Dilaton Quantum Gravity

TL;DR

This paper proposes a fixed point scenario in dilaton gravity that could make gravity non-perturbatively renormalizable, with implications for dark energy and the cosmological constant.

Contribution

It introduces a simple fixed point framework in scalar dilaton gravity, linking scale symmetry breaking to realistic gravity and dark energy.

Findings

Gravity can be asymptotically safe at a fixed point.

Spontaneous scale symmetry breaking yields a nonzero Planck mass.

The model predicts a vanishing cosmological constant at late times.

Abstract

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.