Constraints on real scalar inflation from preheating of LATTICEEASY

In this paper, we undertake a detailed study of real scalar inflation by employing LATTICEEASY simulations to investigate preheating phenomena. Generally, the scalar inflation potential with non-minimal coupling can be approximated by a quartic potential. We observe that the evolutionary behavior of this potential remains unaffected by the coupling coefficient. Furthermore, the theoretical predictions for the scalar spectral index ($n_s$) and tensor-to-scalar power ratio (r) are also independent of this coefficient. Consequently, the coefficients of this model are not constrained by Planck observations. Fortunately, the properties of preheating after inflation provide a viable approach to examine these coefficients. Through LATTICEEASY simulations, we trace the evolution of particle number density, scale factor, and energy density during the preheating process. Subsequently, we derive the parameters, such as the energy ratio ($\gamma$) and the e-folding number of preheating ($N_{pre}$), which facilitate further predictions of $n_s$ and $r$. We have successfully validated real scalar inflation model using preheating of LATTICEEASY simulations based on the analytical relationship between preheating and inflation models.