Correlation functions in T T ¯ -deformed Conformal Field Theories

We study the correlation functions of local operators in unitary T T ¯ -deformed field theories, using their formulation in terms of Jackiw-Teitelboim gravity. The position of the operators is defined using the dynamical coordinates of this formalism. We focus on the two-point correlation function in momentum space, when the undeformed theory is a conformal field theory. In particular, we compute the large momentum behavior of the correlation functions, which manifests the non-locality of the T T ¯ -deformed theory. The correlation function has UV-divergences, which are regulated by a point-splitting regulator. Renormalizing the operators requires multiplicative factors depending on the momentum, unlike the behavior in local QFTs. The large momentum limit of the correlator, which is the main result of this paper, is proportional to |q|−q2π|Λ| , where q is the momentum and 1/|Λ| is the deformation parameter. Interestingly, the exponent here has a different sign from earlier results obtained by resummation of small q computations. The decay at large momentum implies that the operators behave non-locally at the scale set by the deformation parameter.