Description
We present a recent progress towards experiments with hydrogen atoms at ultra-low energies, nearly at rest planned by an international collaboration GRASIAN* (Gravity, Spectroscopy and Interferometry with Atoms and Neutrons, https://grasian.eu/). We will probe the ultralow-energy domain with hydrogen, the lightest and simplest of neutral atoms, which has served as a test probe of the fundaments of physics throughout the era of modern physics. The thermal motion of atoms has set limits to the accuracy of experiments. Therefore, using hydrogen atoms nearly at rest one expects to obtain unprecedented levels of precision.
