The imprint of primordial gravitational waves on the CMB intensity
  profile
  We use the induced geometry on the two dimensional transverse cross section
of a photon beam propagating on a perturbed Friedmann-Robertson-Walker (FRW)
spacetime to find the Cosmic Microwave Background (CMB) photon distribution
over a telescope's collecting area today. It turns out that at each line of
sight the photons are diluted along a transverse direction due to gravitational
shearing. The effect can be characterized by two spin-weight-two variables,
which are reminiscent of the Stokes polarization parameters. Similar to that
case, one can construct a scalar and a pseudo-scalar function where the latter
only gets contributions from the tensor modes. We analytically determine the
power spectrum of the pseudo-scalar at superhorizon scales in a simple
inflationary model and briefly discuss possible observational consequences.
