Optics and Spectroscopy

Diagonal invariance and quasi-trapped states in the micromaser model based on N-atom clusters

Ilya P Vadeiko, George P. Miroshnichenko, Andrei V. Rybin, Yu. Timonen

Published Aug 1, 2000• 6 citations

Abstract

The model of a micromaser based on unpolarized N-atom clusters described by the Tavis-Cummings Hamiltonian is considered. The properties of the evolution superoperator Γ( t ) that acts on the reduced density matrix of the field are investigated. This superoperator was found to have an integral of motion that leads to a specific type of the matrix element dynamics called diagonal invariance. The same property also holds for the Liouvillian of the interaction between the field and the thermal bath. Within the framework of the considered micromaser model, the anomalous dependence of the average photon number inside the cavity on the quality factor of the cavity and its temperature was discovered. These features of the field evolution were explained by the existence of eigenstates of Γ( t ), which are localized in the Fock basis and have eigenvalues close to unity. These states were called the quasi-trapped states.

DOI: 10.1134/1.1307451

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