Liouville Theory: Ward Identities for Generating Functional and Modular Geometry

Abstract

We continue the study of quantum Liouville theory through Polyakov's functional integral \cite{Pol1,Pol2}, started in \cite{T1}. We derive the perturbation expansion for Schwinger's generating functional for connected multi-point correlation functions involving stress-energy tensor, give the ``dynamical'' proof of the Virasoro symmetry of the theory and compute the value of the central charge, confirming previous calculation in \cite{T1}. We show that conformal Ward identities for these correlation functions contain such basic facts from K\"{a}hler geometry of moduli spaces of Riemann surfaces, as relation between accessory parameters for the Fuchsian uniformization, Liouville action and Eichler integrals, K\"{a}hler potential for the Weil-Petersson metric, and local index theorem. These results affirm the fundamental role, that universal Ward identities for the generating functional play in Friedan-Shenker modular geometry \cite{FS}.