Dynamical dark energy simulations: high accuracy power spectra at high redshift

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, so obtaining key information on Dark Energy nature. This calls for high precision simulations, covering the whole functional space of w(z) state equations and taking also into account the admitted ranges of other cosmological parameters; surely a difficult task. A procedure was however suggested, able to match the spectra at z = 0, up to k ∼ 3 hMpc −1, in cosmologies with an (almost) arbitrary w(z), by making recourse to the results of N–body simulations with w = const, from which extended Halofit expressions were obtained. In this paper we extend such procedure to z> 0 and test our approach through a series of N–body gravitational simulations, finding that beyond a given crossover redshift zco even this technique apparently fails. We also outline that, in some models, zco could be as low as ∼ 1. Simulations leave a further open question, whether real sample variance will go beyond the expected precision level of observations. PACS numbers: 98.80.-k, 98.65.-rHigh accuracy power spectra 2 1.