Northwestern University

Feb
15
Fri 4:00 PM

Colloquium: Jim Sethna : Sloppy models, differential geometry, and the space of model predictions

When: Friday, February 15, 2019
4:00 PM - 5:00 PM  

Where: Technological Institute, L211, 2145 Sheridan Road, Evanston, IL 60208 map it

Audience: Faculty/Staff - Student - Public - Post Docs/Docs - Graduate Students

Contact: Yassaman   847.491.7650

Group: Physics and Astronomy Colloquia

Category: Academic

Description:

Models of systems biology, climate change, ecology, complex instruments, and macroeconomics have parameters that are hard or impossible to measure directly. If we fit these unknown parameters, fiddling with them until they agree with past experiments, how much can we trust their predictions? We have found that predictions can be made despite huge uncertainties in the parameters – many parameter combinations are mostly unimportant to the collective behavior. We will use ideas and methods from differential geometry and approximation theory to explain sloppiness as a ‘hyper-ribbon’ structure of the manifold of possible model predictions. We show that physics theories are also sloppy – that sloppiness may be the underlying reason why the world is comprehensible. We will present new methods for visualizing this model manifold for probabilistic systems – such as the space of possible universes as measured by the cosmic microwave background radiation.

 

Seminar Speaker: Jim Sethna, Cornell University 

 Host: Garg

Keywords: Physics, Astronomy, Seminar, Colloquium

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