Alladi Ramakrishnan Hall

Inflationary three-point functions

L Sriramkumar

IIT Madras

Inflation is currently considered the most promising paradigm to describe the origin of perturbations in the early universe. It is easily achieved using scalar fields, and there exist a plethora of models to drive inflation. Until rather recently, inflationary models were compared with the cosmological data at the level of two-point functions. Over the last decade it has been realized that non-Gaussianities in general and the three-point functions in particular can play a significant role in arriving at stronger constraints on inflationary models. On the one hand, there has been tremendous development on the theoretical front towards the calculation of non-Gaussianities generated during inflation and in post-inflationary scenarios. On the other, the expectation alluded to above has been corroborated to a large extent by the strong constraints that have been arrived at by the Planck mission on the scalar non-Gaussianity parameter. In this talk, which is divided into two parts, I initially introduce the scalar bispectrum and the corresponding non-Gaussianity parameter, and discuss the recent constraints on the parameter. In the second part, I describe our work towards the numerical computation of the inflationary three-point functions (including those involving tensors) and understanding their characteristics (particularly, their behavior in the so-called squeezed limit).