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It has previously been shown that varying the numerical timestep during a symplectic orbital integration leads to a random walk in energy and angular momentum, destroying the phase space-conserving property of symplectic integrators. Here…

Instrumentation and Methods for Astrophysics · Physics 2015-05-20 Nathan A. Kaib , Thomas Quinn , Ramon Brasser

This paper describes a fourth-order integration algorithm for the gravitational N-body problem based on discrete Lagrangian mechanics. When used with shared timesteps, the algorithm is momentum conserving and symplectic. We generalize the…

Astrophysics · Physics 2010-11-11 Will M. Farr , Edmund Bertschinger

Spin-orbit coupling of planetary systems plays an important role in the dynamics and habitability of planets. However, symplectic integrators that can accurately simulate not only how orbit affects spin but also how spin affects orbit have…

Earth and Planetary Astrophysics · Physics 2021-10-04 Renyi Chen , Gongjie Li , Molei Tao

In this work, we present a symplectic integration scheme to numerically compute space debris motion. Such an integrator is particularly suitable to obtain reliable trajectories of objects lying on high orbits, especially geostationary ones.…

Earth and Planetary Astrophysics · Physics 2015-06-03 Ch. Hubaux , A. Lemaître , N. Delsate , T. Carletti

We apply one of the exactly symplectic integrators, that we call HB15, of \cite{HB15}, along with the Kepler problem solver of \cite{WH15}, to solve planetary system $N$-body problems. We compare the method to Wisdom-Holman methods (WH) in…

Earth and Planetary Astrophysics · Physics 2017-03-03 David M. Hernandez

Direct N-body simulations and symplectic integrators are effective tools to study the long-term evolution of planetary systems. The Wisdom-Holman (WH) integrator in particular has been used extensively in planetary dynamics as it allows for…

Earth and Planetary Astrophysics · Physics 2019-10-02 Hanno Rein , Daniel Tamayo , Garett Brown

In this work we propose a new numerical approach to distinguish between regular and chaotic orbits in Hamiltonian systems, based on the simultaneous integration of both the orbit and the deviation vectors using a symplectic scheme, hereby…

Chaotic Dynamics · Physics 2015-03-17 Anne-Sophie Libert , Charles Hubaux , Timoteo Carletti

We present a new time-stepping criterion for N-body simulations that is based on the true dynamical time of a particle. This allows us to follow the orbits of particles correctly in all environments since it has better adaptivity than…

Astrophysics · Physics 2009-10-12 Marcel Zemp , Joachim Stadel , Ben Moore , C. Marcella Carollo

Coherent or exact equations of motion for a post-Newtonian Lagrangian formalism are the Euler-Lagrange equations without any terms truncated. They naturally conserve energy {and} angular momentum. Doubling the phase-space variables of…

General Relativity and Quantum Cosmology · Physics 2021-12-14 Guifan Pan , Xin Wu , Enwei Liang

We introduce a class of fourth order symplectic algorithms that are ideal for doing long time integration of gravitational few-body problems. These algorithms have only positive time steps, but require computing the force gradient in…

Astrophysics · Physics 2007-05-23 Siu A. Chin , C. R. Chen

Symplectic integrators can be excellent for Hamiltonian initial value problems. Reasons for this include their preservation of invariant sets like tori, good energy behaviour, nonexistence of attractors, and good behaviour of statistical…

Numerical Analysis · Mathematics 2018-09-19 Robert I McLachlan , Christian Offen

By combining a standard symmetric, symplectic integrator with a new step size controller, we provide an integration scheme that is symmetric, reversible and conserves the values of the constants of motion. This new scheme is appropriate for…

General Relativity and Quantum Cosmology · Physics 2012-12-07 Jonathan Seyrich , Georgios Lukes-Gerakopoulos

Symplectic integrators are widely used for the study of planetary dynamics and other $N$-body problems. In a study of the outer Solar system, we demonstrate that individual symplectic integrations can yield biased errors in the semi-major…

Earth and Planetary Astrophysics · Physics 2021-04-15 David M. Hernandez , Eric Agol , Matthew J. Holman , Sam Hadden

Most numerical integration algorithms are not designed specifically for Hamiltonian systems and do not respect their characteristic properties, which include the preservation of phase space volume with time. This can lead to spurious…

Astrophysics · Physics 2015-06-24 David JD Earn

Many Hamiltonian problems in the Solar System are separable or separate into two analytically solvable parts, and thus give a great chance to the development and application of explicit symplectic integrators based on operator splitting and…

General Relativity and Quantum Cosmology · Physics 2022-12-07 Xin Wu , Ying Wang , Wei Sun , Fu-Yao Liu , Wen-Biao Han

The intention of this article is to illustrate the use of methods from symplectic geometry for practical purposes. Our intended audience is scientists interested in orbits of Hamiltonian systems (e.g. the three-body problem). The main…

Symplectic Geometry · Mathematics 2023-03-10 Urs Frauenfelder , Dayung Koh , Agustin Moreno

Hamilton's equations of motion form a fundamental framework in various branches of physics, including astronomy, quantum mechanics, particle physics, and climate science. Classical numerical solvers are typically employed to compute the…

Machine Learning · Computer Science 2024-10-25 Priscilla Canizares , Davide Murari , Carola-Bibiane Schönlieb , Ferdia Sherry , Zakhar Shumaylov

The shearing sheet is a model dynamical system that is used to study the small-scale dynamics of astrophysical disks. Numerical simulations of particle trajectories in the shearing sheet usually employ the leapfrog integrator, but this…

Earth and Planetary Astrophysics · Physics 2011-06-17 Hanno Rein , Scott Tremaine

The phase space of a Hamiltonian system is symplectic. However, the post-Newtonian Hamiltonian formulation of spinning compact binaries in existing publications does not have this property, when position, momentum and spin variables $[X, P,…

General Relativity and Quantum Cosmology · Physics 2010-05-12 Xin Wu , Yi Xie

Explicit symplectic integrators have been important tools for accurate and efficient approximations of mechanical systems with separable Hamiltonians. For the first time, the article proposes for arbitrary Hamiltonians similar integrators,…

Numerical Analysis · Mathematics 2016-10-19 Molei Tao