PUG Seminar

PUG Seminar

Whitmore 321

2025-03-21

Speaker Michael Plesser will be presenting on the requirements of a non-abelian gauge theory.

Title: “Why (Non-Abelian) Gauge Theory?”

Abstract: Combining (flat-space) Lorentz-invariance with quantum mechanics in D=4 you inevitably describe a Quantum Field Theory (QFT), so the widespread interest in QFTs is understandable. Much more mysterious for many students is the passage to gauge theory, which introduces many sophisticated mathematical notions prone to overwhelming the uninitiated. Just as QFT arises as a necessary framework assuming certain basic principles, we will describe reasonable sounding theories for which non-abelian gauge theory is the necessary framework. The concrete statement we will argue is the following: a unitary, local, and Lorentz-invariant theory of massless, self-interacting, spin-1 particles in D=4 is necessarily a non-abelian gauge theory. Time allowing, we may discuss other interesting aspects of gauge theory relevant to my research.

Schedule for PUG Seminar
Time	Speaker	Title
14:00	Michael Plesser	Why (Non-Abelian) Gauge Theory?

The IGC wordmark was created by Monica Rincon Ramirez, while she was a graduate student at the Institute for Gravitation and the Cosmos (IGC). Monica enjoys drawing new connections between fundamental theory and observations. Her graduate work includes specialized topics in general relativity, loop quantum gravity, and quantum fields in cosmological backgrounds. In particular, her thesis work focused on finding effective quantum corrections to gravitational phenomena from spinfoams, and applications to cosmology. She received her PhD in 2024.

The wordmark symbolizes the scope and variety of research at the IGC. The base of the image represents quantum gravity, evoking the quantum geometrical picture from spinfoams and loop quantum gravity. These are among the approaches to fundamental questions studied at the Center for Fundamental Theory. The middle of the image represents the Center for Theoretical and Observational Cosmology by galaxies embedded in a smooth surface, characteristic of spacetime in general relativity and the much larger physical scales studied in cosmology. Finally, at the top, the surface curves to an extreme, representing a supermassive black hole accompanied by an energetic jet. These elements depict an active galactic nucleus, inspired by Centaurus A. Just to the right, a pair of black holes approaches merger. This top portion of the wordmark represents the Center for Multimessenger Astrophysics, which specializes in the study of high-energy phenomena in the universe.