September 30, 2015 to October 3, 2015
Yerevan, Armenia
Etc/GMT+4 timezone

Piercing the Vainshtein screen: local constraints on modified gravity

Oct 2, 2015, 2:00 PM
Small Hall, Guesthouse

Small Hall, Guesthouse


Dr Hermano Velten (Centre de Physique Théorique UMR 7332)


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)

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