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We examine the consistency of the thermodynamics of irrotational and non-isentropic perfect fluids complying with matter conservation by looking at the integrability conditions of the Gibbs-Duhem relation. We show that the latter is always…

General Relativity and Quantum Cosmology · Physics 2010-04-06 Hernando Quevedo , Roberto Sussman

A set of new exact analytical General Relativity (GR) solutions with time-dependent and spatially inhomogeneous quintessence demonstrate 1) a static non-empty space-time with a horizon-type singular surface; 2) time-dependent spatially…

Astrophysics · Physics 2014-10-13 Arthur D. Chernin , David I. Santiago , Alexander S. Silbergleit

The evolution of spatially homogeneous and isotropic cosmological models containing a perfect fluid with equation of state p=w\rho\ and a cosmological constant \Lambda\ is investigated for arbitrary combinations of w and \Lambda, using…

Physics Education · Physics 2012-09-19 Sebastiano Sonego , Vittorino Talamini

The present status of the shear-free perfect fluid conjecture in general relativity is discussed: I give a review of recent work and present a new formalism which may provide a better understanding of the problems encountered.

General Relativity and Quantum Cosmology · Physics 2025-09-17 Norbert Van den Bergh

In this talk we would like to review recent results on non-singular cosmological models. It has been recently shown that among stiff perfect fluid inhomogeneous spacetimes the absence of singularities is more common than it was expected in…

General Relativity and Quantum Cosmology · Physics 2009-04-29 L. Fernández-Jambrina , L. M. González-Romero

The present paper deals with the nonhomogeneous incompressible asymmetric fluids equations in dimension $d= 2,3$. The aim is to prove the unique global solvability of the system with only bounded nonnegative initial density and $H^{1}$…

Analysis of PDEs · Mathematics 2020-10-20 Fuyi Xu , Mingxue Zhang , Liening Qiao

The evolution of an electrically conducting imcompressible fluid with nonconstant density can be described by a set of equations combining the continuity, momentum and Maxwell's equations; altogether known as the inhomogeneous…

Analysis of PDEs · Mathematics 2024-05-24 Diogo Arsénio , Haroune Houamed , Belkacem Said--Houari

We present solutions describing homogeneous and isotropic cosmologies in the massive gravity theory with two dynamical metrics recently proposed in arXiv:1109.3515 and claimed to be ghost free. These solutions can be spatially open, closed,…

High Energy Physics - Theory · Physics 2015-05-30 Mikhail S. Volkov

We consider the extension of the Majumdar-type class of static solutions for the Einstein-Maxwell equations, proposed by Ida to include charged perfect fluid sources. We impose the equation of state $\rho+3p=0$ and discuss spherically…

General Relativity and Quantum Cosmology · Physics 2009-11-11 V. Varela

We investigate global existence and optimal decay rates of a generic non-conservative compressible two--fluid model with general constant viscosities and capillary coefficients.The main novelty of this work is three--fold: First, for any…

Analysis of PDEs · Mathematics 2021-08-21 Yin Li , Huaqiao Wang , Guochun Wu , Yinghui Zhang

We prove well-posedness of the initial value problem for the Einstein equations for spatially-homogeneous cosmologies with data at an isotropic cosmological singularity, for which the matter content is either a cosmological constant with…

General Relativity and Quantum Cosmology · Physics 2008-11-26 Paul Tod

We analyze the static and spherically symmetric perfect fluid solutions of Einstein field equations inspired by the non commutative geometry. In the framework of the non commutative geometry this solution is interpreted as a mini black hole…

General Relativity and Quantum Cosmology · Physics 2009-12-04 Ivan Arraut Guerrero , Davide Batic , Marek Nowakowski

We present a new formulation of non-dissipative relativistic spin hydrodynamics that incorporates spin degrees of freedom into the divergence-type theory framework. Due to the divergence-type structure, it is straightforward to enforce…

Nuclear Theory · Physics 2025-11-26 Nick Abboud , Lorenzo Gavassino , Rajeev Singh , Enrico Speranza

We establish the existence of solutions of fully nonlinear parabolic second-order equations like $\partial_{t}u+H(v,Dv,D^{2}v,t,x)=0$ in smooth cylinders without requiring $H$ to be convex or concave with respect to the second-order…

Analysis of PDEs · Mathematics 2017-10-18 N. V. Krylov

To seek for a singularity free model universe from a perfect fluid scalar-metric cosmology, we work in the "\emph{Emergent Cosmology}" (EC) paradigm which is a non-singular alternative for cosmological inflation. By using two methods…

General Relativity and Quantum Cosmology · Physics 2018-06-26 Mohsen Khodadi , Kourosh Nozari

The properties of a transformation previously considered for generating new perfect-fluid solutions from known ones are further investigated. It is assumed that the four-velocity of the fluid is parallel to the stationary Killing field, and…

General Relativity and Quantum Cosmology · Physics 2009-10-30 Istvan Racz , Jozsef Zsigrai

This paper presents a new wormhole solution by assuming that a homogeneously distributed fluid with equation of state $p=\omega\rho$ can be adapted to an anisotropic spacetime such as a wormhole and that this spacetime admits a…

General Relativity and Quantum Cosmology · Physics 2017-07-14 Peter K. F. Kuhfittig

We consider a class of inhomogeneous self-similar cosmological models in which the perfect fluid flow is tangential to the orbits of a three-parameter similarity group. We restrict the similarity group to possess both an Abelian $G_{2}$,…

General Relativity and Quantum Cosmology · Physics 2021-08-11 Sepehr Rashidi , C. G. Hewitt , Benoit Charbonneau

This paper investigates the evolution of collapsing FRW models with a scalar field having the potential which arises in the conformal frame of high order gravity theories, coupled to matter described by a perfect fluid with energy density…

General Relativity and Quantum Cosmology · Physics 2010-03-24 Roberto Giambò

This work concerns with the existence and detailed asymptotic analysis of Type II singularities for solutions to complete non-compact conformally flat Yamabe flow with cylindrical behavior at infinity. We provide the specific blow-up rate…

Differential Geometry · Mathematics 2018-09-17 Beomjun Choi , Panagiota Daskalopoulos , John King
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