Speaker: Timothy Kutnink (ISU)

Title: Mass and Charge Renormalization of Fermions using the Relativistic, Minimally Coupled, Time-Dependent Dirac Equation

Abstract: Theoretical understanding of the mass spectra of mesons is an important area of research within nuclear physics that is still actively being pursued. Much of our work has been extensively studying the relativistic self-coupled electromagnetic fermion case, which I will discuss here, to eventually apply this to a quark-antiquark system and hopefully achieve those results. Our approach uses an MSD2 algorithm for direct numerical solving of the electromagnetic time-dependent Dirac equation with the self-coupling making it non-linear needing special attention to stability. A statistical method, employing a canonical ensemble whose temperature is the inverse of the spatial-grid size, is used to remove the momentum dependence. We have obtained finite results of a 10% increase in renormalized mass and a 30% decrease in renormalized charge in the continuum limit for the electromagnetically self-coupled case. Various other results from the electromagnetic case will also be discussed further in this talk, such as a Klein Effect arising from positive and negative energy projections separating from each other in both space and time due to self-interactions. Current on-going work is using the method developed from the self-coupled electromagnetic case serves as our basis for the mutually coupled strong interaction between a quark-antiquark pair.

Bio: Timothy Kutnink currently works as a teaching lab specialist preparing and curating the vast ISU Physics and Astronomy Department’s collection of demonstrations. The research presented was done in collaboration with Dr. Athanasios Petridis and other undergraduate students during his time at Drake University (2013 – 2024) while as a laboratory instructor for their Physics and Astronomy Department. He received both his B.S. (2009) and M.S. (2012) from ISU.