Speaker
Dr
Hermano Velten
(Centre de Physique Théorique UMR 7332)
Description
By using observations of the Hulse-Taylor pulsar we constrain the gravitational wave (GW) speed
to the level of $10^{-2}$. We apply this result to scalar-tensor theories that generalize Galileon 4 and
5 models, which display anomalous propagation speed and coupling to matter for GWs. We argue
that this effect survives conventional screening due to the persistence of a scalar field gradient inside
virialized overdensities, which effectively “pierce” the Vainshtein screening. In specific branches of
solutions, our result allows to directly constrain the cosmological couplings in the effective field
theory of dark energy formalism.
Primary author
Dr
Hermano Velten
(Centre de Physique Théorique UMR 7332)