Recent results and implications of no-core MCSM calculations for nuclear structure

Owing to recent progress in computational environments and nuclear many-body calculational techniques, ab-initio approaches to nuclear structure and reactions have advanced greatly and are providing first principles results for low-energy nuclear theory. As one of these ab-initio many-body methods, the no-core Monte Carlo shell model (MCSM) has also been developed and applied. In this contribution, we will briefly summarize the current status of no-core MCSM calculations. No-core MCSM results in p-shell nuclei with realistic two-nucleon forces will be given as one of the demonstrations for the capability of our method. Regarding the inclusion of three-body-force effects, the no-core MCSM calculations with chiral EFT interactions will be presented. Our attempts for the study on alpha-cluster structure and molecular-orbital states in light nuclei will also be mentioned, focusing on the Be and C isotopes.