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We investigate small-scale signatures of the inflationary particle content. We consider the case of a light spin-2 particle sourcing primordial gravitational waves by employing an effective field theory description. Upon allowing…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-08 Laura Iacconi , Matteo Fasiello , Hooshyar Assadullahi , David Wands

We investigate the formation of primordial black holes (PBHs), their spin and abundance, in a single-field inflationary model based on a mutated hilltop potential inserted with a small step-like feature. This step induces a brief phase of…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-08 Abolhassan Mohammadi , Yogesh , Qiang Wu , Tao Zhu

We investigate the production of primordial black holes (PBHs) and scalar-induced gravitational waves (GWs) for cosmological models in the Horndeski theory of gravity. The cosmological models of our interest incorporate the derivative…

General Relativity and Quantum Cosmology · Physics 2021-07-20 Pisin Chen , Seoktae Koh , Gansukh Tumurtushaa

One of the fundamental characteristics of slow roll inflation is its generation of tensor perturbations, which manifest as stochastic gravitational waves (GWs). Slow roll inflation results in a nearly scale-invariant GW spectrum that…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-02 Suvashis Maity , Md Riajul Haque

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

The study of reheating in inflationary models is crucial for understanding the early universe and gaining insights into inflationary dynamics and parameters. The reheating temperature $T_{re}$ and the duration of the reheating phase,…

Cosmology and Nongalactic Astrophysics · Physics 2024-04-02 Gabriel German , Juan Carlos Hidalgo , Luis E. Padilla

In a recently proposed approach to testing models of inflation by Cosmic Microwave Background (CMB) radiation the reheating temperature is directly expressed in terms of the CMB observables. Its model independent bounds translate in a given…

High Energy Physics - Phenomenology · Physics 2026-04-21 Michał Marciniak , Marek Olechowski , Stefan Pokorski

Due to universality and attractor properties, $\alpha$-attractor quintessential inflation establishes direct relations between inflationary observables such as the scalar tilt $n_s$ and the tensor-to-scalar ratio $r$, and late-time dark…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-26 William Giarè , Eleonora Di Valentino , Eric V. Linder , Enrico Specogna

The formation of primordial black holes is studied using superconformal inflationary $\alpha$-attractors. An inflaton potential is constructed with a plateau-like region which brings about the onset of an ultra slow-roll region where the…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-05 Rafid Mahbub

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

The inflationary origin of primordial black holes (PBHs) relies on a large enhancement of the power spectrum $\Delta_\zeta$ of the curvature fluctuation $\zeta$ at wavelengths much shorter than those of the cosmic microwave background…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-17 Gonzalo A. Palma , Spyros Sypsas , Cristobal Zenteno

Primordial black holes (PBH) have been shown to arise from high peaks in the matter power spectra of multi-field models of inflation. Here we show, with a simple toy model, that it is also possible to generate a peak in the curvature power…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-01 Juan Garcia-Bellido , Ester Ruiz Morales

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

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…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-09 Chengjie Fu , Shao-Jiang Wang

In this paper, inflationary cosmology is reviewed, paying particular attention to its observational signatures associated with large-scale density perturbations generated from quantum fluctuations. In the most general scalar-tensor theories…

Cosmology and Nongalactic Astrophysics · Physics 2014-06-13 Shinji Tsujikawa

Inflationary models predicting abundant primordial black holes (PBHs) and large amplitude of scalar-induced gravitational waves (SIGWs) often rely on amplified fluctuations over limited scales, typically driven by phase transitions,…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-15 Mohammad Hossein Namjoo , Bahar Nikbakht

We investigate an inflationary model with a non-minimal derivative coupling, where the coupling function contains both constant and periodic components. On large scales, the model is in excellent agreement with the latest…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-10 Li-Shuai Wang , Qiong-Tao Xie , Li-Yang Chen

A scenario with two subsequent periods of inflationary expansion in the very early universe is examined. The model is based on a potential motivated by symmetries being found in field theory at high energy. For various parameter sets of the…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-13 Simon Schettler , Jurgen Schaffner-Bielich

Massive particles produced during inflation impact soft limits of primordial correlators. Searching for these signatures presents an exciting opportunity to uncover the particle spectrum in the inflationary epoch. We present…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-12 Samuel Goldstein , Oliver H. E. Philcox , J. Colin Hill , Lam Hui

In this brief review we will discuss how a well motivated particle theory beyond the eletroweak Standard Model provides ingredients and conditions for a successful inflation. We will mainly focus on a low energy supersymmetric Standard…

High Energy Physics - Phenomenology · Physics 2007-07-26 A. Mazumdar