# Damping of tensor modes in cosmology

@article{Weinberg2004DampingOT, title={Damping of tensor modes in cosmology}, author={Steven Weinberg}, journal={Physical Review D}, year={2004}, volume={69}, pages={023503} }

An analytic formula is given for the traceless transverse part of the anisotropic stress tensor due to free streaming neutrinos, and used to derive an integro-differential equation for the propagation of cosmological gravitational waves. The solution shows that anisotropic stress reduces the squared amplitude by 35.6% for wavelengths that enter the horizon during the radiation-dominated phase, independent of any cosmological parameters. This decreases the tensor temperature and polarization…

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