Jointly modelling Cosmic Inflation and Dark Energy

Konstantinos Dimopoulos

doi:10.1088/1742-6596/2105/1/012001

Abstract

Quintessential inflation utilises a single scalar field to account for the observations of both cosmic inflation and dark energy. The requirements for modelling quintessential inflation are described and two explicit successful models are presented in the context of α-attractors and Palatini modified gravity.

Highlights

The 14 Gy history of the Universe requires special initial conditions, which are arranged by cosmic inflation [1]
Quintessential inflation utilises a single scalar field to account for the observations of both cosmic inflation and dark energy
Inflation is typically modelled through the inflationary paradigm, which considers that the Universe undergoes inflation when dominated by the potential energy density of a scalar field, called the inflaton field

Summary

Introduction

The 14 Gy history of the Universe requires special initial conditions, which are arranged by cosmic inflation [1]. The superluminal expansion of space during inflation amplifies the quantum fluctuations of the inflaton field and renders them into classical perturbations of this field, through a process called quantum decoherence This means that the critical value φend is reached at slightly different times at different points in space. The PDPs are predominantly adiabatic, which means that they are originally at the same level (∼ 10−5) in all components of the Universe content (neutrinos, dark matter etc.) This strongly suggests that the primordial plasma is comprised by the decay products of a single degree of freedom, which could be the inflaton field. This approximate scale-invariance suggests that inflation is of a special type, called quasi-de Sitter inflation, where the energy density during inflation is almost constant What does this translate into, in the inflationary paradigm?

Quartic hilltop inflation

N and r

Quintessence as dark energy

Findings

Conclusions