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Lagrangian formalism

Least action principle

The Lagrangian formalism is a universal approach to describe the evolution of a physical system. The basic idea is the least action principle, the idea that the evolution minimizes some quantity (for example the energy).

The resulting equations are called the Euler-Lagrange equations. This formalism can be applied to all known physical theories, such as classical mechanics, general relativity or quantum field theory.


A nice explanation in three steps (intuitive, example, abstract) can be found here:

  • Hamiltonian formalism
  • Euler-Lagrange equation
lagrangian_formalism.txt · Last modified: 2021/09/13 12:29 by alex_th