POSTPONED DUE TO ILLNESS; NEW DATE TBC

Title: Kinetic Field Theory – a particle-based approach to cosmic structure formation

Abstract: Thus far, the non-linear regime of structure formation is only accessible through expensive numerical N-body simulations since the conventional analytic treatment of cosmic density fluctuations based on the hydrodynamical equations runs into severe problems even in a mildly non-linear regime. However, there is a dire need for analytical approaches to cosmic structure formation. First of all, ideally, they allow us to not only reproduce the correct large-scale structures that we observe in the universe, but they help us to understand the physics behind them. Second of all, higher-order statistics will become increasingly relevant in order to extract the full information content from the next generations of large-scale surveys. Theoretical predictions of such signals so far need to be based on costly numerical simulations, with the inevitable problems of shot noise, limited resolution and incomplete coverage of the relevant range of scales. Without a fundamental understanding of cosmic structure formation, it will not be possible to reliably analyse large portions of the data. And last but not least, being confronted with the unexplained postulates of dark matter and dark energy, alternatives should be studied for the standard cosmological model and for the theory of gravity, i.e. general relativity. For scanning satisfactorily wide spaces of possible theories, numerical simulations with the required spatial and temporal resolution would be far too costly.


In this talk, I will introduce Kinetic Field Theory, a novel particle-based analytic approach to cosmic  large-scale structure formation, which provides a density fluctuation power spectrum that agrees well with state of the art N-body simulations far into the non-linear regime. I will first give an explanation of how Kinetic Field Theory avoids the difficulties of Eulerian standard perturbation theory already by construction. I will then show recent results for the density-fluctuation power spectrum obtained within KFT and briefly discuss applications in the analysis of survey data.