TY - JOUR
T1 - Challenges for scaling cosmologies
AU - Amendola, Luca
AU - Quartin, Miguel
AU - Tsujikawa, Shinji
AU - Waga, Ioav
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2006
Y1 - 2006
N2 - 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.
AB - 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.
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U2 - 10.1103/PhysRevD.74.023525
DO - 10.1103/PhysRevD.74.023525
M3 - Article
AN - SCOPUS:33746320555
VL - 74
JO - Physical Review D - Particles, Fields, Gravitation and Cosmology
JF - Physical Review D - Particles, Fields, Gravitation and Cosmology
SN - 1550-7998
IS - 2
M1 - 023525
ER -