International Conference on Precision Physics of Simple Atomic Systems

Session

Session 6

19 May 2026, 11:00

Festsaal (ÖAW)

91. Precision determination of the alpha–helion particle charge radius difference with ultracold helium

Kjeld S.E. Eikema (Vrije Universiteit Amsterdam)

19/05/2026, 11:00

Invited Talk

Precision spectroscopy measurements on calculable systems are widely used to perform tests of theory, but also for determinations of fundamental constants, nuclear charge radii, and as a probe of physics beyond the standard model. We will present spectroscopy in ultracold $^3$He and $^4$He, on the 2 $^3$S$_1$ – 2 $^1$S$_0$ transition at 1557 nm.

Our latest measurement have been performed...

33. Postselection shifts the transition frequency of helium in an atomic beam

Dr Jinlu Wen (Institute of Advanced Light Source Facilities, Shenzhen)

19/05/2026, 11:40

Talk

Precision spectroscopy of few-electron systems, such as hydrogen and helium, has significantly advanced modern physics. By comparing high-precision spectroscopy measurements in these simple atomic systems with theoretical calculations, we can test quantum electrodynamics (QED), determine fundamental physical constants, and impose constraints on physics beyond the Standard Model. Over the past...

93. High Precision theory for the Rydberg $P$-states of helium and comparison with experiment up to principal quantum number $n=102$

Gordon Drake (University of Windsor)

19/05/2026, 12:00

Talk

High-precision measurements of transition frequencies to the $P$-states of helium [1] for principal quantum number $n$ as high as 102 have confirmed a 9$\sigma$ disagreement between theory and experiment for the ionization energy of the $1s2s\;^3S_1$ state. However, traditional theoretical methods of calculation fail in this range of high $n$ for comparison. This paper presents high precision...