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Related papers: Primordial non-Guassianity in inflation with gravi…

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We analyze primordial non-gaussianities in presence of an ultra-slow phase during the inflationary dynamics, focusing on scenarios relevant for the production of primordial black holes. We compute the three-point correlation function of…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-25 Marco Taoso , Alfredo Urbano

The most promising mechanism of generating PBHs is by the enhancement of power spectrum of the primordial curvature perturbation, which is usually accompanied by the the enhancement of non-Gaussianity that crucially changes the abundance of…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-11 Shi Pi

In the curvaton scenario, the curvature perturbation is generated after inflation at the curvaton decay, which may have a prominent non-Gaussian effect. For a model with a non-trivial kinetic term, an enhanced curvature perturbation on a…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-22 Shi Pi , Misao Sasaki

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…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-02 Chengjie Fu , Puxun Wu , Hongwei Yu

We study the non-Gaussianity and secondary Gravitational Waves (GWs) in the process of the Primordial Black Holes (PBHs) production from inflation. In our work, we focus on the $\alpha$-attractor inflation model in which a tiny bump in the…

General Relativity and Quantum Cosmology · Physics 2022-08-31 Kazem Rezazadeh , Zeinab Teimoori , Saeid Karimi , Kayoomars Karami

We resolve the potential-restriction problem in K/G inflation by introducing nonminimal coupling. In this context, Higgs field successfully drives inflation satisfying CMB observations while enhancing curvature perturbations at small…

General Relativity and Quantum Cosmology · Physics 2023-02-02 Jiong Lin , Shengqing Gao , Yungui Gong , Yizhou Lu , Zhongkai Wang , Fengge Zhang

A significant abundance of primordial black hole (PBH) dark matter can be produced by curvature perturbations with power spectrum $\Delta_\zeta^2(k_{\mathrm{peak}})\sim \mathcal{O}(10^{-2})$ at small scales, associated with the generation…

General Relativity and Quantum Cosmology · Physics 2021-09-09 Fengge Zhang , Jiong Lin , Yizhou Lu

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…

Cosmology and Nongalactic Astrophysics · Physics 2024-08-06 Xinpeng Wang , Ying-li Zhang , Misao Sasaki

The physics of primordial black holes can be affected by the non-Gaussian statistics of the density fluctuations that generate them. Therefore, it is important to have good theoretical control of the higher-order correlation functions for…

High Energy Physics - Theory · Physics 2024-04-16 Gianmassimo Tasinato

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 (PBHs) cannot be produced abundantly enough to be the dark matter in canonical single-field inflation under slow roll. This conclusion is robust to local non-Gaussian correlations between long- and short-wavelength…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-27 Samuel Passaglia , Wayne Hu , Hayato Motohashi

Enormous information about interactions is contained in the non-Gaussianities of the primordial curvature perturbations, which are essential to break the degeneracy of inflationary models. We study the primordial bispectra for G-inflation…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-21 Fengge Zhang , Yungui Gong , Jiong Lin , Yizhou Lu , Zhu Yi

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

For primordial perturbations, deviations from Gaussian statistics on the tail of the probability distribution can be associated with non-perturbative effects of inflation. In this paper, we present some particular examples in which the tail…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-02 Yi-Fu Cai , Xiao-Han Ma , Misao Sasaki , Dong-Gang Wang , Zihan Zhou

The discovery of gravitational waves from merging binary black holes has generated considerable interest in examining whether these black holes could have a primordial origin. If a significant number of black holes have to be produced in…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-07 H. V. Ragavendra , L. Sriramkumar

Non-Gaussianity in the primordial curvature perturbation is a crucial element of the early universe due to its significant impact on the primordial black hole (PBH) production. In this work, we focus on the effects of negative…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-08 Sayantan Choudhury , Kritartha Dey , Siddhant Ganguly , Ahaskar Karde , Swapnil Kumar Singh , Pranjal Tiwari

We give a concise formula for the non-Gaussianity of the primordial curvature perturbation generated on super-horizon scales in multi-scalar inflation model without assuming slow-roll conditions. This is an extension of our previous work.…

Astrophysics · Physics 2013-01-11 Shuichiro Yokoyama , Teruaki Suyama , Takahiro Tanaka

We analyse models of inflation in which isocurvature perturbations present during inflation are converted into the primordial curvature perturbation during instant preheating. This can be due to an asymmetry between the fields present…

Astrophysics · Physics 2014-11-18 Christian T. Byrnes

We study the formation of primordial black hole (PBH) dark matter and the generation of scalar induced secondary gravitational waves (SIGWs) in a non-supersymmetric model of hybrid inflation with chaotic (polynomial-like) potential,…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-27 Waqas Ahmed , M. Junaid , Umer Zubair

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
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