Hierarchy of time scales and quasitrapping in the N-atom micromaser

Miroshnichenko, Georgii; Rybin, Andrei; Vadeiko, Ilia; Timonen, Jussi

Hierarchy of time scales and quasitrapping in the N-atom micromaser

Authors

Miroshnichenko, Georgii

Rybin, Andrei

Vadeiko, Ilia

Timonen, Jussi

Description

We study the dynamics of the reduced density matrix(RDM) of the field in the micromaser. The resonator is pumped by N-atomic clusters of two-level atoms. At each given instant there is only one cluster in the cavity. We find the conditions of the independent evolution of the matrix elements of RDM belonging to a (sub)diagonal of the RDM, i.e. conditions of the diagonal invariance for the case of pumping by N-atomic clusters. We analyze the spectrum of the evolution operator of the RDM and discover the existence of the quasitrapped states of the field mode. These states exist for a wide range of number of atoms in the cluster as well as for a broad range of relaxation rates. We discuss the hierarchy of dynamical processes in the micromaser and find an important property of the field states corresponding to the quasi-equilibrium: these states are close to either Fock states or to a superposition of the Fock states. A possibility to tune the distribution function of photon numbers is discussed.
9 pages, 6 figures