Mark Neyrinck

Structures ("wrinkles") in the Universe like filaments and haloes are essential components of the arrangement of matter on large scales. They form in analogy to the origami-folding of a sheet of dark-matter. I will discuss some uses of this Lagrangian viewpoint, for instance an ORIGAMI algorithm that identifies structures in a natural way, finding particle crossings in N-body simulations. While these structures are fascinating, and conveniently allow observers like us to exist, they also make it harder to extract cosmological information on nonlinear scales. In particular, sharp peaks greatly diminish the power of the power spectrum and two-point correlation function, the most widely used statistics in cosmology. In the second part of my talk, I will discuss how to fix these statistics with logarithmic glasses. |