120420225
Algebraic Programming in the Hamiltonian Treatment of the Einstein–Maxwell Equations
We present new procedures in REDUCE language using the EXCALC package (adapted for IBM-PC machines) for algebraic programming in the hamiltonian formulation of Einstein–Maxwell equations. The dynamic and the constraint equations containing specific terms of the interaction of gravity with source-free electromagnetic field are translated into computer procedures. The results obtained by processing some examples of space-time models are presented.
119451934
On the use of algebraic programming in the general relativity
This is a review devoted to some results of Algebraic Programming (Computer Algebra) used in treating several problems of general relativity, based mainly on already published articles. The article contains the talk given by the author at The Albert Einstein Institut, Max Planck Institut fur Gravitationstheorie, Golm, Germany, september 2000
6965842
The use of the algebraic programming in teaching general relativity
The article presents some aspects on the use of computer in teaching general relativity for undergraduate students with some experience in computer manipulation. The article presents some simple algebraic programming (in REDUCE+EXCALC package) procedures for obtaining and the study of some exact solutions of the Einstein equations in order to convince a dedicated student in general relativity about the utility of a computer algebra system.
120250632
Classical Gaussian bag in (1+1) general relativity
Abstract Relativistic geometric models generated by Gaussian conformally flat (1+1) metrics are considered. These metrics are depending on a fixed parameter and another variable parameter that play the role of coupling constant. It is shown that these models are of open bags where the relativistic massive particles remain confined for energies less than the rest one. By using numeric methods it is pointed out that inside of the bag the motion is close to an harmonic one. The dispersion function is also calculated for different values of the free parameter.
14129986
Maple+GrTensorII libraries for cosmology
The article mainly presents some results in using MAPLE platform for computer algebra (CA) and GrTensorII package in doing calculations for theoretical and numerical cosmology. AMS Subject Classification: 68W30, 83C05, 85A40
10985262
Doing Numerical Cosmology with the Cactus Code
The article presents some aspects concerning the construction of a new thorn for the Cactus code, a complete 3-dimensional machinery in numerical relativity. This thorn is dedicated to numerical simulations in cosmology, that means it can provide evolutions of different cosmological models, mainly based on Friedman-Robertson-Walker metric. Some numerical results are presented, testing the convergence, stability and the applicability of the code
11698036
Classical oscillators in general relativity
It is shown that in general relativity some static metrics are able to simulate oscillatory motions. Their form depends on two arbitrary real parameters which determine the specific oscillation modes. The conclusion is that these metrics can be used for new geometric models of closed or even open bags.