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The theory and methodology is developed to compute the bispectrum in warm inflation, leading to results for the non-linearity parameter and the shape of the bispectrum. Particular attention is paid to the study of the bispectrum in the…

Cosmology and Nongalactic Astrophysics · Physics 2014-12-10 Mar Bastero-Gil , Arjun Berera , Ian G. Moss , Rudnei O. Ramos

We derive a fast way for measuring primordial non-Gaussianity in a nearly full-sky map of the cosmic microwave background. We find a cubic combination of sky maps combining bispectrum configurations to capture a quadratic term in primordial…

Astrophysics · Physics 2009-11-07 Eiichiro Komatsu , David N. Spergel , Benjamin D. Wandelt

In this review, we discuss how non-Gaussianity of cosmological perturbations arises from inflation. After introducing the in-in formalism to calculate the $n$-point correlation function of quantum fields, we present the computation of the…

High Energy Physics - Theory · Physics 2014-11-20 Kazuya Koyama

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

We compute a novel type of large non-Gaussianity due to small periodic features in general single field inflationary models. We show that the non-Bunch-Davies vacuum component generated by features, although has a very small amplitude, can…

High Energy Physics - Theory · Physics 2010-12-09 Xingang Chen

The lensing convergence field describing the weak lensing effect of the Cosmic Microwave Background (CMB) radiation is expected to be subject to mild deviations from Gaussianity. We perform a suite of full-sky lensing simulations using ray…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-18 Jan Hamann , Yuqi Kang

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

Due to gravitational instability, an initially Gaussian density field develops non-Gaussian features as the Universe evolves. The most prominent non-Gaussian features are massive haloes, visible as clusters of galaxies. The distortion of…

Astrophysics · Physics 2015-06-24 Guido Kruse , Peter Schneider

Spatial fields in the Earth and environmental sciences are often available at multiple scales or resolutions. While coarse-scale data (e.g., from global circulation models) are often abundant, they lack the local detail provided by…

Methodology · Statistics 2026-04-01 Alejandro Calle-Saldarriaga , Paul F. V. Wiemann , Matthias Katzfuss

This paper presents and investigates non-Gaussian perturbations for the warm k-inflation model that is driven by pure kinetic energy. The two complementary components of the overall non-Gaussianity are the three-point and four-point…

General Relativity and Quantum Cosmology · Physics 2023-06-28 Chao-Qun Shen , Xiao-Min Zhang , Zhi-Peng Peng , He Liu , Xi-Bin Li , Peng-Cheng Chu

We develop a class of nearest-neighbor mixture models that provide direct, computationally efficient, probabilistic modeling for non-Gaussian geospatial data. The class is defined over a directed acyclic graph, which implies conditional…

Methodology · Statistics 2022-06-28 Xiaotian Zheng , Athanasios Kottas , Bruno Sansó

Corrections induced by primordial non-Gaussianity to the linear halo bias can be computed from a peak-background split or the widespread local bias model. However, numerical simulations clearly support the prediction of the former, in which…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Vincent Desjacques , Jinn-Ouk Gong , Antonio Riotto

Nonlinear cosmological fields like galaxy density and lensing convergence can be approximately related to Gaussian fields via analytic point transforms. The lognormal transform (LN) has been widely used and is a simple example of a function…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-08 Kunhao Zhong , Gary Bernstein , Supranta S. Boruah , Bhuvnesh Jain , Sanjit Kobla

Quantifying uncertainty in future climate projections is hindered by the prohibitive computational cost of running physical climate models, which severely limits the availability of training data. We propose a data-efficient framework for…

Methodology · Statistics 2026-02-27 Johannes Brachem , Paul F. V. Wiemann , Matthias Katzfuss

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

It is well known that the power spectrum is not able to fully characterize the statistical properties of non-Gaussian density fields. Recently, many different statistics have been proposed to extract information from non-Gaussian…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-11 Core Francisco Park , Erwan Allys , Francisco Villaescusa-Navarro , Douglas P. Finkbeiner

We investigate the complex Gaussian as well as non-Gaussian distributed random analytical and entire functions (complex entire random field) and calculate their domain of definiteness (radius of convergence) as well as some important…

Complex Variables · Mathematics 2020-11-03 Maria Rosaria Formica , Eugeny Ostrovsky , Leonid Sirota

The integration of physical relationships into stochastic models is of major interest e.g. in data assimilation. Here, a multivariate Gaussian random field formulation is introduced, which represents the differential relations of the…

Applications · Statistics 2018-02-14 Rüdiger Hewer , Petra Friederichs , Andreas Hense , Martin Schlather

We address the dual challenge of estimating deviations from Gaussianity arising in models of the Early Universe, whilst retaining information necessary to assess whether a detection of non-Gaussianity is primordial. We do this by…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Dipak Munshi , Alan Heavens

[Abridged]: A detection or nondetection of primordial non-Gaussianity by using the CMB data is crucial not only to discriminate inflationary models but also to test alternative scenarios. Non-Gaussianity offers, therefore, a powerful probe…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-14 A. Bernui , M. J. Reboucas