Source: /cirosantilli/quantum-field-theory-lecture-by-tobias-osborne-2017/lecture-2

= Lecture 2

* the advantage of using <Lagrangian mechanics> instead of directly trying to work out the equations of motion is that it is easier to guess the Lagrangian correctly, while still imposing some fundamental constraints
  * <Lagrangian mechanics> is better for <path integral formulation>. But the <mathematics> of that is fuzzy, so not going in that path.
  * <Hamiltonian mechanics> is better for non-<path integral formulation>
* Hamiltonian formalism requires finding conjugate pairs, and doing a