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We propose the study of constant-roll inflation in $F(R)$ gravity. We use two different approaches, one that relates an $F(R)$ gravity to well known scalar models of constant-roll and a second that examines directly the constant-roll…

General Relativity and Quantum Cosmology · Physics 2017-12-06 S. Nojiri , S. D. Odintsov , V. K. Oikonomou

We obtain conditions for the existence of an attractor in the system of equations describing a tachyon warm inflationary model with bulk viscosity taken into account. When these conditions are met the evolution approaches slow-roll regime.…

General Relativity and Quantum Cosmology · Physics 2018-04-10 Antonella Cid

We study constant-roll inflation in the presence of a gauge field coupled to an inflaton. By imposing the constant anisotropy condition, we find new exact anisotropic constant-roll inflationary solutions which include anisotropic power-law…

High Energy Physics - Theory · Physics 2018-02-13 Asuka Ito , Jiro Soda

In this work, we study constant-roll inflation driven by a scalar field with non-minimal derivative coupling to gravity, via the Einstein tensor. This model contains a free parameter, $\eta$, which quantifies the non-minimal derivative…

General Relativity and Quantum Cosmology · Physics 2019-10-23 A. Oliveros , Hernán E. Noriega

The scenario of the slow-roll inflation is studied in the frame of the scalar-tensor theory of gravity where the scalar field has a non-minimal coupling to the geometric part. After deriving the main dynamical and perturbation equations,…

General Relativity and Quantum Cosmology · Physics 2020-12-01 Abolhassan Mohammadi , Tayeb Golanbari , Jamil Enayati , Shahram Jalalzadeh , Khaled Saaidi

In our paper we consider the validity of slow-roll approximations for Gauss-Bonnet inflation introduced in [1]. In contrast to the cited paper where the coupling function before the Gauss-Bonnet term have been chosen as a decaying function…

General Relativity and Quantum Cosmology · Physics 2026-02-02 Bogdan A. Rudenko , Maria A. Skugoreva , Alexey V. Toporensky

We study the inflationary scenario in the Tsallis entropy-based cosmology. The Friedmann equations in this setup can be derived by using the first law of thermodynamics. To derive the relations of the power spectra of the scalar and tensor…

General Relativity and Quantum Cosmology · Physics 2024-01-26 Zeinab Teimoori , Kazem Rezazadeh , Abasat Rostami

We constrain several models in Tachyonic Inflation derived from the large-$N$ formalism by considering theoretical aspects as well as the latest observational data. On the theoretical side, we assess the field range of our models by means…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-22 Nandinii Barbosa-Cendejas , Josue De-Santiago , Gabriel German , Juan Carlos Hidalgo , Refugio Rigel Mora-Luna

In this paper we study the tachyonic inflation in brane world cosmology with Gauss-Bonnet term in the bulk. We obtain the exact solution of slow roll equations in case of exponential potential. We attempt to implement the proposal of Lidsey…

High Energy Physics - Theory · Physics 2009-11-10 B. C. Paul , M. Sami

The two swampland criteria are generically in tension with the single field slow-roll inflation because the first swampland criterion requires small tensor to scalar ratio while the second swampland criterion requires large tensor to scalar…

General Relativity and Quantum Cosmology · Physics 2018-11-06 Zhu Yi , Yungui Gong

In this paper, we explore a novel observational signature of gravitational corrections during slow-roll inflation. We study the coupling of the inflaton field to higher-curvature tensors in models with a minimal breaking of conformal…

High Energy Physics - Theory · Physics 2016-02-17 Daniel Baumann , Hayden Lee , Guilherme L. Pimentel

In this work we construct a bottom-up reconstruction technique for Loop Quantum Cosmology scalar-tensor theories, from the observational indices. Particularly, the reconstruction technique is based on fixing the functional form of the…

General Relativity and Quantum Cosmology · Physics 2018-05-02 Jaume de Haro , S. D. Odintsov , V. K. Oikonomou

We propose a new approach to constant-roll warm inflation as a generalization of constant-roll inflation. Based on the $\beta$-function formalism, it is shown that constant-roll warm inflation models with a natural end fall into…

General Relativity and Quantum Cosmology · Physics 2021-05-12 Ui Ri Mun

We show how observations of the density perturbation (scalar) spectrum and the gravitational wave (tensor) spectrum allow a reconstruction of the potential responsible for cosmological inflation. A complete functional reconstruction or a…

High Energy Physics - Phenomenology · Physics 2009-10-22 Edmund J. Copeland , Edward W. Kolb , Andrew R. Liddle , James E. Lidsey

Using the latest observational data, we constrain the inflationary dynamics and the subsequent reheating epoch. Predictions for both phases can be significantly improved by employing numerically computed results compared to the slow-roll…

General Relativity and Quantum Cosmology · Physics 2026-01-29 Ying-Ying Ye , Bao-Min Gu

We present a tachyonic field inflationary model in a teleparallel framework. We show that tachyonic coupled with the f(T) gravity model can describe the inflation era in which f(T) is an arbitrary function of torsion scalar T. For this…

General Relativity and Quantum Cosmology · Physics 2020-02-24 Amin Rezaei Akbarieh , Yousef Izadi

We propose new versions of the slow-roll approximation for inflationary models with nonminimally coupled scalar fields. We derive more precise expressions for the standard slow-roll parameters as functions of the scalar field. To verify the…

General Relativity and Quantum Cosmology · Physics 2025-05-30 Ekaterina O. Pozdeeva , Maria A. Skugoreva , Alexey V. Toporensky , Sergey Yu. Vernov

Observations of the cosmic microwave background do not yet determine whether inflation was driven by a slowly-rolling scalar field or involved another physical mechanism. In this paper we discuss the prospects of using the power spectra of…

High Energy Physics - Theory · Physics 2015-12-10 Daniel Baumann , Daniel Green , Rafael A. Porto

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

Within an expansion in slow-roll inflation parameters, we derive the complete second-order expressions relating the ratio of tensor to scalar density perturbations and the spectral index of the scalar spectrum. We find that ``corrections''…

Astrophysics · Physics 2009-10-22 Edward W. Kolb , Sharon L. Vadas