High-precision theory of few-body atomic and molecular systems

高精度少体原子分子系统理论

• 批准号: RGPIN-2019-04092
• 负责人: Yan, ZongChao
• 金额: $ 1.75万
• 依托单位: University of New Brunswick
• 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=679767
• 关键词: precision; theory; few; body; atomic

***Few-body atomic and molecular systems, such as H, He, Li, H2+, H2 are fundamental testing grounds for basic physics. Due to the recent development of experimental techniques, such as the femtosecond optical comb technique, measurements of few-body systems can now reach unprecedented precision, providing many opportunities to explore fundamental physics by performing calculations on important effects, such as relativistic and quantum electrodynamic (QED) effects. Through comparisons between theory and experimental data, one can discover possible new physics, such as violation of fundamental symmetries; one can also extract precise values of fundamental constants, such as the fine structure constant through helium fine structure, and the electron-proton mass ratio through transition frequencies in H2+, and study their variation in time.*******Over the past 20 years, we have made significant advances in obtaining high precision solutions to the Schrodinger equation for three and four body systems, which allows us to calculate relativistic and QED effects precisely. One of the important applications of our work is the determination of the nuclear charge radius of halo 11Li, in collaboration with two leading experimental groups at TRIUMF and GSI. To determine the charge radius, it is necessary to calculate the isotope shifts to high precision, including relativistic and QED corrections. While this has been possible for one and two electron systems since the 1980's, for Li the breakthrough came in 2000 when we succeeded in calculating the mass effect in transitions of Li with an uncertainty better than 5 parts per million. The significance of our method is that no other method is both independent of nuclear structure models and capable of yielding sufficient accuracy for the nuclear charge radius. Comparisons with our results are therefore capable of distinguishing amongst the various possible candidates for the nuclear forces.*******Our high precision theory that is now available creates new opportunities to develop measurement tools that would otherwise not exist, and opens up a new area of study at the interface between atomic and nuclear physics. The proposed research program will advance our efforts to further explore relativistic and QED effects for few-body atomic and molecular systems by developing new computational methods, which will pave the way to even more profound advances at the interface between atomic, molecular, and nuclear physics.*********

* 少体原子和分子系统，如H，He，Li，H2+，H2是基础物理的基本试验场。由于实验技术的最新发展，例如飞秒光梳技术，现在对少体系统的测量可以达到前所未有的精度，提供了许多机会，通过对重要效应进行计算来探索基础物理，例如相对论和量子电动力学（QED）效应。通过理论和实验数据之间的比较，人们可以发现可能的新物理，例如基本对称性的破坏;人们还可以提取基本常数的精确值，例如通过氦精细结构的精细结构常数，以及通过H2+中的跃迁频率的电子-质子质量比，并研究它们随时间的变化。在过去的20年里，我们在获得三体和四体系统薛定谔方程的高精度解方面取得了重大进展，这使我们能够精确地计算相对论和QED效应。我们工作的重要应用之一是与TRIUMF和GSI的两个领先实验组合作确定晕11 Li的核电荷半径。为了确定电荷半径，需要高精度地计算同位素位移，包括相对论和QED修正。虽然自20世纪80年代以来，这对单电子和双电子系统是可能的，但对Li来说，突破性进展出现在2000年，当时我们成功地计算了Li跃迁中的质量效应，其不确定性优于百万分之五。我们的方法的意义是，没有其他方法是既独立于核结构模型，并能够产生足够的精度的核电荷半径。因此，通过与我们的结果进行比较，就能够区分各种可能的核力候选者。我们现在可用的高精度理论为开发否则不存在的测量工具创造了新的机会，并在原子物理和核物理之间的界面开辟了一个新的研究领域。拟议中的研究计划将通过开发新的计算方法，进一步探索少体原子和分子系统的相对论和QED效应，这将为原子，分子和核物理之间的界面上更深远的进展铺平道路。