Certain objects of conformal field theory, for example partition functions on the rectangle and the torus, and one-point functions on the torus, are either invariant or transform simply under the modular group, properties which should be preserved under the TTbar deformation. The formulation and proof of this statement in fact extends to more general functions such as TTbar-deformed modular and Jacobi forms. We show that the deformation acts simply on their Mellin transform, multiplying it by a universal entire function. Finally we show that Maass forms on the torus are eigenfunctions of the TTbar deformation.

https://princeton.zoom.us/j/97195348538?pwd=bEhjczRmbnNIZjNydFpYQXN0bXZ…