Parity violation in pre-inflationary bounce
  The power suppression at largest scale in the CMB TT powerspectrum might
imply the occurrence of a pre-inflationary bounce. We calculate the circularly
polarized gravitational wave, leaded by the gravitational Chern-Simons term
which universally appears in particle physics and string theory, in an
inflationary background with the pre-inflationary bounce. The circularly
polarized gravitational wave will induce TB and EB correlations at CMB last
scatting surface. We find that although the BB powerspectrum at largest scale
is also suppressed, the TB and EB powerspectra at corresponding scales may be
enhanced.
