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GR: Fachverband Gravitation und Relativitätstheorie

GR 16: Quantenaspekte der Gravitation und vereinheiltichender Theorien 2

GR 16.2: Vortrag

Freitag, 17. März 2017, 08:50–09:10, SFG 0140

Towards apparent convergence in asymptotically safe quantum gravity — Tobias Denz¹, Jan M. Pawlowski^1,2, and •Manuel Reichert¹ — ¹Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 16, 69120 Heidelberg, Deutschland — ²ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung mbH, Planckstr. 1, 64291 Darmstadt, Deutschland

The asymptotic safety scenario in gravity is accessed within the systematic vertex expansion scheme for functional renormalisation group flows. In the present work this expansion scheme includes propagators, the graviton three-point function and, for the first time, the graviton four-point function. This provides us with a closed flow equation for the graviton propagtor: all vertices and propagators involved are deduced by their own flows. In terms of a covariant operator expansion the current approximation gives access to Λ, R, R² as well as R_µν² and higher derivative operators. We find a UV fixed point with three attractive and two repulsive directions, thus confirming previous studies on the relevance of the first three operators. In the infrared we find trajectories that correspond to classical general relativity and further show non-classical behaviour in some fluctuation couplings. We also find signatures for the apparent convergence of the systematic vertex expansion. This opens a promising path towards finally establishing asymptotically safe gravity in terms of apparent convergence.