Title: Supersymmetric field theories and geometric Langlands: The other side of the coin,
Abstract: This note announces results on the relations between the approach of
Beilinson and Drinfeld to the geometric Langlands correspondence based on
conformal field theory, the approach of Kapustin and Witten based on $N=4$ SYM,
and the AGT-correspondence. The geometric Langlands correspondence is described
as the Nekrasov-Shatashvili limit of a generalisation of the AGT-correspondence
in the presence of surface operators. Following the approaches of Kapustin -
Witten and Nekrasov - Witten we interpret some aspects of the resulting picture
using an effective description in terms of two-dimensional sigma models having
Hitchin's moduli spaces as target-manifold.