Renormalization Group Approaches to Quantum Gravity

The talk will review recent tests of the asymptotic safety conjecture within functional renormalisation group studies and progress in understanding the properties that such a fixed point would have.

I will review the approach of Causal Dynamical Triangulations to nonperturbative quantum gravity, high-lighting some frequently mis- or ununderstood features, emphasizing recent developments and discussing some interesting open issues.

Tensor models generalize matrix models and provide a framework for the study of random geometries in arbitrary dimensions. Like matrix models they support a 1/N expansion, where N is the size of the tensor, with an analytically controlled large N limit. In this talk I will present some recent…

Group field theories are tensorial models enriched with group-theoretic data in order to define proper field theories of quantum geometry. They can be understood as a second quantised (Fock space) reformulation of loop quantum gravity kinematics and dynamics. The renormalization group provides, as a…

Given (a set of) fundamental models of quantum space time, for instance spin foam models, we aim to understand the large scale physics encoded in these fundamental models. Renormalization and coarse graining address this issue and help to understand how large scale physics depends on parameters in…

We know how to make perturbative calculations in quantum gravity using the framework of effective field theory. I will describe the basics of the effective field theory treatment and look at several calculations. There are obstacles to describing these with running coupling constants. Finally, I…

Two aspects of asymptotic safety are highlighted. First, I discuss how asymptotic safety can be tested with the help of a bootstrap strategy. This is then applied to high-order polynomial actions of the Ricci scalar and beyond. Second, I discuss how phenomenological signatures of asymptotic safety…

The connection between two-dimensional Euclidean gravity and pure matrix models has lead to may fundamental insights about quantum gravity and string theory. The pure matrix model is thus a blueprint for the connection between discrete models and Euclidean quantum gravity. I will report on work with…

An attempt is made to define "lines of contant physics" in CDT and relate the corresponding picture to non-trivial UV fixed points as they appear in the asymptotic safety scenario.