Open Access

A new theoretical concept of the quantum mechanical processes in spin filter for the separation ofmetastable hydrogen atoms in individual hyperfine substates enables a number of new applications.For example, it is now possible to build a new generation of Lamb-shift polarimeter that canseparate not only 𝛼 but also the 𝛽 substates with mJ=−1/2. This opens up completely newpossibilities for the search of hydrogen atoms in forbidden substates after the bound beta decayof the neutron. [...]