Cosmological scalar fields and Big-Bang nucleosynthesis

TL;DR

This paper explores a unified scalar field model that accounts for dark matter, dark energy, and inflation, analyzing how Big-Bang nucleosynthesis constrains such models and their impact on element abundances.

Contribution

It introduces a comprehensive scalar field model unifying dark matter, dark energy, and inflation, and evaluates constraints from Big-Bang nucleosynthesis.

Findings

Scalar fields can unify dark matter, dark energy, and inflation.

Big-Bang nucleosynthesis constrains scalar field models.

Element abundances are affected by primordial scalar fields.

Abstract

The nature of dark matter and of dark energy which constitute more than $95\%$ of the energy in the Universe remains a great and unresolved question in cosmology. Cold dark matter can be made of an ultralight scalar field dominated by its mass term which interacts only gravitationally. The cosmological constant introduced to explain the recent acceleration of the Universe expansion can be easily replaced by a scalar field dominated by its potential. More generally, scalar fields are ubiquitous in cosmology: inflaton, dilatons, moduli, quintessence, fuzzy dark matter, dark fluid, etc. are some examples. One can wonder whether all these scalar fields are independent. The dark fluid model aims at unifying quintessence and fuzzy dark matter models with a unique scalar field. One step futher is to unify the dark fluid model with inflation. In the very early Universe such scalar fields are not strongly constrained by direct observations, but Big-Bang nucleosynthesis set constraints on scalar field models which lead to a modification on the abundance of the elements. In this talk we will present a scalar field model unifying dark matter, dark energy and inflation, and study constraints from Big-Bang nucleosynthesis on primordial scalar fields.