Giant quadrupole resonances in time-dependent density-matrix theory Original Research Article

Damping of an isoscalar giant quadrupole resonance (GQR) in 40Ca is studied using an extended version of the time-dependent Hartree-Fock theory known as the time-dependent density-matrix theory (TDDM). The Skyrme III force is used as an effective interaction for the calculation of both a mean-field potential and a two-body correlation function, and a correlated state is used as the ground state on which GQR is built. It is found that the calculated strength of GQR is split into a major component and a minor component. The spreading width of the major component is found small as compared with experimental data. A double giant quadrupole resonance (DGQR) is also studied in TDDM, and it is found that DGQR given in TDDM has properties of the double phonon state of GQR calculated in the random phase approximation.