  Quantum-mechanical initial conditions for the fluctuations of the geometry
can be assigned in excess of a given physical wavelength. The two-point
functions of the scalar and tensor modes of the geometry will then inherit
corrections depending on which Hamiltonian is minimized at the initial stage of
the evolution. The energy density of the background geometry is compared with
the energy-momentum pseudo-tensor of the fluctuations averaged over the initial
states, minimizing each different Hamiltonian. The minimization of adiabatic
Hamiltonians leads to initial states whose back-reaction on the geometry is
negligible. The minimization of non-adiabatic Hamiltonians, ultimately
responsible for large corrections in the two-point functions, is associated
with initial states whose energetic content is of the same order as the energy
density of the background.
