Superrandiance and superfluidity in 4He

We study the effect of the superfluidity of 4He of a superradiant interaction among the 4He-atoms. We show that: i) a microscopic two-fluid picture emerges; ii) the T-dependence of the roton energy Δ(T) is correctly described; iii) the p = 0 fraction of the Bose condensate is ρc 0.15; iv) the observed values of the critical velocity vcrit can be adequately understood.