I’ve just posted another new article in the physics for mathematicians series. This one introduces interacting quantum field theories, including a discussion of how to talk about particles in an interacting theory, moving from there to a discussion of particle scattering and a result called the LSZ formula, which we’ll use in the subsequent installment to do computations with the famous Feynman diagrams.

More than any other topic I’ve covered in this series, I am very aware that this one is reaching an even smaller audience than usual. It’s a topic I care a lot about, and I’m going to keep working on it for that reason, but I think for the next physics article I’d like to aim for a topic with a bit more reach. (By the way, if you’re enjoying the QFT articles and I haven’t heard from you, you should reach out!) Right now I’m thinking that that means general relativity, which has the advantage of not requiring a lot of physics background to appreciate, but I am of course open to suggestions.