  In the present work the Rabi Problem, involving the response of a spin 1/2
particle subjected to a magnetic field, is considered in a second quantized
approach. In this concrete physical scenario, we show that the second
quantization procedure can be applied directly in a non-covariant theory. The
proposed development explicits not only the relation between the full quantum
treatment of the problem and the semiclassical Rabi model, but also the
connection of these approaches with the Jaynes-Cummings model. The consistency
of the method is checked in the semiclassical limit. The treatment is then
extended to the matter component of the Rabi problem so that the Schr\"odinger
equation is directly quantized. Considering the spinorial field, the appearance
of a negative energy sector implies a specific identification between
Schr\"odinger's and Maxwell's theories. The generalized theory is consistent,
strictly quantum and non-relativistic.
