Structures and chaos in parametric Rabi oscillations

In the strong-coupling limit, the nonlinear dynamics of interaction of two-level atoms with their own emission field in a cavity with a periodically modulated length was studied. An analytical analysis was made that shows the appearance of regions in the pseudophase space of Maxwell-Bloch equations that are responsible for the origin of dynamic chaos for the smallest possible modulation depth, and the homoclinic mechanism of their formation was revealed. In the model of a Rydberg maser with a modulated cavity, a special type of chaos was numerically discovered. This chaos, which was called structural, manifests itself under certain conditions in parametric oscillations of atomic population. On the one hand, these Rabi oscillations demonstrate sensitivity to initial conditions with a positive maximum Lyapunov exponent, and, on the other hand, they represent a signal with a long-term structure that is caused by modulation.