http://arxiv.org/abs/1312.5256
In performing cosmological N-body simulations, it is widely appreciated that the growth of structure on the largest scales within a simulation box will be inhibited by the finite size of the simulation volume. Following ideas set forth in Seto 1999, this paper shows that standard (a.k.a. 1-loop) cosmological perturbation theory (SPT) can be used to predict at an order-of-magnitude level the deleterious effect of the box scale on the power spectrum of density fluctuations in simulation volumes. Alternatively, this approach can be used to quickly estimate post facto the effect of the box scale on power spectrum results from existing simulations. In this way SPT can help determine whether larger box sizes or other more-sophisticated methods are needed to achieve a particular level of precision for a given application (e.g. simulations to measure the non-linear evolution of baryon acoustic oscillations). I focus on SPT in this note and show that its predictions are order-of-magnitude accurate compared to N-body simulations, but doubtless the estimation of box-scale numerical effects would be improved using more-sophisticated perturbation theory models. An appendix compares the simulation results at outputs where box-scale effects are minimal to the SPT-based prediction of Scoccimarro 1997 and the corrected SPT formula from Pajer & Zaldarriaga 2013. The power spectrum measurements from simulation are made available for future comparisons to other perturbation theory models.
Thu, 19 Dec 13
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