CMB anisotropies are deviations of the temperature of the black body emission mainly (but not only) by photons, which have to climb out gravitational potential of higher density concentrations during recombination epoch and during their spatio-temporal trajectory till now (Sachs-Wolfe effect)...
Gravitational waves generated during inflation should produce a special component in linear polarization in the CMB. Why? Could anyone give an easy qualitative explanation?
Thanx.