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The fundamental "two-fluid" model for describing plasma dynamics is given by the Euler-Maxwell system, in which compressible ion and electron fluids interact with their own self-consistent electromagnetic field. We prove global stability of…

Analysis of PDEs · Mathematics 2013-03-06 Yan Guo , Alexandru D. Ionescu , Benoit Pausader

In this work we use the Euler hydrodynamic equations of fluids to study a model of galactic halos minimally coupled to a complex scalar field, which in the Newtonian limit they become the Schr\"odinger-Poisson system. Applying a Madelung…

Astrophysics of Galaxies · Physics 2017-08-23 Mario A. Rodríguez-Meza , Alberto Hernández-Almada y Tonatiuh Matos

We consider a cosmological model dominated by stiff fluid with a constant bulk viscosity. We classify all the possible cases of the universe predicted by the model and analyzing the scale factor, density as well as the curvature scalar. We…

General Relativity and Quantum Cosmology · Physics 2015-06-19 Titus K Mathew , Aswathy M B , Manoj M

We show that, for the scalar field cosmology with exponential potential, the set of values of the coupling parameter for which the solutions undergo a transient period of acceleration is much larger than the set discussed in the literature.…

General Relativity and Quantum Cosmology · Physics 2014-01-29 Mustapha Azreg-Aïnou

We propose and study a nonlocal Euler system with relaxation, which tends to a strictly hyperbolic system under the hyperbolic scaling limit. An independent proof of the local existence and uniqueness of this system is presented in any…

Analysis of PDEs · Mathematics 2020-10-07 Manas Bhatnagar , Hailiang Liu

We consider the motion of the interface separating a vacuum from an inviscid, incompressible, and irrotational fluid, subject to the self-gravitational force and neglecting surface tension, in two space dimensions. The fluid motion is…

Analysis of PDEs · Mathematics 2015-11-04 Lydia Bieri , Shuang Miao , Sohrab Shahshahani , Sijue Wu

At large scales of space and time, the nonequilibrium dynamics of local observables in extensive many-body systems is well described by hydrodynamics. At the Euler scale, one assumes that each mesoscopic region independently reaches a state…

Statistical Mechanics · Physics 2023-07-26 Benjamin Doyon , Gabriele Perfetto , Tomohiro Sasamoto , Takato Yoshimura

The late time accelerated expansion of the universe can be realized using scalar fields with given self-interacting potentials. Here we consider a straightforward approach where a three cosmic fluid mixture is assumed. The fluids are…

General Relativity and Quantum Cosmology · Physics 2018-07-25 Parth Shah , Gauranga C. Samanta , Salvatore Capozziello

In this paper, we consider the compressible Euler-Maxwell equations arising in semiconductor physics, which take the form of Euler equations for the conservation laws of mass density and current density for electrons, coupled to Maxwell's…

Analysis of PDEs · Mathematics 2015-03-17 Jiang Xu

We establish the existence of $1$-parameter families of $\epsilon$-dependent solutions to the Einstein-Euler equations with a positive cosmological constant $\Lambda >0$ and a linear equation of state $p=\epsilon^2 K \rho$, $0<K\leq 1/3$,…

General Relativity and Quantum Cosmology · Physics 2018-06-21 Chao Liu , Todd A. Oliynyk

The paper examines stochastic diffusion within an expanding space-time framework. It starts with providing a rationale for the considered model and its motivation from cosmology where the expansion of space-time is used in modelling various…

Probability · Mathematics 2023-12-22 Philip Broadbridge , Illia Donhauzer , Andriy Olenko

We prove the existence of a large class of one parameter families of solutions to the Einstein-Euler equations that depend on the singular parameter $\ep=v_T/c$ $(0<\ep < \ep_0)$, where $c$ is the speed of light, and $v_T$ is a typical…

General Relativity and Quantum Cosmology · Physics 2010-02-23 Todd A. Oliynyk

It has been argued that the small perturbations to the homogeneous and isotropic configurations of a canonical scalar field in an expanding universe do not grow. We show that this is not true in general, and clarify the root of the…

General Relativity and Quantum Cosmology · Physics 2015-09-23 Miguel Alcubierre , Axel de la Macorra , Alberto Diez-Tejedor , José M. Torres

This paper invokes a new mechanism for reducing a coupled system of fields (including Einstein's equations without a cosmological constant) to equations that possess solutions exhibiting characteristics of immediate relevance to current…

General Relativity and Quantum Cosmology · Physics 2019-11-05 Robin W. Tucker , Timothy J. Walton , Manuel Arrayás , José L. Trueba

We consider the evolution of perturbed cosmological spacetime with multiple fluids and fields in Einstein gravity. Equations are presented in gauge-ready forms, and are presented in various forms using the curvature (\Phi or \phi_\chi) and…

Astrophysics · Physics 2010-05-28 J. Hwang , H. Noh

We study the well-posedness and the spatial behavior at infinity of perfect fluid flows on $\R^d$ with initial data in a scale of weighted Sobolev spaces that allow spatial growth/decay at infinity as $|x|^\beta$ with $\beta<1/2$. In…

Analysis of PDEs · Mathematics 2021-02-11 Robert McOwen , Peter Topalov

This paper discusses the leading-order correction induced by cosmological perturbations on the average expansion rate of an expanding spacetime, containing one or many perfect fluids. The calculation is carried out up to the second order in…

General Relativity and Quantum Cosmology · Physics 2023-04-28 Vincent Comeau

A class of cosmological solutions of higher dimensional Einstein field equations with the energy-momentum tensor of a homogeneous, isotropic fluid as the source are considered with an anisotropic metric that includes the direct sum of a…

General Relativity and Quantum Cosmology · Physics 2013-10-24 Ozgur Akarsu , Tekin Dereli

The Euler Poisson equations describe important physical phenomena in many applications such as semiconductor modeling and plasma physics. This paper is to advance our understanding of critical threshold phenomena in such systems in the…

Analysis of PDEs · Mathematics 2020-10-28 Manas Bhatnagar , Hailiang Liu

We introduce a time-delay function in bulk viscosity cosmology. Even for bulk viscosity functions where closed-form solutions are known, because of the time-delay term the exact solutions are lost. Therefore in order to study the…

General Relativity and Quantum Cosmology · Physics 2022-11-23 Andronikos Paliathanasis