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We consider a simple inflation model with a complex scalar field coupled to gravity non-minimally. Both the modulus and the angular directions of the complex scalar are slowly rolling, leading to two-field inflation. The modulus direction…

High Energy Physics - Phenomenology · Physics 2015-05-28 Jinn-Ouk Gong , Hyun Min Lee

Inflationary dynamics driven by multiple fields, especially with nonminimal couplings, allow for highly interesting features such as isocurvature, non-Gaussianity, and preheating. In this paper, we study two-field inflation in the context…

General Relativity and Quantum Cosmology · Physics 2021-12-01 Hemza Azri , Isaac Bamwidhi , Salah Nasri

We study the evolution of cosmological perturbations on large scales, up to second order, for a perfect fluid with generic equation of state. Taking advantage of super-horizon conservation laws, it is possible to follow the evolution of the…

Astrophysics · Physics 2009-11-10 N. Bartolo , S. Matarrese , A. Riotto

We study the slow-roll inflation models, where the inflaton slow-rolls along a trajectory whose orthogonal directions are lifted by potentials with masses of order the Hubble parameter. In these models large non-Gaussianities can be…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-06 Xingang Chen , Yi Wang

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 present a detailed study of the trispectrum of the curvature perturbation generated within a stable, well defined and predictive theory which comprises an inflationary phase. In this model the usual shift symmetry is enhanced up to the…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-18 Frederico Arroja , Nicola Bartolo , Emanuela Dimastrogiovanni , Matteo Fasiello

We calculate the bispectrum of the gravitational field fluctuations generated during warm inflation, where dissipation of the vacuum potential during inflation is the mechanism for structure formation. The bispectrum is non--zero because of…

Astrophysics · Physics 2011-05-10 S. Gupta , A. Berera , A. F. Heavens , S. Matarrese

We explore extensions of hybrid inflationary models in the context of supersymmetric D-term inflation. We point out that a large variety of inflationary scenarios can be encountered when the field content is extended. It is not only…

High Energy Physics - Phenomenology · Physics 2008-11-26 Francis Bernardeau , Tristan Brunier

In the Horndeski's most general scalar-tensor theories, we derive the three-point correlation function of scalar non-Gaussianities generated during single-field inflation in the presence of slow-variation corrections to the leading-order…

High Energy Physics - Theory · Physics 2015-06-12 Antonio De Felice , Shinji Tsujikawa

We study primordial non-gaussianity in supersolid inflation. The dynamics of supersolid is formulated in terms of an effective field theory based on four scalar fields with a shift symmetric action minimally coupled with gravity. In the…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-07 Marco Celoria , Denis Comelli , Luigi Pilo , Rocco Rollo

We construct explicit models of multi-field inflation in which the primordial metric fluctuations do not necessarily obey Gaussian statistics. These models are realizations of mechanisms in which non-Gaussianity is first generated by a…

Astrophysics · Physics 2008-11-26 Francis Bernardeau , Jean-Philippe Uzan

Tensor non-Gaussianity represents an important future probe of the physics of inflation. Inspired by recent works, we elaborate further on the possibility of significant primordial tensor non-Gaussianities sourced by extra fields during…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-20 Emanuela Dimastrogiovanni , Matteo Fasiello , Gianmassimo Tasinato , David Wands

Primordial non-Gaussianities from multi-field inflation are a leading target for cosmological observations, because of the possible large correlations generated between long and short distances. These signatures are captured by the local…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-31 Dong-Gang Wang , Guilherme L. Pimentel , Ana Achúcarro

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

Inflation is an early period of accelerated cosmic expansion, thought to be sourced by high energy physics. A key task today is to use the influx of increasingly precise observational data to constrain the plethora of inflationary models…

Cosmology and Nongalactic Astrophysics · Physics 2013-08-05 Joseph Elliston

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 compute analytic expressions for the non-linearity parameters characterizing the bi- and tri-spectrum of primordial curvature perturbations generated during an inflationary epoch of the early universe driven by an arbitrary number of…

High Energy Physics - Theory · Physics 2011-11-04 Diana Battefeld , Thorsten Battefeld

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 study the generation of non-Gaussianity in models of hybrid inflation with two inflaton fields, (2-brid inflation). We analyse the region in the parameter and the initial condition space where a large non-Gaussianity may be generated…

Astrophysics · Physics 2010-04-30 Christian T. Byrnes , Ki-Young Choi , Lisa M. H. Hall

The non-Gaussianity of inflationary perturbations, as encoded in the bispectrum (or 3-point correlator), has become an important additional way of distinguishing between inflation models, going beyond the linear Gaussian perturbation…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-23 Bartjan van Tent