EPSILON-EXPANSION IN QUANTUM-FIELD THEORY IN CURVED SPACE-TIME

We discuss E-expansion in curved space-time for asymptotically free an d asymptotically nonfree theories. The existence of stable and unstabl e fixed points is investigated for f phi(4) theory and SU(2) gauge the ory. It is shown that a-expansion maybe compatible with asymptotic fre edom on special solutions of the RG equations in a special case (super symmetric theory). Using epsilon-expansion RG technique, the effective Lagrangian for covariantly constant gauge SU(2) field and effective p otential for gauged NJL model are found in (4 - epsilon)-dimensional c urved space (in Linear curvature approximation). The curvature-induced phase transitions from symmetric phase to asymmetric phase (chromomag netic vacuum and chiral symmetry broken phase, respectively) are discu ssed for the above two models.