Hartree Approximation to the One Loop Quantum Gravitational Correction
  to the Graviton Mode Function on de Sitter
  We use the Hartree approximation to the Einstein equation on de Sitter
background to solve for the one loop correction to the graviton mode function.
This should give a reasonable approximation to how the ensemble of inflationary
gravitons affects a single external graviton. At late times we find that the
one loop correction to the plane wave mode function $u(\eta,k)$ goes like $G
H^2 \ln(a)/a^2$, where $a$ is the inflationary scale factor. One consequence is
that the one loop corrections to the "electric" components of the linearized
Weyl tensor grow compared to the tree order result.
