Speaker
Description
The late universe contains a wealth of information about fundamental physics and gravity, wrapped up in non-Gaussian fields. To make use of as much information as possible it is necessary to go beyond power spectra. Rather than going to higher order N-point correlation functions, this talk will demonstrate that the probability distribution function (PDF) of spheres in the matter field (a 1-point function) already contains a large fraction of this non-Gaussian information. The matter PDF dissects different density environments which are lumped together in 2 point statistics, making it particularly useful for probing modifications of gravity or expansion history.
With an analytic model for the matter PDF we extend this formalism into cosmologies beyond ΛCDM, including $f(R)$ and DGP modified gravity and evolving dark energy. In all cases, the matter PDF provides an excellent complement to the matter power spectrum. Combining weakly non-linear power spectrum information with the matter PDF yields $5\sigma$ detections of both modified gravity theories, and increases the Figure of Merit for dark energy by a factor of 5 beyond power spectrum information alone.
