Link to lecture notes: http://www.mit.edu/~kardar/teaching/LesHouches18/lectures/index.html

Link to movie of lectures (one lecture appears to be missing…):
Lecture one
Lecture two
Lecture three
Lecture four
Lecture five

If you want to learn more on divergent series, wikipedia is good:
https://en.wikipedia.org/wiki/Divergent_series
as are many places easily found by google, e.g.
https://brilliant.org/wiki/sums-of-divergent-series/