A Robust Measure of Cosmic Structure beyond the Power-Spectrum: Cosmic   Filaments and the Temperature of Dark Matter
  We discover that the mass of dark matter particles mDM is imprinted in phase-correlations of the cosmic density field more significantly than in the 2-point correlation. In particular, phase-correlations trace mDM out to scales about five times larger than the 2-point correlation. This result relies on a new estimator l(r) of pure phase-information in Fourier space, which can be interpreted as a parameter-free and scale-invariant tracer of filament-like structure. Based on simulated density fields we show how mDM can, in principle, be measured using l(r), given a suitably reconstructed density field. 
Danail Obreschkow, Chris Power, Martin Bruderer, Camille Bonvin
astro-ph.CO physics.data-an