Seminarium "High Energy, Cosmology and Astro-particle Physics (HECA)"

In the first part of the seminar, we focus on unitarity and optical theorem and their relation to quantum kinetic theory. Using the holomorphic modification of cutting rules, we demonstrate that even when starting with zero-temperature Feynman rules and classical phase-space densities, thermal mass and quantum statistical effects inconspicuously enter the Boltzmann equation. The second part will then focus on calculating reaction rate CP asymmetries necessary to source the matter-antimatter asymmetry according to Sakharov's conditions. It will be shown how the direct use of unitarity allows for tracking the asymmetry cancellations in a purely diagrammatic way.