Multi-Instantons and Maldacena's Conjecture

We examine certain n-point functions G_n in N=4 supersymmetric SU(N) gauge theory at the conformal point. In the large-N limit, we are able to evaluate all leading-order multi-instanton contributions exactly. We find compelling evidence for Maldacena's conjecture: (1) The large-N instanton collective coordinate space has the geometry of AdS_5 x S^5. (2) At the k-instanton level $G_n \sim \sqrt{N} g^8 k^n {\cal Z}_k F_n(x_1,...,x_n)$, where F_n is identical to a convolution of n bulk-to-boundary SUGRA propagators, and {\cal Z}_k is the partition function for 10-dimensional N=1 SU(k) gauge theory on flat space, reduced to 0 dimensions; this is in agreement with type IIB superstring calculations, up to an unknown k-dependent normalization factor for {\cal Z}_k.