Tensor perturbations during inflation in a spatially closed Universe
  In a recent paper [17], we studied the evolution of the background geometry
and scalar perturbations in an inflationary, spatially closed
Friedmann-Lema\^itre-Robertson-Walker (FLRW) model having constant positive
spatial curvature and spatial topology $\mathbb S^3$. Due to the spatial
curvature, the early phase of slow-roll inflation is modified, leading to
suppression of power in the scalar power spectrum at large angular scales. In
this paper, we extend the analysis to include tensor perturbations. We find
that --- similarly to the scalar perturbations --- the tensor power spectrum
also shows power suppression for long wavelength modes. The correction to the
tensor spectrum is limited to the very long wavelength modes, therefore the
resulting observable CMB B-mode polarization spectrum remains practically the
same as in the standard scenario with flat spatial sections. However, since
both the tensor and scalar power spectra are modified, there are scale
dependent corrections to the tensor-to-scalar ratio that lead to violation of
the standard slow-roll consistency relation.
