High Energy Physics Notes

These notes are my effort to understand QFT. If you are anything like me, you find that you need to work out as much as possible in detail, including all the formula, before you really understand something. For me, it also helps a lot, if I write down everything explicitly.

This website first came online in December 2019 and it still is very much WIP. I claim no originality or correctness whatsoever. If you have any comments, suggestions or feedback feel free to contact hep.notes@hotmail.com.

These Notes are about my effort to understand QFT. This started by reading Peskin & Schroeder and so a large part of these notes are essentially working out details of that book. However, there are additions coming from Weinberg, Zee, Schwartz, Muta, Cheng Lee, Carroll, Nair a.o.

Since first published in 2021, about two thirds of the original notes have been reviewed and updated and more than 15 new sections have been added.

QFT Notes Update August 2025

The approach to these notes, is different from the QFT Notes. Here I just comment on Polchinski’s String Theory book, deriving most of the formula in detail, or adding context, where I feel it is useful to me. It contains the first 8 chapters of volume 1.

Joe’s Book: String Theory Notes November 2020

These notes provide my personal road to understanding general relativity and the beginnings of cosmology. There are fortunately several excellent text books and lecture notes on the subjects, so I cannot not claim any originality to my approach.

General Relativity and Cosmology Notes January 2023

I would like to thank you for providing such a helpful resource to understand the famous Big Joe’s Book. (G.V.)

Your website was a huge help for me, especially in string theory. Thank you for your help. (N.A.)

 I can’t express how happy I am to finally find a book from which I can easily self learn. (N.A.T.)

I would sincerely like to thank you for your notes, or better, detailed calculations, which make Polchinski`s book understandable. Actually, I bought his book only, because I found your extensive calculations in advance.  (H.K.)

I am writing to express my sincere appreciation for your QFT notes. The content has been immensely helpful in my studies, and I particularly value the detailed mathematical formulations you have included. (D.W.)

I am reading Polchinski’s string theory book, and I occasionally found you note on it, which is very well written and helpful. (W.Y)

I would like to thank you for generously making your detailed notes on Quantum Field Theory (QFT) available for free. They have been incredibly helpful to me. (S.S.)

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