The Nuclear Force from Lattice QCD

The nucleon-nucleon (NN) potential V_{NN}(r) is studied by the lattice QCD simulations in the quenched approximation, using the plaquette gauge action and the Wilson quark action on a 32^4 \simeq (4.4 fm)^4) lattice. From the equal-time Bethe-Salpeter wave function, we extract the central part of the NN potentials in the ^1S_0 and ^3S_1 channels. The extracted potential has a strong repulsive core of a few hundred MeV at short distances (r \alt 0.5 fm) surrounded by a relatively weak attraction at medium and long distances. These features are consistent with the empirical structure of the nuclear force