Primordial Gravitational Waves and Cosmology
  The observation of primordial gravitational waves could provide a new and
unique window on the earliest moments in the history of the universe, and on
possible new physics at energies many orders of magnitude beyond those
accessible at particle accelerators. Such waves might be detectable soon in
current or planned satellite experiments that will probe for characteristic
imprints in the polarization of the cosmic microwave background (CMB), or later
with direct space-based interferometers. A positive detection could provide
definitive evidence for Inflation in the early universe, and would constrain
new physics from the Grand Unification scale to the Planck scale.
