  Recently, we have started to investigate behavior of a composite quantum body
in an external gravitational field in the framework of General Relativity [see,
for a review, A. G. Lebed, Mod. Phys. Lett. A, {\bf 35}, 2030010 (2020)]. As
the simplest example, we have considered a hydrogen atom in a weak
gravitational field. Our results are the following. The Einstein's Equivalence
Principle survives for the most of macroscopic ensembles of the atoms,
containing the stationary quantum states. On the other hand, we have
demonstrated that this principle is sometimes broken. In particular, it is
broken for the so-called Gravitational demons, which are the coherent
macroscopic ensembles of two or more stationary quantum states in the hydrogen
atoms. In the above cited paper we have considered the Gedanken experiment,
where the gravitational field is suddenly switched on in a free from
gravitation space. In the current paper we consider the much more realistic
from experimental point of view Gedanken experiment and come to the same
conclusion about violations of the Einstein's Equivalence Principle for the
Gravitational demons.
