Physically-Motivated Modeling of Kinetic Inductance Phonon-Mediated Detector for Light Dark Matter Searches

Citation

Cap, Chi Lan (2025) Physically-Motivated Modeling of Kinetic Inductance Phonon-Mediated Detector for Light Dark Matter Searches. Senior thesis (Major), California Institute of Technology. doi:10.7907/nd6z-1y53. https://resolver.caltech.edu/CaltechTHESIS:06172025-193756039

Abstract

The properties of dark matter (DM) is one of the most exciting mysteries in astrophysics, and they are important in understanding cosmological structure formation and could potentially reveal new physics. Direct searches for DM necessitate using ultra-sensitive quantum sensors, one of which is the kinetic inductance phonon-meditated detector (KIPM). Understanding KIPM response is vital to understanding the device's energy resolution. Here, we present a physically-motivated model of KIPM response based on quasiparticle and phonon lifetimes. We examine its adherence to experimental data in three formulations, which either six, five, or four time constants. We examined the temperature-dependence of these time constants and compare them to the results of previous models. All three models fit to data at below 75 mK, with successful fits up to 150 mK in some cases; the five time constants model presents the closest match of temperature-dependence of quasiparticle and phonon lifetimes to existing knowledge, while goodness of fit indicates that the six time constant model have the potential to fit high temperature data better. This paper detailed both the behaviors of the physically-motivated models as well as fitting considerations for the behaviors of the fit.

Thesis Files