In the article Limits on possible new nucleon monopole-dipole interactions from the spin relaxation rate of polarized $^3$He gas, new limits on short-range, Axion-like interactions are presented. In this comment it is shown that the theoretical treat
ement of the data overestimates the sensitivity of the proposed method. We provide the corrected limits.
We propose a method for observation of the quasi-stationary states of neutrons, localized near the curved mirror surface. The bounding effective well is formed by the centrifugal potential and the mirror Fermi-potential. This phenomenon is an example
of an exactly solvable quantum bouncer problem that could be studied experimentally. It could provide a promising tool for studying fundamental neutron-matter interactions, as well as quantum neutron optics and surface physics effects. We develop formalism, which describes quantitatively the neutron motion near the mirror surface. The effects of mirror roughness are taken into account.
