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We have studied primordial non-Gaussian features from a model of potential driven single field DBI Galileon inflation. We have computed the bispectrum from the three point correlation function considering all possible cross correlation…

High Energy Physics - Theory · Physics 2015-06-08 Sayantan Choudhury , Supratik Pal

We present perturbative error bounds for the non-Markovian dynamics of observables in open quantum systems interacting with Gaussian environments, governed by a general Liouville dynamics. This extends the work of [Mascherpa et al., Phys.…

Quantum Physics · Physics 2025-12-16 Zhen Huang , Yuanran Zhu , Gunhee Park , Lin Lin

Gas-poor galaxies can be modelled as composite collisionless stellar systems, with a dark matter halo and one or more stellar components, representing different stellar populations. The dynamical evolution of such composite systems is often…

Astrophysics of Galaxies · Physics 2021-03-24 Carlo Nipoti , Giacomo Cherchi , Giuliano Iorio , Francesco Calura

A simple method is presented for the rapid simulation of statistically-isotropic non-Gaussian maps of CMB temperature fluctuations with a given power spectrum and analytically-calculable bispectrum and higher-order polyspectra. The…

Astrophysics · Physics 2009-11-10 Graca Rocha , M. P. Hobson , Sarah Smith , Pedro Ferreira , Anthony Challinor

We develop the effective theory of large-scale structure for non-Gaussian initial conditions. The effective stress tensor in the dark matter equations of motion contains new operators, which originate from the squeezed limit of the…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-18 Valentin Assassi , Daniel Baumann , Enrico Pajer , Yvette Welling , Drian van der Woude

We develop a theory of nonlinear cosmological perturbations on superhorizon scales for a single scalar field with a general kinetic term and a general form of the potential. We employ the ADM formalism and the spatial gradient expansion…

Cosmology and Nongalactic Astrophysics · Physics 2010-06-24 Yu-ichi Takamizu , Shinji Mukohyama , Misao Sasaki , Yoshiharu Tanaka

We study the scale-dependence of halo bias in generic (non-local) primordial non-Gaussian (PNG) initial conditions of the type motivated by inflation, parametrized by an arbitrary quadratic kernel. We first show how to generate non-local…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-30 Roman Scoccimarro , Lam Hui , Marc Manera , K. C. Chan

We introduce an exact Bayesian approach to search for non-Gaussianity of local type in Cosmic Microwave Background (CMB) radiation data. Using simulated CMB temperature maps, the newly developed technique is compared against the…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-15 Franz Elsner , Benjamin D. Wandelt

In the framework of inflationary models with non-vacuum initial states for cosmological perturbations, we study non-Gaussian signatures on the cosmic microwave background radiation produced by a broken-scale-invariant model which…

Astrophysics · Physics 2019-04-03 Alejandro Gangui

We present trispectrum estimation methods which can be applied to general non-separable primordial and CMB trispectra. We present a general optimal estimator for the connected part of the trispectrum, for which we derive a quadratic term to…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 D. M. Regan , E. P. S. Shellard , J. R. Fergusson

Nonparametric Bayesian approaches based on Gaussian processes have recently become popular in the empirical learning community. They encompass many classical methods of statistics, like Radial Basis Functions or various splines, and are…

Data Analysis, Statistics and Probability · Physics 2007-05-23 J. C. Lemm

The non-Gaussian distribution of primordial perturbations has the potential to reveal the physical processes at work in the very early Universe. Local models provide a well-defined class of non-Gaussian distributions that arise naturally…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 David Wands

In this paper we will consider the problem of the numerical simulation of non-Gaussian, scalar random fields with a prescribed correlation structure provided either by a theoretical model or computed on a set of observational data.…

Astrophysics · Physics 2009-11-06 Roberto Vio , Paola Andreani , Willem Wamsteker

We give a concise formula for the non-Gaussianity of the primordial curvature perturbation generated on super-horizon scales in multi-scalar inflation model without assuming slow-roll conditions. This is an extension of our previous work.…

Astrophysics · Physics 2013-01-11 Shuichiro Yokoyama , Teruaki Suyama , Takahiro Tanaka

Primordial non-Gaussianity has emerged as one of the most promising probes of the inflationary epoch. While the cosmic microwave background and large-scale halo bias currently provide the most stringent constraints on the non-Gaussian…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Marilena LoVerde , Kendrick M. Smith

The initial conditions for Newtonian $N$-body simulations are usually generated by applying the Zel'dovich approximation to the initial displacements of the particles using an initial power spectrum of density fluctuations generated by an…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-23 Christian Fidler , Cornelius Rampf , Thomas Tram , Robert Crittenden , Kazuya Koyama , David Wands

We consider gravitational clustering from primoridal non-Gaussian fluctuations provided by a $\chi^2$ model, as motivated by some models of inflation. The emphasis is in signatures that can be used to constrain this type of models from…

Astrophysics · Physics 2009-10-31 Roman Scoccimarro

Developing suitable approximate models for analyzing and simulating complex nonlinear systems is practically important. This paper aims at exploring the skill of a rich class of nonlinear stochastic models, known as the conditional Gaussian…

Numerical Analysis · Mathematics 2022-06-01 Nan Chen , Yingda Li , Honghu Liu

The $\delta N$ formalism has been the major computational tool to study the superhorizon evolution of the scalar type perturbation sourced by scalar fields. Recently, this formalism was generalized to compute an arbitrary scalar, vector,…

General Relativity and Quantum Cosmology · Physics 2024-09-30 Takahiro Tanaka , Yuko Urakawa

Motivated by the properties of early universe scenarios that produce observationally large local non-Gaussianity, we perform N-body simulations with non-Gaussian initial conditions from a generalized local ansatz. The bispectra are…

Cosmology and Nongalactic Astrophysics · Physics 2011-03-18 Sarah Shandera , Neal Dalal , Dragan Huterer