High accuracy Power Spectra at high redshift in Dynamical Dark Energy simulations

Accurate predictions on non-linear power spectra, at various redshift z, will be a basic tool to interpret cosmological data from next generation mass probes. We need then high precision simulations, exploring the functional space of w (a) DE state equations, for the admitted cosmological parameter ranges. A procedure was however suggested, making recourse to suitable w = const. auxiliary models, and yielding a ∼1% precision at z = 0. The precision of this procedure, however, worsens at higher z. Here we follow a different criterion for high z. Our N-body gravitational simulations then show that auxiliary w = const. models still meet given w (a) model spectra within 1% at z = 0, but are much better at higher redshift, where they approach a permil precision.