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A multispecies, collisionless plasma is modeled by the Vlasov-Poisson system. Assuming that the electric field decays with sufficient rapidity as $t \to\infty$, we show that the velocity characteristics and spatial averages of the particle…

Analysis of PDEs · Mathematics 2022-01-25 Stephen Pankavich

Properties of $\sim$ 6 000 Ly-$\alpha$ absorbers observed in 19 high resolution spectra of QSOs are investigated using the model of formation and evolution of DM structure elements based on the Zel'dovich theory. This model asserts that…

Astrophysics · Physics 2009-11-11 M. Demianski , A. G. Doroshkevich , V. I. Turchaninov

This paper is concerned with the asymptotic behavior of small data solutions to the three-dimensional Vlasov-Maxwell system in the exterior of a light cone. The plasma does not have to be neutral and no compact support assumptions are…

Analysis of PDEs · Mathematics 2020-12-14 Léo Bigorgne

It is shown how quantum fluctuations of the radiation during the contraction era of a CBE (Comes Back Empty) cyclic cosmology can provide density fluctuations which re-enter the horizon during the subsequent expansion era and at lowest…

General Relativity and Quantum Cosmology · Physics 2016-05-25 Paul Howard Frampton

The evolution of small scale cosmological perturbations is carefully re-examined. Through the interaction with photons via electrons, baryon perturbations show interesting behavior in some physical scales. Characteristic features of the…

Astrophysics · Physics 2009-10-30 Kazuhiro Yamamoto , Naoshi Sugiyama , Humitaka Sato

A model-independent determination of the primordial power spectrum of matter density fluctuations could uniquely probe physics of the very early universe, and provide powerful constraints on inflationary models. We parametrize the…

Astrophysics · Physics 2009-10-31 Yun Wang , Grant J. Mathews

Many scaling relations are observed for self-gravitating systems in the universe. We explore the consistent understanding of them from a simple principle based on the proposal that the collision-less dark matter fluid terns into a turbulent…

Astrophysics · Physics 2010-02-04 Akika Nakamichi , Masahiro Morikawa

We obtain the non-linear relation between cosmological density and velocity perturbations by examining their joint dynamics in a two dimensional density-velocity divergence phase space. We restrict to spatially flat cosmologies consisting…

Cosmology and Nongalactic Astrophysics · Physics 2013-01-08 Sharvari Nadkarni-Ghosh

We consider the relativistic Vlasov-Maxwell system in three dimensions and study the limiting asymptotic behavior as $t \to \infty$ of solutions launched by small, compactly supported initial data. In particular, we prove that such…

Analysis of PDEs · Mathematics 2024-03-12 Stephen Pankavich , Jonathan Ben-Artzi

We provide predictions on small-scale cosmological density power spectrum from supernova lensing dispersion. Parameterizing the primordial power spectrum with running $\alpha$ and running of running $\beta$ of the spectral index, we exclude…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-11 Ido Ben-Dayan , Ryuichi Takahashi

We perform a cosmological analysis in which we allow the primordial power spectrum of scalar perturbations to assume a shape that is different with respect to the usual power-law, arising from the simplest models of cosmological inflation.…

Cosmology and Nongalactic Astrophysics · Physics 2016-06-22 Stefano Gariazzo

We study a system of hard-core particles sliding downwards on a fluctuating one-dimensional surface which is characterized by a dynamical exponent $z$. In numerical simulations, an initially random particle density is found to coarsen and…

Statistical Mechanics · Physics 2009-10-31 Dibyendu Das , Mustansir Barma

We critically examine how the evolution of the matter density field in cosmological simulations is affected by details of setting up initial conditions. We show that it is non-trivial to realise an initial distribution of matter in…

Astrophysics · Physics 2009-11-07 Naoki Yoshida , Naoshi Sugiyama , Lars Hernquist

Building upon the recent pioneering work by Mazenko and by Das and Mazenko, we develop a microscopic, non-equilibrium, statistical field theory for initially correlated canonical ensembles of classical microscopic particles obeying…

Statistical Mechanics · Physics 2019-04-08 Matthias Bartelmann , Felix Fabis , Daniel Berg , Elena Kozlikin , Robert Lilow , Celia Viermann

This paper investigates the asymptotic behavior of the Helmholtz free energy of mixtures at small compressibility. We start from a general representation for the local free energy that is valid in stable subregions of the phase diagram. On…

Mathematical Physics · Physics 2021-04-20 Dieter Bothe , Wolfgang Dreyer , Pierre-Etienne Druet

A systematic asymptotic expansion is developed for the gravitational wave degrees of freedom of a class of expanding, vacuum Gowdy cosmological spacetimes. In the wave map description of these models, the evolution of the gravitational wave…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Beverly K. Berger

We study a phenomenological dark matter model described as a collisionless relativistic kinetic gas in a spatially flat Friedmann-Lema\^itre-Robertson-Walker universe. After normalization to the observed present-day dark matter abundance,…

General Physics · Physics 2026-02-10 Francisco X. Linares Cedeño , Ulises Nucamendi , Olivier Sarbach

We study a two-dimensional spinless particle in a disordered gaussian magnetic field with short time fluctuations, by means of the evolution equation for the density matrix $<x^{(1)} |\hat{\rho} (t)| x^{(2)}>$; in this description the two…

Statistical Mechanics · Physics 2009-10-31 V. G. Benza , B. Cardinetti

If a magnetic field is frozen into a plasma that undergoes spherical compression then the magnetic field B varies with the plasma density \rho according to B \propto \rho^{2/3}. In the gravitational collapse of cosmological density…

Astrophysics · Physics 2007-05-23 Emma J. King , Peter Coles

We present a new approach to model the gravitational dynamics of large-scale structures. Instead of solving the equations of motion up to a finite perturbative order or building phenomenological models, we follow the evolution of the…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-01 Patrick Valageas