Hall 123

Modular invariance in 2d quantum field theories

Shouvik Datta

UCLA

Modular invariance in 2d conformal field theories (CFTs) relates low-energy data to high-energy asymptotics. In the first part of this talk, I shall demonstrate how modular properties of correlation functions on the torus (and its orbifolds) can be used to extract high-energy asymptotics of coefficients appearing in the CFT operator product expansion. The results are universal and have implications for 2-to-2 scattering of black holes and thermalization. In the second half, I shall discuss a special class 2d QFTs, arising from deformations of 2d CFTs. This deformation turns out to be unique, once we require modular invariance along with a one-to-one map between the spectra of the deformed and undeformed theories.