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In this paper, an elegant mathematical approach is introduced to solve the equations of warm inflationary model without using extra approximations other than slow-roll. This important inflationary method known as Hamilton-Jacobian…

General Relativity and Quantum Cosmology · Physics 2020-04-08 R. Saleem , M. Zubair

Inflationary potentials, with Planckian field excursions, described by a 6th degree polynomial are studied. We solve the Mukhanov-Sasaki equations exactly and employ a probabilistic approach as well as multinomial fitting to analyse the…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-14 Ira Wolfson , Ram Brustein

We study inflation within the framework of non-canonical scalar field. In this scenario, we obtain the inflationary observables such as the scalar spectral index, the tensor-to-scalar ratio, the running of the scalar spectral index as well…

General Relativity and Quantum Cosmology · Physics 2017-05-31 Zeinab Teimoori , Kayoomars Karami

Cosmic Microwave Background (CMB) is an important probe for understanding the inflationary era of the Universe. We consider the Perturbed Power Law (PPL) model of inflation which is a soft deviation from Power Law (PL) inflationary model.…

Cosmology and Nongalactic Astrophysics · Physics 2015-02-03 Suvodip Mukherjee , Santanu Das , Minu Joy , Tarun Souradeep

If a coupling between the inflaton and the Gauss-Bonnet term is introduced, many models of inflation that were ruled out by the most recent Planck data can be made viable again. The predictions for the scalar spectral index and…

General Relativity and Quantum Cosmology · Physics 2025-04-22 Kamil Mudrunka , Kazunori Nakayama

We point out that the prediction of the minimal chaotic inflation model is altered if a scalar field takes a large field value close to the Planck scale during inflation due to a negative Hubble induced mass. In particular, we show that the…

High Energy Physics - Phenomenology · Physics 2016-03-09 Keisuke Harigaya , Masahiro Ibe , Masahiro Kawasaki , Tsutomu T. Yanagida

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

We use a mathematical approach based on the constraints systems in order to reconstruct the equation of state and the inflationary potential for the inflaton field from the observed spectral indices for the density perturbations $n_{s}$ and…

General Relativity and Quantum Cosmology · Physics 2018-06-12 John D. Barrow , Andronikos Paliathanasis

Possibly, the most general action in the background of isotropic and homogeneous space-time has been considered to study the quantum evolution of the early universe, apart from a cosmological constant. The hermiticity of the effective…

High Energy Physics - Theory · Physics 2020-10-30 Ranajit Mandal , Dalia Saha , Mohosin Alam , Abhik Kumar Sanyal

In the scenario of single-field inflation, this field is done in terms of Jacobian elliptic functions. This approach provides, when constrained to particular cases, analytic solutions already known in the past, generalizing them to a bigger…

General Relativity and Quantum Cosmology · Physics 2015-06-11 J. R. Villanueva , Emanuel Gallo

We study analytically and numerically the inflationary solutions for various type scalar potentials in the nonminimally coupled scalar field theory. The Hamilton-Jacobi equation is used to deal with nonlinear evolutions of inhomogeneous…

Astrophysics · Physics 2009-11-11 Seoktae Koh , Sang Pyo Kim , Doo Jong Song

We elucidate the counting of the relevant small parameters in inflationary perturbation theory. Doing this allows for an explicit delineation of the domain of validity of the semi-classical approximation to gravity used in the calculation…

High Energy Physics - Theory · Physics 2018-02-21 Peter Adshead , C. P. Burgess , R. Holman , Sarah Shandera

In this paper, we study the Starobinsky model of inflation in the context of gravity's rainbow theory. We propose that gravity rainbow functions can be written in the power-law form of the Hubble parameter. We present a detailed derivation…

General Relativity and Quantum Cosmology · Physics 2016-02-11 Auttakit Chatrabhuti , Vicharit Yingcharoenrat , Phongpichit Channuie

In the present work we study the consequences of considering a new family of single-field inflation models, called power-law plateau inflation, in the warm inflation framework. We consider the inflationary expansion is driven by a standard…

General Relativity and Quantum Cosmology · Physics 2017-05-24 Abdul Jawad , Nelson Videla , Faiza Gulshan

We study a model of inflation based on $\mathcal{N}=1$ supergravity essentially depending on one effective parameter. Under a field transformation we show that this model turns out to be equivalent to a previously studied supergravity model…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-13 Gabriel Germán , Juan Carlos Hidalgo , Francisco X. Linares Cedeño , Ariadna Montiel , J. Alberto Vázquez

Single field inflationary models with a non-minimal kinetic term (also called k-inflationary models) can be characterised by the so-called sound flow functions, which complete the usual Hubble flow hierarchy. These parameters appear in the…

Astrophysics · Physics 2008-11-26 Larissa Lorenz , Jerome Martin , Christophe Ringeval

This paper is devoted to study the warm inflation using vector fields in the background of locally rotationally symmetric Bianchi type I universe model. We formulate the field equations, slow-roll and perturbation parameters (scalar and…

General Relativity and Quantum Cosmology · Physics 2015-06-18 M. Sharif , Rabia Saleem

In this work, we investigate warm inflationary models in the context of a general scalar-tensor theory of gravity which is coupled to radiation through a dissipation term. We first derive the potential of exponential and hyperbolic tangent…

General Relativity and Quantum Cosmology · Physics 2022-04-06 Waluka Amake , Apirak Payaka , Phongpichit Channuie

The Hamilton-Jacobi approach is a powerful tool to describe super-Hubble dynamics during cosmological inflation in a non-linear way. A key assumption of this framework is to neglect anisotropic perturbations on large scales. We show that…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-15 Danilo Artigas , Emmanuel Frion , Tays Miranda , Vincent Vennin , David Wands

We introduce a new class of models of Higgs inflation using the superconformal approach to supergravity by modifying the K$\ddot{a}$hler geometry. Using such a mechanism, we construct a phenomenological functional form of a new…

High Energy Physics - Theory · Physics 2014-02-03 Sayantan Choudhury , Trina Chakraborty , Supratik Pal