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Related papers: A critical threshold for the cosmological Euler-Po…

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We provide a complete description of the critical threshold phenomena for the two-dimensional localized Euler-Poisson equations, introduced by the authors in [Liu & Tadmor, Comm. Math Phys., To appear]. Here, the questions of global…

Analysis of PDEs · Mathematics 2007-05-23 Hailiang Liu , Eitan Tadmor

We attempt to find new symmetries in the space-time structure, leading to a modified gravitation at large length scales, which provides the foundations of a quantum gravity at very low energies. This search begins by considering a unified…

General Relativity and Quantum Cosmology · Physics 2007-09-13 Claudio Nassif

We investigate a class of cosmological solutions of Einstein's field equations in higher dimensions with a cosmological constant and an ideal fluid matter distribution as a source. We discuss the dynamical evolution of the universe subject…

General Relativity and Quantum Cosmology · Physics 2013-02-15 Ozgur Akarsu , Tekin Dereli

We investigate the three-dimensional compressible Euler-Maxwell system, a model for simulating the transport of electrons interacting with propagating electromagnetic waves in semiconductor devices. First, we show the global well-posedness…

Analysis of PDEs · Mathematics 2024-07-02 Timothée Crin-Barat , Yue-Jun Peng , Ling-Yun Shou , Jiang Xu

We present the particular case of the Stephani solution for shear-free perfect fluid with uniform energy density and non-uniform pressure. Such models appeared as possible alternative to the consideration of the exotic forms of matter like…

General Relativity and Quantum Cosmology · Physics 2020-01-22 Elena Kopteva , Irina Bormotova , Maria Churilova , Zdenek Stuchlik

Context. Explaining the accelerated expansion of the Universe is one of the fundamental challenges in physics today. Cosmography provides information about the evolution of the universe derived from measured distances, assuming only that…

Cosmology and Nongalactic Astrophysics · Physics 2016-10-05 Marek Demianski , Ester Piedipalumbo , Disha Sawant , Lorenzo Amati

This paper is the third part of a trilogy dedicated to the following problem: given spherically symmetric characteristic initial data for the Einstein-Maxwell-scalar field system with a cosmological constant $\Lambda$, with the data on the…

General Relativity and Quantum Cosmology · Physics 2017-05-22 João L. Costa , Pedro M. Girão , José Natário , Jorge Drumond Silva

Due to the nonlinearity of the Euler{Poisson equations, it is possible that the nonlinear Jeans instability may lead to a faster density growing rate than the rate in the standard theory of linearized Jeans instability, which motivates us…

Analysis of PDEs · Mathematics 2022-02-15 Chao Liu , Yiqing Shi

The dynamics of cosmological gravitating system is governed by the Euler and the Poisson equations. Tiny fluctuations near the big bang singularity are amplified by gravitational instability into the observed structure today. Given the…

Astrophysics · Physics 2008-11-26 Adi Nusser

It is generally believed that one cannot obtain a large Universe from quantum cosmological models without an inflationary phase in the classical expanding era because the typical size of the Universe after leaving the quantum regime should…

General Relativity and Quantum Cosmology · Physics 2009-04-29 Nelson Pinto-Neto

We study noncommutative classical Friedmann-Robertson-Walker cosmological models. The constant curvature of the spatial sections can be positive ($k=1$), negative ($k=-1$) or zero ($k=0$). The matter is represented by a perfect fluid with…

General Relativity and Quantum Cosmology · Physics 2017-01-06 G. Oliveira-Neto , A. R. Vaz

Scenarios of cosmological evolution having inflationary stages are studied by using equations of state (EoS) inspired by the quark bag model. A crucial point is the existence of states where the specific enthalpy of the cosmological fluid…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-30 L. L. Jenkovszky , V. I. Zhdanov , E. J. Stukalo

A linear relationship between the Hubble expansion parameter and the time derivative of the scalar field is assumed in order to derive exact analytic cosmological solutions to Einstein's gravity with two fluids: a barotropic perfect fluid…

General Relativity and Quantum Cosmology · Physics 2009-09-29 Olga Arias , Tame Gonzalez , Israel Quiros

We introduce a new universal framework describing fluctuations and correlations in quantum and classical many-body systems, at the Euler hydrodynamic scale of space and time. The framework adapts the ideas of the conventional macroscopic…

Statistical Mechanics · Physics 2023-10-04 Benjamin Doyon , Gabriele Perfetto , Tomohiro Sasamoto , Takato Yoshimura

The regime of exponentially fast expansion in 5D cosmological models was investigated. Many limit cases was also studied. It was shown that there is a possibility to particle creation in a static 4D spacetime if it embedded in an bulk with…

General Relativity and Quantum Cosmology · Physics 2012-11-14 Wagner Utiel

Fluid cosmologies are consistent with the generally accepted observational evidence during intermediate and late times, and they need not have singular behavior in primordial times. A general form for fluid cosmology consistent with…

General Relativity and Quantum Cosmology · Physics 2009-01-20 James Lindesay

We study the growth of perturbations in an expanding Newtonian universe with Bose-Einstein condensate dark matter. We first ignore special relativistic effects and derive a differential equation governing the evolution of the density…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Pierre-Henri Chavanis

Time evolution of modes of density contrast, in particular the growing modes, dictate the structure formation in Universe. In this paper we explicitly show how (spatial) Non-Commutativity (NC) can affect the behavior of the modes, that is…

High Energy Physics - Theory · Physics 2018-11-07 Arpan Krishna Mitra , Rabin Banerjee , Subir Ghosh

A linear evolution of the cosmological scale factor is a feature in several models designed to solve the cosmological constant problem via a coupling between scalar or tensor classical fields to the space-time curvature as well as in some…

Astrophysics · Physics 2009-11-07 Deepak Jain , Abha Dev , J. S. Alcaniz

We study the classical and quantum models of a Friedmann-Robertson-Walker (FRW) cosmology, coupled to a perfect fluid, in the context of the scalar-metric gravity. Using the Schutz' representation for the perfect fluid, we show that, under…

General Relativity and Quantum Cosmology · Physics 2014-11-20 Babak Vakili