Whether time is discrete at the fundamental level is still unknown. But for computational purposes, it is very useful to have a form of mechanics in which time increases in finite steps. Each step must be a canonical transformation. Using the Poincare-Birkhoff-Witt lemma (also called the Baker-Campbell-Hausdorff formula) this chapter derives first and second order symplectic integrators that allow a discrete time formulation of mechanics. The example of the standard map of Chiriikov (discrete time form of the pendulum) gives the first example of chaos. Arnold's cat map is introduced in an exercise.
Oxford Scholarship Online requires a subscription or purchase to access the full text of books within the service. Public users can however freely search the site and view the abstracts and keywords for each book and chapter.
If you think you should have access to this title, please contact your librarian.