  Quantum states in the Earth's gravitational field were observed, when
ultra-cold neutrons fall under gravity. The experimental results can be
described by the quantum mechanical scattering model as it is presented here.
We also discuss other geometries of the experimental setup which correspond to
the absence or the reversion of gravity. Since our quantum mechanical model
describes, particularly, the experimentally realized situation of reversed
gravity quantitatively, we can practically rule out alternative explanations of
the quantum states in terms of pure confinement effects.
