| Institute of Theoretical Physics |
| Chinese Academy of Sciences |
| State Key Laboratory of Theoretical Physics |
| Seminar |
| Title 题目 | Microscopic Understanding of Energy-Dependent Collective Potential and Friction Parameter in Fusion Reaction |
| Speaker 报告人 | Professor Fumihiko Sakata |
| Affiliation 所在单位 | Ibaraki University, Japan and Institute of Theoretical Physics, Chinese Academy of Sciences |
| Date 日期 | 2014年4月28日（周一）上午10：00 |
| Venue 地点 | Conference Hall 322, ITP/理论物理所322报告厅 |
| Abstract 摘要 | Applying a macroscopic reduction procedure on the improved quantum molecular dynamics (ImQMD), a set of macroscopic collective potential, friction parameter and random force characterizing the Langevin-type description of the heavy-ion fusion process is extracted. Systematic calculation of the ImQMD shows that an approximate fluctuation-dissipation relation in a symmetric heavy-ion fusion head-on reaction just above the Coulomb barrier fades out when the incident energy increases. It turns out that this systematics is caused by specific behavior of friction parameter which directly depends on the microscopic dynamical process how the collective energy of relative motion is transferred into the intrinsic excitation energy. It is clearly shown that the microscopic mechanism of energy dissipation is controlled by two-competitive processes; One is caused by the nucleon exchange between two fusing nuclei, and the other is due to a rearrangement process of forming a new coherent and collective state in the nucleus where many nucleons are exchanged with the other nucleus. The former mechanism increases the dissipative energy, while the latter plays a role to suppress it. The latter mechanism depends on an adiabatic parameter characterized by a velocity of relative motion between two fusing nuclei and that of the intrinsic motion, and is responsible for the energy dependence of the fusion potential as well as a fading out mechanism of the fluctuation-dissipation relation. |
| Contact Person 所内合作者 | 周善贵 |
