ISOLDE Seminar

Atomic antimatter physics at CERN and prospects for colder and larger samples of anti-atoms through deexcitation

by Tim Hilmar Wolz (Technische Universitaet Darmstadt (DE))




Controlled antihydrogen production and atom/anti-atom comparative measurements have been fascinating fields of research at CERN's Antiproton Decelerator. Impressive spectroscopy experiments have been reported with trapped antihydrogen [1,2,3] and efforts toward complementary studies in a beam as well as gravity measurements are ongoing. Despite the high precision already achieved in traps, experiments are still mainly limited by the achievable number of trapped atoms [4] or small ground state beam rates [5]. I will introduce novel ideas [6,7] and first proof-of-principle experimental results [8] to stimulate the decay of the initially formed Rydberg antihydrogen atoms toward ground state right after their formation. Stimulated deexcitation offers the potential of a drastically improved ground state production rate opening new possibilities for more efficient beam formation and further applications toward enhanced trapping of the produced anti-atomic samples.


[1] Ahmadi, M., Alves, B.X.R., Baker, C.J. et al. Observation of the 1S–2P Lyman-α transition in antihydrogen, Nature 561, 211–215 (2018)

[2] Ahmadi, M., Alves, B.X.R., Baker, C.J. et al. Characterization of the 1S–2S transition in antihydrogen, Nature 557, 71–75 (2018)

[3] The ALPHA Collaboration. Investigation of the fine structure of antihydrogen, Nature 578, 375–380 (2020)

[4] Ahmadi, M., Alves, B.X.R., Baker, C.J. et al. Antihydrogen accumulation for fundamental symmetry tests, Nat Commun 8, 681 (2017)

[5] Kolbinger B. et al. Measurement of the principal quantum number distribution in a beam of antihydrogen atoms, Eur. Phys. J. D, 75 3 91 (2021)

[6] Comparat D. and Malbrunot C. Stimulated decay and formation of antihydrogen atoms, Phys. Rev. A 99, 013418 (2019)

[7] Wolz T., Malbrunot C., Vieille-Grosjean M., and Comparat D. Stimulated decay and formation of antihydrogen atoms, Phys. Rev. A 101, 043412 (2020)

[8] Vieille-Grosjean M., Dimova E., Mazzotta Z., Comparat D., Wolz T. and Malbrunot C. Induced THz transitions in Rydberg caesium atoms for application in antihydrogen experiments, Eur. Phys. J. D 75:27 (2021)