High-energy bounds on total cross sections in N=4 SYM from AdS/CFT

Abstract: Using the AdS/CFT correspondence, we study the high-energy behavior of scattering amplitudes in N=4 SYM gauge theory for dipole-dipole soft elastic scattering, described in the Wilson-loop correlator formalism. The amplitudes are evaluated in the dual picture, at large impact-parameter, by considering the exchange of supergravity fields between certain minimal surfaces in Euclidean AdS_5, and performing the appropriate analytic continuation to Minkowskian signature. The purely elastic behavior at large impact-parameter is then combined with the unitarity constraint in the central region, in order to derive an absolute bound on the high-energy behavior of the dipole-dipole total cross section. The possibility to obtain a stronger bound by assuming a larger domain of validity for the AdS/CFT result is also discussed.