Numerical investigation of non-gaussianities in the phase and modulus of density fourier modes

ABSTRACT We numerically investigate the non-Gaussianities in late-time cosmological density field Fourier space. explore various statistics, including two- and three-point probability distribution function (PDF) of phase modulus, their correlation function. Significant non-Gaussianity is observed for certain configurations. Comparing measurement from simulation with theoretical expansion prediction, we find that (600 Mpc h-1)3 volume, $\mathcal {O}(V^{-1/2})$ order term alone sufficiently accurate to describe all measured not only PDFs, but also correlations. phase-modulus cross-correlation contributes $\sim 50{{\ \rm per\ cent}}$ bispectrum, further verifying accuracy prediction. This work demonstrates cosmic simpler space, may facilitate data analysis era precision cosmology.