# Relation between QFT and algebraic geometry

So, I've read this article who mentioned that physicists in LHC, while calculating the Feynman diagrams in one of their experiments, noticed a strange pattern: the numbers emerging from Feynman's diagrams were the same of periods in algebraic geometry.

Original source : Quanta Magazine , which seems well worth reading.

Over the last decade physicists and mathematicians have been exploring a surprising correspondence that has the potential to breathe new life into the venerable Feynman diagram and generate far-reaching insights in both fields. It has to do with the strange fact that the values calculated from Feynman diagrams seem to exactly match some of the most important numbers that crop up in a branch of mathematics known as algebraic geometry. These values are called “periods of motives,” and there’s no obvious reason why the same numbers should appear in both settings. Indeed, it’s as strange as it would be if every time you measured a cup of rice, you observed that the number of grains was prime.

So, my question is:

If there is, actually, this relation between algebraic geometry and quantum mechanics, what would be the greatest implications and how would it be helpful for physics?

• Interesting article, but pretty high level on anything. Is there a real article that does a survey of where the idea is, with some real physics and math backgrounds? To me, it's suggestive, but certainly not a paper for a serious summary and depiction of the standing of the hypothesis. Not too different, in that sense of semi-superficiality, to the other Quanta article on Verlinde's hypothesi that gravity is an entropic entity and also by the way due to entanglement, of which there have been multiple write ups arguing vs it. We need some serious treatments, this is titillation, IMHO. – Bob Bee Dec 1 '16 at 3:49
• Are there other examples of similar coincidences on the past? Maybe it would help answer my question, and thus serve as an example of how these "coincidences" are benefical or not for physics (by not benefical, i meant something that is not bad, but doesn't help at all). – Vitor C Goergen Dec 1 '16 at 12:06

The Quanta magazine article you link references "Knots and Numbers in $\varphi^4$ Theory to 7 Loops and Beyond" by Broadhurst and Kreimer from 1995 which does not even mention the word "period" anywhere in it, but nevertheless draws connections between the numbers appearing in amplitudes via Feynman diagram computations and combinatorial objects, the Catalan numbers.
• The "Knots and Numbers..." article may not mention periods, but the infinite sum on $p$ in the abstract gives values of the Riemann zeta function, which are related to periods ($\zeta(2)=\pi^2/6$ for example.) The Catalan number coefficient, being integer, is not as interesting. I asked a similar question at MathOverflow: mathoverflow.net/questions/255331/… – Stopple Dec 2 '16 at 16:56