QUANTUM PHASE FROM THE GLAUBER MODEL OF LINEAR-PHASE AMPLIFIERS

Using the Glauber model of linear phase insensitive amplifier as the b asis, we establish a general condition which must be obeyed by every o perator referred to the quantum phase. We demonstrate that this condit ion defines a class of acceptable Hermitian quantum phase operators, a nd 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].