Tensor force and Delta excitation for the structure of light nuclei

We treat explicitly Δ (1232) isobar degrees of freedom using bare nucleonnucleon interaction, which can be the origin of the three-body forces via the pion exchange. We adopt the Argonne delta model potential (AV28) and study the explicit role of Δ in light nuclei. It is surprising that the additional Δ states generate strong tensor correlations from the transitions between N and Δ states, and change various matrix elements from the results with only the nucleon space.