Disappearing cosmological constant in f( R) gravity
Abstract
For higherderivative f( R) gravity, where R is the Ricci scalar, a class of models is proposed, which produce viable cosmology different from the ACDM at recent times and satisfy cosmological, Solar System, and laboratory tests. These models have both flat and de Sitter spacetimes as particular solutions in the absence of matter. Thus, a cosmological constant is zero in a flat spacetime, but appears effectively in a curved one for sufficiently large R. A “smoking gun” for these models would be a small discrepancy in the values of the slope of the primordial perturbation power spectrum determined from galaxy surveys and CMB fluctuations. On the other hand, a new problem for dark energy models based on f( R) gravity is pointed out, which is connected with the possible overproduction of new massive scalar particles (scalarons) arising in this theory in the very early Universe.
 Publication:

Soviet Journal of Experimental and Theoretical Physics Letters
 Pub Date:
 October 2007
 DOI:
 10.1134/S0021364007150027
 arXiv:
 arXiv:0706.2041
 Bibcode:
 2007JETPL..86..157S
 Keywords:

 04.50.+h;
 95.36.+x;
 98.80.k;
 Astrophysics;
 General Relativity and Quantum Cosmology;
 High Energy Physics  Theory
 EPrint:
 8 pages, footnote clarified, grammatical typo corrected, references added, final version to be published in JETPL