XylyXylyX: QED Prerequisites
Seventy-eight lessons assembling everything QED assumes you already know
About this series
A quantum electrodynamics course spends its first weeks on machinery: Dirac notation, spin, Lorentz transformations, least action, scattering theory. This series from XylyXylyX spends 78 lessons on exactly that machinery, deriving each piece instead of citing it — the Pauli matrices are built from scratch, Maxwell's equations are rebuilt three separate times (vector calculus, differential forms, geometric algebra), and Thomas precession is actually calculated.
Read it alongside the written QFT prerequisites before starting the QFT course. The tensor machinery it leans on is covered in the same author's tensor series.
Lesson 1 — Dirac Formalism Part I (redux)
Lesson 2 — Dirac Formalism Part 2
Lesson 3 — Dirac Formalism Part 3
Lesson 4 — Dirac Formalism Part 4
Lesson 5 — Dirac Formalism Part 5
Lesson 6 — Dirac Formalism Part 6
Lesson 7 — Dirac Formalism Part 7
Lesson 8 — Dirac Formalism Part 8
About these lectures
The author's numbering has gaps and half-steps — lesson 15 and 1/3, lesson 27.5, no lesson 17 or 21 — and the later lectures drop numbering altogether. Titles here are his, so the sequence is the one he published rather than a tidied version of it. The geometric algebra block is long enough to be a course in its own right and can be taken separately.
All content is publicly available on YouTube and belongs to its creator. Watch the full series on the original playlist.