Frank Saueressig: Form Factors in Asymptotic Safety

By definition, form factors capture the momentum dependence of a theory’s n-point function. For example, they may encode corrections to the propagation of fields away from the canonical $1/p^2$-behavior. In this talk, I will discuss the technology of computing form factors in gravity and gravity-matter systems in a self-consistent way. The general framework is applied to two specific examples, the form factor determining the momentum-dependence of the scalar propagator in a fluctuating spacetime and the form factor entering the propagator of transverse-traceless graviton fluctuations. As a first application we follow Donoghues computation of the quantum corrected Newtonian potential where we find that the non-perturbative propagator leads to a potential which is finite as the distance between the two gravitating bodies approaches zero. The talk is based on the two publications L. Bosma, B. Knorr and F. Saueressig “Resolving Spacetime Singularities within Quantum Gravity”, arXiv:1904.04845 and B. Knorr, C. Ripken and F. Saueressig “Form Factors in Asymptotic Safety – conceptual ideas and computational toolbox”, forthcoming.