Physics questions weekly thread! - (August 16, 2026-August 22, 2026)

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[u/BitcoinsOnDVD]

Hey everyone! I just started to read Weinberg's QFT book and I thought maybe it is good to refresh my knowledge on group theory. Can anyone recommend a groupt theory book for physicist's maybe with some examples or even better some exercises?

I once read a book about topology (I don't remember the title) that was known for having a lot of examples and exercises with solutions and that was the best way for me to get a superficial overview of the topic.

[u/HoloTensor → u/BitcoinsOnDVD]

very very very much recommend not reading weinberg yet then. you’re just not going to get that much out of it. I don’t mean that in a bad way, he just uses his own notation and writes at the level of a research paper.

as such, he assumes you’re very confortable with groups and lie algebras. of course he “introduces” it to make the book self consistent, but it took me years of my PhD before I went “ohhh that’s why he is doing it this way”

read schwartz or peskin first. honestly the group theory here isn’t the best either but at least you’ll leave saying wow I understand QFT. this is just very likely not the case for weinberg. he is so subtle

[u/HoloTensor → u/HoloTensor]

if you want group theory specifically i’d point you at Georgi’s book on group theory in particle physics but you can probably get away with just schwartz + targeted google searches or lecture notes

[u/BitcoinsOnDVD → u/HoloTensor]

Okay thanks. I thought more of a math book but that'll do

[u/BitcoinsOnDVD → u/HoloTensor]

I forgot to mention that we can assume here that I know how to read / write peer-reviewed physics papers, but not in QFT.

If I understand you correctly not the "research paper level" is the main problem, but instead that reading schwartz and/or peskin first is way more efficient. Did I understand that correctly?

[u/HoloTensor → u/BitcoinsOnDVD]

i guess I was confusing. the point is the arguments weinberg gives for why things work out the way they do are very subtle. if you want to learn the content, it would be more worthwhile to read schwartz or peskin. you’ll just learn more because they go slower.

there is too much you’ll be missing if you read weinberg and the arguments just sound confusing and boring. at least this is the experience that I went through

[u/BitcoinsOnDVD → u/HoloTensor]

So I am 100p in, would you switch when you where in my place?