We investigate the physical properties of complex quantum systems, such as quantum Brownian systems, mesoscopic systems, unconventional superconductors, nanowires and macromolecules and superconducting platforms for quantum information In the context of QUANTERA and in the SIUCs project major focus is on superconducting cavity QED systems in the ultrastrong coupling regime. One major aim is to tailor their properties with the help of intense microwave radiation.