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Related papers: A Conformal Boundary Ansatz for Warm Inflation Ini…

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We study the two-phase scenario following inflation, where the initial step is preheating, accompanied by a step of perturbative reheating at which inflaton field decays transferring all of its energy to create relativistic particles, the…

General Relativity and Quantum Cosmology · Physics 2021-05-03 Khalil El Bourakadi

The recently released data from the $\textit{Atacama Cosmology Telescope}$ (ACT) confirms that the primordial scalar spectrum is extremely flat. This, together with current upper bounds on the tensor-to-scalar ratio, implies that the…

High Energy Physics - Theory · Physics 2025-11-24 Arjun Berera , Suddhasattwa Brahma , Zizang Qiu , Rudnei O. Ramos , Gabriel S. Rodrigues

We show how a radiation dominated universe subject to space-time quantization may give rise to inflation as the radiation temperature exceeds the Planck temperature. We consider dispersion relations with a maximal momentum (i.e. a mimimum…

High Energy Physics - Theory · Physics 2009-11-07 Stephon Alexander , Robert Brandenberger , Joao Magueijo

Warm inflation in the framework of locally rotationally symmetric Bianchi type I universe model in the Hamilton-Jacobi formalism is being considered. Matter-Radiation fluid in warm inflation, endowed with and without a viscous pressure. For…

General Relativity and Quantum Cosmology · Physics 2023-10-25 M Tirandari , A Mohammadi

We consider the classical evolution of the inflaton field $\phi(t)$ and the Hubble parameter $H(t)$ in homogeneous and isotropic single-field inflation models. Under an extremely broad assumption, we show that the universe generically…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-19 W. J. Handley , S. D. Brechet , A. N. Lasenby , M. P. Hobson

We revisit the renormalizable polynomial inflection point model of inflation, focusing on the small field scenario which can be treated fully analytically. In particular, the running of the spectral index is predicted to be $\alpha = -1.43…

High Energy Physics - Phenomenology · Physics 2021-09-22 Manuel Drees , Yong Xu

We revisit a cosmological scenario based on the classically conformal $U(1)_{B-L}$-extension of the Standard Model. Our focus is on the mechanism of reheating after inflation and the constraints on the model parameters. In this scenario,…

High Energy Physics - Phenomenology · Physics 2023-07-26 Shinsuke Kawai , Nobuchika Okada

The minimal warm inflation scenario proposed in Ref. [1] -- featuring an axionlike inflaton coupled to Standard Model (SM) gluons via the standard interaction $\phi G \tilde G$ -- offers a compelling bridge between inflationary dynamics and…

High Energy Physics - Phenomenology · Physics 2025-06-18 Rudnei O. Ramos , Gabriel S. Rodrigues

Constant-roll warm inflation is introduced in this work. A novel approach to finding an exact solution for Friedman equations coupled to scalar field equation of motion is presented for cold inflation and is extended to warm inflation with…

General Relativity and Quantum Cosmology · Physics 2020-07-17 Vahid Kamali , Michał Artymowski , Mohammad Reza Setare

Ideas borrowed from renormalization group are applied to warm inflation to characterize the inflationary epoch in terms of flows away from the de Sitter regime. In this framework different models of inflation fall into universality classes.…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-03 Arjun Berera , Joel Mabillard , Mauro Pieroni , Rudnei O. Ramos

We analyze the dynamics and observational predictions of supersymmetric hybrid inflation in the warm regime, where dissipative effects are mediated by the waterfall fields and their subsequent decay into light degrees of freedom. This…

High Energy Physics - Phenomenology · Physics 2015-06-18 Mar Bastero-Gil , Arjun Berera , Thomas P. Metcalf , Joao G. Rosa

Warm inflation dynamics is fundamentally based on a system-reservoir configuration in which the dynamics is dictated by a fluctuation-dissipation relation. Recent work by Cerioni et. al. (arXiv:0804.0163) examined dissipative dynamics with…

Astrophysics · Physics 2008-05-15 Arjun Berera , Lisa M. H. Hall , Ian G. Moss , Hiranya V. Peiris

We compute the primordial curvature spectrum generated during warm inflation, including shear viscous effects. The primordial spectrum is dominated by the thermal fluctuations of the radiation bath, sourced by the dissipative term of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 M. Bastero-Gil , A. Berera , R. O. Ramos

The warm inflationary scenario is investigated in the context of affine gravity formalism. A general framework is provided for studying different single-field potentials. Using the sphaleron mechanism we explain the continuous dissipation…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-14 Mahmoud AlHallak

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 consider warm inflation with a Dirac-Born-Infeld (DBI) kinetic term in which both the nonequilibrium dissipative particle production and the sound speed parameter slow the motion of the inflaton field. We find that a low sound speed…

High Energy Physics - Theory · Physics 2021-08-19 Meysam Motaharfar , Rudnei O. Ramos

We propose an inflation model in which the inflationary era is driven by the strong dynamics of $Sp(2)$ gauge theory. The quark condensation in the confined phase of $Sp(2)$ gauge theory generates the inflaton potential comparable to the…

High Energy Physics - Phenomenology · Physics 2023-02-22 Gongjun Choi , Weikang Lin , Tsutomu T. Yanagida

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

Cosmic inflation is arguably the most favoured paradigm of the very early Universe. It postulates an early phase of fast, nearly exponential, and accelerated expansion. Inflationary models are capable of explaining the overall flatness and…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-08 Cristian Joana

A dissipative mechanism is presented, which emerges in generic interacting quantum field systems and which leads to robust warm inflation. An explicit example is considered, where using typical parameter values, it is shown that…

High Energy Physics - Phenomenology · Physics 2009-11-07 Arjun Berera , Rudnei O. Ramos