ABSTRACT
We have already shown that the coherent states are very close
to the classical state of the well-defined amplitude and phase.
A question not answered yet is: Does there exist an analogous
quantum mechanical observable for the phase that is given by some
Hermitian operator? We know from classical optics that phase of
an EM field is an observable quantity. Hence, in quantum physics it
should be associated with a Hermitian operator. In order to set up
a quantitative description of the phase operator, we will introduce
some of the ideas presented in the literature which led to the
formulation of the Hermitian phase operator.
