Tensionless AdS3/CFT2 and single trace TT

One of the few cases of AdS/CFT where both sides of the duality are under good control relates tensionless k = 1 strings on AdS3 to a two-dimensional symmetric product CFT. Building on prior observations, we propose an exact duality between string theory on a spacetime which is not asymptotically AdS and a non-conformal feld theory. The bulk theory is constructed as a marginal deformation of the k = 1 AdS3 string while the spacetime dual is a single trace TT-deformed symmetric orbifold theory. As evidence for the duality, we match the one-loop bulk and boundary torus partition functions. This correspondence provides a framework to both learn about quantum gravity beyond AdS and understand how to defne physical observables in TT-deformed feld theories.