2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/182945We consider a physically viable cosmological model that has a field dependent Gauss-Bonnet coupling in its effective action, in addition to a standard scalar field potential. The presence of such terms in the four dimensional effective action gives rise to several novel effects, such as a four dimensional flat Friedmann-Robertson-Walker universe undergoing a cosmic inflation at early epoch, as well as a cosmic acceleration at late times. The model predicts, during inflation, spectra of both density perturbations and gravitational waves that may fall well within the experimental bounds. Furthermore, this model provides a mechanism for reheating of the early universe, which is similar to a model with some friction terms added to the equation of motion of the scalar field, which can imitate energy transfer from the scalar field to matter35 pages, 21 eps figs; section 6 expanded improving explanations, refs added, final in JCAPHigh Energy Physics - TheoryAstrophysicsGeneral Relativity and Quantum Cosmologytext