Abstract:
   The neutrino mass sum is a fundamental particle physics parameter that will be measured cosmologically over the next several years, though a robust determination will require a precise understanding of neutrino clustering.  Recently I developed a non-linear cosmological perturbation theory for massive neutrinos.  It combines three ingredients: multi-fluid perturbation theories discretizing neutrinos' Fermi-Dirac distribution, Time-RG non-linear mode couplings, and Fast Fourier Transform acceleration.  I will describe the resulting neutrino power spectrum, including its dependence upon time and neutrino momentum, and test it against N-body simulations.  Finally, I will discuss ongoing and planned work on observable weak lensing predictions and improvements to N-body neutrino simulations.