Breaking a Dark Degeneracy with Gravitational Waves

  title={Breaking a Dark Degeneracy with Gravitational Waves},
  author={L. Lombriser and A. Taylor},
  journal={arXiv: Cosmology and Nongalactic Astrophysics},
  • L. Lombriser, A. Taylor
  • Published 2015
  • Physics
  • arXiv: Cosmology and Nongalactic Astrophysics
  • We identify a scalar-tensor model embedded in the Horndeski action whose cosmological background and linear scalar fluctuations are degenerate with the concordance cosmology. The model admits a self-accelerated background expansion at late times that is stable against perturbations with a sound speed attributed to the new field that is equal to the speed of light. While degenerate in scalar fluctuations, self-acceleration of the model implies a present cosmological tensor mode propagation at 5… CONTINUE READING
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