Št. zadetkov: 22
Izvirni znanstveni članek
Oznake:
primordial black holes;early universe;gravitational collapse;threshold;
Primordial black holes may have formed in the radiative era of the early Universe from the collapse of large enough amplitude perturbations of the metric. These correspond to non linear energy density perturbations characterized by an amplitude larger than a certain threshold, measured when the pert ...
Leto:
2019
Vir:
Repozitorij Univerze v Novi Gorici (RUNG)
Samostojni znanstveni sestavek ali poglavje v monografski publikaciji
Oznake:
primordial black holes;threshold;
The aim of this chapter is to present a consistent description of the mathematical and numerical investigation on primordial black hole formation from the collapse of adiabatic cosmological perturbations performed in the last 25 years, describing the mechanism of gravitational collapse. Despite the ...
Leto:
2025
Vir:
Repozitorij Univerze v Novi Gorici (RUNG)
Izvirni znanstveni članek
Oznake:
primordial black holes;peak theory;dark matter;
In this Letter, combining peak theory and the numerical analysis of gravitational collapse in the radiation dominated era, we show that the abundance of primordial blacks holes, generated by an enhancement in the inflationary power spectrum, is extremely dependent on the shape of the peak. Given the ...
Leto:
2019
Vir:
Repozitorij Univerze v Novi Gorici (RUNG)
Izvirni znanstveni članek
Oznake:
primordial black holes;anisotropic fluid;early Universe;
This work investigates the formation of primordial black holes within a radiation fluid with an anisotropic pressure. We focus our attention on the initial conditions describing cosmological perturbations in the super horizon regime, using a covariant form of the equation of state in terms of pressu ...
Leto:
2022
Vir:
Repozitorij Univerze v Novi Gorici (RUNG)
Izvirni znanstveni članek
Oznake:
primordial black holes;early Universe;quasi-homogenous solution;
This work is part of an ongoing research programme to study possible Primordial Black Hole (PBH) formation during the radiation dominated era of the early universe. Working within spherical symmetry, we specify an initial configuration in terms of a curvature profile, which represents initial condit ...
Leto:
2007
Vir:
Repozitorij Univerze v Novi Gorici (RUNG)
Izvirni znanstveni članek
Oznake:
primordial black holes;early Universe;self similarity;critical collapse;
Following on after three previous papers discussing the formation of primordial black holes during the radiative era of the early universe, we present here a further investigation of the critical nature of the process involved, aimed at making contact with some of the basic underlying ideas from the ...
Leto:
2013
Vir:
Repozitorij Univerze v Novi Gorici (RUNG)
Izvirni znanstveni članek
Oznake:
cosmological perturbation theory;non-Gaussianity;primordial black holes;
Primordial black holes could have been formed in the early universe from sufficiently large cosmological perturbations re-entering the horizon when the Universe is still radiation dominated. These originate from the spectrum of curvature perturbations generated during inflation at small-scales. Beca ...
Leto:
2019
Vir:
Repozitorij Univerze v Novi Gorici (RUNG)
Izvirni znanstveni članek
Oznake:
primordial black holes;QCD phase transitionž;threshold;mass distribution;abundance;
Primordial black hole (PBH) formation during cosmic phase transitions and annihilation periods, such as the QCD transition or the e+e- annihilation, is thought to be particularly efficient due to a softening of the equation of state. We present a detailed numerical study of PBH formation during the ...
Leto:
2024
Vir:
Repozitorij Univerze v Novi Gorici (RUNG)
Izvirni znanstveni članek
Oznake:
nonlinear electrodynamics;inflation;evolution of the universe;
We establish for the first time the conditions that must be imposed on the action for a magnetic universe in a theory of nonlinear electrodynamics in order to have an asymptotically de Sitter initial state followed by a slow roll inflationary phase. We show that models so far proposed in the literat ...
Leto:
2025
Vir:
Univerza v Novi Gorici (UNG)
Izvirni znanstveni članek
Oznake:
primordial black holes;early Universe;critical collapse;
Results are presented from general relativistic numerical computations of primordial black-hole formation during the radiation-dominated era of the universe. Growing-mode perturbations are specified within the linear regime and their subsequent evolution is followed as they become nonlinear. We use ...
Leto:
2005
Vir:
Repozitorij Univerze v Novi Gorici (RUNG)