Post-Inflationary Scalar Field Phase Dynamics

We present a brief summary of the results of Charters et al. [1] where a simple model of a massive inflation field ϕ coupled to another scalar filed χ with interaction term g 2ϕ2χ2 for the first stage of preheating, and we give a full description of the dynamics of the χ field modes, including the behaviour of the phase, in terms of the iteration of a simple family of circle maps.