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The reheating of the universe after hybrid inflation proceeds through the nucleation and subsequent collision of large concentrations of energy density in the form of bubble-like structures moving at relativistic speeds. This generates a…

General Relativity and Quantum Cosmology · Physics 2008-01-29 Juan Garcia-Bellido , Daniel G. Figueroa

Recently a mechanism was proposed whereby the primordial density perturbations are generated at the end of inflation. We continue the analysis of the proposed model of this mechanism and calculate the maximum extent to which the density…

Astrophysics · Physics 2009-11-13 Michael P. Salem

Inflation may have been driven by a component which violated the Null-Energy Condition, thereby leading to {\it super inflation}. We provide the formalism to study cosmological perturbations when such a component is described by a scalar…

Astrophysics · Physics 2010-09-21 Marco Baldi , Fabio Finelli , Sabino Matarrese

We present a simple way to calculate non-Gaussianity in inflation using fully non-linear equations on long wavelengths with stochastic sources to take into account the short-wavelength quantum fluctuations. Our formalism includes both…

Astrophysics · Physics 2009-11-10 G. I. Rigopoulos , E. P. S. Shellard , B. J. W. van Tent

Observations of the cosmic microwave background do not yet determine whether inflation was driven by a slowly-rolling scalar field or involved another physical mechanism. In this paper we discuss the prospects of using the power spectra of…

High Energy Physics - Theory · Physics 2015-12-10 Daniel Baumann , Daniel Green , Rafael A. Porto

Cosmic inflation provides a window to the highest energy densities accessible in nature, far beyond those achievable in any realistic terrestrial experiment. Theoretical insights into the inflationary era and its observational probes may…

Nongaussian statistics are a powerful discriminant between inflationary models, particularly those with noncanonical kinetic terms. Focusing on theories where the Lagrangian is an arbitrary Lorentz-invariant function of a scalar field and…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-19 Clare Burrage , Raquel H. Ribeiro , David Seery

We analyze in detail the background cosmological evolution of a scalar field coupled to a massless abelian gauge field through an axial term $\frac{\phi}{f_\gamma} F \tilde{F}$, such as in the case of an axion. Gauge fields in this case are…

High Energy Physics - Theory · Physics 2016-12-28 Alessio Notari , Konrad Tywoniuk

Dissipative effects appear in many early-Universe scenarios, yet their universal observational signatures and systematic confrontation with data remain largely unexplored. We employ the Open Effective Field Theory of Inflation (Open EFToI)…

Cosmology and Nongalactic Astrophysics · Physics 2026-03-17 Santiago Agüí Salcedo , Thomas Colas , Petar Suman , Bowei Zhang , James Fergusson , E. P. S. Shellard

The cosmological observations of cosmic microwave background and large-scale structure indicate that our universe has a nearly scaling invariant power spectrum of the primordial perturbation. However, the exact origin for this primordial…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-21 Qing-Yang Wang , Yong Tang , Yue-Liang Wu

Primordial spectral indices are calculated to second order in slow-roll parameters for three closely-related models of inflation, all of which contain a scalar field non-minimally coupled to the Ricci curvature scalar. In most cases, $n_s$…

Astrophysics · Physics 2010-11-01 David Kaiser

We calculate the contribution of the fluctuations with the thermal origin to the inflationary nonGaussianity. We find that even a small component of radiation can lead to a large nonGaussianity. We show that this thermal nonGaussianity…

High Energy Physics - Theory · Physics 2009-12-15 Bin Chen , Yi Wang , Wei Xue

Oscillons are massive, long-lived, localized excitations of a scalar field. We show that in a large class of well-motivated single-field models, inflation is followed by self-resonance, leading to copious oscillon generation and a lengthy…

Cosmology and Nongalactic Astrophysics · Physics 2012-08-09 Mustafa A. Amin , Richard Easther , Hal Finkel , Raphael Flauger , Mark P. Hertzberg

A class of non-canonical inflationary models is identified, where the leading-order contribution to the non-Gaussianity of the curvature perturbation is determined by the sound speed of the fluctuations in the inflaton field. Included in…

High Energy Physics - Theory · Physics 2008-11-26 Ian Huston , James E. Lidsey , Steven Thomas , John Ward

Cosmological perturbations generated during inflation exhibit striking quantum features, including entanglement and high circuit complexity. Yet their observational signatures remain effectively indistinguishable from classical stochastic…

High Energy Physics - Theory · Physics 2025-12-12 S. Shajidul Haque , Ghadir Jafari , Bret Underwood

We consider non-canonical generalizations of two classes of simple single-field inflation models. First, we study the non-canonical version of "ultra-slow roll" inflation, which is a class of inflation models for which quantum modes do not…

Astrophysics · Physics 2009-11-13 Konstantinos Tzirakis , William H. Kinney

The presence of multiple fields during inflation might seed a detectable amount of non-Gaussianity in the curvature perturbations, which in turn becomes observable in present data sets like the cosmic microwave background (CMB) or the large…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-27 Sebastian Dorn , Erandy Ramirez , Kerstin E. Kunze , Stefan Hofmann , Torsten A. Enßlin

We construct a hybrid-inflation model where the inflaton potential is generated radiatively, as gauge symmetries guarantee it to be accidentally flat at tree level. The model can be regarded as a small-field version of Natural Inflation,…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-18 Felix Brümmer , Giacomo Ferrante , Michele Frigerio

A new model of inflation is described. An unusual form for the inflationary potential is obtained because the inflaton corresponds to a non-trivial path in the configuration space of the two real scalar fields of the model. The model…

Astrophysics · Physics 2009-10-22 Ewan D. Stewart

In a recent paper of Linde and Mukhanov, a hybrid inflationary model with nongaussian density perturbations and a ``blue'' spectral index n > 1 was presented. In this comment we point out that this model can be considered as a particular…

Astrophysics · Physics 2007-05-23 Ignatios Antoniadis , Pawel O. Mazur , Emil Mottola