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The gravitational potential of initially Poisson distributed primordial black holes (PBH) can induce a stochastic gravitational-wave background (SGWB) at second order in cosmological perturbation theory. This SGWB was previously studied in…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-01 Theodoros Papanikolaou

The gravitational potential of a gas of initially randomly distributed primordial black holes (PBH) can induce a stochastic gravitational-wave (GW) background through second-order gravitational effects. This GW background can be abundantly…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-12 Theodoros Papanikolaou , Charalampos Tzerefos , Spyros Basilakos , Emmanuel N. Saridakis

We study realistic models predicting primordial black hole (PBH) formation from density fluctuations generated in a first-order phase transition. We show that the second-order correction in the expansion of the bubble nucleation rate is…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-27 Marek Lewicki , Piotr Toczek , Ville Vaskonen

We study primordial black hole (PBH) formation in a minimally coupled $f(T)$ teleparallel cosmology that generates a transient departure from standard radiation domination. The model is constructed so that modified-gravity effects are…

General Relativity and Quantum Cosmology · Physics 2026-03-27 Gerasimos Kouniatalis , Theodoros Papanikolaou , Spyros Basilakos , Emmanuel N. Saridakis

Primordial black hole (PBH) mergers have been proposed as an explanation for the gravitational wave events detected by the LIGO collaboration. Such PBHs may be formed in the early Universe as a result of the collapse of extremely rare…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-20 Tomohiro Nakama , Joseph Silk , Marc Kamionkowski

Ultra-light primordial black holes (PBHs) with masses $M_\mathrm{PBH}<5\times 10^{8}\mathrm{g}$ can trigger an early matter-dominated (eMD) era before Big Bang Nucleosynthesis (BBN) and reheat the Universe through their evaporation.…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-07 Theodoros Papanikolaou , Salvatore Capozziello

We perform a consistent calculation of primordial black hole (PBH) mass spectrum and second-order induced gravitational wave (GW) background produced from primordial scalar perturbations in radiation era of the early Universe. It is shown…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-26 Edgar Bugaev , Peter Klimai

Primordial Black Holes (PBH) could be the cold dark matter of the universe. They could have arisen from large (order one) curvature fluctuations produced during inflation that reentered the horizon in the radiation era. At reentry, these…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-20 Juan Garcia-Bellido , Marco Peloso , Caner Unal

Gravitational waves (GWs) induced by primordial fluctuations can be affected by the modification of the sound speed $c^2_{\rm s}$ and the equation of state parameter $w$ once the curvature fluctuations reenter the cosmological horizon. That…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-12 Albert Escrivà , Yuichiro Tada , Chul-Moon Yoo

We investigate a new mechanism to create large curvature perturbations on small scales due to parameter resonance in a single-field inflationary model with a small periodic structure upon the potential. After reentering the horizon, the…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-17 Rong-Gen Cai , Zong-Kuan Guo , Jing Liu , Lang Liu , Xing-Yu Yang

Recently we have proposed a novel method to probe primordial gravitational waves from upper bounds on the abundance of primordial black holes (PBHs). When the amplitude of primordial tensor perturbations generated in the early Universe is…

General Relativity and Quantum Cosmology · Physics 2016-08-18 Tomohiro Nakama , Teruaki Suyama

We use the wide-used \textsf{Einstein Toolkit} to solve the Einstein constraints and then simulate the expansion of primordial black hole lattices (PBHLs) with different value of $f_{\mathrm{PBH}}$ and $m_{\mathrm{PBH}}$. We find that…

General Relativity and Quantum Cosmology · Physics 2020-01-08 Ke Wang

Primordial Black Holes (PBH's) can form in the early Universe from the collapse of large density fluctuations. Tight observational limits on their abundance constrain the amplitude of the primordial fluctuations on very small scales which…

Cosmology and Nongalactic Astrophysics · Physics 2013-08-20 Christian T. Byrnes , Edmund J. Copeland , Anne M. Green

In this paper, we review in detail different mechanisms of generation of large primordial fluctuations and their implications for the production of primordial black holes (PBHs) and scalar-induced secondary gravity waves (SIGW), with the…

General Relativity and Quantum Cosmology · Physics 2024-11-28 Sayantan Choudhury , M. Sami

We calculate the gravitational waves (GWs) induced by the density fluctuations due to inhomogeneous distribution of primordial black holes (PBHs) in the case where PBHs eventually dominate and reheat the universe by Hawking evaporation. The…

General Relativity and Quantum Cosmology · Physics 2025-06-06 Guillem Domènech , Chunshan Lin , Misao Sasaki

For a variety of on-going and planned gravitational-wave (GW) experiments, we study expected constraints on the fraction ($f_{\rm PBH}$) of primordial black holes (PBHs) in dark matter by evaluating the energy-density spectra of two kinds…

Cosmology and Nongalactic Astrophysics · Physics 2020-03-26 Sai Wang , Takahiro Terada , Kazunori Kohri

As potential candidates of dark matter, primordial black holes (PBHs) are within the core scopes of various astronomical observations. In light of the explosive development of gravitational wave (GW) and radio astronomy, we thoroughly…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-23 Yi-Fu Cai , Chao Chen , Xi Tong , Dong-Gang Wang , Sheng-Feng Yan

With the enhancement mechanism provided by a noncanonical kinetic term with a peak, the amplitude of primordial curvature perturbations can be enhanced by seven orders of magnitude at small scales while keeping to be consistent with…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-13 Zhu Yi , Qing Gao , Yungui Gong , Zong-hong Zhu

We explore the role of non-Gaussian fluctuations in primordial black hole (PBH) formation and show that the standard Gaussian assumption, used in all PBH formation papers to date, is not justified. Since large spikes in power are usually…

Astrophysics · Physics 2016-08-24 James S. Bullock , Joel R. Primack

Primordial Black Holes (PBH) from peaks in the curvature power spectrum could constitute today an important fraction of the Dark Matter in the Universe. At horizon reentry, during the radiation era, order one fluctuations collapse…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-31 Sebastien Clesse , Juan García-Bellido , Stefano Orani
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