  Background: The high momentum distribution of atoms in two spin-state
ultra-cold atomic gases with strong short-range interactions between atoms with
different spins, which can be described using Tan's contact, are dominated by
short range pairs of different fermions and decreases as $k^{-4}$. In atomic
nuclei the momentum distribution of nucleons above the Fermi momentum ($k>k_F
\approx 250$ Mev/c) is also dominated by short rangecorrelated
different-fermion (neutron-proton) pairs.
  Purpose: Compare high-momentum unlike-fermion momentum distributions in
atomic and nuclear systems.
  Methods: We show that, for $k>k_F$ MeV/c, nuclear momentum distributions are
proportional to that of the deuteron. We then examine the deuteron momentum
distributions derived from a wide variety of modern nucleon-nucleon potentials
that are consistent with $NN$-scattering data.
  Results: The high momentum tail of the deuteron momentum distribution, and
hence of the nuclear momentum distributions appears to decrease as $k^{-4}$.
This behavior is shown to arise from the effects of the tensor part of the
nucleon-nucleon potential. In addition, when the dimensionless interaction
strength for the atomic system is chosen to be similar to that of atomic
nuclei, the probability for finding a short range different-fermion pair in
both systems is the same.
  Conclusions: Although nuclei do not satisfy all of the conditions for Tan's
contact, the observed similarity of the magnitude and $k^{-4}$ shape of nuclear
and atomic momentum distributions is remarkable because these systems differ by
about $20$ orders of magnitude in density. This similarity may lead to a
greater understanding of nuclei and the density dependence of nuclear systems.
