Hi and welcome to the second episode in my series on quantum field theory! In it, I will derive the propagator function first in one spatial dimension, and then in four-dimensional spacetime. In this episode I will focus only on the derivation of this abstract quantity, whereas in the next video we will study its workings more closely. I based this video series on the fantastic textbook "Quantum field theory: A diagrammatic approach" by Ronald Kleiss, which I highly recommend getting yourself if you are interested in studying the subject. Book: Music: Made with Manim: