Conditions for the cosmological viability of f(R) dark energy models

By Luca Amendola, R. Gannouji, D. Polarski, S. Tsujikawa. 2006

648 citations recorded by the source corpus.

We derive the conditions under which dark energy models whose Lagrangian densities f are written in terms of the Ricci scalar R are cosmologically viable. We show that the cosmological behavior of f(R) models can be understood by a geometrical approach consisting of studying the m(r) curve on the (r,m) plane, where m{identical_to}Rf{sub ,RR}/f{sub ,R} and r{identical_to}-Rf{sub ,R}/f with f{sub ,R}{identical_to}df/dR. This allows us to classify the f(R) models into four general classes, depending on the existence of a standard matter epoch and on the final accelerated stage. The existence of a viable matter-dominated epoch prior to a late-time acceleration requires that the variable m satisfies the conditions m(r){approx_equal}+0 and dm/dr>-1 at r{approx_equal}-1. For the existence of a viable late-time acceleration we require instead either (i) m=-r-1, ({radical}(3)-1)/2 0 and n<-1 and are thus cosmologically unacceptable. Similarmore » conclusions can be reached for many other examples discussed in the text. In most cases the standard matter era is replaced by a cosmic expansion with scale factor a{proportional_to}t{sup 1/2}. We also find that f(R) models can have a strongly phantom attractor but in this case there is no acceptable matter era.« less

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/92a03689b7a5917296c514547994b14d20e32ec5

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In Astronomy and Astrophysics

  1. S. Tsujikawa
  2. T. Sotiriou
  3. Valerio Faraoni
  4. Pedro G. Ferreira
  5. L. Hernquist
  6. Antonio de Felice
  7. T. Clifton
  8. C. Skordis

In Nuclear and High Energy Physics

  1. S. Tsujikawa
  2. Valerio Faraoni
  3. T. Sotiriou
  4. Antonio de Felice
  5. Pedro G. Ferreira
  6. T. Clifton
  7. C. Skordis
  8. Antonio Padilla

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