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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 the past decade, the importance of dissipation and fluctuation to inflationary dynamics has been realized and has led to a new picture of inflation called warm inflation. Although these phenomena are common to condensed matter systems,…

High Energy Physics - Phenomenology · Physics 2009-11-13 Arjun Berera

We study the problem of initial conditions for slow-roll inflation along a plateau-like scalar potential within the framework of fluctuation-dissipation dynamics. We consider, in particular, that inflation was preceded by a…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-09 Mar Bastero-Gil , Arjun Berera , Robert Brandenberger , Ian G. Moss , Rudnei O. Ramos , Joao G. Rosa

The weak gravity conjecture imposes severe constraints on natural inflation. A trans-Planckian axion decay constant can only be realized if the potential exhibits an additional (subdominant) modulation with sub-Planckian periodicity. The…

Cosmology and Nongalactic Astrophysics · Physics 2020-04-22 Martin Wolfgang Winkler , Martina Gerbino , Micol Benetti

Thermal fluctuations provide the main source of large scale density perturbations in warm inflationary models of the early universe. For the first time, general results are obtained for the power spectrum in the case when the friction…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-28 Chris Graham , Ian G Moss

A general form of warm inflation with the dissipative coefficient $\Gamma=\Gamma_0(\phi /\phi_0) ^n(T/\tau_0) ^m$ in loop quantum cosmology is studied. In this case, we obtain conditions for the existence of a warm inflationary attractor in…

General Relativity and Quantum Cosmology · Physics 2015-06-12 Xiao-Min Zhang , Jian-Yang Zhu

We show that warm inflation can be successfully realized in the high temperature regime through dissipative interactions between the inflaton and a single fermionic degree of freedom, provided that the latter's mass is an oscillatory…

High Energy Physics - Phenomenology · Physics 2023-08-02 Paulo B. Ferraz , João G. Rosa

The constraints on a general form of the power-law potential and the dissipation coefficient in the framework of warm single field inflation imposed by Planck data will be investigated. {By Considering a quasi-static Universe, besides a…

General Relativity and Quantum Cosmology · Physics 2019-12-03 Zahra Ghadiri , Abdollah Refaei , Ali Aghamohammadi , Haidar Sheikhahmadi

The scenario of two components warm tachyon inflation is considered where the tachyon field plays the role of inflaton and drives inflation. During inflation, the tachyon scalar field interacts with the other component of the Universe which…

General Relativity and Quantum Cosmology · Physics 2020-07-02 Abolhassan Mohammadi , Tayeb Golanbari , Haidar Sheikhahmadi , Kosar Sayar , Lila Akhtari , M. A. Rasheed , Khaled Saaidi

Slow-roll inflation requires the inflaton field to have an exceptionally flat potential, which combined with measurements of the scale of inflation demands some degree of fine-tuning. Alternatively, the flatness of the potential could be…

High Energy Physics - Phenomenology · Physics 2015-06-23 Djuna Croon , Veronica Sanz

Observations of the temperature anisotropies in the Cosmic Microwave Background (CMB) radiation show that the models of inflation with the monomial potentials are inconsistent with the allowed $n_s-r$ bounds. However certain monomial…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-17 Richa Arya , Raghavan Rangarajan

Warm inflation is a well-motivated and generalized framework of inflation, describing a coupled inflaton-radiation bath. In this work, we investigate a warm inflation model with a quartic potential and a composite dissipation coefficient…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-14 Ayush Sahu , Richa Arya , Sergio E. Jorás , Karim H. Seleim

Warm inflation is an inflationary scenario in which a thermal bath coexists with the inflaton during inflation. This is unlike standard cold inflation in which the Universe is effectively devoid of particles during inflation. The thermal…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-10 Raghavan Rangarajan

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

Eternal inflation is studied in the context of warm inflation. We focus on different tools to analyze the effects of dissipation and the presence of a thermal radiation bath on the fluctuation-dominated regime, for which the…

Cosmology and Nongalactic Astrophysics · Physics 2016-03-14 Gustavo S. Vicente , Leandro A. da Silva , Rudnei O. Ramos

The generic prediction for the perturbations generated during slow--roll, single--field inflation, as they appear in the cosmic microwave background (CMB), is a flat, close--to--Gaussian spectrum. We calculate the general solution for a…

Astrophysics · Physics 2007-05-23 S. Gupta

An axion-like inflaton coupled to non-Abelian gauge bosons provides a compelling microphysical framework for warm inflation. Starting even from cold initial conditions, in these systems, sphaleron heating may generate thermal friction…

High Energy Physics - Phenomenology · Physics 2026-03-16 Mar Bastero-Gil , Pedro García Osorio , António Torres Manso

The present work examines the possibility of warm inflationary paradigm in the modified gravity theory with fractal geometry. By choosing the normal fluid as radiation fluid and the effective fluid (with the extra term in modified field…

General Relativity and Quantum Cosmology · Physics 2022-04-14 A. Bose , S. Chakraborty

We discuss spontaneous baryogenesis in the warm inflation scenario. In contrast with standard inflation models, radiation always exists in the warm inflation scenario, and the inflaton must be directly coupled to it. Also, the transition to…

High Energy Physics - Phenomenology · Physics 2009-11-10 Robert H. Brandenberger , Masahide Yamaguchi

At finite temperature, the coupling of an axion to non-Abelian gauge fields causes dissipation due to sphaleron heating. This mechanism has been considered as ideal for realizing warm inflation since it can lead to large thermal friction…

High Energy Physics - Phenomenology · Physics 2025-10-21 Sebastian Zell