报告题目：Twisted photons and electrons as a new tool for the investigations 

　　报告人：Dr. Vladimir Zaytsev  

　　Department of Physics, Siant-Petersburg State University, Russia 

　　时间：2017年4月13日（星期四）上午9：30  

　　地点：中国科学院近代物理研究所5号楼911会议室 

　　Abstract：Nowadays, the interest to twisted (or vortex) particles increases significantly from both the experimental and theoretical sides. These particles are characterized by the energy, one of the momentum components which sets the propagation direction, and the projection of the total angular momentum on this direction. The interest in such particles is caused mainly by the nonzero value of this projection, being an additional degree of freedom. Indeed, in contrast to the conventional plane-wave particles, vortex particles can carry much bigger amount of information and, as a result, represent a more powerful tool for the investigations. 

　　报告题目：Relativistic coupled-channel calculations of quantum dynamic of electrons  in low-energy heavy ion-atom collisions 

　　报告人：Dr. Yury Kozhedub 

　　Department of Physics, Siant-Petersburg State University, Russia 

　　时间：2017年4月13日（星期四）上午10：30  

　　地点：近代物理所5号楼911会议室 

　　Abstract：Ultrastrong electromagnetic fields occur in highly-charged heavy ions and can be further increased up to supercritical regime in experiments with heavy ions passing each other. One of the most attractive ways for indirect observation of the supercritical field is to investigate the dynamics of inner-shell electrons in heavy-ion collisions. In the talk, a coupled-channel approach for evaluation of relativistic quantum dynamics of electrons is presented. The method is based on an independent particle model, where the many-particle Hamiltonian is approximated by a sum of single-particle Hamiltonians, thus reducing the electronic many-particle problem to a set of single-particle equations for all electrons in the collision system (including negative-energy continuum ones). After solving this set of effective single-particle equations, the many-particle probabilities (including pair-creation probabilities) can be calculated. Solving the effective single-particle equations is based on the coupled-channel approach with atomic-like Dirac-Fock and Dirac-Fock-Sturm orbitals, localized at the ions (atoms).  These orbitals are obtained by solving numerically the one-center Dirac-Fock  and Dirac-Fock-Sturm equations, respectively. Using the evaluated values of cross section and a X-ray radiative analysis, based on fluorescence yields, radiation and Auger decay individual rates, we obtained X-ray emission intensities that can be compared with experimental data. This approach was successfully applied to calculations of relativistic quantum dynamics of electrons in low-energy heavy-ions collisions. The role of relativistic effects is analyzed.