A solvable model of microscopic frequency modulation

The solvable model of quantum-statistical mechanical frequency modulation, which was proposed previously by the authors, is solved exactly by rigorous treatment of the damping operator for the cases of boson and two-state irrelevant subsystems to obtain the intensity distribution and the response function for a certain operator of the relevant subsystem. The results are compared with the previous ones which were obtained within the conventional treatment of the damping operator.