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We present a dark fluid model which contains the general linear equation of state including the gravitation term. The obtained spherical symmetric Euler equation and the continuity equation was investigated with the Sedov-type…

General Relativity and Quantum Cosmology · Physics 2022-09-08 Imre F. Barna , Mihály A. Pocsai , Gergely Gábor Barnaföldi

This paper deals with isothermal Euler-Poisson system which is used to model collapse of self-gravitating Newtonian star. Density dependent viscosity term is added on the right-hand side of momentum equation and it has been proved that…

Analysis of PDEs · Mathematics 2025-08-19 Marko Nedeljkov , Sanja Ružičić

The fluid model for the dark sector of the universe (darkon fluid) introduced previously in \cite{PRD} is reformulated as a modified model involving only variables from physical phase space. The Lagrangian of the model does not possess a…

High Energy Physics - Theory · Physics 2010-12-15 P. C. Stichel , W. J. Zakrzewski

We consider a self-gravitating collisionless gas as described by the Vlasov-Poisson or Einstein-Vlasov system or a self-gravitating fluid ball as described by the Euler-Poisson or Einstein-Euler system. We give a simple proof for the finite…

General Relativity and Quantum Cosmology · Physics 2013-12-16 Tobias Ramming , Gerhard Rein

We studied the Euler--Poisson equation system in the case of cylindrical symmetry with the von Neumann--Sedov--Taylor type of self-similar Ansatz and present scaling solutions. We have analyzed the scenario governed by Chaplygin's equation…

Mathematical Physics · Physics 2025-03-26 Balázs Endre Szigeti , Imre Ferenc Barna , Gergely Gábor Barnaföldi

We derive an effective gravitational potential, induced by the quantum wavefunction of a physical vacuum of a self-gravitating configuration, while the vacuum itself is viewed as the superfluid described by the logarithmic quantum wave…

General Relativity and Quantum Cosmology · Physics 2020-12-01 Konstantin G. Zloshchastiev

We consider the barotropic Euler equations in dimension d>1 with decaying density at spatial infinity. The phase portrait of the nonlinear ode governing the equation for spherically symmetric self-similar solutions has been introduced in…

Analysis of PDEs · Mathematics 2019-12-24 Frank Merle , Pierre Raphael , Igor Rodnianski , Jeremie Szeftel

In this paper we apply the approach of formal asymptotic expansions and perturbation theory to derive a new highly nonlinear shallow-water model from the full governing equations for two dimensional incompressible fluid with constant…

Analysis of PDEs · Mathematics 2024-01-17 Yu Liu , Xingxing Liu , Min Li

The Schr\"odinger-Poisson formalism has found a number of applications in cosmology, particularly in describing the growth by gravitational instability of large-scale structure in a universe dominated by ultra-light scalar particles. Here…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-15 Peter Coles , Aoibhinn Gallagher

A linear relationship between the Hubble expansion parameter and the time derivative of the scalar field is explored in order to derive exact cosmological, attractor-like solutions, both in Einstein's theory and in Brans-Dicke gravity with…

General Relativity and Quantum Cosmology · Physics 2010-10-27 Olga Arias , Tame Gonzalez , Yoelsy Leyva , Israel Quiros

We Consider a cosmological model based on a generalization of the equation of state proposed by Nojiri and Odintsov [46] and \v{S}tefan\v{c}i'c [47], [48]. We argue that this model works as a dark fluid model which can interpolate between…

General Relativity and Quantum Cosmology · Physics 2023-02-17 Esraa Elkhateeb

We use anisotropic fluid cosmology to describe the present, dark energy-dominated, universe. Similarly to what has been proposed for galactic dynamics, the anisotropic fluid gives an effective description of baryonic matter, dark energy and…

General Relativity and Quantum Cosmology · Physics 2020-07-15 Mariano Cadoni , Andrea P. Sanna , Matteo Tuveri

We consider the gravitational Euler-Poisson system with a linear equation of state on an expanding cosmological model of the Universe. The expansion of the spatial sections introduces an additional dissipating effect in the Euler equation.…

Analysis of PDEs · Mathematics 2025-12-23 David Fajman , Maciej Maliborski , Maximilian Ofner , Todd Oliynyk , Zoe Wyatt

Anisotropic dark energy cosmological models are constructed in the frame work of generalised Brans-Dicke theory with a self interacting potential. Wet dark fluid characterized by a linear equation of state is considered as the source of…

General Physics · Physics 2017-05-10 Sunil K. Tripathy , Dipanjali Behera , Bivudutta Mishra

In this paper, we will deepen the understanding of some fluid models proposed by other authors for the description of dark energy. Specifically, we will show that the so-called (Modified) Berthelot fluid is the hydrodynamic realization of…

General Relativity and Quantum Cosmology · Physics 2023-01-31 Muhsin Aljaf , Daniele Gregoris , Martiros Khurshudyan

The solution of the dark energy problem in models without scalars is presented. It is shown that a late-time accelerating cosmology may be generated by an ideal fluid with some implicit equation of state.

High Energy Physics - Theory · Physics 2007-05-23 O. Gorbunova

Numerical approximations of two classical fluid dynamics systems modelling large structure formation in cosmology are proposed. These systems model nonrelativistic and relativistic fluids submitted to self-gravitation in an expanding…

Numerical Analysis · Mathematics 2009-05-05 M. Colombeau

We study the Einstein-Vlasov system coupled to a nonlinear scalar field with a nonnegative potential in locally spatially homogeneous spacetime, as an expanding cosmological model. It is shown that solutions of this system exist globally in…

General Relativity and Quantum Cosmology · Physics 2009-11-10 Hayoung Lee

In Friedman-Robertson-Walker flat spacetime, we consider a three fluid cosmological model which contains dark matter, dark energy and baryonic matter in the form of perfect fluid with a barotropic equation of state. Dark matter is taken in…

General Relativity and Quantum Cosmology · Physics 2015-12-23 Nilanjana Mahata , Subenoy Chakraborty

Bounce cosmological models containing a dark viscous fluid in a spatially flat Friedmann-Robertson-Walker (FRW) universe are considered. The universe evolution is described in terms of generalized equation of state (EoS) parameters, in…

General Relativity and Quantum Cosmology · Physics 2024-11-19 E. Elizalde , A. V. Yurov , A. V. Timoshkin
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