Status Updates From An Introduction To Quantum ...

:)

sos

Making some serious progress

Wishing myself good luck, cause I'm gonna need it

Not good for beginners

TIL there is something called "Furry's theorem" in QED and it suddenly dawned upon me that I have no idea what furries are, despite seemingly half the internet being populated with them

Chapter 4: Not sure if like that the quantization of the EM field and the derivation of the photon propagator are postponed to several chapters after introducing the Feynman rules for QED. Would not have taken up that much space (my lecture script does this in about 4 pages). But I do appreciate the stepwise build-up from Phi^4 theory to Yukawa theory to QED.

Quantum field theory is literally black magic

Wow. Wasn't aware that not only Feynman, but also Tomonaga and Schwinger each developed their own reformulation of QM in order to simplify the perturbation series for QED. I just assumed they collaborated with Feynman on the path integral formulation since they share a Nobel prize. Very interesting. Maybe I'll check out that QED history book by Schweber (1994).

The QED Lagrangian accounts for "nearly all observed phenomena from macroscopic scales down to 10^-13 m". This is indeed quite astonishing.

Selective reading.

Selective reading.

40

Optical theorem, Cutkowski rules, start of Ward-Takahashi identity