Thesis Defense
Lukas Sumabat
Program: Master’s Program in Physics
Date: Tuesday, September 29, 2026
Time: 12:00pm
Location:P-250
Zoom: TBA
Committee Members
Dr. Fridolin Weber, Physics (Chair)
Dr. Calvin Johnson, Physics
Dr. Jerome Orosz, Astronomy
Abstract
The following words are a summary of the history, theory, and potential application of Einstein-dilaton-Gauss-Bonnet gravity in the decoupling limit; and a test of its proposed characteristics. EdGB is a low-energy, string theory motivated theory, under the broader description of quadratic gravity, and has recently become a topic of discussion due to new advancements. This paper covers the foundational concepts required to describe the theory and outlines the numerical Fortran computations performed over the course of research. It uses multiple equation of state models for compact objects to establish a background stellar profile under traditional general relativity; then fixes that background to solve through the profile, retrieving information on the coupled scalar field which is present in extended theories of gravity. We test the effects of coupling strength and coupling form, though favor the linear form in particular; due to limitations in the program converging towards only the trivial branch of solutions for the quadratic form. Following the investigation on scalar field properties, the paper explored verification tests of a related quantity. All equation of state models are of neutron star sequences; compact objects, which under the theory of EdGB possess no asymptotic scalar monopole charge; finite-radius diagnostics were established and gathered through the same Fortran code, then used to create figures which were analyzed visually to confirm that behavior.