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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 apply the in-in formalism to address the question of whether the size of the one-loop spectrum of curvature fluctuations in ultra-slow-roll inflation models designed for producing a large population of primordial black holes implies a…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-08 Guillermo Ballesteros , Jesús Gambín Egea

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

A standard scenario to form primordial black holes in the early universe is based on a phase of ultra-slow-roll in single-field inflation when the amplitude of the short scale modes is enhanced compared to the CMB plateau. Based on general…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-03 Antonio Riotto

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

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

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

Primordial black holes (PBHs) can be produced from inflation if the primordial curvature power spectrum is strongly enhanced on scales much shorter than those probed by cosmic microwave background (CMB) experiments. In single-field models…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-07 Laura Iacconi

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

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

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

We show that in single field inflationary models the super-horizon evolution of curvature perturbations on comoving slices $\mathcal{R}$, which can cause the production of primordial black holes (PBH), is not due to entropy perturbations,…

Cosmology and Nongalactic Astrophysics · Physics 2019-12-19 Sergio Andrés Vallejo-Peña , Antonio Enea Romano

The next generation of space-borne gravitational wave detectors may detect gravitational waves from extreme mass-ratio inspirals with primordial black holes. To produce primordial black holes which contribute a non-negligible abundance of…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-04 Haoran Di , Yungui Gong

In response to a recent criticism, appeared in arXiv:2303.00341, we argue that the standard scenario to form primordial black holes in the early universe based on a phase of ultra-slow-roll in single-field inflation is not ruled out.

Cosmology and Nongalactic Astrophysics · Physics 2023-03-06 A. Riotto

We investigate the amplification of curvature perturbations in a two-field inflation model featuring a Gaussian potential bump. When the inflaton encounters a potential bump along the inflationary trajectory, its rolling speed is generally…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-10 Chengjie Fu , Chao Chen

Primordial black holes as dark matter may be generated in single-field models of inflation thanks to the enhancement at small scales of the comoving curvature perturbation. This mechanism requires leaving the slow-roll phase to enter a…

Cosmology and Nongalactic Astrophysics · Physics 2018-07-26 Matteo Biagetti , Gabriele Franciolini , Alex Kehagias , Antonio Riotto

We study the growth of superhorizon modes in the curvature perturbation during an ultra-slow-roll or a large-$\eta$ phase in single-field inflation. In a simple toy model, we derive the two-point correlation function of the curvature…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-27 Shu-Lin Cheng , Wolung Lee , Kin-Wang Ng

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 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

Single field models of inflation capable to produce primordial black holes usually require a significant departure from the standard, perturbative slow-roll regime. In fact, in many of these scenarios, the size of the slow-roll parameter…

High Energy Physics - Theory · Physics 2023-08-08 Gianmassimo Tasinato
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