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Non-Maxwellian metaequilibria can exist in low-collisionality plasmas as evidenced by satellite and laboratory measurements. By including the full pressure tensor dynamics in a fluid plasma model, we show that a sheared velocity field can…

Plasma Physics · Physics 2016-05-11 Daniele Del Sarto , Francesco Pegoraro , Francesco Califano

Extensions of Einstein's General Relativity (GR) can formally be given a GR structure in which additional geometric degrees of freedom are mapped on an effective energy-momentum tensor. The corresponding effective cosmic medium can then be…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-11 Winfried Zimdahl , Hermano Velten , William C. Algoner

The semi-review paper studies the null geodesics which appear for black hole solutions in the gravitational $4d$ model with anisotropic fluid. The equations of state for the fluid and solutions itselves depend upon integer parameter $q = 1,…

General Relativity and Quantum Cosmology · Physics 2025-09-11 V. D. Ivashchuk , S. V. Bolokhov , F. B. Belissarova , N. Kydyrbay , A. N. Malybayev , G. S. Nurbakova , B. Zheng

In this paper, we derive multiple anisotropic analogs from the established isotropic model by means of the gravitational decoupling approach in a fluid-geometry interaction based theory. To accomplish this, we initially consider a static…

General Relativity and Quantum Cosmology · Physics 2025-02-24 Tayyab Naseer , G. Mustafa

A formalism for anisotropic fluid dynamics is proposed. It is designed to describe boost-invariant systems with anisotropic pressure. Such systems are expected to be produced at the early stages of relativistic heavy-ion collisions, when…

Nuclear Theory · Physics 2008-11-26 Wojciech Florkowski

In the present paper we have discussed the mechanics of incompressible test bodies moving in Riemannian spaces with non-trivial curvature tensors. For Hamilton's equations of motion the solutions have been obtained in the parametrical form…

Classical Physics · Physics 2020-12-02 Vasyl Kovalchuk , Barbara Gołubowska , Ewa Eliza Rożko

In this talk a sufficient condition for a diagonal orthogonally transitive cylindrical $G_2$ metric to be geodesically complete is given. The condition is weak enough to comprise all known diagonal perfect fluid cosmological models that are…

General Relativity and Quantum Cosmology · Physics 2009-04-14 L. Fernández-Jambrina

We derive the equations of motion for a system undergoing boost-invariant longitudinal and azimuthally-symmetric transverse "Gubser flow" using leading-order anisotropic hydrodynamics. This is accomplished by assuming that the one-particle…

Nuclear Theory · Physics 2015-02-05 Mohammad Nopoush , Radoslaw Ryblewski , Michael Strickland

In this paper, we prove Ruelle's inequality for the geodesic flow in non-compact manifolds with Anosov geodesic flow and some assumptions on the curvature. In the same way, we obtain Pesin's formula for Anosov geodesic flow in non-compact…

Dynamical Systems · Mathematics 2024-09-06 Alexander Cantoral , Sergio Romaña

A new important relation between fluid mechanics and differential geometry is established. We study smooth steady solutions to the Euler equations with the additional property: the velocity vector is orthogonal to the gradient of the…

Mathematical Physics · Physics 2023-02-14 Vladimir Yu. Rovenski , Vladimir A. Sharafutdinov

We propose an effective anisotropic fluid description for a generic infrared-modified theory of gravity. In our framework, the additional component of the acceleration, commonly attributed to dark matter, is explained as a radial pressure…

General Relativity and Quantum Cosmology · Physics 2017-12-06 Mariano Cadoni , Roberto Casadio , Andrea Giusti , Wolfgang Mück , Matteo Tuveri

The primary goal of this paper is to develop robust methods to handle two ubiquitous features appearing in the modeling of geophysical flows: (i) the anisotropy of the viscous stress tensor, (ii) stratification effects. We focus on the…

Analysis of PDEs · Mathematics 2020-11-05 Edoardo Bocchi , Francesco Fanelli , Christophe Prange

We construct a category of examples of partially hyperbolic geodesic flows which are not Anosov, deforming the metric of a compact locally symmetric space of nonconstant negative curvature. Candidates for such example as the product metric…

Dynamical Systems · Mathematics 2013-03-12 Fernando A. Carneiro , Enrique R. Pujals

The affine motion of two-dimensional (2d) incompressible fluids surrounded by vacuum can be reduced to a completely integrable and globally solvable Hamiltonian system of ordinary differential equations for the deformation gradient in ${\rm…

Analysis of PDEs · Mathematics 2020-01-30 Jay Roberts , Steve Shkoller , Thomas C. Sideris

The framework of anisotropic hydrodynamics is generalized to include finite particle masses. Two schemes are introduced and their predictions compared with exact solutions of the kinetic equation in the relaxation time approximation. The…

High Energy Physics - Phenomenology · Physics 2014-05-22 Wojciech Florkowski , Radoslaw Ryblewski , Michael Strickland , Leonardo Tinti

Any closed, oriented, hyperbolic three-manifold with nontrivial second homology has many quasigeodesic flows, where quasigeodesic means that flow lines are uniformly efficient in measuring distance in relative homotopy classes. The flows…

Geometric Topology · Mathematics 2009-09-25 Sérgio Fenley , Lee Mosher

We investigate the geodesic motions of a massive particle and light ray in the hyperplane orthogonal to the symmetry axis in the 5-dimensional hypercylindrical spacetime. The class of the solutions depends on one constant a which is the…

General Relativity and Quantum Cosmology · Physics 2010-11-11 Bogeun Gwak , Bum-Hoon Lee , Wonwoo Lee

A spacetime endowed with an anisotropic fluid is proposed for the interior of a Schwarzschild black hole. The geometry has an instantaneous Minkowski form and is a solution of Einstein's equations with a stress tensor on the r.h.s. obeying…

High Energy Physics - Theory · Physics 2008-01-31 Hristu Culetu

It is shown that small elements of perfect fluid in adiabatic processes move along geodesic lines of a Riemannian space-time.

General Relativity and Quantum Cosmology · Physics 2008-11-26 L. V. Verozub

The elusive physical nature of Horndeski gravity is elucidated in a new approach depicting this class of theories as a dissipative effective fluid. Requiring the constitutive equations of the latter to be those of a Newtonian fluid…

General Relativity and Quantum Cosmology · Physics 2023-07-14 Marcello Miranda , Daniele Vernieri , Salvatore Capozziello , Valerio Faraoni