared renormalization group arguments in theoretical physics. We will introduce a new notion of "coarse-grained ellipticity,” recover some classical results from elliptic regularity under this softer ellipticity assumption, and discuss applications to certain physical models, including high contrast resistor networks and long-time behavior of diffusions in random drifts.