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Related papers: One-loop power spectrum in ultra slow-roll inflati…

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It is known that the single-field inflation with a transient ultra-slow-roll phase can produce a large curvature perturbation at small scales for the formation of primordial black holes. In our previous work, we have considered quantum loop…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-09 Shu-Lin Cheng , Da-Shin Lee , Kin-Wang Ng

We revisit the one-loop correction in curvature perturbation power spectrum in models of single field inflation which undergo a phase of ultra slow-roll (USR) inflation. We include the contributions from both the cubic and quartic…

Cosmology and Nongalactic Astrophysics · Physics 2023-10-06 Hassan Firouzjahi

Primordial black holes can be formed from the collapse of large-amplitude perturbation on small scales in the early Universe. Such an enhanced spectrum can be realized by introducing a flat region in the potential of single-field inflation,…

High Energy Physics - Theory · Physics 2024-05-30 Jason Kristiano , Jun'ichi Yokoyama

We propose a simple analytic fit for the power spectrum of scalar (curvature) perturbations during inflation, in order to describe slow roll of inflaton and formation of primordial black holes in the early universe, in the framework of…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-24 Daniel Frolovsky , Sergei V. Ketov

Using the $\delta N$ formalism we calculate the one-loop correction to the large-scale power spectrum of the curvature perturbation in the standard scenario where primordial black holes are formed in the early universe thanks to a phase of…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-18 Hassan Firouzjahi , Antonio Riotto

We revisit one-loop corrections to the power spectrum of curvature perturbations $\zeta$ in an inflationary scenario containing a transient ultra-slow-roll (USR) period. In Ref.[1], it was argued that one-loop corrections to the power…

High Energy Physics - Theory · Physics 2024-12-17 Ryodai Kawaguchi , Shinji Tsujikawa , Yusuke Yamada

We discuss the issue of perturbativity in single-field inflationary models with a phase of ultra slow-roll (USR) tailor suited to generate an order-one abundance of primordial black holes (PBHs). More in detail, we impose the condition that…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-01 Gabriele Franciolini , Antonio Junior Iovino , Marco Taoso , Alfredo Urbano

Primordial black holes may arise through ultra slow-roll inflation. In this work we study a toy model of ultra slow-roll inflation with a shallow dip. The ultra slow-roll stage enhances the curvature perturbations and thus the primordial…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-02 Bao-Min Gu , Fu-Wen Shu , Ke Yang

The most widely studied formation mechanism of a primordial black hole is collapse of large-amplitude perturbation on small scales generated in single-field inflation. In this Letter, we calculate one-loop correction to the large-scale…

High Energy Physics - Theory · Physics 2024-05-30 Jason Kristiano , Jun'ichi Yokoyama

The decrease of both the rolling speed of the inflaton and the sound speed of the curvature perturbations can amplify the curvature perturbations during inflation so as to generate a sizable amount of primordial black holes. In the…

General Relativity and Quantum Cosmology · Physics 2024-01-17 Rongrong Zhai , Hongwei Yu , Puxun Wu

Recently, it has been claimed that inflationary models with an inflection point in the scalar potential can produce a large resonance in the power spectrum of curvature perturbation. In this paper however we show that the previous analyses…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-06 Cristiano Germani , Tomislav Prokopec

In order to produce appreciable amount of primordial black holes (PBHs), the square amplitude of curvature perturbation must take a large value of $\mathcal{O}(0.01)$, namely, seven digits larger than the value observed by cosmic microwave…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-08 Jason Kristiano , Jun'ichi Yokoyama

We analytically compute the power spectrum of primordial curvature perturbations in Type III hilltop inflation models under the slow-roll approximation. The model parameters are constrained using current Cosmic Microwave Background (CMB)…

General Relativity and Quantum Cosmology · Physics 2024-11-28 Chia-Min Lin , Harish Dhananjay Nalla , Chen-Pin Yeh , Da-Shin Lee

An estimate of the one-loop correction to the power spectrum of the primordial curvature perturbation is given, assuming it is generated during a phase of single-field, slow-roll inflation. The loop correction splits into two parts, which…

Astrophysics · Physics 2010-02-09 David Seery

Inflationary models predicting a scale-dependent large amplification of the density perturbations have recently attracted a lot of attention because the amplified perturbations can seed a sizable amount of primordial black holes (PBHs) and…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-28 Keisuke Inomata , Matteo Braglia , Xingang Chen , Sébastien Renaux-Petel

We present a detailed exposition on the prospects of the formation of Primordial Black Holes (PBHs) during Slow Roll (SR) to Ultra Slow Roll (USR) sharp transitions in the framework of single-field inflation. We use an effective field…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-15 Sayantan Choudhury , Sudhakar Panda , M. Sami

We study the generation of a large power spectrum, necessary for primordial black hole formation, within the effective theory of single-field inflation. The mechanisms we consider include a transition into a ghost-inflation-like phase and…

High Energy Physics - Theory · Physics 2022-02-02 Guillermo Ballesteros , Sebastián Céspedes , Luca Santoni

We examine the quantum loop effects on the single-field inflationary models in a spatially flat Friedmann-Robertson-Walker (FRW) cosmological space-time with a general self-interacting scalar field potential, which is modeled in terms of…

General Relativity and Quantum Cosmology · Physics 2020-02-05 Wei-Can Syu , Da-Shin Lee , Kin-Wang Ng

The possibility that primordial black holes constitute a fraction of dark matter motivates a detailed study of possible mechanisms for their production. Black holes can form by the collapse of primordial curvature fluctuations, if the…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-06 Ogan Özsoy , Gianmassimo Tasinato

The one-loop corrections (1LC) to the power spectrum of scalar perturbations arising from cubic interactions in the single-field E-type $\alpha$-attractor models of inflation and primordial black hole (PBH) production are numerically…

General Relativity and Quantum Cosmology · Physics 2025-05-19 Daniel Frolovsky , Sergei V. Ketov
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