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We present a non-perturbative method for calculating the abundance of primordial black holes given an arbitrary one-point probability distribution function for the primordial curvature perturbation, $P(\zeta)$. A non-perturbative method is…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-01 Andrew D. Gow , Hooshyar Assadullahi , Joseph H. P. Jackson , Kazuya Koyama , Vincent Vennin , David Wands

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

Large-scale clustering of highly biased tracers of large-scale structure has emerged as one of the best observational probes of primordial non-Gaussianity of the local type (i.e. f_{NL}^{local}). This type of non-Gaussianity can be…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Kendrick M. Smith , Marilena LoVerde

We review models which generate a large non-Gaussianity of the local form. We first briefly consider three models which generate the non-Gaussianity either at or after the end of inflation; the curvaton scenario, modulated (p)reheating and…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-13 Christian T. Byrnes , Ki-Young Choi

The presence of multiple fields during inflation might seed a detectable amount of non-Gaussianity in the curvature perturbations, which in turn becomes observable in present data sets like the cosmic microwave background (CMB) or the large…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-27 Sebastian Dorn , Erandy Ramirez , Kerstin E. Kunze , Stefan Hofmann , Torsten A. Enßlin

By assuming the field seeding the curvature perturbations $ \zeta $ is a dynamically arising condensate, we are able to derive the relation $ f_{NL} ^2 \simeq 10^8 H / M_c $ between the non-Gaussianity parameter $ f_{NL} $ and the ratio of…

Cosmology and Nongalactic Astrophysics · Physics 2010-10-25 G. L. Alberghi , R. Casadio

We propose a method to probe higher-order correlators of the primordial density field through the inhomogeneity of local non-Gaussian parameters, such as f_NL, measured within smaller patches of the sky. Correlators between n-point…

Cosmology and Nongalactic Astrophysics · Physics 2012-09-28 Christian T. Byrnes , Sami Nurmi , Gianmassimo Tasinato , David Wands

While usually cosmological initial conditions are assumed to be Gaussian, inflationary theories can predict a certain amount of primordial non-Gaussianity which can have an impact on the statistical properties of the lensing observables. In…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 F. Pace , L. Moscardini , M. Bartelmann , E. Branchini , K. Dolag , M. Grossi , S. Matarrese

Non-Gaussian statistics in the distribution of large scale structure, and in temperature fluctuations of the cosmic microwave background, can be used to constrain inflationary models. Data on the cosmic microwave background from Planck…

General Relativity and Quantum Cosmology · Physics 2018-03-06 Nick Woods

We use the local curvature to investigate the possible existence of non-Gaussianity/asymmetry in the WMAP data. Considering the full sky we find results which are consistent with the Gaussian assumption. However, strong non-Gaussian…

Astrophysics · Physics 2010-04-06 Frode K. Hansen , Paolo Cabella , Domenico Marinucci , Nicola Vittorio

We simulate CMB maps including non-Gaussianity arising from cubic order perturbations of the primordial gravitational potential, characterized by the non-linearity parameter $g_{NL}$. The maps are used to study the characteristic nature of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Pravabati Chingangbam , Changbom Park

We extend the formalism to calculate non-Gaussianity of primordial curvature perturbations produced by preheating in the presence of a light scalar field. The calculation is carried out in the separate universe approximation using the…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-31 Pulkit S. Ghoderao , Arttu Rajantie

We extend the \delta N formalism so that it gives all of the stochastic properties of the primordial curvature perturbation \zeta if the initial field perturbations are gaussian. The calculation requires only the knowledge of some family of…

Astrophysics · Physics 2011-06-08 David H. Lyth , Yeinzon Rodriguez

In [1], a most general higher curvature non-local gravity action was derived that admits a particular $R^2$-like inflationary solution predicting the spectral index of primordial scalar perturbations $n_s(N)\approx 1-\frac{2}{N}$, where $N$…

High Energy Physics - Theory · Physics 2023-07-18 Alexey S. Koshelev , K. Sravan Kumar , Alexei A. Starobinsky

This is a review of models of inflation and of their predictions for the primordial non-Gaussianity in the density perturbations which are thought to be at the origin of structures in the Universe. Non-Gaussianity emerges as a key…

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

We investigate the clustering of halos in cosmological models starting with general local-type non-Gaussian primordial fluctuations. We employ multiple Gaussian fields and add local-type non-Gaussian corrections at arbitrary order to cover…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Takahiro Nishimichi

We classify models generating large local-type non-Gaussianity into some categories by using some "consistency relations" among the non-linearity parameters f_{NL}^{local}, \tau_{NL}^{local} and g_{NL}^{local}, which characterize the size…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-02 Teruaki Suyama , Tomo Takahashi , Masahide Yamaguchi , Shuichiro Yokoyama

We analyze primordial non-gaussianities in presence of an ultra-slow phase during the inflationary dynamics, focusing on scenarios relevant for the production of primordial black holes. We compute the three-point correlation function of…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-25 Marco Taoso , Alfredo Urbano

In this note we examine the derivation of scale-dependent bias due to primordial non-Gaussianity of the local type in the context of general relativity. We justify the use of the Poisson equation in general relativistic perturbation theory…

Cosmology and Nongalactic Astrophysics · Physics 2009-07-30 David Wands , Anze Slosar

Long-short mode coupling during inflation, encoded in the squeezed bispectrum of curvature perturbations, induces a dependence of the local, small-scale power spectrum on long-wavelength perturbations, leading to a scale-dependent halo…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-19 Giovanni Cabass , Enrico Pajer , Fabian Schmidt