Resurrecting quartic and quadratic inflaton potentials in a two-field inflationary model

Abstract

The release of the PLANCK data made it evident that the inflationary paradigm has stood the test of time. However, realizing the inflationary paradigm in a particle physics model is difficult because the present observations have ruled out the simplest quartic and quadratic inflationary potentials, which generically arise in particle physics. We show that such inflationary potentials can evade discrepancies with observations, if the inflaton field is assisted by another scalar during inflation. Moreover, unlike other multifield models, our model yields no isocurvature perturbations and negligible non-Gaussianity, making it more compatible with the present data. Above all, our model can also be realized within the framework of supergravity theory.