https://doi.org/10.1140/epjd/s10053-023-00634-4
Regular Article – Atomic Physics
GRASIAN: towards the first demonstration of gravitational quantum states of atoms with a cryogenic hydrogen beam
1
Stefan Meyer Institute for Subatomic Physics, Austrian Academy of Sciences, Kegelgasse 27, 1030, Vienna, Austria
2
Institute for Particle Physics and Astrophysics, ETH, Zurich, 8093, Zurich, Switzerland
3
Department of Physics and Astronomy, University of Turku, 20014, Turku, Finland
4
Laboratoire Kastler Brossel, Sorbonne Université, CNRS, ENS-PSL Université, Collège de France, 75252, Paris, France
5
Institut Max von Laue - Paul Langevin, 71 avenue des Martyrs, 38042, Grenoble, France
Received:
2
February
2023
Accepted:
12
March
2023
Published online:
29
March
2023
At very low energies, a light neutral particle above a horizontal surface can experience quantum reflection. The quantum reflection holds the particle against gravity and leads to gravitational quantum states (gqs). So far, gqs were only observed with neutrons as pioneered by Nesvizhevsky and his collaborators at ill. However, the existence of gqs is predicted also for atoms. The Grasian collaboration pursues the first observation and studies of gqs of atomic hydrogen. We propose to use atoms in order to exploit the fact that orders of magnitude larger fluxes compared to those of neutrons are available. Moreover, recently the q-Bounce collaboration, performing gqs spectroscopy with neutrons, reported a discrepancy between theoretical calculations and experiment which deserves further investigations. For this purpose, we set up a cryogenic hydrogen beam at 6 
. We report on our preliminary results, characterizing the hydrogen beam with pulsed laser ionization diagnostics at 243 
.
Precision Physics of Simple Atomic Systems
Guest editors: Paolo Crivelli, Krzysztof Pachucki, Wim Ubachs, Thomas Udem, and Stefan Ulmer.
Copyright comment corrected publication 2023
© The Author(s) 2023. corrected publication 2023
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
