GROUND-STATE PROPERTIES OF 2-DIMENSIONAL QUANTUM FLUID HELIUM - VARIATIONAL HYPERNETTED-CHAIN METHODS

We calculate the ground-state energies and the radial distribution fun ctions of two-dimensional quantum fluid He-4, mass 3 boson He-3 and He -3 within a hypernetted chain and a Fermi hypernetted chain summation method To get more accurate results, we include three-body con elation functions in the trial wavefunctions and consider the contributions a rising from elementary diagrams via scaling approximations. The two-di mensional 4He system has a binding energy, of 0.84 K at an equilibrium density 0.042 Angstrom(-2), which is closer to the result of a Green' s function Monte Carlo calculation than previous ones, while mass 3 bo son He-3 has 0.286 K at 0.025 Angstrom(-2). The He-3 system is not sel f-bound and therefore not a liquid state due to ifs statistics and lig ht mass of the He-3 atom. We calculate the ground-state energy of two- dimensional liquid He-4 through a Lennard-Jones potential and that of Aziz to compare the results of both. Aziz's potential gives lower and more accurate energies than the Lennard-Jones potential, as in three d imensions.