Quantum phase properties of the field in a lossless micromaser cavity

Phase properties of the micromaser field are studied for different initial states of the cavity field and the atom. It is shown that a multipeak phase structure develops when the cavity field is initially in a coherent state and the atoms enter the cavity in their excited state, which eventually leads to the randomization of the phase. If initially the field is thermal and the atoms entering the cavity are polarized, the steady state with a considerably well defined phase is reached, which asymptotically can be one of the cotangent states or some mixed state depending on the atom-cavity interaction time. An interesting effect of switching between the two- and three-peak phase structure caused by each subsequent atom passing the cavity has been found.