Theory of atomic processes and interactions

这项提议的统一主题是通过将高精度理论和实验结合起来应用于原子来开发新的测量工具。两个例子是精细结构常数的一个重要的新值，它是自然界的基本常数之一，以及奇异原子核大小的桌面测量。最近在Argonne(美国)、GSI(德国)和TRIUMF(加拿大)取得的成功侧重于具有额外行星中子的所谓富含中子的“晕”核，如He-6。这些结果的意义在于，它们使人们能够区分为将原子核连接在一起的有效力而提出的各种理论模型。通过研究容易解体的结构，我们了解了将它们结合在一起的力量。未来一个引人入胜的新项目涉及到在基本粒子标准模型之外寻找新的物理，正如晕核贝塔衰变后的角关联所揭示的那样。 最近的两项进展使这些倡议成为可能。首先，在根据第一性原理计算原子性质方面，我们的工作取得了前所未有的精度。其中一些需要SHARCNET的高性能计算设施，以及由于相对论和量子电动力学而计算基本修正的方法方面的根本进步。在SHARCNET的专门资源的帮助下，我已经与加拿大的其他研究人员和中国组成了一个国际合作小组来开展这项工作。其次，我们与世界各地的顶级实验小组密切合作，他们进行精确和灵敏的测量。捕获和研究单个原子的能力起着关键作用。这些合作导致了发表在《物理评论快报》上的一长串联合论文。我们的理论结果主导了这一领域的文献，它们为世界各地的几个实验小组提供了动力，推动了高精度激光计量的最新技术。

The unifying theme of this proposal is the development of new measurement tools through the combined application of both high precision theory and experiment to atoms. Two examples are a significant new value for the fine structure constant, which is one of the fundamental constants of nature, and table-top measurements of the size of exotic atomic nuclei. Recent successes at Argonne (U.S.), GSI (Germany) and TRIUMF (Canada) have focused on the so-called neutron-rich "halo" nuclei with extra planetary neutrons, such as He-6. The significance of the results is that they enable one to distinguish amongst the various theoretical models proposed for the effective forces holding the nucleus together. By studying structures that fall apart easily, we learn about the forces holding them together. A fascinating new project for the future involves a search for new physics beyond the standard model of elementary particles, as revealed by angular correlations following beta decay of the halo nucleus. Two recent advances have made these initiatives possible. First, our work has yielded unprecedented levels of accuracy in calculating the properties of atoms from first principles. Some of this requires the high performance computing facilities of SHARCNET, together with fundamental advances in methods to calculate essential corrections due to relativity and quantum electrodynamics. I have formed an international collaboration of other researchers in Canada and China to carry out this work, with the help of dedicated resources from SHARCNET. Second, we work in close collaboration with the top experimental groups around the world who perform measurements of exquisite accuracy and sensitivity. The ability to trap and study just a single atom plays a key role. A long sequence of joint papers published in Physical Review Letters has resulted from these collaborations. Our theoretical results dominate the literature in this area, and they are providing the motivation for several experimental groups around the world to advance the state-of-the-art for high precision laser metrology.