Observational imprints of primordial non-Gaussianity through loop-level contributions

In this talk, I intend to discuss the observational signatures of scalar non-Gaussianity through their loop-level contributions to the power spectra, using two specific approaches. The first is a classical approach, by which I shall illustrate the imprints of non-Gaussian contributions from cubic-order action on observables namely, the cosmic microwave background and the scalar-induced secondary gravitational waves (GWs) [1,2]. The second is a quantum field theoretic approach, through which I shall present the computation of loop-level contribution due to the quartic-order action [3]. In these computations, I shall mainly focus on a specific class of inflationary models called ultra slow roll models, which is a promising candidate for the production of primordial black holes (PBHs) and secondary GWs. Through these results using different approaches at different orders and on different observables, I shall emphasize that the non-Gaussian contributions can seriously affect the structure and amplitude of the power spectra and hence warrant careful consideration in calculations while comparing models against data. Lastly, I shall discuss the outlook of these results, particularly in the context of observational quantities that have non-linear dependence on the scalar power, such as the computation of PBH population.

References:
1. Barnali Das and H. V. Ragavendra, arXiv:2304.05941 [astro-ph.CO];
2. H. V. Ragavendra, Phys. Rev. D 105, 063533 (2022) [arXiv:2108.04193 [astro-ph.CO]];
3. Suvashis Maity, H. V. Ragavendra, Shiv K. Sethi and L. Sriramkumar, arXiv:2307.13636 [astro-ph.CO].