Dynamical analysis of modified gravity with nonminimal gravitational coupling to matter

TL;DR

This paper analyzes a generalized modified gravity theory with nonminimal coupling to matter, revealing different cosmological phases, an attractor solution for late-time acceleration, and compatibility with supernova data.

Contribution

It introduces a phase space analysis of a nonminimally coupled gravity model, identifying conditions for late-time acceleration and thermodynamic consistency.

Findings

Existence of an attractor solution for late-time acceleration

Different Lagrangian choices lead to different cosmological phases

Model compatible with supernova type Ia data

Abstract

We perform a phase space analysis of a generalized modified gravity theory with nonminimally coupling between geometry and matter. We apply the dynamical system approach to this generalized model and find that in the cosmological context, different choices of Lagrangian density will apparently result in different phases of the Universe. By carefully choosing the variables, we prove that there is an attractor solution to describe the late time accelerating universe when the modified gravity is chosen in a simple power-law form of the curvature scalar. We further examine the temperature evolution based on the thermodynamic understanding of the model. Confronting the model with supernova type Ia data sets, we find that the nonminimally coupled theory of gravity is a viable model to describe the late time Universe acceleration.