GRAVITATIONAL-WAVES AND THE POLARIZATION OF THE COSMIC MICROWAVE BACKGROUND

We discuss the influence of gravitational waves (GWs) upon the polarization of the cosmic microwave background (CMB) radiation. We show how to compute the rms temperature anisotropy and polarization of the CMB radiation induced by GWs of arbitrary wavelength. We find that the ratio of polarization, II, to anisotropy, A, can be as large as similar to 40 per cent, but is sensitively dependent upon the GW spectrum and the cosmological ionization history. We argue that CMB radiation polarization measurements can provide useful constraints on cosmological models.