Related papers: Could PBHs and secondary GWs have originated from …
Inflation provides a suitable environment for the formation of Primordial Black Holes(PBHs). In this article, we examine the formation of primordial black holes in the Mutated Hilltop inflation model coupled with the Einstein-Gauss-Bonnet…
Primordial black holes (PBH) can form in the early Universe from peaks of the primordial curvature perturbations. The statistics of the peaks determines the abundance of PBHs, and is related to the amplitude of the primordial curvature…
We present a numerical investigation of primordial black hole (PBH) formation from super-horizon curvature perturbations and the subsequent generation and propagation of sound waves, which can serve as a new source of stochastic…
We propose a new single field inflation model in which the usual slow-roll inflation is joined to a new period of slow-climb and slow-roll inflation through a short intermediate non-inflationary phase. We then show that primordial curvature…
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…
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…
We investigate the stochastic gravitational wave background (SGWB) generated by the ringdown phase of primordial black holes (PBHs) formed in the early universe. As the ringdown signal is independent of the PBH formation mechanism, the…
Primordial Black Holes (PBHs) may form in the early Universe, from the gravitational collapse of large density perturbations, generated by large quantum fluctuations during inflation. Since PBHs form from rare over-densities, their…
We investigate a model of $R^2$-gravity with a non-minimally coupled scalar field that gives rise to two-stage inflation with a break, that is, with an intermediate stage where inflation momentarily halts. We find that the power spectrum of…
The recent detection of a stochastic gravitational wave background (SGWB) at nanohertz frequencies by pulsar timing arrays (PTAs) has sparked a flurry of interest. Beyond the standard interpretation that the progenitor is a network of…
The primordial black hole (PBH) productions from the inflationary potential with an inflection point usually rely heavily on the fine-tuning of the model parameters. We propose in this work a new kind of the $\alpha$-attractor inflation…
Mounting evidence suggests that the semi-classical description of a black hole breaks down at the latest after losing an O(1) fraction of its mass. As a result, effects such as memory burden can slow down evaporation so that small…
Primordial scalar curvature perturbations ($\zeta$), typically probed on large cosmological scales via CMB and LSS observations, can be significantly enhanced on smaller scales by various early Universe mechanisms, for instance, non-minimal…
Primordial black holes (PBHs) can be both candidates of dark matter and progenitors of binary black holes (BBHs) detected by the LIGO-Virgo-KAGRA collaboration. Since PBHs could form in the very early Universe through the gravitational…
The possibility that primordial black holes (PBHs) represent all of the dark matter (DM) in the Universe and explain the coalescences of binary black holes detected by LIGO/Virgo has attracted a lot of attention. PBHs are generated by the…
Various mechanisms have been suggested for the formation of Primordial Black Holes (PBHs), and this thesis focuses on the standard mechanism based on the critical collapse of cosmological fluctuations. The underlying idea is that during…
Primordial black holes (PBHs) are supposed to form from the collapse of over-densed regions generated by large scalar curvature perturbations in the radiation dominated era. Despite decades of various independent observations, the nature of…
A sharp step on a chaotic potential can enhance primordial curvature fluctuations on smaller scales to the $\mathcal{O}(10^{-2})$ to form primordial black holes (PBHs). The present study discusses an inflationary potential with a sharp step…
Primordial black holes (PBHs) are a profound signature of primordial cosmological structures and provide a theoretical tool to study nontrivial physics of the early Universe. The mechanisms of PBH formation are discussed and observational…
Using the concept of apparent horizon for dynamical black holes, we revisit the formation of primordial black holes (PBH) in the early universe for both linear and non-linear regimes. First, we develop the perturbation theory for…