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

Evidence for ultraviolet gravitational fixed points in asymptotic safety quantum gravity has been found over the past years. The non-trivial interplay of matter and gravity can either spoil fixed points or enhance predictive power in infrared scales. In the first part of the talk, I will summarize the status of the field and explore the “asymptotic safety landscape” by considering dark-universe-motivated models in the matter sectors. Besides, the field of gravitational waves has flourished over the past decade. The search for a gravitational wave background across different energy scales is a tantalizing probe of new physics as it is complementary to CMB. In the second part of the talk, I will summarize the status of searches and show that nHz PTA data are already competitive to constrain BSM and cosmology particle physics models.