The Physics Colloquium: Dylan Yost (Colorado State University) "Precision tests of quantum electrodynamics through hydrogen spectroscopy and vacuum birefringence"

Quantum electrodynamics (QED) is the most highly tested theory in science, with predictions made and experimentally confirmed at the parts-per-trillion level.  Because of this extremely accurate theory, testing QED predictions with increased precision can provide more accurate determinations of fundamental constants or reveal deviations that indicate new physics.  In this talk, I will discuss our lab’s efforts to test QED predictions through two avenues.  The first is our ongoing effort in precision hydrogen spectroscopy where we recently measured narrow 2S-nS two-photon transitions. The second is a new experimental effort where we will attempt to detect photon-photon interaction using femtosecond lasers coupled to high finesse optical cavities.