High-resolution laser spectroscopy is an established powerful tool in the study of nuclear
shape, size and multipole moments. Measurements of the hyperfine structures and isotope …

The current status of bound state quantum electrodynamics calculations of transition
energies for few-electron ions is reviewed. Evaluation of one and two body QED correction …

Highly accurate results from frequency measurements on neutral hydrogen molecules H 2,
HD, and D 2 as well as the HD+ ion can be interpreted in terms of constraints on possible …

The energy levels of hydrogen-like atomic systems can be calculated with great precision.
Starting from their quantum mechanical solution, they have been refined over the years to …

Precision physics aims to use atoms and molecules to test and develop the fundamental
theory of matter, possibly beyond the Standard Model. Most of the atomic and molecular …

We critically examine the current status of theoretical calculations of the energies, the fine
structure, and the isotope shift of the lowest-lying states of helium, searching for unresolved …

In a recent breakthrough in first-principles calculations of two-electron systems, Patkóś,
Yerokhin, and Pachucki [Phys. Rev. A 103, 042809 (2021) PLRAAN 2469-9926 …

The neutron-rich He 6 and He 8 isotopes exhibit an exotic nuclear structure that consists of a
tightly bound He 4-like core with additional neutrons orbiting at a relatively large distance …

The very high precision of current measurements and theory predictions of spectral lines in
few-electron atoms allows us to efficiently probe the existence of exotic forces between …

The 2 S 3–2 P 3 transition of He 4 was measured by comb-linked laser spectroscopy using a
transverse-cooled atomic beam. The centroid frequency was determined to be 276 736 495 …