Nonclassical effects in the dynamics of atom-light interactions

A wide range of nonclassical effects such as wavepacket revivals and fractional revivals, and interesting changes in quantum entanglement can be observed in several bipartite systems of atoms interacting with the radiation field, as they evolve in time. The role of quantum observables in the complex dynamics of bipartite quantum systems is also well-known. As a quantum system governed by a nonlinear Hamiltonian evolves unitarily, the subsystems interact dissipatively. The naive Ehrenfest connection between classical motion and the dynamics of quantum expectation values has to be appropriately modified in this context. An analysis of the time series of relevant subsystem observables can bring to light interesting ergodicity properties ranging from periodic behaviour to exponential sensitivity to the initial state of the system under consideration, and the role played by the parameters in the Hamiltonian in determining the details of the dynamics. I will illustrate the foregoing using simple and generic bipartite models of relevance to optics.