Anisotropic Four-Dimensional NS-NS String Cosmology

TL;DR

This paper investigates the evolution of an anisotropic four-dimensional universe within string theory, analyzing the effects of the dilaton and axion-like fields in different frames.

Contribution

It introduces a detailed study of anisotropic cosmology in the NS-NS sector of string theory, considering both Einstein and string frames.

Findings

Describes the universe's evolution in anisotropic string cosmology.

Analyzes the impact of dilaton and axion fields on cosmic dynamics.

Provides insights into frame-dependent cosmological behaviors.

Abstract

An anisotropic (Bianchi type I) cosmology is considered in the four-dimensional NS-NS sector of low-energy effective string theory coupled to a dilaton and an axion-like $H$-field within a de Sitter-Einstein frame background. The time evolution of this Universe is discussed in both the Einstein and string frames.