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Condensed Matter Seminar - "When details matter: learning coarse-grained physics from first principles"

Event Type
Seminar/Symposium
Sponsor
Physics - Condensed Matter
Location
ESB 190
Date
Jan 24, 2025   1:10 pm  
Speaker
Lucas Wagner, University of Illinois at Urbana-Champaign
Contact
Stephen Bullwinkel
E-Mail
bullwink@illinois.edu
Phone
217-333-1652
Views
11
Originating Calendar
Physics - Condensed Matter Seminar

Many quote Andersons' "More is different" paper to say that "details don't matter" in collective motion. However, that is not what the paper says. Indeed, at the end of the paper, he quotes Marx as "quantitative differences become qualitative ones." A key concept is that even though almost everything is made of nuclei and electrons, quantitative differences in how they are arranged result in qualitative differences in behavior at the macroscale. However, our macroscale models are typically based on very approximate calculations, symmetry rules, and other considerations. 

I will talk about how progress in solving the Schroedinger equation for nuclei and electrons has enabled us to make progress in computing macroscale models that are both accurate and parsimonious, in that they only include the details required to describe the basic physics. This involves essentially learning renormalization from microscopic calculations. 

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