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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

We analyze various phases of inflation based on the anomaly-induced effective action of gravity (modified Starobinsky model), taking the cosmological constant Lambda and k=0, +/- 1 topologies into account. The total number of the…

High Energy Physics - Phenomenology · Physics 2009-11-07 A. M. Pelinson , I. L. Shapiro , F. I. Takakura

The original model of axion natural inflation produces a tensor-to-scalar ratio above the experimental limit. Aligned axion inflation admits inflationary trajectories that originate near a saddle point of the two-field potential, and…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-20 Federico Greco , Marco Peloso

This note makes a self-contained exposition of the basic facts of big bang cosmology as they relate to inflation. The fundamental problems with that model are then explored. A quartic scalar potential model of inflation is evaluated which…

General Physics · Physics 2014-12-09 Dan Green

In this paper we consider a new approach to unify inflation and the late universe with dark energy and dark matter formulated in a model that includes a non-Riemannian metric independent measure and a scalar field with spontaneously broken…

General Relativity and Quantum Cosmology · Physics 2025-01-31 Eduardo Guendelman , Ramon Herrera

The large hierarchy between the Planck scale and the weak scale can be explained by the dynamical breaking of supersymmetry in strongly coupled gauge theories. Similarly, the hierarchy between the Planck scale and the energy scale of…

High Energy Physics - Phenomenology · Physics 2017-11-22 Keisuke Harigaya , Kai Schmitz

In this paper we investigate the general features of "Oscillatory Inflation". In adiabatic approximation, we derive a general formula for the number of e-foldings $\tilde{N}$ which reduces to the standard expression in case of the slow role…

General Relativity and Quantum Cosmology · Physics 2014-11-17 M. Sami

In this work, we consider intermediate inflation in context of the Generalized Non-Minimal Derivative Coupling (GNMDC) model. In this model, inflation is driven by a canonical scalar field that is coupled not only to gravity but also to the…

High Energy Physics - Theory · Physics 2024-10-04 Parviz Goodarzi

We have explicitly demonstrated that scalar coupled Gauss-Bonnet gravity in four dimension can have non-trivial effects on the early inflationary stage of our universe. In particular, we have shown that the scalar coupled Gauss-Bonnet term…

General Relativity and Quantum Cosmology · Physics 2018-11-13 Sumanta Chakraborty , Tanmoy Paul , Soumitra SenGupta

By incorporating both the tensor-to-scalar ratio and the measured value of the spectral index, we set a bound on solo small field inflation of $\Delta \phi / m_{Pl} \geq 1.00 \sqrt{r/0.1}$. Unlike previous bounds which require monotonic…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-30 Joseph Bramante , Sean Downes , Landon Lehman , Adam Martin

Little is known about the microscopic physics that gave rise to inflation in our universe. There are many reasons to wonder if the underlying description requires a careful arrangement of ingredients or if inflation was the result of an…

High Energy Physics - Theory · Physics 2015-06-23 Daniel Green

There are many single field inflationary models that are consistent with the recent Planck 2018 measurements of the spectral index $n_s$ and tensor-to-scalar ratio $r$. Despite good agreement with observational data some of these models…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-18 Josh Hoffmann , David Sloan

If dark matter is made of QCD axions, its abundance is determined by the vacuum expectation value acquired by the axion field during inflation. The axion is usually assumed to follow the equilibrium distribution arising from quantum…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-27 Vadim Briaud , Kenji Kadota , Shinji Mukohyama , Alireza Talebian , Vincent Vennin

The current epoch of accelerated cosmic expansion is postulated to be driven by dark energy, which in the standard model takes the form of a cosmological constant with equation of state parameter $w=-1$. We propose an innovative perspective…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-17 Sveva Castello , Stéphane Ilić , Martin Kunz

Modern physics has unlocked a number of mysteries regarding the early Universe, such as the baryogenesis, the unification of the strong and electroweak forces and the nucleosynthesis. However, understanding the very early Universe, close to…

Quantum Physics · Physics 2017-10-13 Sandra Stupar , Vlatko Vedral

One of the fundamental objectives of contemporary cosmology is to understand the physics of the inflationary universe, owing to its observably verifiable predictions about the very early universe with an energy scale of $\sim 10^{16}$ GeV.…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-14 Aayush Randeep , Rajib Saha

We show that a single uncharged chiral superfield, canonically coupled to \mbox{$N=1$} supergravity with vanishing superpotential, naturally drives inflation in the early universe for a class of simple Kahler potentials. Inflation occurs…

High Energy Physics - Theory · Physics 2011-07-19 Gabriel Lopes Cardoso , Burt A. Ovrut

Phantom Cosmology provides an unique opportunity to "connect" the phantom driven (low en- ergy meV scale) dark energy phase to the (high energy GUT scale) inflationary era. This is possible because the energy density increases in phantom…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-29 Cosmin Ilie , Tirthabir Biswas , Katherine Freese

We examine the power-law Starobinsky model, a generalized version of the Starobinsky inflation model, characterized by a power-law correction to Einstein gravity. Employing the $f(R)$ formalism, the scalar and tensor power spectra were…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-10 Saisandri Saini , Akhilesh Nautiyal

In the early Universe matter can be described as a conformal invariant ultra-relativistic perfect fluid, which does not contribute, on classical level, to the evolution of the isotropic and homogeneous metric. If we suppose that there is…

High Energy Physics - Theory · Physics 2009-10-31 J. C. Fabris , A. M. Pelinson , I. L. Shapiro