Recent progress on the chiral unitary approach to meson meson and meson baryon interactions

We report on recent progress on the chiral unitary approach, analogous to t he effective range expansion in Quantum Mechanics, which is shown to have a much larger convergence radius than ordinary chiral perturbation theory, a llowing one to reproduce data for meson meson interaction up to 1.2 GeV. Ap plications to physical processes so far unsuited for a standard chiral pert urbative approach are presented. Results for the extension of these ideas t o the meson baryon sector are discussed, together with applications to kaon s in a nuclear medium and K- atoms.