Abstract
This paper describes the dynamics of the Wehrl entropy and Wehrl phase distribution of a degenerate two-photon of a single mode interacting with a two-level system with a nonlinear medium. A general analytic expression for the Husimi Q function is obtained. The influence of various parameters on the Wehrl entropy and Wehrl phase distribution are explored. It is shown that features of the Wehrl entropy and Wehrl phase distribution were influenced significantly by changing the nonlinear medium, Stark shift and the detuning. For certain amounts of the nonlinear effect, superstructure of atomic Rabi oscillation and changes of the quasi-period of the entropy evolution are observed.