Scattering amplitudes in strongly coupled N=4 SYM from semiclassical strings in AdS

Understand

Very recently in arXiv:0705.0303 Alday and Maldacena gave a string theory prescription for computing (all) planar amplitudes in N=4 supersymmetric gauge theory at strong coupling using the AdS/CFT correspondence.

• These amplitudes are determined by a classical string solution and contain a universal exponential factor involving the action of the classical string.
• On the gauge theory side, expressions for perturbative amplitudes at strong coupling were previously proposed only for specific helicities of external particles -- the maximally helicity violating or MHV amplitudes.
• These follow from the exponential ansatz of Bern, Dixon and Smirnov for MHV amplitudes in N=4 SYM.