Functional renormalization group approach and gauge dependence in gravity theories V´ıtor F. Barraa1, Peter M. Lavrovb,c2, Eduardo Antonio dos Reisa3, Tib´erio de Paula Nettod4, Ilya L. Shapiroa,b,c5 a Departamento de F´ısica, ICE, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, MG, Brazil b Department of Theoretical Physics, Tomsk State Pedagogical University, 634061 Tomsk, Russia c National Research Tomsk State University, 634050 Tomsk, Russia d Departament of Physics, Southern University of Science and Technology, 518055 Shenzhen, China Abstract We investigate the gauge symmetry and gauge fixing dependence properties of the effective average action for quantum gravity models of general form. Using the background field formalism and the standard BRST-based arguments, one can establish the special class of regulator functions that preserves the back- ground field symmetry of the effective average action. Unfortunately, regardless the gauge symmetry is preserved at the quantum level, the non-invariance of the regulator action under the global BRST transformations leads to the gauge fixing dependence even under the use of the on-shell conditions. Keywords: quantum gravity, background field method, functional renormal- ization group approach, gauge dependence arXiv:1910.06068v3 [hep-th] 5 Mar 2020 1 Introduction The interest to the non-perturbative formulation in quantum gravity has two strong motivations. First, there are a long-standing expectations that even the perturbatively non- renormalizable models such as the simplest quantum gravity based on general relativity 1E-mail address:
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[email protected] 5E-mail address: shapiro@fisica.ufjf.br may be quantum mechanically consistent due to the asymptotic safety scenario [1] (see [2, 3] for comprehensive reviews).