Scale invariance, unimodular gravity and dark energy

TL;DR

This paper shows that combining unimodular gravity, scale invariance, and a massless dilaton can produce a universe evolution consistent with observations, including inflation, matter dominance, and current acceleration, with all mass scales originating from a single source.

Contribution

It introduces a unified framework linking unimodular gravity, scale invariance, and a massless dilaton to explain cosmic evolution and dark energy.

Findings

Reproduces inflation, radiation, matter, and accelerated expansion phases

All mass scales originate from a single source

Consistent with current cosmological observations

Abstract

We demonstrate that the combination of the ideas of unimodular gravity, scale invariance, and the existence of an exactly massless dilaton leads to the evolution of the universe supported by present observations: inflation in the past, followed by the radiation and matter dominated stages and accelerated expansion at present. All mass scales in this type of theories come from one and the same source.