Nonperturbative study of the damping of giant resonances in hot nuclei

The damping of dipole and quadrupole motion in ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ at zero and finite temperature is studied including particle-particle and particle-hole interactions to all orders of perturbation. We find that the dipole dynamics in these light nuclei is well described in terms of mean-field theory (time-dependent Hartree-Fock), while the quadrupole motion is strongly damped through the coupling to more complicated configurations. Both the centroid and the damping width of the quadrupole and dipole giant resonances show a clear stability with temperature as a consequence of the weakening of the interaction, which contrasts with the increase of the phase space.