Grant: Discovery Grants Program - Individual

Since the early days of quantum mechanics, he helium atom has posed a special challenge to theorists because it is the simplest atomic system for which the Schroedinger equation cannot be solved exactly.  Our aim is to construct solutions for two- and three-electron atoms (helium and lithium) that are essentially exact for all practical purposes, and to use this as a platform for the exploration of relativistic and quantum electrodynamic  effects at levels of accuracy that were not previously accessible.  In addition to extending and testing basic theory per se, the motivation is to construct new tools to obtain data that would not otherwise be possible, through comparisons with high precision laser resonance measurements.  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 exotic nuclear radii.  Recent successes of experiments at Argonne (U.S.), GSI (Germany) and TRIUMF (Canada) have focused on the so-called neutron-rich "halo" nuclei.  Our combination of theory and experiment creates a unique tool to measure the core inside the neutron halo.  The significance of the results is that they enable one to distinguish amongst the various models proposed for the effective forces holding all nuclei together.   In summary, our theoretical results for the atomic structure of two- and three-electron atoms 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.