Cosmic Degeneracies III: N-body Simulations of Interacting Dark Energy
  with Non-Gaussian Initial Conditions
  We perform for the first time N-body simulations of Interacting Dark Energy
assuming non-Gaussian initial conditions, with the aim of investigating
possible degeneracies of these two theoretically independent phenomena in
different observational probes. We focus on the large-scale matter
distribution, as well as on the statistical and structural properties of
collapsed halos and cosmic voids. On very large scales, we show that it is
possible to choose the Interaction and non-Gaussian parameters such that their
effects on the halo power spectrum cancel, and the power spectrum is
indistinguishable from a $\mathrm{\Lambda CDM}$ model. On small scales,
measurements of the non-linear matter power spectrum, halo-matter bias, halo
and subhalo mass function and cosmic void number function validate the
degeneracy determined on large scales. However, the internal structural
properties of halos and cosmic voids, namely halo concentration-mass relation
and void density profile, are very different from those measured in the
$\mathrm{\Lambda CDM}$ model, thereby breaking the degeneracy. In practice, the
values of $\mathrm{f_{NL}}$ required to cancel the effect of interaction are
already ruled by observations. Our results show in principle that the
combination of large- and small-scale probes is needed to constrain Interacting
Dark Energy and Primordial non-Gaussianity separately.
