SUPERFLUID DENSITY OF HE-4 NEAR T-LAMBDA IN 2-LOOP ORDER

We present the results of a renormalization group calculation of the s uperfluid density of He-4 near T-lambda at finite superfluid velocity v(s). Within the phi(4) model for an order parameter with O(n) symmetr y and using field theory in three dimensions, we have computed to two- loop order the amplitude function for the superfluid density up to O(( v(s)/v(sc))(2)). We also give the two-loop expression for the amplitud e function of the order parameter at v(s) = 0. Applications of these r esults are briefly discussed.