On the universal behavior of TTbar-deformed CFTs | Joint HEP-TH Seminar

Abstract

The torus partition function of TTbar-deformed CFTs is modular invariant. Using this fact, it is shown that TTbar-deformed CFTs exhibit a universal free energy in the high temperature limit and a universal spectrum in the high energy limit. In this work, we show that a much stronger form of universality holds in TTbar-deformed CFTs with a large central charge c for both the double and single-trace version. In the double-trace case, we specify sparseness conditions for the light states for which the free energy is universal at all alowed values of the temperature. In the single-trace case, we show that the torus partition function can be written in terms of the untwisted partition function and its modular images, the latter of which can be obtained from the action of a generalized Hecke operator. In addition, the single-trace partition function is universal and the density of light states saturates the sparseness condition.