Séminaire / Seminar GReCO |
| « Non-Gaussian contributions to inflationary power spectra » |
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H. V. Ragavendra |
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Primordial non-Gaussianities arising from inflationary models are unique probes of non-trivial dynamics of the inflaton field and its possible interactions with other fields. There have been efforts to compute the loop level contributions arising from them to the scalar and tensor power spectra, but they are largely negligible in typical models of slow-roll inflation. Recent literature has rejuvenated the calculation of loop contributions to power spectra, particularly in the context of ultra-slow-roll (USR) model of inflation, which leads to production of primordial black holes and scalar-induced secondary gravitational waves. In this talk, I shall briefly outline the literature in this area and present a few interesting results that we recently obtained regarding loop contribution to scalar power due to the quartic order action in USR models [1]. I shall also illustrate the structure of non-Gaussian contributions arising from cubic order action and discuss the imprints they may leave on the cosmic microwave background and the spectral density of secondary gravitational waves [2,3]. Through these results obtained at different orders and for different observables, I shall try to emphasize that the non-Gaussian contributions can significantly affect the shape and amplitude of the primordial power spectra in non-trivial models of inflation. Hence, the existing fits of certain models against observational data have to be revisited and the non-Gaussian contributions have to be accounted for while comparing models against upcoming observations in future. Lastly, I shall conclude with an outlook of exploring and constraining various kinds of primordial non-Gaussianities through the calculation of loop contributions.
References: 1. Suvashis Maity, H. V. Ragavendra, Shiv K. Sethi and L. Sriramkumar, arXiv:2307.13636 [astro-ph.CO]; 2. Barnali Das and H. V. Ragavendra, arXiv:2304.05941 [astro-ph.CO]; 3. H. V. Ragavendra, Phys. Rev. D 105, 063533 (2022) [arXiv:2108.04193 [astro-ph.CO]] |
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lundi 16 octobre 2023 - 11:00 Salle des séminaires Évry Schatzman Institut d'Astrophysique de Paris |
| Pages web du séminaire / Seminar's webpage |