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We establish the future stability of nonlinear perturbations of a class of homogeneous solutions to the relativistic Euler equations with a linear equation of state $p=K\rho$ on exponentially expanding FLRW spacetimes for the equation of…

General Relativity and Quantum Cosmology · Physics 2021-07-28 Todd A. Oliynyk

This article introduces the notions of asymptotic dust and asymptotic radiation equations of state. With these non-linear generalizations of the well known dust or (incoherent) radiation equations of state the perfect-fluid equations loose…

General Relativity and Quantum Cosmology · Physics 2023-05-19 Helmut Friedrich

We present a new regularized Oldroyd-B model in three dimensions which satisfies an energy estimate analogous to that of the standard model, and maintains the positive semi-definiteness of the conformation tensor. This results in the unique…

Analysis of PDEs · Mathematics 2025-07-14 Jaroslaw S. Jaracz , Young Ju Lee

Why is the Universe so homogeneous and isotropic? We summarize a general study of a $\gamma$-law perfect fluid alongside an inhomogeneous, massless scalar gauge field (with homogeneous gradient) in anisotropic spaces with General…

General Relativity and Quantum Cosmology · Physics 2019-09-27 Ben David Normann , Sigbjørn Hervik , Angelo Ricciardone , Mikjel Thorsrud

We prove the global existence and uniqueness of smooth solutions to the one-dimensional barotropic Navier-Stokes system with degenerate viscosity $\mu(\rho)=\rho^\alpha$. We establish that the smooth solutions have possibly two different…

Analysis of PDEs · Mathematics 2020-04-22 Moon-Jin Kang , Alexis Vasseur

We investigate the gravitational field of static perfect-fluid in the presence of electric field. We adopt the equation of state $p(r)=-\rho(r)/3$ for the fluid in order to consider the closed ($S_3$) or the open ($H_3$) background spatial…

General Relativity and Quantum Cosmology · Physics 2019-01-21 Inyong Cho

We investigate some exact static cylindrically symmetric solutions for a perfect fluid in the metric $f(R)$ theory of gravity. For this purpose, three different families of solutions are explored. We evaluate energy density, pressure, Ricci…

General Relativity and Quantum Cosmology · Physics 2015-06-12 M. Sharif , Sadia Arif

We consider dynamics of a flat anisotropic Universe filled by a perfect fluid near a cosmological singularity in quadratic gravity. Two possible regimes are described -- the Kasner anisotropic solution and an isotropic "vacuum radiation"…

General Relativity and Quantum Cosmology · Physics 2017-01-04 A. Toporensky , D. Müller

We present a new bouncing cosmological solution of the non-local theory known as infinite derivative gravity, which goes beyond the recursive ansatz, ${\Box R = r_1 R +r_2}$. The non-local field equations are evaluated using the spectral…

General Relativity and Quantum Cosmology · Physics 2022-02-24 Ivan Kolář , Francisco José Maldonado Torralba , Anupam Mazumdar

We provide a rigorous proof for the existence of homogeneous, isotropic and globally singularity-free cosmological solutions in Einstein-dilaton-Gauss-Bonnet (EdGB) gravity with exponential coupling. While numerical studies suggested such…

Analysis of PDEs · Mathematics 2025-12-02 Chihang He , Chao Liu

We study second-order hydrodynamic transport in strongly coupled non-conformal field theories with holographic gravity duals in asymptotically anti-de Sitter space. We first derive new Kubo formulae for five second-order transport…

High Energy Physics - Theory · Physics 2017-03-28 Philipp Kleinert , Jonas Probst

We prove the global stability of small perturbation near the constant equilibrium for the two dimensional simplified Ericksen-Leslie's hyperbolic system for incompressible liquid crystal model, where the direction function of liquid crystal…

Analysis of PDEs · Mathematics 2026-03-13 Xuecheng Wang

Instead of conformal to flat spacetime, we take the metric conformal to a spacetime which can be thought of as ``minimally'' curved in the sense that free particles experience no gravitational force yet it has non-zero curvature. The base…

General Relativity and Quantum Cosmology · Physics 2009-10-28 Naresh Dadhich

Solutions to the field equations of the Nonsymmetric Gravitational Theory with $g_[i0] = 0$ are obtained for the homogeneous, plane-symmetric, time-dependent case, both in vacuum and in the presence of a perfect fluid. Cosmological…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Pierre Savaria

A spherically symmetric comoving fluid solution of Einstein's equations is adapted for cosmological application by extending the geometry of standard FRW cosmology using a generalised curvature term. The resulting model retains many of the…

General Relativity and Quantum Cosmology · Physics 2009-09-15 Ron Wiltshire

We consider anisotropic cosmological models with an universe of dimension 4 or more, factorized into n>1 Ricci-flat spaces, containing an m-component perfect fluid of m non-interacting homogeneous minimally coupled scalar fields under…

General Relativity and Quantum Cosmology · Physics 2015-06-25 U. Kasper , M. Rainer , A. Zhuk

In a recent paper (Beyer and Hennig, 2012 [9]), we have introduced a class of inhomogeneous cosmological models: the smooth Gowdy-symmetric generalized Taub-NUT solutions. Here we derive a three-parametric family of exact solutions within…

General Relativity and Quantum Cosmology · Physics 2014-04-18 Florian Beyer , Jörg Hennig

We show that the solution published in Ref.1 is geodesically complete and singularity-free. We also prove that the solution satisfies the stronger energy and causality conditions, such as global hyperbolicity, causal symmetry and causal…

General Relativity and Quantum Cosmology · Physics 2009-11-10 F. J. Chinea , L. Fernandez-Jambrina , J. M. M. Senovilla

In this paper, we study the steady solutions of Euler-Poisson equations in bounded domains with prescribed angular velocity. This models a rotating Newtonian star consisting of a compressible perfect fluid with given equation of state…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Tao Luo , Joel Smoller

New results are obtained for global regularity and long-time behavior of the solutions to the 2D Boussinesq equations for the flow of an incompressible fluid with positive viscosity and zero diffusivity in a smooth bounded domain. Our first…

Analysis of PDEs · Mathematics 2016-08-24 Ning Ju