Work

Luminal scalar-tensor theories for a not so dark dark energy

Year: 2025
Type: article
Abstract: In general the speed of gravitational waves (GWs) in scalar-tensor modifications of Einstein’s gravity is different from the speed of light. Nevertheless, it has been measured that their speeds are nearly the same. For the most general scalar-tensor theories classified to date that do propagate a graviton—DHOST, —we show that, remarkably, up to five self-consistent couplings of the scalar of dark energy (DE) to the photon are enough to make their GWs luminal in a wide set of cases. We find at least one luminal BH theory for which the GW decay into DE is suppressed in any cosmological background.
Language: English
Open Access status: hybrid
OpenAlex ID: W4410159251
FWCI: 1.808
Cites: 35
Cited by: 4
Related to: 10