Self-accelerating universe in scalar-tensor theories after GW170817
Abstract
The recent simultaneous detection of gravitational waves and a gamma ray burst from a neutron star merger significantly shrank the space of viable scalar-tensor theories by demanding that the speed of gravity is equal to that of light. The survived theories belong to the class of degenerate higher order scalar-tensor theories. We study whether these theories are suitable as dark energy candidates. We find scaling solutions in the matter dominated universe that lead to de Sitter solutions at late times without the cosmological constant, realising self-acceleration. We evaluate quasi-static perturbations around self-accelerating solutions and show that the stringent constraints coming from astrophysical objects and gravitational waves can be satisfied, leaving interesting possibilities to test these theories by cosmological observations.
Keywords
Cite
@article{arxiv.1712.06556,
title = {Self-accelerating universe in scalar-tensor theories after GW170817},
author = {Marco Crisostomi and Kazuya Koyama},
journal= {arXiv preprint arXiv:1712.06556},
year = {2018}
}
Comments
15 pages, 4 figures, references added, typos corrected, published version