Precision experiments with stored ions and antimatterMax Planck Institute for Nuclear PhysicsUniversity of HeidelbergEuropean Research Council
Ultracold Ions and Antimatter Research
Contakt Contact
Priv.-Doz. Dr. Alban Kellerbauer

Tel.: +49-6221-516-138
Fax: +41-22-7669185 (efax)

Max Planck Institute for Nuclear Physics
Room Bo-164
Saupfercheckweg 1
69117 Heidelberg


Ultracold Ions and Antimatter Research


to the website of the group of Dr. Alban Kellerbauer. Our work centers around the measurement of ground state properties of exotic atoms and the study of antimatter systems. In order to allow such measurements and/or improve the achievable precisions, we study novel techniques for ion manipulation and cooling. Please use the navigation menu to discover our research projects.

Recent news


CERN Ph.D. stipend for Stefan Erlewein

Stefan Erlewein received a full CERN Ph.D. stipend via the German Gentner program. Congratulations! He will carry out his Ph.D. on the Borealis project at CERN, which aims at laser cooling the molecular anion C2-.

Giovanni Cerchiari passes his Ph.D.

This morning Giovanni Cerchiari passed his doctoral exam with with straight "1.0" marks. Auguri! In his thesis, Giovanni completed the characterization of the potential laser cooling transition in the lanthanum anion by performing a combination of collinear and transverse spectroscopy on a La- beam. In this way, he was able to measure the cross-section of the resonant transition and deduce the transition rate, which limits the laser cooling time. In addition, he studied the capture and cooling (by electrons) of anions in a Penning trap. Giovanni will continue to work in our group as a post-doc at least until June.

Doctoral exam Giovanni
Giovanni sporting his custom-made doctoral hat after the exam

Reference to thesis: G. Cerchiari, “Laser spectroscopy of La- and anion trapping with a view to laser cooling,” Ph.D. thesis, University of Heidelberg (2018).

New article on La- spectroscopy published

A new article on high-resolution laser spectroscopy and highly precise calculations on La- has just appeared in Physical Review Letters. Using a combination of collinear and transverse spectroscopy, we measured the cross-section of the potential laser cooling transition and deduced a transition rate of about 10 kHz, a factor 200 higher than in the previous laser cooling candidate Os-. Theoretician Marianna Safronova (University of Delaware) contributed calculations of energy levels, transition rates and branching ratios that help understand the decay channels of the excited state. This work completes our spectroscopic study of La-. As a final result, we now know that La- can be laser-cooled and are working towards an experimental realization of the technique. The article has been selected by Physical Review Letters as an “Editors' Suggestion.”

Detail of laser spectroscopy setup
Detail of the laser spectroscopy setup used to measure the transition rate of the potential laser cooling transition in La-

Reference: G. Cerchiari et al., “Ultracold anions for high-precision antihydrogen experiments,” Phys. Rev. Lett. 120 (2018) 133205.

Stefan Erlewein graduates from M.Sc. program in physics

In a formal ceremony at the University of Heidelberg, Stefan Erlewein today officially received his M.Sc. diploma. In his thesis, Stefan investigated the trapping, confinement and storage of anions in a linear Paul trap. This is a crucial preliminary step to the laser cooling of negative ions. In excellent vacuum conditions (few 10-11 mbar), he was able to load up to 107 anions into the trap and observed storage times exceeding one hour. Stefan will pursue a doctoral degree within the Borealis project of the AEGIS experiment at CERN.

Graduation of Stefan Erlewein
Stefan Erlewein (left) proudly displays his M.Sc. diploma after the formal graduation ceremony at the University of Heidelberg

Reference: S. Erlewein, “Trapping of gold anions in a linear Paul trap,” M.Sc. thesis, University of Heidelberg (2017).