Our group studies few-electron systems in strong electromagnetic fields, i.e., highly charged ions (HCI). Especially hydrogen-like and lithium-like heavy ions, such as 207Pb81+, 209Bi80+, 209Bi82+ or 235U91+, offer the unique possibility to investigate fundamental processes and symmetries. This includes the high-precision spectroscopy of dipole-forbidden transitions in highly charged ions to determine the contributions of strong-field quantum electrodynamics in bound systems to the transition energies. This comprises the QED predicted effects known as „vacuum polarization“ and „self energy“, which become very significant in high fields, as they exist around the core of high-Z atoms. Due to the Z9-dependence of the hyperfine-splitting in these ions the M1 transitions can be accessed by well-known laser spectroscopy techniques to resolve these QED contributions with very high precision.
These types of experiments are performed by our group either on HCI-beams trapped in the (ESR) or on cold and dense ion clouds confined in a Penning trap. experimental storage ring