Origin of the Six-Gluon Amplitude in Planar N=4 Supersymmetric Yang-Mills Theory

We study the maximally-helicity-violating six-gluon scattering amplitude in planar N = 4 super-Yang-Mills theory at finite coupling when all three cross ratios are small. It exhibits a double logarithmic scaling in the cross ratios, controlled by a handful of "anomalous dimensions" that are functions of the coupling constant alone. Inspired by known seven-loop results at weak coupling and the integrability-based pentagon operator product expansion, we present conjectures for the all-order resununation of these anomalous dimensions. At strong coupling, our predictions agree perfectly with the string theory analysis. Intriguingly, the simplest of these anomalous dimensions coincides with one describing the lightlike limit of the octagon, namely, the four-point function of large-charge Bogomol'nyi-Prasad-Sommerfield (BPS) operators.