Frequency combs for precision metrology

• Elmer Gründeman (ETH Zürich)

Over the last century, our efforts to understand the spectrum of simple atomic systems such as hydrogen have led to the development of quantum mechanics, quantum-electrodynamics, and to the precise determination of fundamental constants. Constant improvements in both experimental techniques and theoretical models have pushed the precision of measurements and calculations to an astonishing level. The development of the frequency comb laser in 2000 has been instrumental for precision spectroscopy, as it solved a long-standing issue of measuring optical frequencies in terms of the Cs primary standard. Instead of using such a laser as an “optical ruler”, one can also use its pulsed output for direct frequency comb spectroscopy. I will talk about the working principle of these frequency comb lasers, and how we plan on using them to perform the first measurement of the 1S-2S transition in He+, which was the subject of my PhD research.

Geometrical Approaches to Evaluate Feynman Integrals

• Sumit Banik (Indian Institute of Science)

Experimental measurements of physical observables in high-energy particle colliders, such as the LHC, rely on precise theoretical predictions to validate theoretical models and detect signals of new physics. These predictions, within the perturbative framework of quantum field theory, require the computation of complicated integrals, commonly known as Feynman integrals. In this talk, I will briefly discuss two new approaches that use school-level geometry for the analytic evaluation of scalar Feynman diagrams.