Abstract: Considerable effort in cosmology today is focused on understanding the statistical nature and evolution of the (dark matter) density field that underlies the observed large-scale structure. Information about this field is mostly phrased in terms of two-point statistics, such as the power spectrum of galaxies or weak lensing, essentially approximating the large-scale structure as a Gaussian random field. However, the Universe is far more complex than that: Gravitational collapse turns the simple initial conditions into the cosmic web consisting of halos, filaments, and large voids we see today.

In my talk, I will show how we can use the abundance of galaxy clusters residing in the ​“knots” of the cosmic web to probe the non-Gaussian shape of the density field. This gives us insights into the physics of structure formation, and provides at the same time a new method to search for deviations from the cosmological standard model.