How to simulate the Universe in a box? Testing modified gravity with a N-body simulation code

In this paper we present preliminary results from cosmological simulations of modified gravity in the dark matter sector. Our results show improvements over standard cold dark matter cosmology. The abundance of low-mass haloes in the modified gravity model fit observations better than the conventional theory, while the differences of the modified density fluctuation power spectrum differs from the standard, $\Lambda$CDM power spectrum are small enough to make these two models observationally indistinguishable at large scales.