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Related papers: Non-slow-roll dynamics in $\alpha-$attractors

200 papers

We study inflation driven by a slow-rolling inflaton field, characterised by a quadratic potential, and incorporating radiative corrections within the context of supergravity. In this model the energy scale of inflation is not overly…

High Energy Physics - Phenomenology · Physics 2011-02-16 Gabriel German , Graham Ross , Subir Sarkar

This study examines how inflationary dynamics are affected by $f(R)$ theories with a non-minimal coupling between matter and curvature. Both positive and negative corrections to the minimal coupling of General Relativity are considered, and…

General Relativity and Quantum Cosmology · Physics 2026-01-29 Miguel Barroso Varela , Orfeu Bertolami , Andreas Mantziris

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

We consider slow-roll inflationary models in a class of modified theories of gravity which contains non-minimal curvature-inflaton couplings, i.e., the $f(R,T)$ gravity, where $R$ is the Ricci scalar and $T$ is the trace of the inflaton…

General Relativity and Quantum Cosmology · Physics 2022-11-07 Che-Yu Chen , Yakefu Reyimuaji , Xinyi Zhang

We investigate in detail the attractor behavior of some inflationary models based on braneworld dynamics under the constant-roll condition. We describe the dynamics of the models, assuming that the second slow-roll parameter remains…

General Relativity and Quantum Cosmology · Physics 2025-04-29 Goran S. Djordjevic , Neven Bilić , Dragoljub D. Dimitrijevic , Milan Milosevic , Marko Stojanovic

We study the dynamics of inflation in a generalized scalar-torsion gravity scenario by assuming a canonical scalar field non-minimally coupled to torsion with a Galileon-type self-interaction. After obtaining the field equations for a flat…

General Relativity and Quantum Cosmology · Physics 2019-08-26 Manuel Gonzalez-Espinoza , Giovanni Otalora , Nelson Videla , Joel Saavedra

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

We present $\alpha$-attractor models for inflation based on ${\cal N}=1$ supergravity with flat K\"ahler manifolds. The function form of the associated K\"ahler potential in these models are logarithmic square in nature and has a visible…

High Energy Physics - Theory · Physics 2018-12-19 Tony Pinhero

The conventional slow-roll approximation is broken in the so-called "ultra slow-roll" models of inflation, for which the inflaton potential is exactly (or extremely) flat. The interesting nature of (canonical) ultra slow-roll inflation is…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-18 Shin'ichi Hirano , Tsutomu Kobayashi , Shuichiro Yokoyama

Usual inflation is realized with a slow rolling scalar field minimally coupled to gravity. In contrast, we consider dynamics of a scalar with a flat effective potential, conformally coupled to gravity. Surprisingly, it contains an attractor…

High Energy Physics - Theory · Physics 2008-11-26 Lev Kofman , Shinji Mukohyama

We study the possibility that inflation is driven by a scalar field together with a vector field minimally coupled to gravity. By assuming an effective potential that incorporates both fields into the action, we explore two distinct…

General Relativity and Quantum Cosmology · Physics 2024-12-09 Manuel Gonzalez-Espinoza , Ramon Herrera

Slow-roll of the inflaton field defines the standard dynamics of the inflationary epoch. However, the inflationary system deviates from slow-roll when it encounters an extremely flat region of the inflaton potential, and enters a phase…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-04 Sandip Biswas , Kaushik Bhattacharya , Suratna Das

An appealing feature of inflationary cosmology is the presence of a phase-space attractor, "slow roll", which washes out the dependence on initial field velocities. We investigate the robustness of this property under backreaction from…

General Relativity and Quantum Cosmology · Physics 2021-04-05 Julien Grain , Vincent Vennin

In this letter, we propose a single-field inflation model that realizes a slow-roll-to-ultra-slow-roll transition while keeping the second slow-roll parameter smoothly varying throughout. The model is built through a minimal modification by…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-19 Diego Cruces , Minxi He , Shi Pi , Jianing Wang , Masahide Yamaguchi , Yuhang Zhu

In this paper we wish to point out the possibility of using a complex scalar field in a constant roll inflationary model, as needed for observational viability. We extend the idea of real field inflaton with constant rate of roll to a…

General Relativity and Quantum Cosmology · Physics 2023-07-04 Ali Mohammadi , Nahid Ahmadi , Mehdi Shokri

In this paper, we study a constant-roll inflationary model in the presence of a noncommutative parameter with a homogeneous scalar field minimally coupled to gravity. The specific noncommutative inflation conditions proposed new…

High Energy Physics - Theory · Physics 2023-02-14 J. Sadeghi , S. Noori Gashti

We discuss the introduction of a non minimal coupling between the inflaton and gravity in terms of the recently proposed $\beta$-function formalism for inflation\cite{Binetruy:2014zya}. Via a field redefinition we reduce to the case of…

High Energy Physics - Phenomenology · Physics 2016-09-27 Mauro Pieroni

We consider the familiar problem of a minimally coupled scalar field with quadratic potential in flat Friedmann-Lema\^itre-Robertson-Walker cosmology to illustrate a number of techniques and tools, which can be applied to a wide range of…

General Relativity and Quantum Cosmology · Physics 2015-06-19 Artur Alho , Claes Uggla

We study (p)reheating in alpha-attractor T-models of inflation, taking into account both scalar fields present in these models: the inflaton and the spectator. The two-field model has a negative field-space curvature which, at the end of…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-04 Tomasz Krajewski , Krzysztof Turzyński , Michał Wieczorek

Inflationary slow-roll dynamics in Einstein gravity with a non-minimal scalar-curvature coupling can be equivalent to that in the certain f(R) gravity theory. We review the correspondence and extend it to N=1 supergravity. The non-minimal…

High Energy Physics - Theory · Physics 2015-06-04 Sergei V. Ketov , Alexei A. Starobinsky