Konwersatorium im. Leopolda Infelda

Hydrogenic systems like H, $mu$H, muonium, and positronium are being considered for the determination of fundamental physical constants and for low-energy tests of the Standard Model. The precision of these tests, however, is limited either by a short natural life-time or by uncertainties in the nuclear structure.
Additionally, the mean square charge radius observed for the proton structure in electronic and muonic hydrogen differs significantly, and the source of this disagreement remains unknown. This so-called proton radius puzzle results in large uncertainty in the Rydberg R$_infty$ constant.

I propose to perform high-precision calculations for two- and three-electron systems, such as helium- and lithium-like ions, and H$_2$ molecule. Together with ongoing and planned high precision measurements, this will lead to the improved determination of the absolute nuclear charge radii.
Moreover, combined with the muonic determination of nuclear charge radii, this will allow low energy tests of the Standard Model and improved determination of fundamental physical constants.