New emergent observational constraints in f(Q,T) gravity model

Abstract

In the current study, we inspect the late-time acceleration of the universe in f(Q,T) gravity. In this theory, Q represents the non-metricity term and with Tμν the energy-momentum tensor, with T its trace. To explore the solutions in the theory for the Friedmann-Lemaitre-Robertson-Walker (FLRW) model, we propose a new scale factor called the emergent scale factor, which yields the Hubble parameter, H(z), having the form H(z)=nb(−B+1(A(z+1))1b) with a new relation a(t)=11+z). By using the SNIa from Pantheon, BAO from (6dFGS, BOSS-LOWZ, SDSS DR7 MGS, BOSS-DR12, BOSS-CMASS, WiggleZ and Lya), CMB from Planck 2018, and the 36 data points from Hubble datasets using the Monte-Carlo Markov Chain (MCMC) approach, we estimate the parameters of the model. The variation in time of the deceleration parameter in the model shows that a phase of deceleration transits to a phase of acceleration. Further, we examine the behaviour of the jerk parameter and carry out a statefinder analysis. In order to complete the current study, we consider two forms for f(Q,T), specifically, f(Q,T)=a1Qm+a2T and f(Q,T)=γQ2+ηQ+λT where a1, a2, m, γ, η, and λ are the model's parameters that need to satisfy observations. Finally, we present an appraisal of our current analysis.