Arimitsu, T.; Willeboordse, H.F.; Iwasaki, T. - In: Physica A: Statistical Mechanics and its Applications 182 (1992) 1, pp. 214-227
The optical absorption of a localized electron is investigated with the help of an analytically solvable model and the operator algebra of non-equilibrium thermo field dynamics. The structure of the absorption spectra, for the cases of slow as well as fast modulation, is investigated dynamically.