The tensor-to-scalar ratio in punctuated inflation
  Recently, we have shown that scalar spectra with lower power on large scales
and certain other features naturally occur in {\it punctuated inflation}, i.e.
the scenario wherein a brief period of rapid roll is sandwiched between two
stages of slow roll inflation. Such spectra gain importance due to the fact
that they can lead to a better fit of the observed Cosmic Microwave Background
(CMB) anisotropies, when compared to the conventional, featureless, power law
spectrum. In this paper, with examples from the canonical scalar field as well
as the tachyonic models, we illustrate that, in punctuated inflation, a drop in
the scalar power on large scales is {\it always} accompanied by a rise in the
tensor power and, hence, an even more pronounced increase in the
tensor-to-scalar ratio $r$ on these scales. Interestingly, we find that $r$
actually {\it exceeds well beyond unity} over a small range of scales. {\it To
our knowledge, this work presents for the first time, examples of single scalar
field inflationary models wherein $r\gg 1$.} This feature opens up interesting
possibilities. For instance, we show that the rise in $r$ on large scales
translates to a rapid increase in the angular power spectrum, $C_{\ell}^{\rm
BB}$, of the B-mode polarization of the CMB at the low multipoles. We discuss
the observational implications of these results.
