Ab initio many-body perturbation theory and no-core shell model

In many-body perturbation theory (MBPT) we always introduce a parameter N-shell to measure the maximal allowed major harmonic-oscillator (HO) shells for the single-particle basis, while the no-core shell model (NCSM) uses N-max(sic)Omega HO excitation truncation above the lowest HO configuration for the many-body basis. It is worth comparing the two different methods. Starting from "bare" and Okubo-Lee-Suzuki renormalized modern nucleon-nucleon interactions, NNLOopt and JISP16, we show that MBPT within Hartree-Fock bases is in reasonable agreement with NCSM within harmonic oscillator bases for He-4 and O-16 in "close" model space. In addition, we compare the results using "bare" force with the Okubo-Lee-Suzuki renormalized force.National Key Basic Research Program of China [2013CB834402]; National Natural Science Foundation of China [11235001, 11320101004, 11575007]; CUSTIPEN (China-U.S. Theory Institute for Physics with Exotic Nuclei) - U.S. Department of Energy, Office of Science [DE-SC0009971]SCI(E)ARTICLE104