NONPERTURBATIVE PATH-INTEGRAL OF 2D DILATON GRAVITY AND 2-LOOP EFFECTS FROM SCALAR MATTER

Performing a non-perturbative path integral for the geometric part of a large class of 2d theories without a kinetic term for the dilaton fi eld, the quantum effects from scalar matter fields are treated as a pe rturbation. When integrated out to two-loops they yield a correction t o the Polyakov term which is still exact in the geometric part. Intere stingly enough the effective action only experiences a renormalization of the dilaton potential. (C) 1998 Elsevier Science B.V.