We calculate the cooperon for a system of noninteracting electrons in the presence of random potentials with correlations W(r)= W08(r)+ W,r-<d+u> in d dimensions, for arbitrary values a and d, to first order in W1. Our detailed results confirm the exactitude of the universal form for the cooperon proposed earlier by other authors based on general principies. We find that the system will have short-range (long-range) behavior according to a being positive (negative).
Physical review. B, Condensed matter, New York. Vol. 52, no. 7 (Aug. 1995), p. 4631-4634