Time: 13:30-15:00 2023/03/03
Location: Room 401, No. 7 building, KITS, UCAS ZhongGuanCun Campus
Speaker: Boyang Yu (Peking University)
We study universal properties of the torus partition function of TTbar-deformed CFTs under the assumption of modular invariance, for both the double-trace version and the single-trace version. In the double-trace case, we specify sparseness conditions for the light states for which the partition function at low temperatures is dominated by the vacuum when the central charge of the undeformed CFT is large. For the single-trace TTbar deformation, we show that modular invariance implies 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. The partition function and the energy of twisted states match holographic calculations in previous literature, thus providing further evidence for the conjectured holographic correspondence. In addition, we show that the single-trace partition function is universal when the central charge of the undeformed CFT is large and the density of light states saturates the sparseness condition.