DYNAMICAL PROPERTIES OF THE LANDAU-GINZBURG MODEL WITH LONG-RANGE CORRELATED QUENCHED IMPURITIES

We investigate the critical dynamics of the time-dependent Landau-Ginz burg model with nonconserved n-component order parameter (model A) in the presence of long-range correlated quenched impurities. We use a sp ecial kind of long-range correlations g(\r-r'\)similar to\r-r'\(-a), a =4-delta previously introduced by Weinrib and Halperin. The parameter delta similar to epsilon, where epsilon=4-d is the usual small paramet er within the Wilson-Fisher renormalization group theory. Using a doub le expansion in epsilon and delta we calculate the critical exponent z up to second order on the small parameters. We show that quenched imp urities of this kind affect the critical dynamics already in first ord er of epsilon and delta leading to a relevant correction for the mean field value of the exponent z.