Team

Trapped ions

Scientific activity

The experiment developed at the LKB enables vibrational spectroscopy of H₂⁺ ions for metrology of the m_p/m_e ratio of proton to electron mass. The aim is to obtain 12 significant digits. The experiment uses H₂⁺ ions cooled sympathetically by laser-cooled Be⁺ ions. The lasers used to excite the vibrational transitions are referenced to the international system via the REFIMEVE network.

The theoretical part involves high-precision calculations of the energy levels of molecular hydrogen ions. The models used are the Schrôdinger equation of the three-body problem with relativistic corrections, or the Dirac equation with two centers, with, in both cases, the calculation of radiative and hyperfine structure corrections.

The experiment developed in collaboration with the MPQ laboratory at Université Paris-Cité and the PIIM laboratory in Marseille involves the sympathetic cooling of light ions (Be⁺) by laser-cooled Sr⁺ ions, to simulate the GBAR experiment and study the stopping power of charged plasmas.

© Johannes Heinrich – Thomas Louvradoux – Laurent HILICO (01/05/2018)

Figure: Fluorescence image of a planar Coulomb crystal made up of 95 Be⁺ ions and one H₂⁺ ion, which appears in black at the center of the cloud.