The dark degeneracy: On the number and nature of dark components

Feb, 2007
4 pages
Published in:
  • Phys.Rev.D 80 (2009) 123001
e-Print:

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20072012201720222025051015
Abstract: (arXiv)
We use that gravity probes only the total energy momentum tensor to show how this leads to a degeneracy for generalised dark energy models. Because of this degeneracy, Omega_m cannot be measured. We demonstrate this explicitely by showing that the CMB and supernova data is compatible with very large and very small values of Omega_m for a specific family of dark energy models. We also show that for the same reason interacting dark energy is always equivalent to a family of non-interacting models. We argue that it is better to face this degeneracy and to parametrise the actual observables.
  • 95.36.+x
  • 95.35.+d
  • 98.80.Jk
  • dark energy
  • gravitation
  • tensor: energy-momentum
  • cosmic background radiation
  • supernova
  • dark matter: density
  • equation of state