Landau parameters and thermodynamic properties of liquid helium II

The variation of the Landau parameters with density and hard-core diameter is calculated for liquid helium using interparticle potentials composed of a hard core followed by a combination of a repulsive and an attractive Gaussian potential, and a hard core followed by a Lennard-Jones potential. Calculations are done only for high-density boson systems. The calculations of specific heat and entropy show good agreement with the experimental results in the very low-temperature region (T<1.0 K) and for the Gaussian potential only