Solving peak theory in the presence of local non-gaussianities

• Published in: arXiv.org
• Main Authors: Riccardi, Flavio, Taoso, Marco, Urbano, Alfredo
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 27.07.2021
• Subjects: Black holes; Curvature; Density distribution; Fields (mathematics); Gravitation; Gravitational collapse; Gravitational waves; Physics - Cosmology and Nongalactic Astrophysics; Physics - General Relativity and Quantum Cosmology; Physics - High Energy Physics - Phenomenology; Physics - High Energy Physics - Theory
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2102.04084

We compute the probability density distribution of maxima for a scalar random field in the presence of local non-gaussianities. The physics outcome of this analysis is the following. If we focus on maxima whose curvature is larger than a certain threshold for gravitational collapse, our calculations illustrate how the fraction of the Universe's mass in the form of primordial black holes (PBHs) changes in the presence of local non-gaussianities. We find that previous literature on the subject exponentially overestimate, by many orders of magnitude, the impact of local non-gaussianities on the PBH abundance. We explain the origin of this discrepancy, and conclude that, in realistic single-field inflationary models with ultra slow-roll, one can obtain the same abundance found with the gaussian approximation simply changing the peak amplitude of the curvature power spectrum by no more than a factor of two. We comment about the relevance of non-gaussianities for second-order gravitational waves.