Is the Spectrum of Gravitational Waves the "Holy Grail" of Inflation?
  It is often said that detecting a spectrum of primordial gravitational waves
via observing B-mode polarization of the Cosmic Microwave Background is the
"Holy Grail" of inflation. The purpose of this short note is to point out that
it is indeed of immense scientific interest to search for a signal of
gravitational waves in B-mode polarization. However, rather than proving that
inflation is the right paradigm of early universe cosmology, a positive signal
of direct primordial B-mode polarization might well be due to other sources
than inflation. In fact, a careful characterization of the spectrum of B-mode
polarization might even falsify the inflationary paradigm.
