Critical temperature of the superfluid transition in bose liquids
A phenomenological criterion for the superfluid transition is proposed, which is similar to the Lindemann criterion for the crystal melting. Then we derive a new formula for the critical temperature, relating $T_λ$ to the mean kinetic energy per particle above the transition. The suppression of the critical temperature in a sufficiently dense liquid is described as a result of the quantum decoherence phenomenon. The theory can account for the observed dependence of $T_λ$ on density in liquid helium and results in an estimate $T_λ \sim 1.1$ K for molecular hydrogen.
cond-mat.stat-mech↗