Tensor-induced B modes with no temperature fluctuations
  The recent indications for a tensor-to-scalar ratio $ r \simeq 0.2$ from
BICEP2 measurements of the cosmic microwave background (CMB) B-mode
polarization present some tension with upper limits $r \lesssim 0.1$ from
measurements of CMB temperature fluctuations. Here we point out that tensor
perturbations can induce B modes in the CMB polarization without inducing any
temperature fluctuations nor E-mode polarization whatsoever, but only, at the
expense of violating the Copernican principle. We present this mathematical
possibility as a new ingredient for the model-builder's toolkit in case the
tension between B modes and temperature fluctuations cannot be resolved with
more conventional ideas.
