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We calculate the general solutions for a warm inflationary scenario with weak dissipation, reviewing the dissipative dynamics of the two-fluid system, and calculate the bispectrum of the gravitational field fluctuations generated in the…

Astrophysics · Physics 2008-11-26 Sujata Gupta

The simplest inflationary model $V=\frac12 m^2\phi^2$ represents the benchmark for future constraints. For a quadratic potential, the quantity $(n_s-1)+r/4+11 (n_s-1)^2/24$ vanishes (up to corrections which are cubic in slow roll) and can…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-15 Paolo Creminelli , Diana López Nacir , Marko Simonović , Gabriele Trevisan , Matias Zaldarriaga

We compute the covariant three-point function near horizon-crossing for a system of slowly-rolling scalar fields during an inflationary epoch, allowing for an arbitrary field-space metric. We show explicitly how to compute its subsequent…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-10 Joseph Elliston , David Seery , Reza Tavakol

We study small field models of inflation, which, against previous expectations, yield significant Gravitational Wave (GW) signal while reproducing other measured observable quantities in the Cosmic Microwave Background (CMB). We numerically…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-01 Ira Wolfson

A perturbative strategy for inflation described by two-inflaton fields is developed using a mathematical analogy with the renormalization-group. Two small quantities, $\alpha$ and $\lambda$, corresponding to standard slow-roll parameters…

High Energy Physics - Theory · Physics 2025-06-10 Bohdan Grzadkowski , Marco Piva

We study the planar regime of curvature perturbations for single field inflationary models in an axially symmetric Bianchi I background. In a theory with standard scalar field action, the power spectrum for such modes has a pole as the…

High Energy Physics - Theory · Physics 2014-06-13 Anindya Dey , Ely D. Kovetz , Sonia Paban

We use cosmic microwave background and large scale structure data to test a broad and physically well-motivated class of inflationary models: those with flat tree-level potentials (typical in supersymmetry). The non-trivial features of the…

High Energy Physics - Phenomenology · Physics 2009-03-24 G. Ballesteros , J. A. Casas , J. R. Espinosa , R. Ruiz de Austri , R. Trotta

We provide a formula for the scaling behaviour of the inflationary bispectrum in the 'squeezed' limit where one momentum becomes much smaller than the other two. This determines the scaling of the halo bias at low wavenumber and will be an…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Mafalda Dias , Raquel H. Ribeiro , David Seery

In this short note we clarify the role of the boundary terms in the calculation of the leading order tree-level bispectrum in a fairly general minimally coupled single field inflationary model, where the inflaton's Lagrangian is a general…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-30 Frederico Arroja , Takahiro Tanaka

We evaluate the dimensionless non-Gaussianity parameter $h_{_{\rm NL}}$, that characterizes the amplitude of the tensor bispectrum, numerically for a class of two field inflationary models such as double inflation, hybrid inflation and…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-26 Rathul Nath Raveendran , L. Sriramkumar

We consider a class of multi-component hybrid inflation models whose evolution may be analytically solved under the slow-roll approximation. We call it multi-brid inflation (or $n$-brid inflation where $n$ stands for the number of inflaton…

Astrophysics · Physics 2009-10-09 Misao Sasaki

We propose a general inverse formula for extracting inflationary parameters from the observed power spectrum of cosmological perturbations. Under the general slow-roll scheme, which helps to probe the properties of inflation in a model…

Astrophysics · Physics 2009-11-10 Minu Joy , Ewan D. Stewart , Jinn-Ouk Gong , Hyun-Chul Lee

Enormous information about interactions is contained in the non-Gaussianities of the primordial curvature perturbations, which are essential to break the degeneracy of inflationary models. We study the primordial bispectra for G-inflation…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-21 Fengge Zhang , Yungui Gong , Jiong Lin , Yizhou Lu , Zhu Yi

We calculate the scale dependence of the bispectrum and trispectrum in (quasi) local models of non-Gaussian primordial density perturbations, and characterize this scale dependence in terms of new observable parameters. They can help to…

Cosmology and Nongalactic Astrophysics · Physics 2010-10-12 Christian T. Byrnes , Mischa Gerstenlauer , Sami Nurmi , Gianmassimo Tasinato , David Wands

We use WMAP 9-year bispectrum data to constrain the free parameters of an 'effective field theory' describing fluctuations in single-field inflation. The Lagrangian of the theory contains a finite number of operators associated with unknown…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Gemma J. Anderson , Donough Regan , David Seery

Ultra slow-roll inflation has recently been used to challenge the non-Gaussianity consistency relation. We show that this inflationary scenario belongs to a one parameter class of models and we study its properties and observational…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Jerome Martin , Hayato Motohashi , Teruaki Suyama

Canonical models of single-field, slow-roll inflation do not lead to appreciable non-Gaussianity, unless derivative interactions of the inflaton become uncontrollably large. We propose a novel slow-roll scenario where scalar perturbations…

High Energy Physics - Theory · Physics 2016-05-25 David Pirtskhalava , Luca Santoni , Enrico Trincherini , Filippo Vernizzi

We use a numerical code for accurate computation of the amplitude of linear density perturbations and gravitational waves generated by single-field inflation models to study the accuracy of existing analytic results based on the slow-roll…

Astrophysics · Physics 2009-10-28 Ian J Grivell , Andrew R Liddle

We show that theories of inflation with multiple, rapidly turning fields can generate large amounts of non-Gaussianity. We consider a general theory with two fields, an arbitrary field-space metric, and a potential that supports sustained,…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-21 Oksana Iarygina , M. C. David Marsh , Gustavo Salinas

Weak lensing of the cosmic microwave background is rapidly emerging as a powerful probe of neutrinos, dark energy, and new physics. We present a fast computation of the non-linear CMB lensing power spectrum which combines non-linear…