Physicist Elmer Gründeman conducted research in fundamental physics, developing techniques to enable precise measurements. The energy structure of simple atoms (consisting of an atomic nucleus and an electron) can be calculated with extreme accuracy. At the same time, this energy structure can be measured very precisely using lasers.
Gründeman compared the experimental results with theoretical predictions, allowing him to test and refine the underlying theory. The energy structure of the helium ion (He+) is highly sensitive to effects we cannot yet fully describe but is difficult to measure accurately due to the large energy difference between the ground state (1S) and the first excited state (2S). Gründeman developed a laser capable of bridging this energy gap and demonstrated that this transition can indeed be crossed. He also established the infrastructure to conduct precision measurements of this transition in the future.
More information on the thesis