Description:

Abstract: In this talk, we'll discuss the current state-of-the-art for constructing multi-loop integrands in N=4 super-Yang-Mills.  After briefly covering some of the key goals, background, and ideas behind the multiloop integrand program, we turn to the cutting edge: constructing the complete (planar and non-planar) integrand for the six-loop four-point amplitude in maximal D <= 10 super-Yang-Mills. This construction employs new advances that combat the proliferation of loops and state-sums when evaluating multi-loop D-dimensional unitarity cuts.  Concretely, it uses two graph-based approaches, applicable in a range of theories, to evaluating generalized unitarity cuts in D dimensions: 1) recursively from lower-loop cuts, or 2) directly from known higher-loop planar cuts.  Neither method relies on explicit state sums or any sewing of tree-level amplitudes.  The first method meshes particularly well with the Method of Maximal Cuts to allow direct construction of the complete six-loop integrand.

Speaker: Alex Edison, Uppsala University, Sweden

Host: John Joseph Carrasco