quantization. Uses a more or less standard way to guess the quantized system from the classical one using Hamiltonian mechanics.
youtu.be/fnMcaq6QqTY?t=1179 remembers how to solve the non-field quantum harmonic oscillator
youtu.be/fnMcaq6QqTY?t=2008 puts hats on everything to make the field version of things. With the Klein-Gordon equation Hamiltonian, everything is analogous to the harmonic oscilator

 Ancestors

Lecture 4