Dynamical study of the hyperextended scalar-tensor theory in the empty Bianchi type I model

TL;DR

This paper investigates the dynamics of hyperextended scalar-tensor theories in Bianchi type I models, providing methods to predict cosmological behaviors like expansion, contraction, bouncing, or inflation, and presents exact solutions.

Contribution

It introduces a method to determine the sign of derivatives of metric functions in scalar-tensor theories, enabling prediction of various cosmological scenarios, and analyzes string-inspired models without antisymmetric fields.

Findings

Method to predict cosmological behavior based on derivative signs

Exact solutions for specific scalar-tensor models

Analysis of string-inspired theories without antisymmetric fields

Abstract

The dynamics of the hyperextended scalar-tensor theory in the empty Bianchi type I model is investigated. We describe a method giving the sign of the first and second derivatives of the metric functions whatever the coupling function. Hence, we can predict if a theory gives birth to expanding, contracting, bouncing or inflationary cosmology. The dynamics of a string inspired theory without antisymetric field strength is analysed. Some exact solutions are found.