The AdS/CFT correspondence relates string theory on an Anti de Sitter (AdS) background to a dual conformal field theory (CFT) living on the boundary of AdS. One promising strategy for how to prove the duality is to consider the `tensionless' limit of string theory in which the dual CFT becomes weakly coupled. For the case of string theory on AdS3 we have recently identified a solvable world-sheet description for this tensionless limit. This opens the way towards proving the AdS/CFT correspondence, at least for this specific set-up. Please contact Dionysios Anninos (dionysios.anninos@kcl.ac.uk) for the zoom link.

String theory on AdS3 x S3 x T4 with one unit of NS-NS flux is argued to be exactly dual to the symmetric orbifold of T4 in the large N limit. The string theory background can be described in terms of a solvable world-sheet theory. This allows one to compute the complete single-string spacetime spectrum and thereby demonstrate that it agrees with the that of the symmetric orbifold of T4. Furthermore, the structure of the symmetric orbifold correlators can be reproduced from the world-sheet perspective.

The conjectured relation between higher spin theories on anti de-Sitter (AdS) spaces and weakly coupled conformal field theories is reviewed. I shall then outline the evidence in favour of a concrete duality of this kind, relating a specific higher spin theory on AdS3 to a family of 2d minimal model CFTs. Finally, I shall explain how this relation fits into the framework of the familiar stringy AdS/CFT correspondence.