Dark energy generated from a (super)string effective action with higher order curvature corrections and a dynamical dilaton

TL;DR

This paper explores how higher-order string corrections and a dynamical dilaton can produce dark energy solutions, with a focus on the bosonic string, and analyzes their stability and construction methods.

Contribution

It demonstrates the existence of dark energy solutions in bosonic string models with higher-order curvature corrections and provides a method to reconstruct such theories from cosmic expansion histories.

Findings

Dark energy solution exists for bosonic string

Type II and heterotic strings do not produce realistic dark energy

Stability analysis of de-Sitter solutions in bosonic string

Abstract

We investigate the possibility of a dark energy universe emerging from an action with higher-order string loop corrections to Einstein gravity in the presence of a massless dilaton. These curvature corrections (up to $R^4$ order) are different depending upon the type of (super)string model which is considered. We find in fact that Type II, heterotic, and bosonic strings respond differently to dark energy. A dark energy solution is shown to exist in the case of the bosonic string, while the other two theories do not lead to realistic dark energy universes. Detailed analysis of the dynamical stability of the de-Sitter solution is presented for the case of a bosonic string. A general prescription for the construction of a de-Sitter solution for the low-energy (super)string effective action is also indicated. Beyond the low-energy (super)string effective action, when the higher-curvature correction coefficients depend on the dilaton, the reconstruction of the theory from the universe expansion history is done with a corresponding prescription for the scalar potentials.