Chain inflation revisited

TL;DR

This paper thoroughly analyzes the chain inflation model, demonstrating its viability for solving key cosmological problems and generating appropriate perturbations, with new detailed formulas and a potential embedding in string theory.

Contribution

It provides a comprehensive evolution analysis, explicit perturbation spectrum formula, and a novel embedding approach into flux compactified string theory.

Findings

Chain inflation can solve horizon, entropy, and flatness problems.

The model generates the correct amplitude of adiabatic perturbations.

Results differ significantly from previous studies on chain inflation.

Abstract

This paper represents an in-depth treatment of the chain inflation scenario. We fully determine the evolution of the universe in the model, the necessary conditions in order to have a successful inflationary period, and the matching with the observational results regarding the cosmological perturbations. We study in great detail, and in general, the dynamics of the background, as well as the mechanism of generation of the perturbations. We also find an explicit formula for the spectrum of adiabatic perturbations. Our results prove that chain inflation is a viable model for solving the horizon, entropy and flatness problem of standard cosmology and for generating the right amount of adiabatic cosmological perturbations. The results are radically different from those found in previous works on the subject. Finally, we argue that there is a natural way to embed chain inflation into flux compactified string theory. We discuss the details of the implementation and how to fit observations.