ИСТИНА

The large scale structure of the Universe will become the leading observational probe in cosmology in the near future. However, the proper analysis of structure formation at small scales requires non-linear effects to be taken into account. Straightforward attempts to do so within perturbation theory faced a lot of problems such as the appearance of non-physical infra-red (IR) divergences at each given loop correction. These spurious IR - divergencies, although cancelled out upon summing over all contributions, complicate tremendously the analysis of physical IR - effects. In my talk I will propose a new method to account for non-linear clustering of dark matter. This method is based on the ideas of path integral and RG flow. I will show that this approach is free of spurious IR-divergencies and makes possible to resumm the effects of long-wavelength perturbations that are crucial for the BAO peaks.