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We introduce the concept of a "transitory" dynamical system---one whose time-dependence is confined to a compact interval---and show how to quantify transport between two-dimensional Lagrangian coherent structures for the Hamiltonian case.…

Chaotic Dynamics · Physics 2015-03-17 B. A. Mosovsky , J. D. Meiss

Formulation of the Lagrangian approach is presented for studying features of motions of stellar bodies with non-zero rest mass in the vicinity of fast-spinning black holes. The structure of Lagrangian is discussed. The general method is…

Astrophysics of Galaxies · Physics 2018-08-02 Elizabeth P. Tito , Vadim I. Pavlov

A new approach to relativistic mechanics is proposed, suitable to describe dynamics of different kinds of relativistic particles. Mathematically it is based on an application of the recent geometric theory of nonholonomic systems on fibred…

Mathematical Physics · Physics 2009-04-21 Olga Krupkova , Jana Musilova

A new fully kinetic system is proposed for modeling collisionless magnetic reconnection. The formulation relies on fundamental principles in Lagrangian dynamics, in which the inertia of the electron mean flow is neglected in the expression…

Plasma Physics · Physics 2013-01-29 Cesare Tronci

We investigate the physical properties of equilibrium sequences of non-self-gravitating surfaces that characterize thick disks around a rotating deformed compact object described by a stationary generalization of the static q-metric. The…

General Relativity and Quantum Cosmology · Physics 2025-02-14 Shokoufe Faraji , Audrey Trova , Hernando Quevedo

In the present work, a consistent Lagrangian model that encapsulates fully kinetic ions and gyrokinetic electrons for solar wind electromagnetic turbulence is formulated. Using a consistent method, where both electrons and protons are…

We consider the question of counting the degrees of freedom in theoretical models, with an emphasis on theories of fields and gravity. Among the possible approaches, the Hamiltonian formulation remains one of the most systematic and robust…

High Energy Physics - Theory · Physics 2026-01-16 Anamaria Hell , Elisa G. M. Ferreira , Dieter Lust , Misao Sasaki

A generalization of the Lagrangian introduced earlier in [2011 {\it J. Phys. G} ${\bf 37}$ 105001] for a classical color spinning particle interacting with background non-Abelian gauge and fermion fields for purpose of considering a change…

High Energy Physics - Theory · Physics 2011-12-12 Yuri A. Markov , Margarita A. Markova , Alexey A. Shishmarev , Alexander N. Vall

The process of equilibration of a colliding hard-disks system is studied in the framework of classical mechanic. The method consists of dividing the nonequilibrium system into the interacting subsystems; the evolution one of these…

Statistical Mechanics · Physics 2014-11-17 V. M. Somsikov

We numerically investigate, through discrete element simulations, the steady flow of identical, frictionless spheres sheared between two parallel, bumpy planes in the absence of gravity and under a fixed normal load. We measure the spatial…

Soft Condensed Matter · Physics 2024-07-25 Dalila Vescovi , Astrid S. de Wijn , Graham L. W. Cross , Diego Berzi

The sticky particle system is a system of partial differential equations which assert the conservation of mass and momentum of a collection of particles that interact only via inelastic collisions. These equations arise in Zel'dovich's…

Analysis of PDEs · Mathematics 2019-06-18 Ryan Hynd

When placed on an inclined plane, a perfect 2D disk or 3D sphere simply rolls down in a straight line under gravity. But how is the rolling affected if these shapes are irregular or random? Treating the terminal rolling speed as an order…

Classical Physics · Physics 2024-07-30 Daoyuan Qian , Yeonsu Jung , L. Mahadevan

Homogeneous isotropic cosmological models built in the framework of the Poincar\'e gauge theory of gravity based on general expression of gravitational Lagrangian with indefinite parameters are analyzed. Special points of cosmological…

General Relativity and Quantum Cosmology · Physics 2014-12-23 A. S. Garkun , V. I. Kudin , A. V. Minkevich

Lagrangian of electronic liquid in magneto-inhomogeneous micro-conductor has been constructed. A corresponding Euler-Lagrange equation has been solved. It was shown that the described system has eigenmodes of spin polarization and total…

Mesoscale and Nanoscale Physics · Physics 2015-01-15 P. V. Pyshkin , A. I. Kopeliovich , A. V. Yanovsky

Nonholonomic systems are variational models commonly used for mechanical systems with ideal no-slip constraints. This note provides a differential-geometric derivation of the nonholonomic equations of motion for an arbitrary rigid body…

Mathematical Physics · Physics 2018-02-20 George W. Patrick

This paper outlines an exact analytic model for self-gravitating thin disc galaxies with flat rotation curves. It is shown that thin discs of matter alone can support perfectly flat rotation curves under Newtonian gravity, without needing…

Astrophysics of Galaxies · Physics 2013-07-24 Niall Ryan

Lagrangian multiform theory is a variational framework for integrable systems. In this article we introduce a new formulation which is based on symplectic geometry and which treats position, momentum and time coordinates of a…

Mathematical Physics · Physics 2025-04-01 Vincent Caudrelier , Derek Harland

The purpose of this paper is to introduce a new way to inquire the quantum cosmology for a certain gravitational theory. Normally, the quantum cosmological model is introduced as the minisuperspace theory which is obtained by reducing the…

General Relativity and Quantum Cosmology · Physics 2016-06-07 Miao He , Zi-Liang Wang , Jian-Bo Deng , Hua Chen

We discuss some 3D numerical simulations of accretion discs using the SPH method and a polytropic equation of state. We show that discs exist even for as large value of the polytropic index as 1.2, and that these discs are always in…

Astrophysics · Physics 2007-05-23 Henri M. J. Boffin , Kei Haraguchi , Takuya Matsuda

We develop the BRST approach for all massless integer and half-integer higher spins in 4D Minkowski space, using the two component spinor nota- tion and develop the Lagrangian formulation for supersymmetric higher spin models. It is shown…

High Energy Physics - Theory · Physics 2016-01-27 I. L. Buchbinder , K. Koutrolikos