(Non)singular Kantowski-Sachs universe from quantum spherically reduced matter - art. no. 024008

Using the s-wave and large-N approximation the one-loop effective action fo r 2D dilaton coupled scalars and spinors which are obtained by spherical re duction of 4D minimal matter is found. Quantum effective equations for redu ced Einstein gravity are written. Their analytical solutions corresponding to a 4D Kantowski-Sachs (KS) universe are presented. For quantum-corrected Einstein gravity we get a nonsingular KS cosmology which represents (1) a q uantum-corrected KS cosmology which existed on a classical level or (2) a p urely quantum solution which had no classical limit. The analogy with the N ariai BH is briefly mentioned. For purely induced gravity (no Einstein term ) we found a general analytical solution but all KS cosmologies under discu ssion are singular. The corresponding equations of motion are reformulated as a classical mechanics problem of motion of a unit mass particle in some potential V. [S0556-2821(99)08112-6].