  Gravitational potentials of the Milky Way and extragalactic structures can
influence the propagation of the cosmic neutrino background (CNB). Of
particular interest to future CNB observatories, such as PTOLEMY, is the CNB
number density on Earth. In this study, we have developed a simulation
framework that maps the trajectories of relic neutrinos as they move through
the local gravitational environment. The potentials are based on the dark
matter halos found in state-of-the-art cosmological N-body simulations,
resulting in a more nuanced and realistic input than the previously employed
analytical models. We find that the complex dark matter distributions, along
with their dynamic evolution, influence the abundance and anisotropies of the
CNB in ways unaccounted for by earlier analytical methods. Importantly, these
cosmological simulations contain multiple instances of Milky Way-like halos
that we employ to model a variety of gravitational landscapes. Consequently, we
notice a variation in the CNB number densities that can be primarily attributed
to the differences in the masses of these individual halos. For neutrino masses
between $0.01$ and $0.3$ eV, we note clustering factors within the range of
$1+\mathcal{O}(10^{-3})$ to $1+\mathcal{O}(1)$. Furthermore, the asymmetric
nature of the underlying dark matter distributions within the halos results in
not only overdense, but intriguingly, underdense regions within the full-sky
anisotropy maps. Gravitational clustering appears to have a significant impact
on the angular power spectra of these maps, leading to orders of magnitude more
power on smaller scales beyond multipoles of $\ell = 3$ when juxtaposed against
predictions by primordial fluctuations. We discuss how our results reshape our
understanding of relic neutrino clustering and how this might affect
observability of future CNB observatories such as PTOLEMY.
