Development of Next-Generation Relativistic Program for All-Order Treatment of Many-Electron Systems

对原子和分子结构以及碰撞的定量理解是理论原子和分子物理学的主要研究领域之一。这一领域的研究成果是对包括天体物理、等离子体科学和量子信息在内的广泛基础和应用科学领域的基础理论和实验研究的关键投入。此外，这项研究对具有重要社会意义的重要实际应用具有重要意义，例如为GPS系统开发更好的时钟。迄今为止，这一领域的成功主要限于对较简单的原子系统的研究；对元素周期表中较复杂的原子还没有达到类似的理解水平。该项目的重点是开发一种高精度的理论和计算方法，力求将对过渡金属复杂原子的理论理解提高到目前只提供给简单得多的原子系统的相同复杂程度。如果成功，这些结果可能会打开元素周期表的大部分应用，而在此之前，只有最简单的原子才能实现这些应用。因此，该项目为学生和博士后研究员在物理学科学研究前沿课题上的培训提供了充足的机会。该项目旨在开发一种基于大规模组态相互作用和全阶线性耦合团簇方法的新一代完全相对论广泛适用的原子代码，能够以几个百分点的精度预测开壳原子的性质。该代码的主要特点是能够处理目前无法准确描述原子性质的系统。虽然最近在高精度原子计算方面取得了巨大的进展，但处理d壳层和f壳层开放系统中的关联对AMO理论提出了前沿挑战。这个项目将解决目前处理d壳层和f壳层原子开放系统中的关联所需方法的以下缺点：省略了三体相互作用，启动势的选择有限，以及需要有效地选择最重要的组态来构建非常大的组态空间。生成的程序将能够计算广泛的原子性质，包括能量、g因子、超精细常数、各种跃迁矩阵元素、电偶极和电四极的静态和动态极化率、长程相互作用势参数、各种P(宇称)奇效应和T(时间)奇效应、精细结构常数变化测试的灵敏度因子以及局域洛伦兹不变性的原子测试。新一代代码的性能将在具有几个价电子的系统中进行测试。

The quantitative understanding of atomic and molecular structure and collisions represents one of the main areas of research in theoretical atomic and molecular physics. Results from this area of research form key input to fundamental theoretical and experimental studies in a broad range of basic and applied scientific fields, including astrophysics, plasma science, and quantum information. In addition, this research is relevant for important practical applications with important societal implications, such as the development of better clocks for GPS systems. To date success in this area has been primarily restricted to studies of the simpler atomic systems; comparable levels of understanding have not been achieved for more complex atoms in the Periodic Table. This project focuses on developing a high-precision theoretical and computational approach that seeks to bring the theoretical understanding of complicated atoms of transition metals to the same level of sophistication afforded presently only to much simpler atomic systems. If successful, the results could open up much of the Periodic Table to applications that heretofore could only be pursued with the simplest atoms. As such, this project provides ample opportunities for the training of students and post-doctoral fellows on topics at the leading edge of scientific research in physics. This project aims to develop a next-generation fully relativistic broadly applicable atomic code, based on the combination of large-scale configuration interaction and all-order linearized coupled-cluster method capable of predicting properties of open-shell atoms with precision of a few percent. The main feature of the code is to be able to treat systems where no accurate description of atomic properties is presently possible. While tremendous progress has been made recently in high-precision atomic calculations, treatment of correlation in d- and f-shell open systems present frontier challenges to AMO theory. This project will address the following short comings of current approaches needed for the treatment of correlations in d- and f-shell atomic open systems: omission of three-body interactions, limited choice of the starting potential, and the need for efficient selection of most important configurations for the construction of very large configuration spaces. The resulting code will be able to calculate a wide range of atomic properties including energies, g-factors, hyperfine constants, various transition matrix elements, electric-dipole and electric-quadrupole static and dynamic polarizabilities, long-range interaction potential parameters, various P(parity)-odd and T(time)-odd effects, sensitivity factors for tests of variation of the fine-structure constant and atomic tests of local Lorentz invariance. The performance of the new-generation code will be tested for systems with several valence electrons.