Non-Gaussianity from Particle Production during Inflation

Figure 4

The power spectrum of inflaton modes induced by rescattering (normalized to the usual vacuum fluctuations) as a function of ln(𝑘/𝑘_⋆), plotted for three representative time steps in the evolution, showing the cascading of power into the IR. For each time step we plot the analytical result (the solid line) and the data points obtained using lattice field theory simulations (diamonds). The time steps correspond to the following values of the scale factor: 𝑎=1.03,1.04,2.20 (where 𝑎=1 at the moment when 𝜙=𝜙₀). By this time the amplitude of fluctuations is saturated due to the expansion of the universe. The vertical lines show the range of scales from our lattice simulation.