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Related papers: Velocity Differences as a Probe of Non--Gaussian D…

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Recent advances in single particle tracking and supercomputing techniques demonstrate the emergence of normal or anomalous, viscoelastic diffusion in conjunction with non-Gaussian distributions in soft, biological, and active matter…

Statistical Mechanics · Physics 2018-01-23 Jakub Ślęzak , Ralf Metzler , Marcin Magdziarz

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

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

Generative modeling of spatio-temporal fields is crucial for a variety of applications, including stochastic weather generators and climate-model surrogates. However, many such fields exhibit complex dependence structures that vary across…

Methodology · Statistics 2026-05-06 Carrie J. Lei-Cramer , Jian Cao , Matthias Katzfuss

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

Non-Gaussian diffusion is commonly considered as a result of fluctuating diffusivity, which is correlated in time or in space or both. In this work, we investigate the non-Gaussian diffusion in static disordered media via a quenched trap…

Statistical Mechanics · Physics 2018-04-25 Liang Luo , Ming Yi

We study how the two-point density correlation properties of a point particle distribution are modified when each particle is divided, by a stochastic process, into an equal number of identical "daughter" particles. We consider generically…

Statistical Mechanics · Physics 2009-11-13 Andrea Gabrielli , Michael Joyce

The mass density distribution of Newtonian self-gravitating systems is studied analytically in field theoretical method. Modeling the system as a fluid in hydrostatical equilibrium, we apply Schwinger's functional derivative on the average…

Astrophysics of Galaxies · Physics 2021-07-21 Yang Zhang , Qing Chen , Shuguang Wu

Diffusion Models (DMs) are powerful generative models that add Gaussian noise to the data and learn to remove it. We wanted to determine which noise distribution (Gaussian or non-Gaussian) led to better generated data in DMs. Since DMs do…

Machine Learning · Computer Science 2023-04-13 Alexia Jolicoeur-Martineau , Kilian Fatras , Ke Li , Tal Kachman

Following the discovery of the CMB, the hot big-bang model has become the standard cosmological model. In this theory, small primordial fluctuations are subsequently amplified by gravity to form the large-scale structure seen today.…

Astrophysics · Physics 2015-06-24 Licia Verde

The anisotropies in the galaxy two-point correlation function measured from redshift surveys exhibits deviations from the predictions of the linear theory of redshift space distortion on scales as large 20 Mpc/h where we expect linear…

Astrophysics · Physics 2009-11-10 Biswajit Pandey , Somnath Bharadwaj

Local-type primordial non-Gaussianity couples statistics of the curvature perturbation \zeta on vastly different physical scales. Because of this coupling, statistics (i.e. the polyspectra) of \zeta in our Hubble volume may not be…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Marilena LoVerde , Elliot Nelson , Sarah Shandera

I derive a nonlinear local relation between the redshift-space density field and the real-space velocity field. The relation accounts for radial character of redshift distortions, and it is not restricted to the limit of the distant…

Astrophysics · Physics 2015-06-24 Michal Chodorowski

The uniform longitudinal flow is characterized by a linear longitudinal velocity field $u_x(x,t)=a(t)x$, where $a(t)={a_0}/({1+a_0t})$ is the strain rate, a uniform density $n(t)\propto a(t)$, and a uniform granular temperature $T(t)$.…

Soft Condensed Matter · Physics 2018-09-10 Antonio Astillero , Andrés Santos

We demonstrate that the Einstein relation for the diffusion of a particle in the random energy landscape with the Gaussian density of states is an exclusive 1D property and does not hold in higher dimensions. We also consider the analytical…

Disordered Systems and Neural Networks · Physics 2020-02-21 S. V. Novikov

A compressible flow characterized by a velocity field $u_x(x,t)=ax/(1+at)$ is analyzed by means of the Boltzmann equation and the Bhatnagar-Gross-Krook kinetic model. The sign of the control parameter (the longitudinal deformation rate $a$)…

Statistical Mechanics · Physics 2007-05-23 Andres Santos

We compute the skewness of the matter distribution arising from non-linear evolution and from non-Gaussian initial perturbations. We apply our result to a very generic class of models with non-Gaussian initial conditions and we estimate…

Astrophysics · Physics 2009-12-30 Ruth Durrer , Roman Juszkiewicz , Martin Kunz , Jean-Philippe Uzan

Non-gaussianity represents the statistical signature of physical processes such as turbulence. It can also be used as a powerful tool to discriminate between competing cosmological scenarios. A canonical analysis of non-gaussianity is based…

Astrophysics · Physics 2009-10-31 O. Forni , N. Aghanim

The line-of-sight peculiar velocities are good indicators of the gravitational fluctuation of the density field. Techniques have been developed to extract cosmological information from the peculiar velocities in order to test the…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-08 Fei Qin

This work propose an application of the concept of fluctuating diffusivity to the diffusion of gas molecules in cementitious materials, particularly through a two-state fluctuating diffusivity (2SFD) model. The 2SFD model is utilized to…

Soft Condensed Matter · Physics 2023-11-28 Fumiaki Nakai , Takato Ishida
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