Superfluid transition temperature from the Lindemann-like criterion

We further analyze the recently proposed criterion, according to which a superfluid transition occurs whenever the r.m.s. displacement of a particle from its initial position in imaginary time reaches a certain fraction of the interparticle distance. The critical temperature Tλ is expressed in terms of the single particle mobility. Within the Drude approximation for the mobility Tλ is determined by the friction coefficient (or by the viscosity for dense liquids). To check the validity of the criterion the resulting formula is applied to nonideal Bose gas, to liquid helium and to 3He-4He mixtures. A reasonable qualitative agreement with available experiments is obtained in all cases. In the case of the Bose gas the present approach results also in an upper bound on the peak value of Tλ/Tλ0, where Tλ0 is the critical temperature for the ideal gas