contain a large number of purely phenomenological parameters. For example, an updated (Nijm92pp \[9\]) version of the Nijm78 potential contains 39 free parameters.

On the other hand, there are many attempts to impose the symmetries of QCD using an effective Lagrangian of pions and nucleons \[10,11\]. These models only capture the qualitative features of the nuclear interactions and could not compete with the much more successful potential models mentioned above.

Despite many efforts, no potential model has yet been constructed which gives a high-quality description of the empirical data, obeys the symmetries of QCD, and contains only a few number of free phenomenological parameters.

In recent years, holography or gauge-gravity duality gave us a new approach to hadronic physics \[12\] and make new progress in understanding the nuclear force.

Nuclear force, the force between nucleons, exhibits a repulsive core of nucleons at short distances. This repulsive core is quite important for large varieties of physics of nuclei and nuclear matter. For example, the well-known presence of nuclear saturation density is essentially due to this repulsive core. However, from the viewpoint of strongly coupled QCD, the physical origin of this repulsive core has not been well understood. Nuclear force especially the 