**Hamiltonian mechanics** is a reformulation of classical mechanics that was introduced in 1833 by Irish mathematician William Rowan Hamilton.

It arose from Lagrangian mechanics, a previous reformulation of classical mechanics introduced by Joseph Louis Lagrange in 1788, but can be formulated *without* recourse to Lagrangian mechanics using symplectic spaces (see *Mathematical formalism*, below). The Hamiltonian method differs from the Lagrangian method in that instead of expressing second-order differential constraints on an *n*-dimensional coordinate space (where *n* is the number of degrees of freedom of the system), it expresses first-order constraints on a 2*n*-dimensional phase space.

As with Lagrangian mechanics, **Hamilton's equations** provide a new and equivalent way of looking at Newtonian physics. Generally, these equations do not provide a more convenient way of solving a particular problem in classical mechanics. Rather, they provide deeper insights into both the general structure of classical mechanics and its connection to quantum mechanics as understood through Hamiltonian mechanics, as well as its connection to other areas of science.

Read more about Hamiltonian Mechanics: Simplified Overview of Uses, Deriving Hamilton's Equations, As A Reformulation of Lagrangian Mechanics, Geometry of Hamiltonian Systems, Generalization To Quantum Mechanics Through Poisson Bracket, Mathematical Formalism, Riemannian Manifolds, Sub-Riemannian Manifolds, Poisson Algebras, Charged Particle in An Electromagnetic Field, Relativistic Charged Particle in An Electromagnetic Field