Mathematical Field Notes

Archive for August 2016

Nice paper bump

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It’s 7 years old, but I only just came across the following beautiful expository paper of Baez and Huerta on the representation theory underlying the standard model and grand unified theories and I thought I would give it a bump:

https://arxiv.org/abs/0904.1556

It overlaps with some of the material I touch on in the Lie Groups course I teach (using representations to classify particles) but goes into much more gorgeous detail and focuses on fundamental particles rather than baryons/mesons. It is unusually easy to follow (if you know a bit of representation theory) and I learned a lot from reading it.

Written by Jonny Evans

August 31, 2016 at 10:52 pm

Posted in Uncategorized

Is the speed of light constant?

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I recently came across a beautiful argument due to De Sitter (1913), which gave the (first?) experimental evidence that light moves with a constant speed.

Constancy of the speed of light is one of those things that always bothered me, and I spent a couple of days recently trying to unbother myself. De Sitter’s argument is what finally satisfied me. Below, I’m going to explain the background, then I’ll explain De Sitter’s argument. The De Sitter paper is only a couple of paragraphs long and is available via Wikisource, so if you don’t need the introductory remarks in the blogpost below, just follow the link above and read it.

Read the rest of this entry »

Written by Jonny Evans

August 9, 2016 at 5:33 pm

Posted in Physics

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