Conformal Invariance, Accelerating Universe and The Cosmological Constant Problem

TL;DR

This paper explores a conformal invariant gravitational model that explains early universe inflation, relaxes the cosmological constant to observed levels, and predicts late-time cosmic acceleration via a dynamical conformal factor.

Contribution

It introduces a conformal invariant framework where the conformal factor acts as a dynamical field influencing vacuum energy and cosmic acceleration, providing a unified approach to inflation and dark energy.

Findings

The model predicts an inflationary phase in the early universe.

It offers a mechanism for the cosmological constant to relax to small observed values.

The conformal factor functions as a quintessence field driving late-time acceleration.

Abstract

We investigate a conformal invariant gravitational model which is taken to hold at pre-inflationary era. The conformal invariance allows to make a dynamical distinction between the two unit systems (or conformal frames) usually used in cosmology and elementary particle physics. In this model we argue that when the universe suffers phase transitions, the resulting mass scales introduced by particle physics should have variable contributions to vacuum energy density. These variations are controlled by the conformal factor that appears as a dynamical field. We then deal with the cosmological consequences of this model. In particular, we shall show that there is an inflationary phase at early times. At late times, on the other hand, it provides a mechanism which makes a large effective cosmological constant relax to a sufficiently small value consistent with observations. Moreover, we shall show that the conformal factor acts as a quintessence field that leads the universe to accelerate at late times.