Speaker
David Broadhurst
Description
I discuss a family of massive Feynman integrals whose algebraic geometry involves an elliptic curve at two loops, a K3 surface at three loops, and a Calabi-Yau manifold at four loops. They were originally studied in the context of the magnetic moment of the electron. Remarkably, 4-loop integrals yield the areas of black holes in compactifications of 10-dimensional supergravity. At 2 and 3 loops, quasi-modularity leads to resurgence of structure at large and small momenta, which Daniele Dorigoni and I have extended to encompass large and small couplings in topological string theory. As a grace-note, I conclude with a simple example of resurgence that arises from an asymptotic study of combinatorics of the cosmohedron.