Spectroscopy of the 1s2s 3S1 – 1s2s 1S0 transition in quantum degenerate Helium

Remy Notermans, Robert J. Rengelink, W. Vassen

Scott Bergeson, K. G. H. Baldwin, Thomas B. Lucatorto +3 more

Randall D. Knight, Michael H. Prior

The density distribution of metastable 1s2s 3S1 Li+ ions confined in a radio-frequency quadrupole ion trap has been studied using a laser scanning technique. The laser beam, resonant with the 5485-Å 1s2s 3S1–1s2p 3P1 transition, is scanned in a plane normal to the trap z axis. Intercombination photons, 1s2 1S0–1s 2p 3P1 at 202 Å, are counted and stored as a function of laser-beam position. Application of the Abel transform to the data gives the density profile in the plane of the scan. In all cases, the density profiles were consistent with a Gaussian distribution of ions. The radial and axial widths of the distribution were measured as a function of the number of ions and potential well depth and shape. The results are discussed in terms of a model in which the ions are in thermal equilibrium at a temperature of several thousand degrees Kelvin.

Kees Steinebach

Although the Standard Model is highly successful, it is not complete. One approach to searching for effects beyond our current understanding of physics is to measure finite-size effects in simple atomic systems through high-precision spectroscopy. In this thesis, we present new measurements of the 2 3S1 -> 2 1S0 transition in 3He and 4He with the highest precision achieved to date. We perform these measurements in ultracold trapped gases in the quantum-degenerate regime. These spectroscopic measurements are used to determine the difference in charge radius between the helion and the alpha particle, the nuclei of 3He and 4He, respectively. By comparing the extracted charge-radius difference with values obtained from other experiments, we test isotope-shift calculations and bound-state quantum electrodynamics.

Denis Boiron, A. Perrin, Valentina Krachmalnicoff +14 more

Q. Hui, John L. Persson, Jaap H. M. Beijersbergen +1 more