Cosmology and short-distance gravity
  If the observed dark-energy density $\rho_\Lambda$ is interpreted as the net
contribution of the energy density of the vacuum, $\rho_\Lambda \equiv \rho_V
\sim M_V^4$, and the corresponding vacuum length scale $\lambda_V = M_V^{-1}$
as the cutoff scale controlling the low-energy, effective field-theory limit of
gravity, it follows that the conventional cosmological scenario based on the
effective gravitational equations may be valid only up to the Tev energy scale.
Such a possibility would be strongly disfavored by the existence of a relic
background of primordial gravitational radiation of intensity compatible with
present (or near future) experimental sensitivities.
