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We investigate a mechanism of primordial black hole (PBH) formation that avoids any dependence on specific inflationary features or exotic physics. In this scenario, the required large curvature fluctuations leading to PBH formation are…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-04 Ioanna Stamou , Sebastien Clesse

We consider the formation of primordial black holes (PBHs), during the radiation-dominated Universe, generated from the collapse of super-horizon curvature fluctuations that are overlapped with others on larger scales. Using a set of…

General Relativity and Quantum Cosmology · Physics 2024-06-26 Albert Escrivà , Chul-Moon Yoo

We study the formation of primordial black holes (PBHs) in the early Universe during a period of slow reheating after inflation. We demonstrate how the PBH formation mechanism may change even before the end of the matter-dominated phase and…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-04 Bernard Carr , Konstantinos Dimopoulos , Charlotte Owen , Tommi Tenkanen

If primordial black holes (PBHs) formed at the quark-hadron epoch, their mass must be close to the Chandrasekhar limit, this also being the characteristic mass of stars. If they provide the dark matter (DM), the collapse fraction must be of…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-16 Bernard Carr , Sebastien Clesse , Juan García-Bellido

Single-field inflationary models which generate primordial black holes through the enhancement of the curvature primordial power at small scales are commonly criticized and frequently dismissed because they require a large amount of…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-23 A. J. Iovino , A. Riotto

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

Primordial black holes (PBHs) can form in the early Universe from the collapse of rare, large density fluctuations. They have never been observed, but this fact is enough to constrain the amplitude of fluctuations on very small scales which…

Cosmology and Nongalactic Astrophysics · Physics 2013-09-20 Sam Young , Christian T. Byrnes

The computation of PBH (primordial black hole) production from primordial perturbations has recently been improved by considering a more accurate relation between the primordial power spectrum and the PBH mass variance. We present here…

Astrophysics · Physics 2009-11-07 David Blais , Claus Kiefer , David Polarski

In this paper, we show that if passive fluctuations are considered, primordial black holes (PBHs) can be easily produced in the framework of single-field, slow-roll inflation models. The formation of PBHs is due to the blue spectrum of…

High Energy Physics - Phenomenology · Physics 2015-06-05 Chia-Min Lin , Kin-Wang Ng

Primordial black holes (PBHs) are those which may have formed in the early Universe and affected the subsequent evolution of the Universe through their Hawking radiation and gravitational field. To constrain the early Universe from the…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-13 Tomohiro Harada

In this paper, we consider the hypothesis that fractions of dark matter could be constituted by primordial black holes (PBHs). To test this possibility, we work out the observational properties of a static black hole embedded in the dark…

General Relativity and Quantum Cosmology · Physics 2023-03-08 Rocco D'Agostino , Roberto Giambò , Orlando Luongo

Primordial black holes (PBHs) form from large-amplitude initial density fluctuations and may comprise some or all of the dark matter. If PBHs have a broadly extended mass spectrum, or in mixed PBH-particle dark matter scenarios, the extreme…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-29 M. Sten Delos , Joseph Silk

The formation of Primordial Black Holes (PBHs) through the collapse of large fluctuations in the early universe is a rare event. This manifests itself, for instance, through the non-Gaussian tail of the formation probability. To compute…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-20 V. De Luca , A. Riotto

Primordial black holes (PBHs) are a compelling dark matter candidate and a unique probe of small-scale cosmological fluctuations. Their formation is usually attributed to large positive curvature perturbations, which collapse upon Hubble…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-24 Cristian Joana , Zi-Yan Yuwen

The E-type $\alpha$-attractor models of single-field inflation were generalized further in order to accommodate production of primordial black holes (PBH) via adding a near-inflection point to the inflaton scalar potential at smaller…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-21 Daniel Frolovsky , Sergei V. Ketov

Primordial Black Holes (PBHs) serve as a unique probe to the physics of the early Universe, particularly inflation. In light of this, we study the formation of PBHs by the collapse of overdense perturbations generated during a model of warm…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-17 Richa Arya

The recent discovery of critical phenomena arising in gravitational collapse near the threshold of black hole formation is used to estimate the initial mass function of primordial black holes (PBHs). It is argued that the universal scaling…

Astrophysics · Physics 2008-11-26 J. C. Niemeyer , K. Jedamzik

Formation of significant number of primordial black holes (PBHs) is realized if and only if primordial density fluctuations have a large amplitude, which means that tensor perturbations generated from these scalar perturbations as a second…

Astrophysics · Physics 2011-07-06 Ryo Saito , Jun'ichi Yokoyama

Primordial black holes (PBHs) are an important tool in cosmology to probe the primordial spectrum of small-scale curvature perturbations that reenter the cosmological horizon during radiation domination epoch. We numerically solve the…

General Relativity and Quantum Cosmology · Physics 2014-01-31 Tomohiro Nakama , Tomohiro Harada , A. G. Polnarev , Jun'ichi Yokoyama

Primordial black holes (PBHs) are black holes that might have formed in high density regions in the early universe. The presence of local-type non-Gaussianity can lead to large-scale fluctuations in the PBH formation rate. If PBHs make up a…

Cosmology and Nongalactic Astrophysics · Physics 2023-10-30 Raphaël van Laak , Sam Young
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