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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 curvaton scenario, the curvature perturbation is generated after inflation at the curvaton decay, which may have a prominent non-Gaussian effect. For a model with a non-trivial kinetic term, an enhanced curvature perturbation on a…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-22 Shi Pi , Misao Sasaki

We revisit how super-Hubble cosmological fluctuations induce, at any time in the cosmic history, a non-vanishing spatial curvature of the local background metric. The random nature of these fluctuations promotes the curvature density…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-06 Baptiste Blachier , Pierre Auclair , Christophe Ringeval , Vincent Vennin

It is possible that the primordial non-Gaussianity is dominated by the higher order terms, such as that set by $g_{NL}$, not $f_{NL}$. In this paper we derive the spectral index and running of $g_{NL}$ from a single isocurvature scalar…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Qing-Guo Huang

We discuss nontrivial features of the large scale structure of the universe in the simplest curvaton model proposed in our paper astro-ph/9610219. The amplitude of metric perturbations in this model takes different values in different parts…

Astrophysics · Physics 2009-11-11 Andrei Linde , Viatcheslav Mukhanov

We consider possible scale-dependence of the non-linearity parameter f_NL in local and quasi-local models of non-Gaussian primordial density perturbations. In the simplest model where the primordial perturbations are a quadratic local…

Cosmology and Nongalactic Astrophysics · Physics 2010-06-15 Christian T. Byrnes , Sami Nurmi , Gianmassimo Tasinato , David Wands

Employing the perturbative treatment of gravitational clustering, we discuss possible effects of primordial non-Gaussianity on the matter power spectrum. As gravitational clustering develops, the coupling between different Fourier modes of…

Astrophysics · Physics 2009-01-08 Atsushi Taruya , Kazuya Koyama , Takahiko Matsubara

The associations of the angular positions of background quasars with foreground galaxies, clusters of galaxies and quasars are often attributed to the statistical lensing by gravitational potentials of the matter along the lines of sight,…

Astrophysics · Physics 2009-10-28 Xiang-Ping Wu , Li-Zhi Fang , Zonghong Zhu , Bo Qin

It is known than the inclusion of spatial curvature can modify the evolution of matter perturbations and affect the Large Scale Structure (LSS) formation. We quantify the effects of the non-zero space curvature in terms of LSS formation for…

General Relativity and Quantum Cosmology · Physics 2020-12-08 Jhonny A. Agudelo Ruiz , Júlio C. Fabris , Alan M. Velasquez-Toribio , Ilya L. Shapiro

We propose that dark matter (DM) possesses a quadratic equation of state, which becomes significant at high densities, altering the Universe's evolution during its early stages. We derive the modified background evolution equations for the…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-02 Kazem Rezazadeh , Ebrahim Yusofi , Alireza Talebian

The gravitational evolution of the genus of the density field in large-scale structure is analytically studied in a weakly nonlinear regime using second-order perturbation theory. Weakly nonlinear evolution produces asymmetry in the…

Astrophysics · Physics 2009-10-22 T. Matsubara

A recent paper [CGT] studies the evolution of star-shaped mean convex hypersurfaces of the Euclidean space by a class of nonhomogeneous expanding curvature flows. In the present paper we consider the same problem in the real, complex and…

Differential Geometry · Mathematics 2020-10-08 Giuseppe Pipoli

We consider a curvaton scenario in which the late-time domination and the generation of the curvature perturbation is achieved by a non-oscillatory (NO) curvaton potential. Instead of considering the conventional curvaton oscillation, we…

High Energy Physics - Phenomenology · Physics 2008-11-26 Tomohiro Matsuda

We investigate the characteristic modifications in the evolving cosmological perturbations when dark energy interacts with dust-like matter, causing the latter's background energy density fall off with time faster than usual. Focusing in…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-06 Mohit Kumar Sharma , Sourav Sur

On large scales a nonlinear transformation of matter density field can be viewed as a biased tracer of the density field itself. A nonlinear transformation also modifies the redshift space distortions in the same limit, giving rise to a…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Uros Seljak

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

In this paper we examine how primordial non-Gaussianity contributes to nonlinear perturbative orders in the expansion of the density field at large scales in the matter dominated era. General Relativity is an intrinsically nonlinear theory,…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-27 Hedda Alice Gressel , Marco Bruni

We introduce an alternative parametrisation for the scale dependence of the non-linearity parameter $f_{\rm NL}$ in quasi-local models of non-Gaussianity. Our parametrisation remains valid when $f_{\rm NL}$ changes sign, unlike the commonly…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-02 Christian T. Byrnes , Ewan R. M. Tarrant

Primordial black-hole formation depends exponentially on the far tail of the primordial curvature-perturbation distribution. That sensitivity makes the small-scale collapse problem a sharp probe of primordial non-Gaussianity. We study the…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-16 Owais Farooq , Romana Zahoor , Balungi Francis

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