1. Feynman diagram

2. Outline Motivation Feynman integral
Pertubation Thoery in Quantum Mechanics
Pertubation Thoery in Quantum Field Theory
Green Function
Feynman Diagram
Experimental Connection

3. Motivation Compared with experiments
Amplitude of final states from collision of two initial particles
Cross section of collision
Graphical representation and simplicity

4. Pertubation Thoery in Quantum Mechanics
Idea of Pertubation theory
H = H_0 + H_I
Acquire information from H_0
Getting new eigenvector

5. Pertubation Thoery in Quantum Mechanics
Dyson series
How wave function evolute by time when H = H_0 + H_I

6. Pertubation Thoery in Quantum Field Theory
Idea of Quantum Field Theory
Number of particle
Take particle and wave as the same
Solution (Feynman path integral approach)

7. Pertubation Thoery in Quantum Field Theory
<final| exp( int_ (dt H_I)) |initial>

8. Ideal of Green function
Two point Green function
Four point Green function as combination of two point green function

9. Ideal of Green function
Four point Green function as combination of two point green function

10. Feynman Diagram Green function + time evolution of field
Graphical representation

11. Feynman Diagram
Feynman rule: example of lampta Phy^4 theory

12. Feynman Diagram Re-intepretation of anti-particle
Anti-particle in Dirac equation
Anti-charge and positive energe

13. Experimental Connection
Cross section
What’s cross section?
Connection of cross section and experiment

14. Experimental Connection
Calculating cross section
Amplitude
Cross section