Projection approach with coherent-state expansion

The talk will discuss the possibility of applying the projection approach in quantum optics problems for systems consisting of several dissipative subsystems. A special choice of projector makes it possible to obtain an ansatz from which one can derive the generator of reduced dynamics for various environmental states. The results of applying such a modification of the Nakajima–Zwanzig projection approach will be presented for the Jaynes–Cummings model with dissipation as well as for the SPDC model, along with a method of generalizing the results to the case of a multimode system–environment state.