Source: cirosantilli/quantum-field-theory-lecture-by-tobias-osborne-2017/lecture-9

= Lecture 9

https://www.youtube.com/watch?v=zSSjgG9AbgM&list=PLDfPUNusx1EpRs-wku83aqYSKfR5fFmfS&index=9

<Feynman diagram>.