Edmund J. Copeland
Dark Energy after GW170817 Revisited
Copeland, Edmund J.; Kopp, Michael; Padilla, Antonio; Saffin, Paul M.; Skordis, Constantinos
Paul M. Saffin
We revisit the status of scalar-tensor theories with applications to dark energy in the aftermath of the gravitational wave signal GW170817 and its optical counterpart GRB170817A. At the level of the cosmological background, we identify a class of theories, previously declared unviable in this context, whose anomalous gravitational wave speed is proportional to the scalar equation of motion. As long as the scalar field is assumed not to couple directly to matter, this raises the possibility of compatibility with the gravitational wave data, for any cosmological sources, thanks to the scalar dynamics. This newly “rescued” class of theories includes examples of generalized quintic Galileons from Horndeski theories. Despite the promise of this leading order result, we show that the loophole ultimately fails when we include the effect of large scale inhomogeneities.
|Journal Article Type||Article|
|Publication Date||Feb 12, 2019|
|Journal||Physical Review Letters|
|Publisher||American Physical Society|
|Peer Reviewed||Peer Reviewed|
|APA6 Citation||Copeland, E. J., Kopp, M., Padilla, A., Saffin, P. M., & Skordis, C. (2019). Dark Energy after GW170817 Revisited. Physical Review Letters, 122(6), doi:10.1103/physrevlett.122.061301|
|Additional Information||©2019 American Physical Society. All rights reserved.|
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