Remarks on some vacuum solutions of scalar-tensor cosmological models

TL;DR

This paper derives and analyzes exact vacuum solutions in scalar-tensor cosmologies, focusing on de Sitter and warm inflation models, using phase diagram analysis to understand their dynamical behavior.

Contribution

It introduces a class of exact vacuum solutions for scalar-tensor models and applies qualitative phase space analysis to study their properties.

Findings

Solutions correspond to de Sitter and warm inflation scenarios.

Phase diagrams reveal stability and behavior near equilibrium points.

Reductions to planar dynamical systems facilitate analysis.

Abstract

We present a class of exact vacuum solutions corresponding to de Sitter and warm inflation models in the framework of scalar-tensor cosmologies. We show that in both cases the field equations reduce to planar dynamical systems with constraints. Then, we carry out a qualitative analysis of the models by examining the phase diagrams of the solutions near the equilibrium points.