Back where? In front of a classroom teaching quantum field theory, that is. It is a wonderful, fascinating, and super-important subject, and it has been a while since I’ve taught it. I actually managed to dig out some pretty good notes for the last time I taught it. (Thank you, my inner pack rat for keeping those notes and putting them where I could find them!) They’ll be a helpful foundation. (Aren’t they beautiful by the way? Those squiggly diagrams are called Feynman diagrams.)
Important? Quantum field theory (QFT) is perhaps one of the most remarkable
frameworks for describing Nature ever devised. It’s most famous for being the theory you use to describe the elementary particles (electrons, photons, quarks, etc) that make up the known matter and forces, but its also hugely important in other fields, such as condensed matter physics. I’ve got a very interesting mix of students enrolled in the class, from a variety of fields, so it is going to be a really fun course to teach, emphasizing where I can aspects and approaches that fit their various research interests.
Should be fun!