# 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}
}```
• S. Weinberg
• Published 16 June 2003
• Physics
• Physical Review D
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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