Journal of Cosmology and Astroparticle Physics
We use lattice simulations to examine the detailed dynamics of inflaton fragmentation during and after preheating in λφ4 chaotic inflation. The dynamics are qualitatively similar to preheating after m2φ2 inflation, involving the exponential growth and subsequent expansion and collision of bubble-like inhomogeneities of the inflaton and other scalar fields. During this stage fluctuations of the fields become strongly non-Gaussian. In the quartic theory, the conformal nature of the theory allows us to extend our simulations to much greater times than is possible for the quadratic model. With these longer simulations we have been able to determine the time scale on which Gaussianity is restored, which occurs after a time on the order of a thousand inflaton oscillations.
Felder, Gary and Navros, Olga, "Inflaton Fragmentation After λφ4 Inflation" (2007). Faculty Publications. Paper 7.