The giant graviton expansion

We propose and test a novel conjectural relation satisfied by the superconformal index of maximally supersymmetric U(N) gauge theory in four dimensions. Analogous relations appear to be also valid for the superconformal indices of a large collection of other gauge theories, as well as for a broad class of index-like generating functions. The relation expresses the finite N index as a systematic series of corrections to a large N answer. …