Initiative Research Units・Special Research Units
Ulmer Initiative Research Unit
Initiative Research Scientist: Stefan Ulmer (Ph.D.)
We are developing an experiment for the high-precision determination of the magnetic moment of the proton and the antiproton. The magnetic moment of the antiproton is currently known at a level of only 10-3. We are aiming at a millionfold improved measurement of this fundamental quantity.
To this end we set up a new apparatus, where a single antiproton will be stored in a cryogenic double Penning trap for arbitrarily long time. Performing quantum-jump spectroscopy by application of the continuous Stern-Gerlach effect, the magnetic moment of the particle can be determined with high precision.
Recently we observed spin flips with a single trapped proton, which is an important milestone towards this challenging aim. Based on that success the magnetic moment of the particle was determined with a relative precision of 8*10-6. Thus, applying our technique to the antiproton would improve the number by two orders of magnitude already. Experimental efforts for an improvement of our technique towards 10-9 are under way.
In addition to this main project, we are involved in the ASACUSA-CUSP trap experiment, which aims at a high precision measurement of the antihydrogen hyperfine structure. Furthermore we contribute highly sensitive detection systems to several storage ring and Penning trap experiments.
Research Subjects
- High precision measurement of the magnetic moment of the proton and the antiproton.
- Hyperfine spectroscopy of antihydrogen.
- Development of novel techniques for high-precision Penning trap experiments.
Publications
- S. Ulmer, K. Blaum, H. Kracke, A. Mooser, W. Quint, C. C. Rodegheri, and J. Walz.:
"Direct Measurement of the Free Cyclotron Frequency of a Single Particle in a Penning Trap"
Phys. Rev. Lett. 107, 103002 (2011)
- S. Ulmer, C. C. Rodegheri, H. Kracke, K. Blaum, A. Mooser, W. Quint, and J. Walz.:
"Observation of spin flips with a single trapped proton"
Phys. Rev. Lett. 106, 253001 (2011)
- S. Ulmer, H. Kracke, K. Blaum, S. Kreim, A. Mooser, W. Quint, C. C. Rodegheri, and J. Walz.:
"The quality factor of a superconducting rf resonator in a magnetic field"
Phys. Rev. Lett. 80, 123302 (2009)