High Energy Theory Seminar

I review the use of maximal unitarity at two loops, and how to phrase it in terms of multivariate contour integrals.  I show how to use maximal unitarity to reconstruct the ABDK relation between one- and two-loop amplitudes with four and five external legs in the maximally supersymmetric Yang-Mills theory.  I present some of the lessons for the more general maximal unitarity program at two loops.