Abstract

We investigate the particle production due to parametric resonances in a model of inflation where the lightest composite state stemming from the minimal walking technicolor theory plays the role of the inflaton. For this model of inflation, the effective theory couples nonminimally to gravity. Regarding the preheating, we study in detail a model of a composite inflaton field φ coupled to another scalar field χ with the interaction term g2φ2χ2. Particularly, in Minkowski space, the stage of parametric resonances can be described by the Mathieu equation. Interestingly, we discover that broad resonances can be typically achieved and are potentially efficient in our model causing the particle number density in this process to exponentially increase.