Dilaton quantum gravity

We propose a simple fixed-point scenario in the renormalization flow of a scalar dilaton coupled to gravity. This would render gravity non-perturbatively renormalizable and thus constitute a viable theory of quantum gravity. On the fixed point dilatation symmetry is exact and the quantum effective action takes a very simple form. Realistic gravity with a nonzero Planck mass is obtained through a nonzero expectation value for the scalar field, constituting a spontaneous scale symmetry breaking. Furthermore, relevant couplings for the flow away from the fixed point can be associated with a "dilatation anomaly" that is responsible for dynamical dark energy. For the proposed fixed point and flow away from it the cosmological "constant" vanishes for asymptotic time. (C) 2013 Elsevier B.V. All rights reserved.