G-Bounce Inflation: Towards Nonsingular Inflation Cosmology with Galileon Field

TL;DR

This paper proposes a nonsingular bounce inflation model using Galileon fields, avoiding singularities and instabilities, and producing cosmological perturbations consistent with observations.

Contribution

It introduces a novel bounce inflation model based on Horndesky theory that resolves ghost and anisotropy issues, fitting observational data.

Findings

The model avoids Big Bang singularity and instabilities.

Cosmological perturbations match observational data.

Perturbations show distinctive features testable by large scale structure experiments.

Abstract

We study a nonsingular bounce inflation model, which can drive the early universe from a contracting phase, bounce into an ordinary inflationary phase, followed by the reheating process. Besides the bounce that avoided the Big-Bang singularity which appears in the standard cosmological scenario, we make use of the Horndesky theory and design the kinetic and potential forms of the lagrangian, so that neither of the two big problems in bouncing cosmology, namely the ghost and the anisotropy problems, will appear. The cosmological perturbations can be generated either in the contracting phase or in the inflationary phase, where in the latter the power spectrum will be scale-invariant and fit the observational data, while in the former the perturbations will have nontrivial features that will be tested by the large scale structure experiments. We also fit our model to the CMB TT power spectrum.