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Related papers: Ultra slow-roll inflation demystified

200 papers

We explore some issues in slow roll inflation in situations where field excursions are small compared to $M_p$. We argue that for small field inflation, minimizing fine tuning requires low energy supersymmetry and a tightly constrained…

High Energy Physics - Phenomenology · Physics 2015-05-30 Michael Dine , Lawrence Pack

We explore a model of inflation where the inflaton mass-squared is generated at a high scale by gravity-mediated soft supersymmetry breaking, and runs at lower scales to the small value required for slow-roll inflation. The running is…

High Energy Physics - Phenomenology · Physics 2009-10-31 Laura Covi , David H. Lyth , Leszek Roszkowski

We investigate all single-field, slow-roll inflationary models whose slow-roll parameters scale as 1/N in the limit of a large number of e-folds N. We proof that all such models belong to two universality classes, characterised by a single…

High Energy Physics - Theory · Physics 2015-06-17 Diederik Roest

In the cold inflation scenario, the slow roll inflation and reheating via coherent rapid oscillation, are usually considered as two distinct eras. When the slow roll ends, a rapid oscillation phase begins and the inflaton decays to…

General Relativity and Quantum Cosmology · Physics 2017-07-18 Parviz Goodarzi , H. Mohseni Sadjadi

A study of the slow-roll inflation for an exponential potential in the frame of the scalar-tensor theory is performed, where non-minimal kinetic coupling to curvature and non-minimal coupling of the scalar field to the Gauss-Bonnet…

High Energy Physics - Theory · Physics 2019-09-24 L. N. Granda , D. F. Jimenez

We study single-field slow-roll inflation embedded in Palatini $F(R)$ gravity where $F(R)$ grows faster than $R^2$. Surprisingly, the consistency of the theory requires the Jordan frame inflaton potential to be unbounded from below. Even…

General Relativity and Quantum Cosmology · Physics 2024-03-21 Christian Dioguardi , Antonio Racioppi , Eemeli Tomberg

We present the first quantum field theory model of inflation that is renormalizable in the matter sector, with a super-Hubble inflaton mass and sub-Planckian field excursions, which is thus technically natural and consistent with a…

High Energy Physics - Phenomenology · Physics 2021-01-11 Mar Bastero-Gil , Arjun Berera , Rudnei O. Ramos , João G. Rosa

We consider inflation with a constant rate of rolling in which a complex scalar field plays the role of inflaton during the inflationary epoch. We implement the inflationary analysis for an accredited angular speed $\dot{\theta}$ which…

General Relativity and Quantum Cosmology · Physics 2024-05-16 Ramón Herrera , Mehdi Shokri , Jafar Sadeghi

Hyperbolic inflation is an extension of the slow-roll inflation in multi-field models. We extend hyperbolic inflation by adding a gauge field and find four-type attractor solutions: slow-roll inflation, hyperbolic inflation, anisotropic…

High Energy Physics - Theory · Physics 2023-06-27 Chong-Bin Chen , Jiro Soda

We realize and study a model of hybrid inflation in the context of softly broken supersymmetry. The inflaton is taken to be a flat direction in the superfield space and, due to unsuppressed couplings, its soft supersymmetry breaking mass…

High Energy Physics - Phenomenology · Physics 2016-08-25 Laura Covi

Motivated by the aim of producing significant number of primordial black holes, over the past few years, there has been a considerable interest in examining models of inflation involving a single, canonical field, that permit a brief period…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-03 Sagarika Tripathy , Debika Chowdhury , H. V. Ragavendra , L. Sriramkumar

In this paper we show that the dynamics associated with slow-roll models of inflation can be investigated through a method called deformation procedure. Using the latter, we explicitly derive an expression linking two slow-roll inflationary…

General Relativity and Quantum Cosmology · Physics 2015-03-19 Jamilton Rodrigues , Marcos Souza

We generalize the notion of constant-roll inflation earlier introduced in General Relativity (GR) and $f(R)$ gravity to inflationary models in more general scalar-tensor gravity. A number of novel exact analytic solutions for a FLRW…

General Relativity and Quantum Cosmology · Physics 2020-02-25 Hayato Motohashi , Alexei A. Starobinsky

We propose a class of single-field, slow-roll inflation models in which a typical number of $e$-folds can be extremely large. The key point is to introduce a very shallow local minimum near the top of the potential in a hilltop inflation…

High Energy Physics - Phenomenology · Physics 2019-12-16 Naoya Kitajima , Yuichiro Tada , Fuminobu Takahashi

Stochastic inflation, together with the $\Delta N$ formalism, provides a powerful tool for estimating the large-scale behaviour of primordial fluctuations. In this work, we develop a numerical code to capture the non-perturbative statistics…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-10 Devanshu Sharma

We study the trispectrum in a two-phase USR-SR setup of inflation in which the USR stage is extended in the initial phase of inflation while the second stage of inflation proceeds via a slow-roll phase. A key role is played by the sharpness…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-12 Hassan Firouzjahi , Amin Nassiri-Rad

It is usually supposed that inflation is of the slow-roll variety, and that the inflaton generates the primordial curvature perturbation. According to the curvaton hypothesis, inflation need not be slow-roll, and if it is the inflaton…

High Energy Physics - Phenomenology · Physics 2009-07-09 Konstantinos Dimopoulos , David H. Lyth

We find the natural embedding of the (R+R^2)-inflationary model into the recently constructed N=1 F(\cal R)-supergravity. It gives a simple and viable realization of chaotic inflation in supergravity. The only requirement for a slow-roll…

High Energy Physics - Theory · Physics 2011-03-22 Sergei V. Ketov , Alexei A. Starobinsky

We consider a cosmological inflation scenario based on a no-scale supergravity sector with $U(1)_R$ symmetry. It is shown that a tree level $U(1)_R$ symmetric superpotential alone does not lead to a slowly rolling scalar potential. A…

High Energy Physics - Phenomenology · Physics 2019-05-29 Shaaban Khalil , Ahmad Moursy , Abhijit Kumar Saha , Arunansu Sil

We make use of possible high energy correction to the Friedmann equation to implement the bounce and study the behavior of massive scalar field before and after bounce semianalytically and numerically. We find that the slow-roll inflation…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Yun-Song Piao , Yuan-Zhong Zhang