Challenges for scaling cosmologies

Luca Amendola*, Miguel Quartin, Shinji Tsujikawa, Ioav Waga

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

133 Citations (Scopus)


A cosmological model that aims at solving the coincidence problem should show that dark energy and dark matter follow the same scaling solution from some time onward. At the same time, the model should contain a sufficiently long matter-dominated epoch that takes place before acceleration in order to guarantee a decelerated epoch and structure formation. So a successful cosmological model requires the occurrence of a sequence of epochs, namely, a radiation era, a matter-dominated era, and a final accelerated scaling attractor with Ωφ≃0.7. In this paper we derive the generic form of a scalar-field Lagrangian that possesses scaling solutions in the case where the coupling Q between dark energy and dark matter is a free function of the field φ. We then show, rather surprisingly, that the aforementioned sequence of epochs cannot occur for a vast class of generalized coupled scalar-field Lagrangians that includes, to our knowledge, all scaling models in the current literature.

Original languageEnglish
Article number023525
JournalPhysical Review D - Particles, Fields, Gravitation and Cosmology
Issue number2
Publication statusPublished - 2006
Externally publishedYes

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Physics and Astronomy (miscellaneous)


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