Title: The Mira-Titan Universe II: Matter Power Spectrum Emulation,
Abstract: We introduce a new cosmic emulator for the matter power spectrum covering
eight cosmological parameters. Targeted at optical surveys, the emulator
provides accurate predictions out to a wavenumber k~5/Mpc and redshift z<=2.
Besides covering the standard set of LCDM parameters, massive neutrinos and a
dynamical dark energy of state are included. The emulator is built on a sample
set of 36 cosmological models, carefully chosen to provide accurate predictions
over the wide and large parameter space. For each model, we have performed a
high-resolution simulation, augmented with sixteen medium-resolution
simulations and TimeRG perturbation theory results to provide accurate coverage
of a wide k-range; the dataset generated as part of this project is more than
1.2Pbyte. With the current set of simulated models, we achieve an accuracy of
approximately 4%. Because the sampling approach used here has established
convergence and error-control properties, follow-on results with more than a
hundred cosmological models will soon achieve ~1% accuracy. We compare our
approach with other prediction schemes that are based on halo model ideas and
remapping approaches. The new emulator code is publicly available.