Measurement of the Cold Dark Matter-Neutrino Dipole in the TianNu
  Simulation
  Measurements of neutrino mass in cosmological observations rely on two point
statistics that are hindered by significant degeneracies with the optical depth
and galaxy bias. The relative velocity effect between cold dark matter and
neutrinos induces a large scale dipole into the matter density field and may be
able to provide orthogonal constraints to standard techniques. We numerically
investigate this dipole in the TianNu Simulation, which contains cold dark
matter and 50 meV neutrinos. We first compute the dipole using a new linear
response technique where we treat the displacement caused by the relative
velocity as a phase in Fourier space and then integrate the matter power
spectrum over redshift. Then, we compute the dipole numerically in real space
using the simulation density and velocity fields. We find excellent agreement
between the linear response and N-body methods. Utilizing the dipole as an
observational tool will require two tracers of the matter distribution that are
differently biased with respect to the neutrino density.
