One force to rule them all: asymptotic safety of gravity with matter

Understand

We study the asymptotic safety conjecture for quantum gravity in the presence of matter fields.

• A general line of reasoning is put forward explaining why gravitons dominate the high-energy behaviour, largely independently of the matter fields as long as these remain sufficiently weakly coupled.
• Our considerations are put to work for gravity coupled to Yang-Mills theories with the help of the functional renormalisation group.
• In an expansion about flat backgrounds, explicit results for beta functions, fixed points, universal exponents, and scaling solutions are given in systematic approximations exploiting running propagators, vertices, and background couplings.