Physics

Prof. L. Sriramkumar
IIT, Madras

Abstract: Inflation is arguably the most compelling paradigm to describe the origin of perturbations in the early universe. The remarkable success of the inflationary paradigm can be attributed to its simplicity and efficiency. However, the efficacy of the inflationary scenario also seems to be responsible for an important drawback. Despite the strong constraints from Planck on
primordial non-Gaussianities, a rather large set of models seems to remain consistent with the cosmological data, even as new models continue to be proposed. Aiming at a non-specialist audience, I shall begin my talk with an introduction to
the hot big bang model and the need for an epoch of inflation. Thereafter, I shall discuss the inflationary observables and the performance of inflationary models against the cosmological data. I shall also touch upon the status of the possibility of features in the primordial spectrum, an aspect which I have investigated
in some detail. I shall then discuss certain recent developments related to the formation of primordial black holes and constraints on the gravitational wave background from LIGO. Finally, I shall conclude with a few remarks concerning the
status of the inflationary paradigm.