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arXiv · 1903.01502

Damping of cosmological tensor modes in Horndeski theories after GW170817

Mattia Scomparin·Simone Vazzoler
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Abstract

This paper investigates the propagation of cosmological gravitational waves interacting with free-streaming neutrinos within the context of Horndeski theories of gravity constrained by the detection of GW170817. We apply the theory of cosmological perturbations to explicitly derive the Einstein-Boltzmann equation for the damped propagation of first-order transverse traceless gravitational waves. In contrast to general relativity, we argue that modified gravity can give rise to non-vanishing free-streaming damping effects during the cosmological matter dominated era. We also provide an analytic formula for the main multipole order with which modified gravity and free-streaming neutrinos damp the variety of tensor correlation functions of the cosmic microwave background.

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Mattia Scomparin, Simone Vazzoler. 2019-03-04. Damping of cosmological tensor modes in Horndeski theories after GW170817. https://arxiv.org/abs/1903.01502

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