Bouncing and emergent cosmologies from ADM RG flows

TL;DR

This paper explores quantum gravitational effects from Asymptotic Safety in gravity, using ADM formalism to derive RG-improved cosmological equations that lead to bouncing and emergent universe models without exotic matter.

Contribution

It introduces a novel approach combining ADM formalism with RG flow to derive quantum-corrected cosmological equations, enabling new bouncing and emergent universe solutions.

Findings

Bouncing cosmologies without exotic matter.

Emergent universe solutions for various topologies.

Quantum corrections modify Friedmann equations significantly.

Abstract

The Asymptotically Safe Gravity provides a framework for the description of gravity from the trans-Planckian regime to cosmological scales. According to this scenario, the cosmological constant and Newton's coupling are functions of the energy scale whose evolution is dictated by the renormalization group equations. The formulation of the renormalization group equations on foliated spacetimes, based on the Arnowitt-Deser-Misner (ADM) formalism, furnishes a natural way to construct the RG energy scale from the spectrum of the laplacian operator on the spatial slices. Combining this idea with a Renormalization Group improvement procedure, in this work we study quantum gravitational corrections to the Einstein-Hilbert action on Friedmann-Lema\^{i}tre-Robertson-Walker (FLRW) backgrounds. The resulting quantum-corrected Friedmann equations can give rise to both bouncing cosmologies and emergent universe solutions. Our bouncing models do not require the presence of exotic matter and emergent universe solutions can be constructed for any allowed topology of the spatial slices.