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Newtonian dynamical systems which accept the normal shift on an arbitrary Riemannian manifold are considered. For them the determinating equations making the weak normality condition are derived. The expansion for the algebra of tensor…

High Energy Physics - Theory · Physics 2008-02-03 A. Yu. Boldin , V. V. Dmitrieva , S. S. Safin , R. A. Sharipov

Spherical models of collisionless but quasi-relaxed stellar systems have long been studied as a natural framework for the description of globular clusters. Here we consider the construction of self-consistent models under the same physical…

Astrophysics · Physics 2009-11-13 G. Bertin , A. L. Varri

A new class of modified theories of gravity, consisting of the superposition of the metric Einstein-Hilbert Lagrangian with an $f(\cal R)$ term constructed \`{a} la Palatini was proposed recently. The dynamically equivalent scalar-tensor…

General Relativity and Quantum Cosmology · Physics 2013-04-05 Salvatore Capozziello , Tiberiu Harko , Tomi S. Koivisto , Francisco S. N. Lobo , Gonzalo J. Olmo

A system of partial differential equations describing the spatial oscillations of an Euler-Bernoulli beam with a tip mass is considered. The linear system considered is actuated by two independent controls and separated into a pair of…

Optimization and Control · Mathematics 2018-02-13 Alexander L. Zuyev

In sustained growth with random dynamics stationary distributions can exist without detailed balance. This suggests thermodynamical behavior in fast growing complex systems. In order to model such phenomena we apply both a discrete and a…

Statistical Mechanics · Physics 2017-03-22 Tamás Biró , Zoltán Néda

We analyze the cosmological solutions of $f(T,B)$ gravity using dynamical system analysis where $T$ is the torsion scalar and $B$ be the boundary term scalar. In our work, we assume two specific cosmological models. For first model, we…

General Relativity and Quantum Cosmology · Physics 2023-04-26 Amit Samaddar , S. Surendra Singh

Methods of dynamical systems have been used to study homogeneous and isotropic cosmological models with a varying speed of light (VSL). We propose two methods of reduction of dynamics to the form of planar Hamiltonian dynamical systems for…

General Relativity and Quantum Cosmology · Physics 2008-07-22 Marek Szydlowski , Adam Krawiec

We reconcile seemingly conflicting statements in the literature about the behavior of cosmological solutions in modified theories of gravity where the Einstein-Hilbert Lagrangian for gravity is modified by the addition of a function of the…

Astrophysics · Physics 2008-11-26 Ignacy Sawicki , Wayne Hu

We consider scalar-tensor theories of gravity in an accelerating universe. The equations for the background evolution and the perturbations are given in full generality for any parametrization of the Lagrangian, and we stress that apparent…

General Relativity and Quantum Cosmology · Physics 2009-10-31 G. Esposito-Farese , D. Polarski

A general framework for performing event-driven simulations of systems with semi-flexible or rigid bodies interacting under impulsive torques and forces is outlined. Two different approaches are presented. In the first, the dynamics and…

Statistical Mechanics · Physics 2007-05-23 Lisandro Hernandez de la Pena , Ramses van Zon , Jeremy Schofield , Sheldon B. Opps

We formulate a generalized $k$-essence model in the presence of a Palatini $f(\mathcal{R})$ gravitational sector. In the corresponding biscalar-tensor theory, we discuss the distinguished dynamical properties of the two scalar fields,…

General Relativity and Quantum Cosmology · Physics 2026-04-15 Fabio Moretti , Flavio Bombacigno

The concept of random dynamical system is a comparatively recent development combining ideas and methods from the well developed areas of probability theory and dynamical systems. Due to our inaccurate knowledge of the particular physical…

Dynamical Systems · Mathematics 2007-05-23 Vitor Araujo

We construct the first dynamically stable ergostars (equilibrium neutron stars that contain an ergoregion) for a compressible, causal equation of state. We demonstrate their stability by evolving both strict and perturbed equilibrium…

General Relativity and Quantum Cosmology · Physics 2019-12-11 Antonios Tsokaros , Milton Ruiz , Lunan Sun , Stuart L. Shapiro , Kōji Uryū

We derive a new \emph{regular} dynamical system on a 3-dimensional \emph{compact} state space describing linear scalar perturbations of spatially flat Robertson-Walker geometries for relativistic models with a minimally coupled scalar field…

General Relativity and Quantum Cosmology · Physics 2020-12-02 Artur Alho , Claes Uggla , John Wainwright

Understanding the structural evolution of granular systems is a long-standing problem. A recently proposed theory for such dynamics in two dimensions predicts that steady states of very dense systems satisfy detailed-balance. We analyse…

Soft Condensed Matter · Physics 2023-08-16 Alex D. C. Myhill , Raphael Blumenfeld

We will construct a theory which can explain the dynamics toward the steady state self-gravitating systems (SGSs) where many particles interact via the gravitational force. Real examples of SGS in the universe are globular clusters and…

Cosmology and Nongalactic Astrophysics · Physics 2011-08-09 Tohru Tashiro , Takayuki Tatekawa

We discuss the dynamical system approach applied to Higher Order Theories of Gravity. We show that once the theory of gravity has been specified, the cosmological equations can be written as a first-order autonomous system and we give…

General Relativity and Quantum Cosmology · Physics 2009-06-11 S Carloni , P K S Dunsby , A Troisi

The dynamical realisation of the equation of state $p +\rho =0$ is studied. A non-pathological dynamics for the perturbations of such a system mimicking a dynamical cosmological constant (DCC) requires to go beyond the perfect fluid…

High Energy Physics - Theory · Physics 2025-03-06 Giuseppe di Donato , Luigi Pilo

In order to investigate the evolutionary process of many deterministic Dynamical systems with unfixed parameter, a set of dynamical models with parameter changing continuously and the accumulation of this change might be large is introduced…

comp-gas · Physics 2008-02-03 H. P. Fang

The inclusion of convection in stellar evolution models lacks realism, especially near convective-radiative interfaces. Furthermore, the interaction of convection with oscillations prevent us from accurately predicting seismic frequencies,…

Solar and Stellar Astrophysics · Physics 2025-10-31 J. Philidet , K. Belkacem