Ab initio effective interactions for sd -shell valence nucleons AbINITIO EFFECTIVE INTERACTIONS for ... E. DIKMEN et al.

We perform ab initio no-core shell-model calculations for A=18 and 19 nuclei in a 4 Ω, or Nmax=4, model space by using the effective JISP16 and chiral N3LO nucleon-nucleon potentials and transform the many-body effective Hamiltonians into the 0 Ω model space to construct the A-body effective Hamiltonians in the sd shell. We separate the A-body effective Hamiltonians with A=18 and A=19 into inert core, one-, and two-body components. Then we use these core, one-, and two-body components to perform standard shell-model calculations for the A=18 and A=19 systems with valence nucleons restricted to the sd shell. Finally, we compare the standard shell-model results in the 0 Ω model space with the exact no-core shell-model results in the 4 Ω model space for the A=18 and A=19 systems and find good agreement.