  The density of relic neutrinos is expected to be enhanced due to clustering
in our local neighbourhood at Earth. We introduce a novel analytical technique
to calculate the neutrino overdensity, based on kinetic field theory. Kinetic
field theory is a particle-based theory for cosmic structure formation and in
this work we apply it for the first time to massive neutrinos. The
gravitational interaction is expanded in a perturbation series and we take into
account the first-order contribution to the local density of relic neutrinos.
For neutrino masses that are consistent with cosmological neutrino mass bounds,
our results are in excellent agreement with state-of-the-art calculations.
