Dynamical analysis of cosmological models in non-minimal scalar non-metricity gravity

TL;DR

This paper analyzes the evolution of a flat FRW universe within scalar non-metricity gravity, revealing models that include early inflation, matter dominance, and late acceleration, with stability analysis of critical points.

Contribution

It introduces a new class of cosmological models in scalar non-metricity gravity, exploring their dynamical behavior and stability, including late acceleration and early inflation phases.

Findings

The models exhibit late-time acceleration consistent with observations.

Existence of matter-dominated saddle points leading to decelerating phases.

Identification of stable and unstable critical points in the autonomous system.

Abstract

We investigate the evolution of a spatially flat Friedmann-Robertson-Walker (FRW) universe in the framework of scalar non-metricity theory of gravity. In the model, we consider dark matter (DM) and dark energy (DE) described by the scalar field. In the paper, we examine the asymptotic behavior of the evolution of the observed universe. We probe the universe with and without an interaction between DM and the effective energy density including scalar field in the non-metricity theory that describes the DE. The critical points of the autonomous system and their stability are determined to understand the behaviour of the universe. The cosmological models accommodate the late accelerating phase of the universe for a given set of parameters, a matter-dominated saddle point is also found to exist which is flowed by a decelerating phase dominated by stiff fluid like DE. We obtain a new class of cosmological model accommodating early inflation, matter-dominated era, and a future decelerating phase followed by late acceleration of the universe.