Research
The Exotic Ions team uses exotic atoms and highly charged ions to probe fundamental interactions: we test QED in the strongest fields available in the laboratory, measure nuclear charge radii, and look for new physics. We combine experiment and theory, coupling quantum sensors to exotic beams at CERN, PSI, GSI/FAIR and J-PARC, and operating a double crystal spectrometer in Paris.
Jonas Sommerfeldt joins CNRS
A QED theorist, and Leopoldina postdoc in the team since 2024, has been recruited as a permanent CNRS researcher (CRCN) from November 2026.
PIPS test beam at PSI
This October, a dedicated beamtime at PSI’s πM1 beamline sends pions, muons and electrons directly onto a TES detector.
News & Views in Nature: antimatter on the move
Nancy Paul and Davide Gamba (CERN) comment in Nature on the BASE collaboration’s first transport of antiprotons by truck at CERN.
Michael Roosa starts a Marie Skłodowska-Curie fellowship
In September 2026, Michael Roosa started a Marie Skłodowska-Curie postdoctoral fellowship in the team.
First QUARTET physics result submitted
The first physics result of QUARTET, the nuclear charge radius of beryllium-9 from muonic atom spectroscopy, has been submitted for publication.
Paul Indelicato receives the Gentner-Kastler Prize
The German and French physical societies (DPG and SFP) have jointly awarded Paul Indelicato the 2026 Gentner-Kastler Prize.
PAX is the first experiment at CERN’s TELMAX beamline
PAX was the first experiment to use TELMAX, the new antiproton test beamline at CERN’s Antimatter Factory, with beamtimes in 2025 and 2026.
The team
Staff
The team’s permanent researchers are Nancy Paul, Jonas Sommerfeldt and Paul Indelicato (emeritus), all at CNRS. They work with a postdoctoral Marie Skłodowska-Curie fellow, PhD students, and master’s students and interns. We work closely with collaborators at NIST, Lisbon, GSI, CERN, Imperial College, Heidelberg, LNHB, PSI, CEA and many others.
Learn more about Nancy Paul, Jonas Sommerfeldt and Paul Indelicato on their profile pages, or see the whole group:
Jobs
We are always looking for bright, motivated people to join the team. Don’t hesitate to contact one of the team leaders with a CV and motivation letter if you want to join the adventure.
Consult jobs