Feynman Diagrams: Anharmonic Oscillator

This lecture covers the concept of Feynman diagrams for the anharmonic oscillator, focusing on the thermal partition function, Euclidean propagator, and Euclidean action. The instructor explains the correlation functions and Wick's theorem, illustrating the calculations step by step. The lecture also delves into the harmonic oscillator, discussing the ground state energy and perturbation theory. Various examples and exercises are provided to enhance understanding.