Quantum Monte Carlo calculations of A=8 nuclei

By R. Wiringa, S. Pieper, J. Carlson, V. Pandharipande. 2000

194 citations recorded by the source corpus.

We report quantum Monte Carlo calculations of ground and low-lying excited states for A=8 nuclei using a realistic Hamiltonian containing the Argonne v{sub 18} two-nucleon and Urbana IX three-nucleon potentials. The calculations begin with correlated eight-body wave functions that have a filled {alpha}-like core and four p-shell nucleons LS coupled to the appropriate (J{sup {pi}};T) quantum numbers for the state of interest. After optimization, these variational wave functions are used as input to a Green's function Monte Carlo calculation made with a new constrained path algorithm. We find that the Hamiltonian produces a {sup 8}Be ground state that is within 2 MeV of the experimental resonance, but the other eight-body energies are progressively worse as the neutron-proton asymmetry increases. The {sup 8}Li ground state is stable against breakup into subclusters, but the {sup 8}He ground state is not. The excited state spectra are in fair agreement with experiment, with both the single-particle behavior of {sup 8}He and {sup 8}Li and the collective rotational behavior of {sup 8}Be being reproduced. We also examine energy differences in the T=1,2 isomultiplets and isospin-mixing matrix elements in the excited states of {sup 8}Be. Finally, we present densities, momentum distributions, and studies of the intrinsicmore » shapes of these nuclei, with {sup 8}Be exhibiting a definite 2{alpha} cluster structure. (c) 2000 The American Physical Society.« less

Subfields: Atomic and Molecular Physics, and Optics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/a3cd26c43373c53f64e3f6a57c27a6dd618db2fc

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Citations in the corpus

Strangeness in nuclei and neutron stars (2020, methodology): “The ab-initio approaches include schemes based on the variational method [306], quantum-montecarlo techniques [324–326], the correlated basis function formalism [327], diagrammatic methods (Brueckner-BetheGoldstone expansion [328], the DBHF approach [329, 330] and the self-consistent Green’s functio”
Microscopic clustering in light nuclei (2017, methodology): “THSR. 3. Comparison with QMC calculations It is well known that the QMC (Quantum Monte Carlo) calculation by the Argonne group gave the -dumbbell density distribution for the 8Be ground band levels (Wiringa et al., 2000). As for the Hoyle state, the calculated excitation energy is about 2.7 MeV high”
Nuclear weak-interaction processes in stars (2002, methodology): “Exact calculations using realistic nucleonnucleon interactions, e.g. by Green’s Function Monte Carlo techniques, are restricted to light nuclei with mass A ≤ 10 (Carlson and Schiavilla, 1998; Pieper, 2002; Wiringa et al., 2000).”