Abstract

Neutron stars and their mergers create environments of ultra-dense matter where the strong interaction governs the behavior, but where quantum chromodynamics, the theory of the strong interaction, cannot be solved exactly or perturbatively using current methods. Neutron stars are objects with more mass than our Sun, but with a diameter of about 25 km. Observations of neutron star macroscopic properties like their masses and radii, their surface temperatures, and the gravitational-wave and electromagnetic signals from their mergers allow us to use theoretical tools to infer the behavior of matter at a microscopic scale. In this thesis, we explore the static and dynamic properties of dense matter. First, we show how phenomenological models calibrated to the properties of isospin-symmetric nuclear matter and neutron matter are consistent with the observed masses and radii of neutron stars. Second, the procedure used to generate these phenomenological models is used to investigate an unusually low mass compact object, which we determine is consistent with a hybrid star with a mantle made of nuclear matter and a core made of quark matter. Third, we show how a previously unconsidered weak interaction process can cool neutron stars more quickly than previously thought. Fourth and finally, we investigate how neutrinos thermalize in the hot and dense environment of a simulation of a neutron star merger shortly after merger.

Committee Chair

Mark Alford

Committee Members

Robert Pisarski; Saori Pastore; Willem Dickhoff; Zohar Nussinov

Degree

Doctor of Philosophy (PhD)

Author's Department

Physics

Author's School

Graduate School of Arts and Sciences

Document Type

Dissertation

Date of Award

4-27-2026

Language

English (en)

Author's ORCID

https://orcid.org/0000-0001-7708-2073

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