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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…

天体物理学 · 物理学 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…

宇宙学与河外天体物理 · 物理学 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…

宇宙学与河外天体物理 · 物理学 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,…

高能物理 - 理论 · 物理学 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…

宇宙学与河外天体物理 · 物理学 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…

宇宙学与河外天体物理 · 物理学 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…

高能物理 - 唯象学 · 物理学 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…

高能物理 - 理论 · 物理学 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…

宇宙学与河外天体物理 · 物理学 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…

宇宙学与河外天体物理 · 物理学 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…

宇宙学与河外天体物理 · 物理学 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…

高能物理 - 理论 · 物理学 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…

天体物理学 · 物理学 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…

宇宙学与河外天体物理 · 物理学 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…

宇宙学与河外天体物理 · 物理学 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…

高能物理 - 理论 · 物理学 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…

宇宙学与河外天体物理 · 物理学 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…

高能物理 - 唯象学 · 物理学 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…

宇宙学与河外天体物理 · 物理学 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…

宇宙学与河外天体物理 · 物理学 2011-03-22 José Fonseca , David Wands
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