  It is well known that in manifestly Lorentz invariant theories with
nontrivial kinetic terms, perturbations around some classical backgrounds can
travel faster than light. These exotic "supersonic" models may have interesting
consequences for cosmology and astrophysics. In particular, one can show that
in such theories the contribution of the gravitational waves to the CMB
fluctuations can be significantly larger than that in standard inflationary
models. This increase of the tensor-to-scalar perturbation ratio leads to a
larger B-component of the CMB polarization, thus making the prospects for
future detection much more promising. Interestingly, the spectral index of
scalar perturbations and mass of the scalar field considered in the model are
practically indistinguishable from the standard case. Whereas the energy scale
of inflation and hence the reheating temperature can be much higher compared to
a simple chaotic inflation.
