Renormalization-Group Running Induced Cosmic Inflation

TL;DR

This paper proposes a mechanism where renormalization-group running of the inflaton potential, starting from a false vacuum at high energies, naturally sets initial conditions for inflation, aligning with cosmological observations.

Contribution

It introduces a novel scenario where quantum fluctuations and RG running shape the inflaton potential, reducing the need for large initial field fluctuations in inflation models.

Findings

The mechanism applies to a broad class of inflationary potentials.

The model reproduces cosmological data accurately.

Eliminates the necessity of large GUT-scale fluctuations.

Abstract

As a contribution to a viable candidate for a standard model of cosmology, we here show that pre-inflationary quantum fluctuations can provide a scenario for the long-sought initial conditions for the inflaton field. Our proposal is based on the assumption that at very high energies (higher than the energy scale of inflation) the vacuum-expectation value (VeV) of the field is trapped in a false vacuum and then, due to renormalization-group (RG) running, the potential starts to flatten out toward low energy, eventually tending to a convex one which allows the field to roll down to the true vacuum. We argue that the proposed mechanism should apply to large classes of inflationary potentials with multiple concave regions. Our findings favor a particle physics origin of chaotic, large-field inflationary models as we eliminate the need for large field fluctuations at the GUT scale. In our analysis, we provide a specific example of such an inflationary potential, whose parameters can be tuned to reproduce the existing cosmological data with good accuracy.