Covers some specific hardcore subjects, notably quantum electrodynamics, in full mathematical detail, e.g.: "Quantum Field Theory Lecture Series" playlist: www.youtube.com/playlist?list=PLSpklniGdSfSsk7BSZjONcfhRGKNa2uou
As of 2020 Dietterich was a condensed matter PhD candidate or post-doc at the University of Minnesota Twin Cities, and he lives in Minnesota, sources:
Unfortunately the channel is too obsessed with mathematical detail (which it does amazingly), and does not give enough examples/application/intuition, which is what would be useful to most people, thus falling too much on the hardcore side of the missing link between basic and advanced.
This channel does have on merit however: compared to other university courses, it is much more direct, which might mean that you get to something interesting before you got bored to death, Section "You can learn more from older students than from faculty" comes to mind.