The Principles of Canonical Mechanics

Abstract

Canonical mechanics is a central part of general mechanics, where one goes beyond the somewhat narrow framework of Newtonian mechanics with position coordinates in the three-dimensional space, towards a more general formulation of mechanical systems belonging to a much larger class. This is the first step of abstraction, leaving behind ballistics, satellite orbits, inclined planes, and pendulum-clocks; it leads to a new kind of description that turns out to be useful in areas of physics far beyond mechanics. Through d’Alembert’s principle we discover the concept of the Lagrangian function and the framework of Lagrangian mechanics that is built onto it. Lagrangian functions are particularly useful for studying the role symmetries and invariances of a given system play in its description. By means of the Legendre transformation we are then led to the Hamiltonian function, which is central to the formulation of canonical mechanics, as developed by Hamilton and Jacobi.