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The constant-roll inflation is studied where the inflaton is taken as a tachyon field. Since in this approach the second slow-roll parameter is assumed to be of order one instead of being small, then the perturbation parameters will be…

High Energy Physics - Phenomenology · Physics 2018-04-25 A. Mohammadi , Kh. Saaidi , T. Golanbari

We investigate inflation within $f(R,\phi)$-theories, where a dynamical scalar field is coupled to gravity. A class of models which can support early-time acceleration with the emerging of an effective cosmological constant at high…

General Relativity and Quantum Cosmology · Physics 2018-12-13 R. Myrzakulov , L. Sebastiani , S. Vagnozzi

We investigate the phenomenology of warm inflation and present generic results about the evolution of the inflaton and radiation fields. The general conditions required for warm inflation to take place are derived and discussed. A…

Astrophysics · Physics 2009-10-31 A. N. Taylor , A. Berera

We investigate anisotropic inflation within the single-field model featuring an intermediate scale factor. Our analysis reveals that the anisotropic nature of the Friedmann equations in this framework affects the slow-roll parameters, which…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-12 Maryam Roushan , Narges Rashidi , Kourosh Nozari

The consistency relation for the 3-point function of the CMB is a very powerful observational signature which is believed to be true for every inflationary model in which there is only one dynamical degree of freedom. Its importance relies…

High Energy Physics - Theory · Physics 2009-06-11 Clifford Cheung , A. Liam Fitzpatrick , Jared Kaplan , Leonardo Senatore

In the present paper, we aim to generalize the constant-roll inflation in the non-canonical set-up, particularly in the context of scalar Dirac-Born-Infeld (DBI) theory which has emerged to be prospective candidate for describing inflation…

High Energy Physics - Theory · Physics 2018-07-05 Sayantani Lahiri

Sphaleron heating has been recently proposed as a mechanism to realize warm inflation when inflaton is an axion coupled to pure Yang-Mills. As a result of heating, there is a friction coefficient $\gamma \propto T^3$ in the equation of…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-28 Mehrdad Mirbabayi , Andrei Gruzinov

A new model for inflation using modified gravity in the Palatini formalism is constructed. Here non-minimal coupling of scalar field h with the curvature R as a general function f(R,h) is considered. Explicit inflation models for some…

General Relativity and Quantum Cosmology · Physics 2021-05-19 Nayan Das , Sukanta Panda

Warm inflation includes inflaton interactions with other fields throughout the inflationary epoch instead of confining such interactions to a distinct reheating era. Previous investigations have shown that, when certain constraints on the…

High Energy Physics - Phenomenology · Physics 2016-01-06 Mar Bastero-Gil , Arjun Berera , Nico Kronberg

We investigate a single field model in the context of the constant-roll inflation in which inflaton moves down to the minimum point of the potential with a constant rate of rolling. We use a quintessential inflationary model obtained by a…

Cosmology and Nongalactic Astrophysics · Physics 2021-11-23 Mehdi Shokri , Jafar Sadeghi , Saeed Noori Gashti

Warm inflation has normalized two ideas in cosmology, that in the early universe the initial primordial density perturbations generally could be of classical rather than quantum origin and that during inflation, particle production from…

High Energy Physics - Phenomenology · Physics 2023-06-23 Arjun Berera

In this paper we consider the $\alpha-$attractor model and study inflation under a non-slow-roll dynamics. More precisely, we follow the approach recently proposed by Gong and Sasaki \cite{Gong:2015ypa} by means of assuming…

General Relativity and Quantum Cosmology · Physics 2016-04-05 K. Sravan Kumar , João Marto , Paulo Vargas Moniz , Suratna Das

We discuss how dissipative effects and the presence of a thermal radiation bath, which are inherent characteristics of the warm inflation dynamics, can evade the recently proposed Swampland conjectures. Different forms of dissipation terms,…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-18 Meysam Motaharfar , Vahid Kamali , Rudnei O. Ramos

Dissipative effects can lead to a friction term in the equation of motion for an inflaton field during the inflationary era. The friction term may be linear and localised, in which case it is described by a dissipation coefficient. The…

High Energy Physics - Phenomenology · Physics 2007-05-23 Ian G Moss , Chun Xiong

In this work, we investigate the Higgs-Starobinsky (HS) model in the context of warm inflation scenario. The dissipative parameter as a linear form of temperature of warm inflation is considered with strong and weak regimes. We study the HS…

General Relativity and Quantum Cosmology · Physics 2022-02-10 Daris Samart , Patinya Ma-adlerd , Phongpichit Channuie

We investigate the constant-roll inflation with non-minimally kinetic coupling to the Einstein tensor. With the slow-roll parameter $\eta_\phi = -\ddot{\phi}/(H\dot{\phi})$ being a constant, we calculate the power spectra for scalar and…

General Relativity and Quantum Cosmology · Physics 2024-07-22 Jie Liu , Yungui Gong , Zhu Yi

We present WarmSPy, a numerical code in Python designed to solve for the perturbations' equations in warm inflation models and compute the corresponding scalar power spectrum at CMB horizon crossing. In models of warm inflation, a radiation…

Cosmology and Nongalactic Astrophysics · Physics 2024-01-17 Gabriele Montefalcone , Vikas Aragam , Luca Visinelli , Katherine Freese

Quantum gravitational back-reaction offers the potential of simultaneously resolving the problem of the cosmological constant and providing a natural model of inflation in which scalars play no special role. In this model inflation begins…

Astrophysics · Physics 2007-05-23 R. P. Woodard

The two approaches to compute perturbations in warm inflation are examined. It is shown that both approaches lead to different expressions for the amplitude of the primordial spectrum, with a difference between them of $\Upsilon/(4H)$ at…

Cosmology and Nongalactic Astrophysics · Physics 2019-07-30 Mar Bastero-Gil , Arjun Berera , Jaime R. Calderón

We discuss under which conditions multi-field cold and warm inflationary models with canonical kinetic energy terms are compatible with the swampland conjectures about the emergence of de Sitter solutions in string theory. We find that…

General Relativity and Quantum Cosmology · Physics 2022-09-14 Orfeu Bertolami , Paulo M. Sá