Cosmological acceleration, varying couplings, and Lorentz breaking
arXiv:astro-ph/0310344 · doi:10.1103/PhysRevD.69.083513
Abstract
Many candidate fundamental theories contain scalar fields that can acquire spacetime-varying expectation values in a cosmological context. Such scalars typically obey Lorentz-violating effective dispersion relations. We illustrate this fact within a simple supergravity model that also exhibits the observed late-time cosmological acceleration and implies varying electromagnetic couplings.
11 pages, 9 figures, 1 table