Early Universe: inflation and cosmological perturbations

TL;DR

This paper reviews inflationary models of the early Universe, focusing on single and multi-field scenarios, and discusses how primordial perturbations are generated, highlighting recent advances in multi-field inflation theories.

Contribution

It provides a comprehensive overview of inflation models, including recent developments in multi-field inflation, and explains the generation of cosmological perturbations.

Findings

Single scalar field inflation models are foundational.

Multi-field Dirac-Born-Infeld inflation offers new dynamics.

Primordial perturbations are linked to inflationary mechanisms.

Abstract

After a brief summary of general relativity and cosmology, we present the basic concepts underlying inflation, the currently best motivated models for the early Universe. We describe the simplest inflation models, based on a single scalar field, and discuss how primordial cosmological perturbations are generated. We then review some recent developments concerning multi-field inflation models, in particular multi-field Dirac-Born-Infeld inflation.