Measuring the cosmological density field twice: A novel test of dark
  energy using the CMB quadrupole
  The scattering of cosmic microwave background (CMB) radiation in galaxy
clusters induces polarization signals according to the quadrupole anisotropy in
the photon distribution at the cluster location. This `remote quadrupole'
derived from the measurements of the induced polarization provides an
opportunity for reconstructing primordial fluctuations on large scales. We
discuss that comparing the local CMB quadrupoles predicted by these
reconstructed primordial fluctuations and the direct measurements done by CMB
satellites may enable us to test the dark energy beyond cosmic variance limits.
