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We explore the role of dissipative effects during warm inflation leading to the small-scale enhancement of the power spectrum of curvature perturbations. In this paper, we specifically focus on non-canonical warm inflationary scenarios and…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-22 Richa Arya , Rajeev Kumar Jain , Arvind Kumar Mishra

We propose a mechanism of producing a new type of primordial perturbations that collapse to primordial black holes whose mass can be as large as necessary for them to grow to the supermassive black holes observed at high redshifts, without…

General Relativity and Quantum Cosmology · Physics 2016-11-28 Tomohiro Nakama , Teruaki Suyama , Jun'ichi Yokoyama

The abundance of primordial black holes changes in the presence of local non-Gaussianity. A positive non-linear parameter $f_{NL}$ increases the abundance while a negative one reduces it. We show that in non-attractor single-field models of…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-20 Hassan Firouzjahi , Antonio Riotto

We present an end-to-end description of the formation process of globular clusters (GCs) which combines a treatment for their formation and dynamical evolution within galaxy haloes with a state-of-the-art semi-analytic simulation of galaxy…

A recent understanding on how quantum effects may affect black-hole evolution opens new scenarios for dark matter, in connection with the presence of black holes in the very early universe. Quantum fluctuations of the geometry allow for…

General Relativity and Quantum Cosmology · Physics 2018-12-27 Francesca Vidotto

The spherical gravitational collapse and virialization of arbitrary density fluctuations in an expanding universe is studied. In the context of the standard cosmological model and the peak $ansatz$, disk galaxies are supposed to be the…

Astrophysics · Physics 2007-05-23 Vladimir Avila-Reese , Claudio Firmani

The late infall of dark matter onto a galaxy produces structure (such as caustics) in the distribution of dark matter in the halo. We argue that such structure is likely to occur generically on length scales proportional to $l \sim t_0…

Astrophysics · Physics 2009-10-31 William H. Kinney , Pierre Sikivie

In the standard inflationary paradigm, cosmological density perturbations are generated as quantum fluctuations in the early Universe, but then undergo a quantum-to-classical transition. A key role in this transition is played by squeezing…

General Relativity and Quantum Cosmology · Physics 2020-02-19 Roland de Putter , Olivier Doré

We argue that primordial black-hole formation must be described by means of extreme-value theory. This is a consequence of the large values of the energy density required to initiate the collapse of black holes in the early Universe and the…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-28 Florian Kuhnel , Dominik J. Schwarz

It is shown that in a number of scalar potentials with an unstable local maximum at the origin chaotic inflation is followed by new inflation if model parameters are appropriately chosen. In this model density fluctuation can have a…

Astrophysics · Physics 2009-10-30 Jun'ichi Yokoyama

In the pre-reheating era, following cosmic inflation and preceding radiation domination, the energy density may be dominated by an oscillating massive scalar condensate, such as is the case for quadratic chaotic inflation. We have found in…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-27 Karsten Jedamzik , Martin Lemoine , Jerome Martin

We review the non-linear statistics of Primordial Black Holes that form from the collapse of over-densities in a radiation dominated Universe. We focus on the scenario in which large over-densities are generated by rare and Gaussian…

Cosmology and Nongalactic Astrophysics · Physics 2023-09-15 Cristiano Germani , Ravi K. Sheth

Model of supermassive black holes formation inside the clusters of primordial black holes is developed. Namely, it is supposed, that some mass fraction of the universe ~10^-3 is composed of the compact clusters of primordial (relic) black…

Astrophysics · Physics 2009-11-13 V. I. Dokuchaev , Yu. N. Eroshenko , S. G. Rubin

We report a novel prediction from single-field inflation that even a tiny step in the inflaton potential can change our perception of primordial non-Gaussianities of the curvature perturbation. Our analysis focuses on the tail of…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-04 Yi-Fu Cai , Xiao-Han Ma , Misao Sasaki , Dong-Gang Wang , Zihan Zhou

We show that the effect of initial non-Gaussian clustering can significantly enhance the event rate for primordial black hole (PBH) coalescence. The impact of such clustering is studied in a specific scenario of multi-stream inflation.…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-25 Qianhang Ding , Tomohiro Nakama , Joseph Silk , Yi Wang

Many models of inflation predict oscillatory features in the bispectrum of primordial fluctuations. Since it has been shown that primordial non-Gaussianity can lead to a scale-dependent halo bias, we investigate the effect of oscillations…

Cosmology and Nongalactic Astrophysics · Physics 2011-10-20 Francis-Yan Cyr-Racine , Fabian Schmidt

A population of very light primordial black holes which evaporate before nucleosynthesis begins is unconstrained unless the decaying black holes leave stable relics. We show that gravitons Hawking radiated from these black holes would…

Astrophysics · Physics 2009-11-06 Richard Anantua , Richard Easther , John T. Giblin

Primordial black holes might comprise a significant fraction of the dark matter in the Universe and be responsible for the gravitational wave signals from black hole mergers observed by the LIGO/Virgo collaboration. The spatial clustering…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-25 V. De Luca , V. Desjacques , G. Franciolini , A. Riotto

Evidence has accumulated that there are supermassive black holes (SMBHs) in the centers of most galaxies, and that these were formed in the very early universe by some as yet unknown process. In particular, there is evidence [15] that at…

High Energy Physics - Theory · Physics 2024-03-05 Tom Banks , Willy Fischler

Modified matter power spectra with approximately Gaussian bump on sub-Mpc scales can be a result of a complex inflation. We consider five spectra with different Gaussian amplitudes $A$ and locations $k_0$ and run N-body simulations in a…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-15 M. V. Tkachev , S. V. Pilipenko , E. V. Mikheeva , V. N. Lukash
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