Binding energy of liquid4He calculated by the hypernetted-chain method

The hypernetted-chain (HNC) method for quantum many-body calculations is investigated in some detail by means of calculations of the binding energy and the equilibrium density for liquid⁴He. The calculations are done for six different two-body potentials, and the results are compared with experimental results and other theoretical results obtained by the lowest order constrained variation (LOCV) method. Our HNC results are, in general, quite different from the results obtained by the LOCV method—the LOCV binding energies are generally reduced by 2–5 K in the HNC calculations. The results are also very dependent on the chosen potential, especially at high densities.