Quintessence Universe and cosmic acceleration in f (Q, T) gravity

Abstract

The problem of cosmic acceleration and dark energy is one of the mysteries presently posed in the scientific society that general relativity has not been able to solve. In this work, we have considered alternative models to explain this late-time acceleration in a flat Friedmann-Lemaitre-Robertson-Walker (FLRW) Universe within the framework of the f (Q, T) modified gravity theory (where Q is the non-metricity and T is the trace of the energy-momentum tensor) recently proposed by Xu et al. (Eur. Phys. J. C 79 (2019) 708), which is an extension of f (Q) gravity with the addition of the T term. Here, we presume a specific form of f (Q, T) = αQ + βQ 2 + γT where α, β and γ are free model parameters, and obtained the exact solutions by assuming the cosmic time-redshift relation as t(z) = nt 0 m g(z) which produces the Hubble parameter of the form H(z) = mH 0 m+n 1 g(z) + 1 where m and n are the non-negative constants, we find the best values for them using 57 data points of the Hubble parameter H (z). Also, we find the behavior of different cosmological parameters as the deceleration parameter q , energy density ρ , pressure p and EoS parameter (ω) and compare them with the observational results. To ensure the validity of the results, we studied the energy conditions along with jerk parameter. Finally, we found that our model behaves similarly to the quintessence Universe.

Constraining Parameters for the Accelerating Models in Symmetric Teleparallel Gravity

“…However, the effective EoS has shown the transition from an early deceleration to a late-time acceleration. At the present time, the effective EoS parameter for this model (ω eff ) 0 −0.5273, (ω eff ) 0 −0.5980 and (ω eff ) 0 −0.5882 for the constrained free parameters from H(z) data set, Pantheon + Analysis data set and combine H(z) + Pantheon + Analysis data set respectively, which gives the quintessence behavior of the Universe [59]. In a similar note, using Eq.…”

Observational Constraints on Hybrid Scale Factor in f(Q,T)$f(Q,T)$ Gravity with Anisotropic Space‐Time

“…Some more analysis on HSF in GR and MGT can be seen in Refs. [58–63]. At present time ($$t=t_{0}$$), the average scale factor is expressed in the form $$a(t_{0})=a_{0}=t_{0}^{\alpha }e^{\chi t_{0}}$$, where a 0 is the present value of the scale factor.…”

Transit f(Q,T) Gravity Model: Observational Constraints with Specific Hubble Parameter

“…Various cosmological models of f (Q, T) gravity, depending on the nature of the source of matter, are possible. Recently, Koussour et al [52] investigated the quintessence universe and cosmic acceleration in f (Q, T) gravity by presuming a specific form of f (Q, T) = αQ + βQ 2 + γT, where α, β, and γ are free model parameters. Also, in [53], the authors investigated energy conditions in f (Q, T) gravity for two different forms of models.…”