Quantum phase from the Glauber model of linear phase amplifiers
Using the Glauber model of linear phase insensitive amplifier as the basis, we establish a general condition which must be obeyed by every operator referred to the quantum phase. We demonstrate that this condition defines a class of acceptable Hermitian quantum phase operators, and that an additional physical requirement leads to the unique quantum phase operator. It turns out that this is the same operator which for the first time has been suggested by H. Paul [Fortschr. Phys. 22, 657 (1974)] and has been widely discussed in the literature. [S0031-9007(98)06802-1].