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_{Kim Berghaus,
Caltech}

_Abstract:

Dark matter comprises 85% of the matter density of our Universe, yet all of its known evidence lies in its gravitational imprint. One of the most important scientific goals of the next decade in fundamental physics is to reveal the nature of dark matter by measuring its non-gravitational interactions in the laboratory. To accomplish this goal, the experimental landscape must delve deep and search wide. Ensuring success requires overcoming emerging challenges in low threshold dark matter detection, such as quantifying how dark matter signals and backgrounds manifest in detectors. My research bridges the critical intersection of theoretical prediction and experimental verification of signals and backgrounds. As an example, I will discuss my work on quantifying the Migdal effect, a rare atomic ionization process that occurs when a neutron or dark matter scatters off a nucleus, in semiconductors, with relevance for experiments such as SENSEI and DAMIC. I will also discuss the role of phonon backgrounds from gamma-rays for sub-GeV dark matter experiments such as EDELWEISS and SuperCDMS. Lastly, I will show that phonons efficiently couple to paramagnetic qubits, opening up potential new pathways for single phonon detection. 

Timbits, coffee, tea will be served in STI A before the colloquium.