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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

Constraints are found on the spatial variation of finite-time Lyapunov exponents of two and three-dimensional systems of ordinary differential equations. In a chaotic system, finite-time Lyapunov exponents describe the average rate of…

Chaotic Dynamics · Physics 2009-10-31 Jean-Luc Thiffeault , Allen H. Boozer

We consider the Dirichlet problem for a compressible two-fluid model in three dimensions, and obtain the global existence of weak solution with large initial data and independent adiabatic constants \Gamma,\gamma>=9/5. The pressure…

Analysis of PDEs · Mathematics 2021-07-27 Huanyao Wen

Because of absence of time derivatives from scalar potential as a generalized coordinate of gravitation field (GF) in action of nonrelativistic gravitating system, application of the Hamilton method for description of GF mechanics was…

General Relativity and Quantum Cosmology · Physics 2016-03-03 A. A. Stupka

In this paper, the Cauchy problem for the three-dimensional (3-D) full compressible Navier-Stokes equations (CNS) with zero thermal conductivity is considered. First, when shear and bulk viscosity coefficients both depend on the absolute…

Analysis of PDEs · Mathematics 2023-01-18 Qin Duan , Zhouping Xin , Shengguo Zhu

As we are entering the era of precision cosmology, it is necessary to count on accurate cosmological predictions from any proposed model of dark matter. In this paper we present a novel approach to the cosmological evolution of scalar…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-04 L. Arturo Ureña-López , Alma X. Gonzalez-Morales

The Jeans equations do not form a closed system, and to solve them a parametrization relating the velocity moments is often adopted. For axisymmetric models, a phenomenological choice (the "$b$-ansatz") is widely used for the relation…

Astrophysics of Galaxies · Physics 2024-04-11 Leonardo De Deo , Luca Ciotti , Silvia Pellegrini

We prove that there exists a~large-data and global-in-time weak solution to a~system of partial differential equations describing an unsteady flow of an incompressible heat-conducting rate-type viscoelastic stress-diffusive fluid filling up…

Analysis of PDEs · Mathematics 2025-04-18 Michal Bathory , Miroslav Bulíček , Josef Málek

We consider the plane 3 body problem with 2 of the masses small. Periodic solutions with near collisions of small bodies were named by Poincar\'e second species periodic solutions. Such solutions shadow chains of collision orbits of 2…

Dynamical Systems · Mathematics 2011-04-13 Sergey Bolotin , Piero Negrini

We obtain an approximate global stationary and axisymmetric solution of Einstein's equations which can be considered as a simple star model: a self-gravitating perfect fluid ball with constant mass density rotating in rigid motion. Using…

General Relativity and Quantum Cosmology · Physics 2008-11-26 J. A. Cabezas , J. Martin-Martin , A. Molina , E. Ruiz

Quasi-equilibrium models of rapidly rotating triaxially deformed stars are computed in general relativistic gravity, assuming a conformally flat spatial geometry (Isenberg-Wilson-Mathews formulation) and a polytropic equation of state.…

Astrophysics · Physics 2009-01-08 Xing Huang , Charalampos Markakis , Noriyuki Sugiyama , Koji Uryu

We describe the theory and implementation of a three-dimensional fluid dynamics code which we have developed for calculating the surface geometry and circulation currents in the secondaries of interacting binary systems. The main method is…

Astrophysics · Physics 2009-11-07 Martin E. Beer , Philipp Podsiadlowski

Recent work on the equilibrium and stability of ellipsoidal stellar systems is reviewed. The absence of constant-density cores in early-type galaxies implies that chaos and high-order resonances are generic features of the motion in…

Astrophysics · Physics 2007-05-23 David Merritt , Tema Fridman

The initial value problem for the Vlasov-Poisson system is by now well understood in the case of an isolated system where, by definition, the distribution function of the particles as well as the gravitational potential vanish at spatial…

General Relativity and Quantum Cosmology · Physics 2009-10-22 Gerhard Rein , Alan D. Rendall

In these lectures I shall explain how a new-found nonabelian duality can be used to solve some outstanding questions in particle physics. The first lecture introduces the concept of electromagnetic duality and goes on to present its…

High Energy Physics - Theory · Physics 2007-05-23 ST Tsou

The three--dimensional incompressible viscous Boussinesq equations, under the assumption of hydrostatic balance, govern the large scale dynamics of atmospheric and oceanic motion, and are commonly called the primitive equations. To overcome…

Analysis of PDEs · Mathematics 2010-10-27 Chongsheng Cao , Edriss S. Titi

The kinematics of stars in dwarf spheroidal galaxies have been studied to understand the structure of dark matter halos. However, the kinematic information of these stars is often limited to celestial positions and line-of-sight velocities,…

Astrophysics of Galaxies · Physics 2025-06-03 Sung Hak Lim , Kohei Hayashi , Shun'ichi Horigome , Shigeki Matsumoto , Mihoko M. Nojiri

We analyze the Ericksen-Leslie system equipped with the Oseen-Frank energy in three space dimensions. The new concept of dissipative solutions is introduced. Recently, the author introduced the concept of measure-valued solutions to the…

Analysis of PDEs · Mathematics 2020-01-08 Robert Lasarzik

We study the local gravitational instability of non-rotating astrophysical fluids allowing for the presence of an external gravitational potential in addition to the fluid self-gravity. We present a self-consistent linear-perturbation…

Astrophysics of Galaxies · Physics 2026-02-18 Carlo Nipoti

Consider the three-body problem with an attractive $1/r^2$ potential. Modulo symmetries, the dynamics of the bounded zero-angular momentum solutions is equivalent to a geodesic flow on the thrice-punctured sphere, or ``pair of pants''. The…

Dynamical Systems · Mathematics 2007-05-23 Richard Montgomery