Singularities and Phenomenological aspects of Asymptotic Safe Gravity

TL;DR

This paper explores the phenomenological implications of Asymptotic Safety in quantum gravity, analyzing non-singular cosmological and black hole solutions, and deriving a new set of consistent modified Einstein equations.

Contribution

It introduces a novel, consistent set of modified Einstein equations within the AS framework that respects Bianchi identities and extends previous models.

Findings

Identification of non-singular spherically symmetric solutions

Discovery of non-singular cosmological solutions

Derivation of new modified Einstein equations

Abstract

Asymptotic Safety (AS) Program for quantum gravity keeps the same fields and symmetries with General Relativity and studies the associated gravitational action as a fundamental part of the complete theory at the nonperturbative level with the help of functional renormalization group (RG) techniques. An important phenomenological task that can test the new point of view of AS approach is the discovery of RG improved cosmologies and black holes. In this work, we analyze the properties of recently found non-singular spherically symmetric and non-singular cosmological solutions. Furthermore, we derive a novel consistent set of modified Einstein field equations, in the spirit of AS, which respects the Bianchi identities. This new set of equations extend previously published modified Einstein equations which arise by adding appropriate covariant kinetic terms to the action.