Minimal Coupling Between Dark Matter and Dark Energy

Dark energy and dark matter are two of the
biggest mysteries of modern cosmology, and
our understanding of their fundamental nature
is incomplete. Many parameterizations of
couplings between the two have been studied
in the literature, and observational data
from the growth of perturbations can constrain
these parameterizations. Dark matter and
dark energy interact gravitationally over
long distances, so they should at least be
coupled via the graviton. Assuming standard
general relativity with no explicit coupling
between dark energy and dark matter fields
in the Lagrangian, we calculate the gravitational
interaction cross section and examine any
observational implications that may follow.