Late-time acceleration from ekpyrotic bounce in f(Q,T) gravity

Abstract

In this paper, we investigate the late-time accelerated universe evolution in a flat, homogeneous and isotropic model in the context of [Formula: see text] gravity, where [Formula: see text] and [Formula: see text] are non-metricity scalar and trace of energy–momentum tensor, respectively. The scale factor, by construction, yields ekpyrotic contraction era followed by a non-singular bounce. The expanding era of the universe yields late-time dark energy era preceded by matter-dominating decelerating era. The model unifies an ekpyrotic, non-singular bounce with the present dark energy-dominated epoch. The model parameters in the functional form of [Formula: see text] gravity affect the dynamical evolution of the equation of state (EoS) parameter. The theoretical value of EoS parameter is found to be [Formula: see text] for [Formula: see text], respectively, and it lies in range of the estimated value of EoS parameter from the Planck+SNe+BAO observational data. Different aspects of this bouncing model including behavior of geometrical and physical quantities along with energy conditions have been discussed in detail.

Lyra cosmologies with the dynamical system perspective

“…With this notation, dN = Hdt. The dynamical variables (7) are suitable for study of the expanding cosmologies but these will not be well-defined variables in the bouncing models [63][64][65][66]. Since, in the bouncing models, H = 0 at the bounce.…”