New Anisotropic Exact Solution in Multifield Cosmology

Andronikos Paliathanasis

doi:10.3390/universe7090323

Abstract

In the case of two-scalar field cosmology, and specifically for the Chiral model, we determine an exact solution for the field equations with an anisotropic background space. The exact solution can describe anisotropic inflation with a Kantowski–Sachs geometry and can be seen as the anisotropic analogue of the hyperbolic inflation. Finally, we investigate the stability conditions for the exact solution.

Highlights

The early acceleration epoch of the universe is the inflationary era [1], to which the isotropy and homogeneity of the observed universe are due [2]
The Chiral model with an exponential potential provides a new inflationary solution known as hyperbolic inflation [35,36]
In this study we investigate the existence of a new exact solution in Chiral cosmology with an anisotropic background space

Summary

Introduction

The early acceleration epoch of the universe is the inflationary era [1], to which the isotropy and homogeneity of the observed universe are due [2]. In one scalar field cosmology, exact and analytic solutions in a homogeneous and isotropic background space can be found in [5,6,7,8,9,10,11,12,13,14]. The Chiral model with an exponential potential provides a new inflationary solution known as hyperbolic inflation [35,36]. In this study we investigate the existence of a new exact solution in Chiral cosmology with an anisotropic background space. In our consideration for the background space we consider locally rotational spacetimes (LRS) with two scale factors that belong to the family of Bianchi I, Bianchi III and Kantowski– Sachs spacetimes These anisotropic spacetimes have the property that they fall into the spatially flat, closed and open Friedmann–Lemaître–Robertson–Walker (FLRW) spacetime when they reach isotropy.

Chiral Cosmology

Exact Solution

Stability Analysis

Conclusions