A NONPERTURBATIVE TRANSPORT APPROACH INCLUDING PARTICLE COLLISIONS AND DENSITY-FLUCTUATIONS

The dynamical description of correlated nuclear motion is based on cou pled equations of motion for the one-body density matrix rho(11'; t) a nd the two-body correlation function c2(12, 1'2'; t) as obtained from the density-matrix hierarchy. The resulting equations nonperturbativel y describe particle-particle collisions as well as particle-hole inter actions. We propose an approximate solution of the equation of motion for the two-body correlation function c2 which nonperturbatively accou nts for the renormalization of the bare interaction, for in-medium nuc leon-nucleon scattering as well as for the coupling to density fluctua tions or collective phonons. By performing a Wigner transformation and conventional semiclassical limits we obtain a transport equation of t he Vlasov-Uehling-Uhlenbeck type (VUU) coupled to a respective transpo rt equation for the density fluctuations. We present explicit solution s for the ground-state density fluctuations of Ca-40 in phase space an d compare them with the corresponding fluctuations in case of collecti ve monopole excitations.