Exact dynamics of a class of two-level and three-level atoms interacting with quantized field
Ravinder Rupchand Puri · Journal of Modern Optics · 1999
An unified approach to the dynamics of a class encompassing several widely encountered models of a two-level and of a three-level atom interacting with a quantized electromagnetic field is developed. The approach is based on separating the dependence of the dynamics on the field and the atomic operators by expressing the unitary evolution operator in the basis of the atomic operators. The evolution operator then resembles the one for the atoms in an externally applied classical field. The exactly solvable examples of the deterministic, as well as fluctuating, time-dependence of the atom-field coupling are discussed. The issue of an effective two-level description for a three-level system is also analysed. The proposed method not only provides an unified approach to the models belonging to the class considered but is found to uncover several new results even for simple widely studied models.