Algebraic Combinatorics Seminar - Marcel Golz

Title: Chord diagrams, colours, and QED

Abstract:

Feynman graphs in quantum electrodynamics are essentially chord diagrams with photon edges taking the role of chords attached to lines or cycles given by electron edges. The associated Feynman integrals involve traces of Dirac gamma matrices whose computation leads to large sums of scalar Feynman integrals (cf. the earlier talk by O. Schnetz).
I will present a method to compute these traces combinatorially by counting certain coloured subgraphs in chord diagrams.