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A quantum field theory warm inflation model is presented that solves the horizon/flatness problems. The model obtains, from the elementary dynamics of particle physics, cosmological scale factor trajectories that begin in a radiation…

High Energy Physics - Phenomenology · Physics 2008-11-26 Arjun Berera , Marcelo Gleiser , Rudnei O. Ramos

In this work, we study warm inflationary scenario based on a deformation of $R^{2}$ gravity. We start considering $R^{p}$ and assume $p=2(1+\delta)$ with $\delta\ll 1$ so that we simply obtain warm $R^{2}$ inflation when setting $\delta=0$.…

General Relativity and Quantum Cosmology · Physics 2022-12-20 Apirak Payaka , Waluka Amaek , Phongpichit Channuie

One proposed solution of the moduli problem of string cosmology requires that the moduli are quite heavy, their decays reheating the universe to temperatures above the scale of nucleosynthesis. In many of these scenarios, the moduli are…

High Energy Physics - Phenomenology · Physics 2009-11-11 Michael Dine , Ryuichiro Kitano , Alexander Morisse , Yuri Shirman

We propose a new framework for multi-field inflation in which a nearly constant potential energy is maintained during inflation before decreasing rapidly, in a manner analogous to a classical top spinning upright for a long time before…

High Energy Physics - Phenomenology · Physics 2012-08-27 Alejandro Jenkins , Takemichi Okui

Whereas preheating after chaotic and hybrid inflation models has been abundantly studied in the literature, preheating in small field inflation models, where the curvature of the inflaton potential is negative during inflation, remains less…

High Energy Physics - Theory · Physics 2015-03-17 Philippe Brax , Jean-Francois Dufaux , Sophie Mariadassou

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

In this study, we investigate the full nonlinear dynamics of warm inflation driven by the quartic inflaton potential, avoiding any simplifying approximations. The thermal backreaction is incorporated through a dissipation coefficient that…

General Relativity and Quantum Cosmology · Physics 2025-11-20 Bhargabi Saha , Malay K. Nandy

This contribution to the proceedings collects new recent results on preheating after inflation. We discuss tachyonic preheating in the SUSY motivated hybrid inflation; development of equilibrium after preheating; theory of fermionic…

High Energy Physics - Phenomenology · Physics 2007-05-23 Lev Kofman

Cosmological reheating bridges the inflationary epoch and the hot big bang phase, yet its underlying dynamics remain poorly understood. In this work, we investigate a minimal scenario in which the inflaton evolves under a simple power-law…

High Energy Physics - Phenomenology · Physics 2025-09-22 Kunio Kaneta , Tomo Takahashi , Natsumi Watanabe

Gravitinos are expected to be produced in any local supersymmetric model. Using their abundance prediction as a function of the reheating energy scale, it is argued that the next generation of Cosmic Microwave Background experiments could…

High Energy Physics - Phenomenology · Physics 2009-11-10 A. Barrau , N. Ponthieu

We study the effects of the unstable gravitino on the big-bang nucleosynthesis. If the gravitino mass is smaller than \sim 10 TeV, primordial gravitinos produced after the inflation are likely to decay after the big-bang nucleosynthesis…

High Energy Physics - Phenomenology · Physics 2008-11-26 Kazunori Kohri , Takeo Moroi , Akira Yotsuyanagi

We consider the framework of quintessential inflation in the warm background which is caused by the dissipation of the scalar field energy density into relativistic degrees of freedom. The dissipation process has important consequences for…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-03 Mayukh R. Gangopadhyay , Shynaray Myrzakul , Mohammad Sami , Mohit K. Sharma

We propose a new mechanism to generate density perturbations in inflationary models. Spatial fluctuations in the decay rate of the inflaton field to ordinary matter lead to fluctuations in the reheating temperature. We argue that in most…

Astrophysics · Physics 2009-11-07 Gia Dvali , Andrei Gruzinov , Matias Zaldarriaga

We investigate the gravitational production of a scalar field $\chi$ with a mass exceeding the Hubble scale during inflation $m_\chi \gtrsim H_I$, employing both analytical and numerical approaches. We demonstrate that the steepest descent…

High Energy Physics - Phenomenology · Physics 2024-05-24 Davide Racco , Sarunas Verner , Wei Xue

Inflation ends with the formation of a Bose condensate of inflatons. We show that in hybrid inflation models this condensate is typically unstable with respect to spatial perturbations and can fragment to condensate lumps. The case of…

High Energy Physics - Phenomenology · Physics 2009-11-07 John McDonald

We point out that there is no cosmological gravitino problem in a certain class of gauge-mediated supersymmetry-breaking (GMSB) models. The constant term in the superpotential naturally causes small mixings between the standard-model and…

High Energy Physics - Phenomenology · Physics 2009-11-07 Masaaki Fujii , T. Yanagida

We construct a model of quintessential inflation in Palatini $R^2$ gravity employing a scalar field with a simple exponential potential and coupled to gravity with a running non-minimal coupling. At early times, the field acts as the…

General Relativity and Quantum Cosmology · Physics 2022-11-03 Konstantinos Dimopoulos , Alexandros Karam , Samuel Sánchez López , Eemeli Tomberg

As is well known, the gravitational degrees of freedom contained in $R+\zeta R^{2}$ (super)gravity lead to Starobinsky's potential, in a one-field setting for inflationary Cosmology that appears favored by Planck data. In this letter we…

General Relativity and Quantum Cosmology · Physics 2017-02-01 Andrea Addazi , Maxim Yu. Khlopov

The curvaton and the inhomogeneous reheating scenarios for the generation of the cosmological curvature perturbation on large scales represent an alternative to the standard slow-roll scenario where the observed density perturbations are…

Astrophysics · Physics 2009-11-10 L. Pilo , A. Riotto , A. Zaffaroni

We review work on the formation of gravitino condensates via the super-Higgs effect in the early Universe. This is a scenario for both inflating the early universe and breaking local supersymmetry (supergravity), entirely independent of any…

General Relativity and Quantum Cosmology · Physics 2014-12-23 Nick E. Mavromatos