Narrow Results

We use a neural network approach to derive a Runge–Kutta–Nyström pair of orders 8(6) for the integration of orbital problems. We adopt a differential evolution optimization technique to choose the free parameters of the method's family. We train the method to perform optimally in a specific test orbit from the Kepler problem for a specific tolerance. Our measure of efficiency involves the global error and the number of function evaluations. Other orbital problems are solved to test the new pair.

The classical treatment of the Kepler problem leaves room for the description of the space region of the central body by a hyperbolic geometry. If the correspondence between the empty space and the space filled with matter is taken to be a harmonic mapping, then the region of atomic nucleus, like the one of the Sun for the planetary system proper, is described by hyperbolic skyrmions. This fact makes possible the description of the nuclear matter within framework of general relativity. The classical “hedgehog” solution for skyrmions can then be classically interpreted in terms of the characterizations of intra-nuclear forces.

The motion of binary star systems is re-examined in the presence of perturbations from the theory of general relativity. To handle the singularity of the Kepler problem, the equation of motion is regularized and linearized with quaternions. In this way first-order perturbation results are derived using the quaternion-based approach.

This work is focused on searching a geodesic interpretation of the dynamics of a particle under the effects of a Snyder-like deformation in the background of the Kepler problem. In order to accomplish that task, a Newtonian spacetime is used. Newtonian spacetime is not a metric manifold, but allows to introduce a torsion-free connection in order to interpret the dynamic equations of the deformed Kepler problem as geodesics in a curved spacetime. These geodesics and the curvature terms of the Riemann and Ricci tensors show a mass and a fundamental length dependence as expected, but are velocity-independent that is a feature present in other classical approaches to the problem. In this sense, the effect of introducing a deformed algebra is examined and the corresponding curvature terms calculated, as well as the modifications of the integrals of motion.

In this paper, we show, in a systematic way, how to relate the Kepler problem to the isotropic harmonic oscillator. Unlike previous approaches, our constructions are carried over in the Lagrangian formalism dealing, with second order vector fields. We therefore provide a tangent bundle version of the Kustaanheimo-Stiefel map.