Correlation function quantum Monte Carlo calculations for ground and excited states of many-electron atoms and ions in neutron-star magnetic fields

本项目的目标是将关联函数量子蒙特卡罗（CF）方法应用于中子星星磁场中中重原子和离子的原子数据计算。该方法可以计算基态、激发态和跃迁率，已被Jones、Ortiz和Ceperley成功地应用于弱中子星星磁场中原子数据的计算。他们使用具有球对称性的哈特里-福克基组，这限制了他们可以研究的最大场强。这些作者已经指出，对于使用绝热近似的强磁场，可以选择不同的基组。这正是我们想要做的：随着磁场的增加，考虑圆柱对称性的优势越来越大的基组，并将它们纳入CF算法。这些基本状态将通过我们在以前DFG资助的项目中开发的方法计算，即Hartree-Fock-Roothaan基本状态，混合物来自更高的朗道水平，甚至超过绝热近似。该项目的重要性是双重的：在方法方面，我们将测试和展示CF方法的范围和力量。在物理方面，我们将生成中子星星磁场中的中重原子和离子的波长和振子强度的原子数据，这些数据具有前所未有的准确性，与最近在孤立中子星的热发射光谱中发现的特征分析直接相关。

The goal of this project is to apply the correlation function quantum Monte Carlo (CF) method to the calculation of atomic data of medium-heavy atoms and ions in neutron star magnetic fields. The method, which allows for the calculation of both ground and excited states, and transition rates, has been successfully applied by Jones, Ortiz and Ceperley to the calculation of atomic data in weak neutron star magnetic fields. They used Hartree-Fock basis sets with spherical symmetry, which limited the maximum field strength they could study. These authors already remarked that a different basis set could be chosen for strong magnetic fields using the adiabatic approximation . This is exactly what we want to do: Take basis sets which account for the growing dominance of the cylindrical symmetry as the magnetic field is increased and to incorporate them into the CF algorithm. These basis states will be computed by a method that has been developed by us in a previously DFG funded project, namely, Hartree-Fock-Roothaan basis states, with admixtures from higher Landau levels, which even go beyond the adiabatic approximation. The importance of the project is twofold: On the methodological side we will test and demonstrate the scope and power of the CF method. On the physical side we will generate atomic data for wavelengths and oscillator strengths with unprecedented accuracy for medium-heavy atoms and ions in neutron star magnetic fields that are of immediate relevance to the analysis of features recently discovered in the thermal emission spectra of isolated neutron stars.