氦原子低能跃迁魔幻波长的精确理论计算

Precision calculations of the stark effect caused by the interactions between atoms and light are not only a fundamental research project in atomic physics, but also the theoretical basis for the analysis of the systematic errors of the precision measurement experiments. In this project, we will perform high-precision calculations on energies, wavefunctions and dynamic dipole polarizabilities for the low-lying states of helium with Hylleraas variational method, reliable theoretical datas will be provided to analyze the AC stark shifts in helium precision experiments; then the relativistic and QED corrections of dynamic dipole polarizabilities will be precisely calculated with perturbation theoty, on basis of these calculations, magic wavelengths will be determined to ppm level, which can be used to explore the promising candidates for magic wavelength trap design in optical lattice for helium precision experiments; the tune-out wavelength around 413nm for helium 23S1 state will be caculated with greatly improved accuracy to compare with the related experiments carried out in ANU. QED corrections of dynamic dipole polarizabilities are calculated for the first time in this project. Combing the high-precision theoretical predictions of magic wavelength and tune-out wavelength with experiments would provide a precision test of fundamental atomic structure theory.

原子与光相互作用产生的斯塔克频移的精密计算是原子物理的基础研究课题，也是精密光谱实验系统误差分析的理论基础。本项目拟采用Hylleraas基组方法高精度计算氦原子低能态能级、波函数和动力学极化率，为分析氦原子精密测量实验中由斯塔克频移导致的系统误差提供可靠的理论数据；继而利用微扰理论精确计算动力学极化率的相对论与QED修正，实现氦原子低能跃迁魔幻波长ppm量级的理论预言，为光晶格中氦原子精密光谱的实验设计提供精确的理论参数；针对澳大利亚国立大学开展的氦原子23S1亚稳态在413nm附近幻零波长的精密测量实验，提高该幻零波长的计算精度，理论预言精度达到或好于实验测量精度。该项目的实施将首次在氦原子动力学极化率的计算中考虑QED效应，高精度的魔幻波长、幻零波长的理论预言与实验测量的比对将提供原子结构理论的精确检验。

在氦原子光谱精密测量的实验中，AC Strark频移是系统误差的主要来源之一。因此提高氦原子精密测量实验的精度，就需要有效的控制和减少系统的AC Strark频移，而对氦原子动力学极化率的高精密计算又是处理AC Strark频移的关键。本项目采用Hylleraas基组方法高精密计算了氦原子低能态能级，波函数和动力学极化率；发展了计算氦原子静电/动力学极化率相对论及QED效应的理论方法；研究了氦原子23S1亚稳态动力学电偶极极化率的相对论核反冲修正和QED修正，得到了氦原子亚稳态 413 nm 幻零波长迄今为止最高精度的理论预言值413.090 15(4) nm，较澳大利亚国立大学Ken Baldwin小组的实验测量精确25倍；首次提出利用瑞利散射理论来研究幻零波长，并成功实现了长度和速度规范下计算氦原子413nm幻零波长，在此基础上可以计算幻零波长的相对论和QED修正。