We report quantum Monte Carlo calculations of ground and low-lying excited states for nuclei with A ≤ 7 using a realistic Hamiltonian containing the Argonne v 18 two-nucleon and Urbana IX three-nucleon potentials. A detailed description of the Green's function Monte Carlo algorithm for systems with state-dependent potentials is given and a number of tests of its convergence and accuracy are performed. We find that the Hamiltonian being used results in ground states of both 6 Li and 7 Li that are stable against breakup into subclusters, but somewhat underbound compared to experiment. We also have results for 6 He, 7 He, and their isobaric analogs. The known excitation spectra of all these nuclei are reproduced reasonably well and we predict a number of excited states in 6 He and 7 He. We also present spin-polarized onebody and several different two-body density distributions. These are the first microscopic calculations that directly produce nuclear shell structure from realistic interactions that fit NN scattering data.

No abstract

The J$^{\pi}$=0$^+$ ground state of a drop of 8 neutrons and the lowest 1/2$^-$ and 3/2$^-$ states of 7-neutron drops, all in an external well, are computed accurately with variational and Green's function Monte Carlo methods for a Hamiltonian containing the Argonne $v_{18}$ two-nucleon and Urbana IX three-nucleon potentials. These states are also calculated using Skyrme-type energy-density functionals. Commonly used functionals overestimate the central density of these drops and the spin-orbit splitting of 7-neutron drops. Improvements in the functionals are suggested

No abstract