Lorentz-Violating Vector Fields Slow the Universe Down

  title={Lorentz-Violating Vector Fields Slow the Universe Down},
  author={S. Carroll and Eugene A. Lim},
  journal={Physical Review D},
We consider the gravitational effects of a single, fixed-norm, Lorentz-violating timelike vector field. In a cosmological background, such a vector field acts to rescale the effective value of Newton's constant. The energy density of this vector field precisely tracks the energy density of the rest of the universe, but with the opposite sign, so that the universe experiences a slower rate of expansion for a given matter content. This vector field similarly rescales Newton's constant in the… Expand