Conformal field theory on $T\bar{T}$-deformed space and correlators from dynamical coordinate transformations

Abstract

We study the map between two descriptions of the $T\bar{T}$ deformation of conformal field theory (CFT): One is the defining description as a deformation of CFT by the $T\bar{T}$-operator. The other is an alternative description as the undeformed CFT on the dynamical $T\bar{T}$-deformed space that backreacts to the state or operator insertions, reminiscent of the theory of gravity. Instead of adopting the topological gravity description, we develop a more literal CFT-based operator formalism that facilitates systematic and straightforward computations of the $T\bar{T}$-deformation of the stress tensor, operators, and their correlators, while rederiving known results in the literature. Along the way, we discuss the backreaction to the $T\bar{T}$-deformed space in response to local operators and exhibit the hard-disk and free-space structures in the UV-cutoff and Hagedorn phases, respectively, suggested by Cardy-Doyon and Jiang. To capitalize on the alternative description of the $T\bar{T}$-deformed CFT, we focus on the correlators of semi-heavy operators, i.e., the operators of large conformal dimension $\Delta\gg\sqrt{c}$, and show an intuitive and simple way to obtain the $T\bar{T}$-deformed correlators from those of the undeformed CFT on the $T\bar{T}$-deformed space via dynamical coordinate transformations. This may have implications in the holographic dual description, pointing towards a working dictionary for a class of matter correlators in the cutoff AdS picture.