Effect of irreversible atomic relaxation on resonance fluorescence, absorption, and stimulated emission

Even for a single isolated constituent of matter, a recent generalization of quantum mechanics, called quantum thermodynamics, postulates the existence of new nonmechanical individual states, not contemplated within conventional quantum mechanics, for which the time evolution is governed by a novel nonlinear equation of motion, which entails an irreversible, energy-preserving internal redistribution mechanism of relaxation towards stable equilibrium. For a single two-level atom interacting with the quantum electromagnetic field, we show that such irreversible internal redistribution mechanism entails interesting corrections to the conventional quantum electrodynamic predictions on absorption, resonance fluorescence, and stimulated emission. For a two-level atom driven near resonance by a nearly monochromatic laser beam, we estimate the corrections implied on the spectral distribution of resonance fluorescence and on the absorption and stimulated emission line shape. We submit that our predictions call for further high-resolution studies of atom-field interactions. For example, the value or a lower bound to the value of the only unknown constant of the theory, namely, the internal redistribution time constant, can only be established by a quantitative experimental study. © 1985 Plenum Publishing Corporation.