Quantum mechanical treatment of nuclear friction in coupled-channels heavy-ion fusion

Nuclear friction causes energy dissipation in heavy -ion collisions. Its understanding and inclusion in quantum mechanical reaction models are crucial for advancing the physics of heavy -ion reactions forming heavy elements. The effects of nuclear friction on heavy -ion fusion reactions are investigated using the coupled -channels densitymatrix method. In this open -quantum -system description, a phenomenological nuclear friction form factor is introduced along with coherent coupled -channels effects. The key nucleus was the 92 Zr target, due to its high density of low-lying non -collective excited states, which was recently theorised to be cause of nuclear friction. The calculations using the 16 O + 92 Zr collision showed that the inclusion of nuclear friction effects increased the fusion probability significantly, and that the agreement between the theoretical and experimental fusion barrier distributions was improved when nuclear friction effects were included.