  On the example of stationary states of a system consisting of an atom and a
quantized electromagnetic field (the Jaynes-Cummings model in free space), it
is shown that the physical characteristics of the system (as the energy and the
probability distribution of finding the center of mass of the atom) explicitly
depend on the choice of the basis of quantization of the electromagnetic field.
Therefore, the secondary quantization procedure is not independent of the
choice of the quantization basis in the interaction of the field with the
material medium.
