The Universe is a fascinatingly complex dynamical system. The large number and type of interactions along with their essential nonlinearity and extreme dynamic range in both space and time makes it essentially impossible to use analytic methods for understanding and predicting the full range of cosmological dynamical behaviors. Numerical methods and large-scale simulations have been essential in building up our current understanding of structure formation in the Universe. Additionally, the accuracy with which cosmological statistics are now being measured by sky surveys adds additional impetus to developing robust ways of making theoretical predictions; cosmological simulations are absolutely essential for this task.

Within CPAC, we have a number of activities related to pushing the state-of-the-art in cosmological simulations and in analyzing and applying the results obtained to cosmological observations. The extreme-scale HACC code is under continuous development in our group and has been used to run some of the largest cosmological simulations worldwide.