Speaker
Dr
Yuji Satoh
(University of Tsukuba)
Description
We discuss the MHV amplitude/null-polygonal Wilson loop
of $ {¥cal N} =4 $ SYM at strong coupling. The amplitude/Wilson loop is
evaluated by the area of minimal surfaces in AdS, which are analyzed
by integral equations of the thermodynamic Bethe ansatz (TBA) type.
When the surfaces are embedded in AdS$_{3}$ or AdS$_{4}$, the integral
equations are identified with the usual TBA equations of a two-dimensional
integrable model called homogeneous sine-Gordon (HSG) model. The HSG
model is obtained by an integrable deformation of a coset CFT. In special cases,
the associated TBA system reduces to simpler ones for perturbed diagonal
coset CFTs/(W-)minimal models. Based on these facts, we derive an analytic
expansion of the amplitude/Wilson loop around the limit where the Wilson loop
becomes regular polygonal.
