Soumangsu Chakraborty: Non-AdS holography from the worldsheet

Holography in asymptotically non-AdS spacetime, in general, turns out to be a difficult problem to tackle systematically. Recent development in solvable irrelevant deformations (e.g. TTbar and JTbar deformation of CFT2) and its maps to solvable worldsheet AdS_3 deformations allows us to study a certain class of non-AdS holography in a controlled setup. In this talk, I'll introduce a certain class of integrable irrelevant deformation (often called single trace TTbar deformation) of a CFT_2 dual to string theory in AdS_3 with pure NS-NS flux. The dual geometry is no longer asymptotically AdS. It interpolates between AdS_3 in the IR (deep inside the bulk geometry) to flat spacetime with a linear dilaton in the UV (near the boundary). Such a setup can be shown to be holographic with full worldsheet control on the bulk side. The boundary field theory is ``closely related" to the symmetric product of TTbar deformed CFT. The spectrum of a winding w long string can be computed from the worldsheet and can be shown to match exactly with the Z_w twisted sector of the symmetric product of TTbar deformed CFT. Next, I'll put a black hole in the interpolating geometry and talk about its thermodynamics and its resemblance with the thermodynamics of TTbar deformed CFT. As an application to non-AdS holography, I'll construct operators of the boundary theory, compute their correlation functions using worldsheet techniques, and show a match with those obtained by Cardy for TTbar deformed CFT. I'll also talk about certain entanglement properties of the boundary theory with a monotonicaly decreasing c-function.