Power spectrum P(k) vs. k measured from simulation A at five different times. The solid curves show the N‐body power spectrum for k_nl(a) = 58, 29, 14.5, 7.25. The wavenumber k is in units of 2π/L. The dotted lines show the linear spectrum P ∝ a²k⁻² at the same times. The N‐body spectrum at low k shows statistical fluctuations due to the small number of modes available to measure it. At high k the spectrum is plotted up to ﹩\frac{1}{2}﹩ the Nyquist frequency of the FFT grid, k = 512.