Source: cirosantilli/quantum-field-theory-lecture-by-tobias-osborne-2017/lecture-5
= Lecture 5
https://www.youtube.com/watch?v=fnMcaq6QqTY&list=PLDfPUNusx1EpRs-wku83aqYSKfR5fFmfS&index=5
* something about finding a unitary representation of the poincare group