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Related papers: Non-Gaussianity in DHOST inflation

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We study non-Gaussianity of density perturbations generated by an axionic curvaton, focusing on the case that the curvaton sits near the hilltop of the potential during inflation. Such hilltop curvatons can generate a red-tilted density…

Cosmology and Nongalactic Astrophysics · Physics 2013-03-15 Masahiro Kawasaki , Takeshi Kobayashi , Fuminobu Takahashi

If cosmic inflation suffered tiny time-dependent deviations from the slow-roll regime, these would induce the existence of small scale-dependent features imprinted in the primordial spectra, with their shapes and sizes revealing information…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-21 Sander Mooij , Gonzalo A. Palma , Grigoris Panotopoulos , Alex Soto

In the present work we study GUT Coleman-Weinberg inflation with a nonminimal coupling to gravity. In this kind of model one usually finds that either the nonminimal coupling is large or the inflaton self-coupling in unnaturally small. We…

High Energy Physics - Phenomenology · Physics 2014-03-05 Grigoris Panotopoulos

We compute the non-Gaussianities that arise in single field, slow roll inflationary models arising from arbitrary homogeneous initial states, as well as subleading contributions to the power spectrum. Non Bunch-Davies vacuum initial states…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-12 Sina Bahrami , Éanna É. Flanagan

We study a model of multiple-field DBI inflation leading to mixed form of primordial non-Gaussianity, including equilateral and local bispectrum shapes. We present a general formalism based on the Hamilton-Jacobi approach, allowing us to go…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-23 Jon Emery , Gianmassimo Tasinato , David Wands

We investigate primordial non-Gaussianity and dark matter isocurvature fluctuations in the modulated reheating and the curvaton scenarios. In these scenarios, large non-Gaussianity can be generated, on the other hand, depending on how dark…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-06 Tomo Takahashi , Masahide Yamaguchi , Shuichiro Yokoyama

We present an estimate for the non-linear parameter \tau_NL, which measures the non-gaussianity imprinted in the trispectrum of the comoving curvature perturbation, \zeta. Our estimate is valid throughout the inflationary era, until the…

Astrophysics · Physics 2010-10-27 David Seery , James E. Lidsey

We study the statistical descriptors for some cosmological inflationary models that allow us to get large levels of non-gaussianity and violations of statistical isotropy. Basically, we study two different class of models: a model that…

Cosmology and Nongalactic Astrophysics · Physics 2010-05-05 Cesar A. Valenzuela-Toledo

We develop a mathematical construction of non-Gaussian fields whose bispectra satisfy the single-clock inflation consistency relation. At the same order that our basis for bispectra recovers the two simplest single clock templates, we also…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-17 Bekir Baytaş , Sarah Shandera

The methods of effective field theory are used to study generic theories of inflation with a single inflaton field and to perform a general analysis of the associated non-Gaussianities. We investigate the amplitudes and shapes of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Nicola Bartolo , Matteo Fasiello , Sabino Matarrese , Antonio Riotto

We investigate the non-Gaussianities of inflation driven by a single scalar field coupling non-minimally to the Einstein Gravity. We assume that the form of the scalar field is very general with an arbitrary sound speed. For convenience to…

High Energy Physics - Theory · Physics 2011-05-27 Taotao Qiu , Kwei-Chou Yang

Since trans-Planckian considerations can be associated with the re-definition of the initial vacuum, we investigate further the influence of trans-Planckian physics on the spectra produced by the initial quasi-de Sitter (dS) state during…

General Relativity and Quantum Cosmology · Physics 2018-04-06 M. Mohsenzadeh , E. Yusofi

We analyze the power spectrum and the bispectrum of BOSS galaxy-clustering data using the prediction from the Effective Field Theory of Large-Scale Structure at one-loop order for $\textit{both}$ the power spectrum $\textit{and}$ the…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-08 Guido D'Amico , Matthew Lewandowski , Leonardo Senatore , Pierre Zhang

We study the non-Gaussianity generated during multiple-field inflation. We provide an exact expression for the bispectrum parameter f_NL which is valid beyond the slow-roll regime, valid for certain classes of inflationary models. We then…

Cosmology and Nongalactic Astrophysics · Physics 2011-11-04 Christian T. Byrnes , Gianmassimo Tasinato

We study a warm-tachyon inflationary model non-minimally coupled to a Gauss-Bonnet term. The general conditions required for reliability of the model are obtained by considerations of a combined hierarchy of Hubble and Gauss-Bonnet flow…

General Relativity and Quantum Cosmology · Physics 2016-12-21 Maysam Motaharfar , Hamid Reza Sepangi

Heavy scalar fields can undergo an instability during inflation as a result of their kinetic couplings with the inflaton. This is known as the geometrical destabilization of inflation, as it relies on the effect of the negative curvature of…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-07 Sebastian Garcia-Saenz , Sébastien Renaux-Petel , John Ronayne

We present a replica field-theoretic approach to stochastic inflation in which a manifestation of dimensional reduction is found. The scale above which the latter dominates grows exponentially fast with time and thus affects largest…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Florian Kuhnel , Dominik J. Schwarz

We provide analytic solutions for the power spectrum and bispectrum of curvature fluctuations produced by a step feature in the inflaton potential, valid in the limit that the step is short and sharp. In this limit, the bispectrum is…

Cosmology and Nongalactic Astrophysics · Physics 2012-03-02 Peter Adshead , Cora Dvorkin , Wayne Hu , Eugene A. Lim

Inflation universally produces classical almost scale free Gaussian inhomogeneities of any light scalars. Assuming the coupling constants at the time of inflation depend on some light moduli fields, we encounter the generation of modulated…

Astrophysics · Physics 2009-11-10 Francis Bernardeau , Lev Kofman , Jean-Philippe Uzan

We consider gravitational clustering from primoridal non-Gaussian fluctuations provided by a $\chi^2$ model, as motivated by some models of inflation. The emphasis is in signatures that can be used to constrain this type of models from…

Astrophysics · Physics 2009-10-31 Roman Scoccimarro