The group of Professor Garbrecht (b. 1977) performs research on particle physics processes in the early universe. The challenge is that often these cannot be considered as isolated scattering processes. This may be due to the finite temperature after the Big Bang or due to the strongly curved space-time at this time. For this purpose, Professor Garbrecht's group develops methods of describing high-energy reactions out of thermal equilibrium as well as quantum fields in expanding space-times. An important application is the dynamical generation of the matter-antimatter asymmetry of the universe, for which a deviation from thermal equilibrium is a necessary condition. Of particular interest are models that establish a connection with experimental tests of charge-parity violation, of electroweak symmetry breaking and neutrino oscillations.