Asymptotic safety of gravity-matter systems and effective universality

          @misc{ pirsa_PIRSA:18060022,
            doi = {10.48660/18060022},
            url = {https://pirsa.org/18060022},
            author = {Reichert, Manuel},
            keywords = {Cosmology, Particle Physics},
            language = {en},
            title = {Asymptotic safety of gravity-matter systems and effective universality},
            publisher = {Perimeter Institute},
            year = {2018},
            month = {jun},
            note = {PIRSA:18060022 see, \url{https://pirsa.org}}
          }
          

Abstract

We review the status of asymptotically safe gravity-matter systems. The existence of a UV fixed point in such systems is guaranteed if the matter-self couplings are weak and if higher-derivative gravity terms are neglected. We show how this can manifest itself in a functional renormalisation group computation. Such gravity-matter systems contain various avatars of the dynamical Newton's coupling, e.g. gravitational self-couplings or matter-graviton couplings. We uncover an effective universality for the dynamical Newton's coupling on the quantum level: its momentum-dependent avatars are in remarkable quantitative agreement in the scaling regime of the UV fixed point. This emergence of effective universality is a strong indication for the physical nature of the UV fixed point and it provides a guiding principle for setting up future truncations.