Physics and Astronomy -PhD Thesis Defense - Michelle Stephens, Dartmouth College

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Physics and Astronomy -PhD Thesis Defense - Michelle Stephens, Dartmouth College

Title: "Shape is Destiny: How Information Theory Captures the Fate of Bubbles and the Universe"

Monday, June 17, 2019
Wilder 115
Intended Audience(s): Public
Categories: Lectures & Seminars

Abstract: Configurational Entropy (CE), a measure of shape complexity for localized physical systems, has been an excellent predictor of stability and tracker of criticality in numerous systems. I will first discuss the information theory on which CE is based, and differentiate between three similar, but separate measures which have all been called CE in the literature. Oscillons – dynamical solutions in self-interacting scalar field theories – have long required numerical simulation to capture their evolution and eventual decay. I will show how the CE established at the beginning of an oscillon’s evolution provided the first predictive measure of its lifetime. Finally, I will discuss how information theory may provide a novel approach for cosmological parameter estimation, based on the Jensen-Shannon Divergence. Motivation comes from the statistically significant tensions between early-time and local determination of some parameters, most notably the Hubble constant. The testing ground for this approach is the temperature anisotropy data of the Cosmic Microwave Background from the Planck satellite, compared with model predictions coming from Lambda-CDM and some simple extensions based on evolving dark energy. I can’t claim to solve the Hubble tension or determine the fate of the universe, but I’ll conclude with remarks on future work with this method as new observational data becomes available.     

For more information, contact:
Tressena Manning

Events are free and open to the public unless otherwise noted.