Accurate High-Performance Atomic Structure Calculations

准确的高性能原子结构计算

• 批准号: RGPIN-2017-03851
• 负责人: FroeseFischer, Charlotte
• 金额: $ 1.68万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=679136
• 关键词: Accurate; Performance; Atomic; Structure; Calculations

The goal of this project is to improve the accuracy of results from the GRASP2K computational model by a factor of 10 for given computer resources by developing new high-performance software that is more efficient, easier to maintain, and can be modified readily for future developments in atomic theory. This requires:******1) Redesigning programs to adhere to current software engineering principles of design and using efficient algorithms for large cases.******2) Recasting programs in the most advanced scientific programming language for high-performance computing.******3) Introducing a proper modular style that anticipates future changes in the model of the nucleus, the Breit correction, and QED effects that define H.******History shows clearly that accuracy can have tremendous impact on the advancement of science. An example is Tycho Brahe (1546-1601) who dedicated his life to developing tools for recording planetary positions ten times more accurately than before. His data was accurate enough for Kepler to discover that the planets moved in elliptic orbits which gave Newton the clues he needed to establish universal inverse-square gravitation theory.******In quantum mechanics, the state of an electronic system is described by a wave function W that satisfies the wave equation H W = E W. Here H is the Hamiltonian of the system and E the total energy. For an atom with N electrons, the wave equation is a partial differential equation with 3N space variables. What makes the problem challenging are the singularities that occur when the distance between the two electrons goes to zero. Observable properties of the system are expectation values of quantum mechanical operators. Thus, when H and W are known, all atomic properties can be predicted. For light atoms, H often is the non-relativistic Hamiltonian. For heavy elements H needs to be based on fully relativistic Dirac theory that includes quantum electrodynamic effects, and a finite model for the nucleus. H for superheavy elements is a current research topic. In atomic physics an accurate computed result needs to agree with an experimental result reported as a value and an uncertainty. For any given H, a challenge for the computational model are the singularities, i.e. correlation in the motion of the electrons.*** ***Test cases for the development of the software will be drawn from current research topics in physics, done in collaboration with international colleagues. The biggest challenges are presented by calculations for heavy elements or highly ionized atoms. An example is the element Astatine (N=85) that is currently being considered for use in targeted cancer therapy. Experimental studies are planned in Sweden. Another critical test would be spectrum calculations for Uranium (N=92) where reliable results have not been reported. In the case of superheavy elements for the search of “islands of stability”, the code could be an important tool for the development of new physics theory.

该项目的目的是通过开发更有效，更易于维护的新的高性能软件，将GRASP2K计算模型的结果的准确性提高到给定的计算机资源的10倍，并且可以轻松修改原子理论的未来发展。 This requires:******1) Redesigning programs to adhere to current software engineering principles of design and using efficient algorithms for large cases.******2) Recasting programs in the most advanced scientific programming language for high-performance computing.******3) Introducing a proper modular style that anticipates future changes in the model of the nucleus, the Breit correction, and QED effects that define H.******History shows显然，准确性可能会对科学的进步产生巨大影响。一个例子是Tycho Brahe（1546-1601），他将自己的一生致力于开发用于录制行星位置的工具，比以前要准确十倍。他的数据足够准确，可以使Kepler发现行星在椭圆形轨道上移动，这为牛顿提供了他为建立通用的逆平方引力理论所需的线索。******在量子力学中，电子系统的状态通过波动函数W描述，使波动方程满足波的H w = e W = e W.这是H w = E W. H h h h h h h h h h h h h h h h h hmilton is the the the System and e the the System and e the the the System and e the the the System。对于具有N电子的原子，波方程是具有3N空间变量的部分微分方程。问题挑战的原因是当两个电子之间的距离为零时发生的奇异性。系统的可观察性能是量子机械运算符的期望值。当知道H和W时，可以预测所有原子特性。对于光原子来说，H通常是非偏见的哈密顿量。对于重元素，需要基于完全相对论的狄拉克理论，该理论包括量子电动力效应和核us的有限模型。 H对于超重元素的h是当前的研究主题。在原子物理学中，准确的计算结果需要与报告为值和不确定性的实验结果一致。对于任何给定的H，计算模型的挑战是奇异性，即电子运动的相关性。*** ***该软件开发的测试用例将从当前与国际同事合作进行的当前物理研究主题中提出。最大的挑战是通过对重元素或高度电离原子的计算提出的。一个例子是目前正在考虑用于靶向癌症治疗的元素（n = 85）。计划在瑞典进行实验研究。另一个关键测试将是铀（n = 92）的频谱计算，其中尚未报告可靠的结果。对于搜索“稳定岛”的超重元素，该代码可能是开发新物理理论的重要工具。