Strong local oscillator limit of the operational approach for quantum phase measurement

Abstract

We address the problem of strong local oscillator limit of the recently introduced operational approach to phase uncertainty measurements. In this limit the operator character of the local oscillator mode is neglected and its coherent amplitude tends to infinity. Thereby reasonable new operators for the sine and the cosine of the phase difference between an arbitrary signal field and the coherent local oscillator field are found which describe an already well-known physical situation connected with strong amplification of the signal field.