Sina Hooshangi

School of Astronomy, Institute for Research in Fundamental Sciences (IPM)

Tail Diversity from Inflation

Abstract: Primordial black holes (PBHs) hold significant importance in modern cosmology as possible candidates for dark matter and as potential explanations for the origin of some observed gravitational waves. The primary mechanism for the formation of these black holes is the large fluctuations generated during cosmic inflation. However, conventional perturbative methods used to calculate the statistics of these primordial fluctuations may lead to inaccurate estimates of PBH abundance. In this presentation, we examine a non-perturbative method for describing large fluctuations during the inflationary period. Initially, the concept of non-attractor inflation is introduced, which can potentially produce large perturbations with low but non-zero probability during cosmic inflation. Subsequently, the $\delta N$ formalism is discussed as an effective tool for non-perturbative treatment of primordial fluctuations. We then analyze a set of inflationary models in which the non-perturbative treatment of fluctuations shows significant differences from perturbative calculations. This difference is particularly evident in the tail of the probability distribution of primordial fluctuations. The results of this research indicate that the non-linear behavior of curvature perturbations in inflationary models can lead to the formation of non-Gaussian tails in the probability distribution, which may result in more accurate estimates of PBH abundance. These findings highlight the importance of employing non-perturbative methods in studying PBH formation and demonstrate that conventional linear approximations may not be sufficient for accurately predicting the abundance of these objects.

یکشنبه  22 مهر 1403، ساعت 17:00

Sunday 13 October 2024 – 17:00 Tehran Time

Hybrid Seminar

دانشکده فیزیک – طبقه اول – کلاس فیزیک 3 /Physics Department – first floor – Room Physics 3   

https://vc.sharif.edu/ch/cosmology

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