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arXiv · 2308.04642

Constraints on primordial black holes for nonstandard cosmologies

Tadeo D. Gomez-Aguilar·Luis E. Padilla·Encieh Erfani·Juan Carlos Hidalgo
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Abstract

We study how the bounds on the abundance of Primordial Black Holes (PBHs) and the constraints on power spectrum are modified if a non-standard evolution phase takes place between the end of inflation and the Standard radiation-dominated (RD) universe after inflation. The constraints on PBH abundance and power spectrum are computed using the new, freely available, \href{https://github.com/TadeoDGAguilar/PBHBeta}{\faGithubSquare}~\texttt{PBHBeta} library, which accounts for the effects of non-standard expansion and specific criteria for PBH formation in such non-standard scenarios. As working examples, we consider three different cases: a pure matter-dominated (MD) phase, a scalar field-dominated ($φ$D) universe, and a stiff fluid-dominated (SD) scenario. While the background expansion is the same for the MD and $φ$D scenarios, the PBH formation criteria lead to different constraints to power spectrum. On the other hand, the duration of the non-standard expansion phase alters the bounds, with longer MD periods resulting in weaker constraints on power spectrum, and longer SD scenarios leading to an enhanced abundance due to the dust-like redshifting of PBHs. The modifications to the constraints are reported in all cases and we highlight those where the power spectrum may be significantly constrained.

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Tadeo D. Gomez-Aguilar, Luis E. Padilla, Encieh Erfani, Juan Carlos Hidalgo. 2024-11-13. Constraints on primordial black holes for nonstandard cosmologies. https://doi.org/10.1088/1475-7516%2F2024%2F11%2F005

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