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We use the delta N -formalism to investigate the non-Gaussianity of the primordial curvature perturbation in the curvaton scenario for the origin of structure. We numerically calculate the full probability distribution function allowing for…

Astrophysics · Physics 2010-04-06 Misao Sasaki , Jussi Valiviita , David Wands

If more than one curvaton dominate the Universe at different epochs from each other, curvature perturbations can be temporarily enhanced to a value much larger than the observed one 10^{-5}. The traces of the enhancement may be left as…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-29 Teruaki Suyama , Jun'ichi Yokoyama

We consider the generation of primordial curvature perturbation by general non-Abelian vector fields without committing to a particular group. Self-interactions of non-Abelian fields make the field perturbation non-Gaussian. We calculate…

Cosmology and Nongalactic Astrophysics · Physics 2012-01-10 Mindaugas Karciauskas

We use a generalized delta N formalism to study the generation of the primordial curvature perturbation in the curvaton brane scenario inspired by stringy compactifications. We note that the non-Gaussian features, especially the trispectra,…

High Energy Physics - Theory · Physics 2010-12-24 Yi-Fu Cai , Yi Wang

We investigate how the background evolution affects the curvature perturbations generated by the curvaton, assuming a curvaton potential that may deviate slightly from the quadratic one, and parameterizing the background fluid density as…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Kari Enqvist , Tomo Takahashi

We apply the time-renormalization group approach to study the effect of primordial non-Gaussianities in the non-linear evolution of cosmological dark matter density perturbations. This method improves the standard perturbation approach by…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Nicola Bartolo , J. P. Beltran Almeida , Sabino Matarrese , Massimo Pietroni , Antonio Riotto

Density perturbations and their dynamic evolution from early to late times can be used for an improved understanding of interesting physical phenomena both in cosmology and in the context of heavy-ion collisions. We discuss the spectrum and…

High Energy Physics - Phenomenology · Physics 2015-03-11 Nikolaos Brouzakis , Stefan Floerchinger , Nikolaos Tetradis , Urs Achim Wiedemann

The physics of primordial black holes can be affected by the non-Gaussian statistics of the density fluctuations that generate them. Therefore, it is important to have good theoretical control of the higher-order correlation functions for…

High Energy Physics - Theory · Physics 2024-04-16 Gianmassimo Tasinato

We explore possible non-Gaussian features of primordial gravitational waves by constructing model-independent templates for nonlinearity parameters of tensor bispectrum. Our analysis is based on Effective Field Theory of inflation that…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-16 Abhishek Naskar , Supratik Pal

I adopt a formalism previously developed by Catelan and Theuns (CT) in order to estimate the impact of primordial non-Gaussianity on the quasi-linear spin growth of cold dark matter protostructures. A variety of bispectrum shapes are…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 C. Fedeli

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 compute the non-Gaussianity of the curvature perturbation generated by ekpyrotic collapse with multiple fields. The transition from the multi-field scaling solution to a single-field dominated regime converts initial isocurvature field…

High Energy Physics - Theory · Physics 2009-04-29 Kazuya Koyama , Shuntaro Mizuno , Filippo Vernizzi , David Wands

Evolution of power spectrum is studied for non-Gaussian models of structure formation. We generalize the dark-matter-approach to these models and find that the evolved spectrum at weakly nonlinear regime is mainly determined by a simple…

Astrophysics · Physics 2009-11-06 Naoki Seto

We characterise the primordial perturbations produced due to both inflaton and curvaton fluctuations in models where the curvaton has a quadratic, cosine or hyperbolic potential, and the inflaton potential is characterised by the usual…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 José Fonseca , David Wands

We study the effects of a general type of features of the inflaton potential on the spectrum and bispectrum of primordial curvature perturbations. These features correspond to a discontinuity in the $n$-th order derivative of the potential…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-25 Alexander Gallego Cadavid

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

The late-time effect of primordial non-Gaussianity offers a window into the physics of inflation and the very early Universe. In this work we study the consequences of a particular class of primordial non-Gaussianity that is fully…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-09 G. A. Peña , G. N. Candlish

Since a positive future detection of non-linearity in the cosmic microwave background anisotropy pattern might allow to descriminate among different mechanisms giving rise to cosmological adiabatic perturbations, we study the evolution of…

High Energy Physics - Phenomenology · Physics 2010-02-10 N. Bartolo , S. Matarrese , A. Riotto

We explore the use of galaxy bispectrum induced by the nonlinear gravitational evolution as a possible probe to test general scalar-tensor theories with second-order equations of motion. We find that time dependence of the leading…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-20 Daisuke Yamauchi , Shuichiro Yokoyama , Hiroyuki Tashiro

In this paper we consider how non-Gaussianity of the primordial density perturbation and the amplitude of gravitational waves from inflation can be used to determine parameters of the curvaton scenario for the origin of structure. We show…

Cosmology and Nongalactic Astrophysics · Physics 2011-03-22 José Fonseca , David Wands
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