UNIFYING INFLATION-DARK ENERGY THROUGH SCALAR FIELD AND QUADRATIC TELEPARALLEL MODEL CONSTRAINED BY OBSERVATIONAL DATA

The present work investigates two of the most persistent and challenging phases in the dynamical evolution of the Universe. A quadratic teleparallel T2gravity model, coupled to a scalar field assumed to be the sole constituent of the Universe, is constrained using observational data in order to derive meaningful results concerning both the inflationary era and the late-time accelerated expansion driven by dark energy. The Friedmann-like equations arising from the quadratic model are solved using the method of separation of variables. Firstly, explicit expressions for the scalar field and its potential are derived, allowing the computation of inflationary observables, including the number of e-folds analysis. For appropriate choices of the model parameters, a numerical analysis yields results consistent with the latest Planck observations and the BICEP2 experiment. Secondly, the energy density and the pressure of the scalar field are expressed as functions of the redshift z, within a framework where the Hubble parameter-obtained from the resolution of the Friedmann-like equations is constrained by current observational data.