Exploring the dynamics of coincident f(Q) gravity in the presence of DBI-essence scalar field

TL;DR

This paper performs a dynamical system analysis of coincident f(Q) gravity models with a DBI-essence scalar field, revealing stable critical points that correspond to different cosmological epochs and align with observational data.

Contribution

It introduces a detailed dynamical analysis of two specific f(Q) gravity models with a DBI scalar field, exploring their cosmological implications and stability.

Findings

Critical points correspond to various cosmological eras.

Models exhibit late-time acceleration consistent with observations.

Stability analysis identifies conditions for cosmic evolution phases.

Abstract

In theoretical cosmology, symmetric teleparallel gravity or $f(Q)$ gravity based on nonmetricity tensor Q has become an interesting alternative to General relativity in recent years. The present research paper contains a rigorous dynamical system analysis of coincident f (Q) gravity in the presence of a generalized DBI essence scalar field. We have considered two different models of coincident f(Q) gravity, such as power law model $f(Q) = Q + nQ^m$ and exponential model $f(Q) = Q e^{\frac{\beta Q_0}{Q}}$ respectively, where n, m, \b{eta} are constant parameter and Q is the nonmetricity component. In this study, the generalized DBI essence scalar field acts as an additional dark energy component. After obtaining the field equation for the corresponding cosmological model, we employed several dynamical variables to form the dynamical system. The critical points of these dynamical systems are influenced by cosmological parameters and associated with particular epochs in the cosmological timeline. For different combinations of cosmological parameters, the critical points exhibit different cosmological eras, starting from the accelerated stiff matter era to late-time acceleration phenomena. The stability criteria of each critical point are studied by using linear stability theory, and the physical constraints on the cosmological parameters are also considered during this analysis. Furthermore, the current values of energy densities, deceleration parameters, and equation of state parameters obtained from the evolution diagram are compatible with observational data.