DESY/Hamburg U. String Theory Seminar

Correlation functions of heavy half-BPS operators in planar N=4 SYM

by Gregory Korchemsky (IPhT Saclay)

I will report on a recent progress in computing four-point correlation functions of infinitely heavy half-BPS operators in planar N = 4 SYM. Taking advantage of integrability of the theory, it has recently been realized that these correlation functions can be constructed in terms of fundamental building blocks - the octagon form factors. We demonstrate that these functions satisfy a system of nonlinear integro-differential equations which are powerful enough to fully determine their dependence on the ’t Hooft coupling and two cross ratios. At weak coupling, solution to these equations yields a known series representation of the octagon in terms of ladder integrals. At strong coupling, we develop a systematic expansion of the octagon in the inverse powers of the coupling constant and calculate accompanying expansion coefficients analytically.