Asymptotically free AdS3/CFT2
Abstract We propose a new AdS3/CFT2 duality, in which the bulk string theory has a target spacetime AdS3 times a squashed three-sphere $$ {\mathbbm{S}}_{\flat}^3 $$ S ♭ 3 , and the dual CFT2 is a symmetric product of sigma models on ℝϕ×$$ {\mathbbm{S}}_{\flat}^3 $$ S ♭ 3 , deformed by a ϕ-dependent ℤ2 twist operator. The duality maps the asymptotic region of AdS3 to the region ϕ → ∞, where the twist interaction in the CFT2 turns off. The AdS3 backgrounds in question have RAdS< ℓs, and so lie on the string side of the string/black hole correspondence transition. As a consequence, the high energy density of states consists of a string gas in AdS3 rather than an ensemble of BTZ black holes. This property allows us to derive the dual CFT2 by a systematic analysis of the worldsheet string theory on AdS3.