AN EMERGENT COSMOLOGICAL MODEL FROM ASYMPTOTIC SAFETY

Abstract

The modern cosmological models tell us that the early universe has gone through a phase of accelerated expansion, known as inflation, which solves the horizon and flatness problems. In this thesis, I present an inflationary cosmological model based on the Asymptotically Safe behavior of the Newton constant at Planckian energies. Unlike other models, the variability of G is given by a multiplicative coupling constant χ in the matter Lagrangian with a conserved energy-momentum tensor, and the specific functional form of χ is deduced from Asymptotically Safe gravity. In the beginning, the universe undergoes a quasi-de-Sitter phase and, then transitions to the conventional cosmological evolution after the Planck Era.