Determinant Formula for the Octagon Form Factor in N=4 Supersymmetric Yang-Mills Theory

We present a closed expression for the octagon form factor which appears as a building block in a class of four-point correlation functions in N=4 supersymmetric Yang-Mills theory considered recently by Coronado. The octagon form factor is expressed, to all loop orders, as the determinant of a semi-infinite matrix. We find that perturbatively at weak coupling the entries of this matrix are linear combinations of ladder functions with simple...