A general approach to viable modified $f(R)$ gravity is developed in both the Jordan and the Einstein frames. A class of exponential, realistic modified gravities is introduced and investigated with care. Special focus is made on step-class models, most promising from the phenomenological viewpoint and which provide a natural way to classify all viable modified gravities. One- and two-steps models are explicitly considered, but the analysis is extensible to $N$-step models. Both inflation in the early universe and the onset of recent accelerated expansion arise in these models in a natural, unified way. Moreover, it is demonstrated that models in this category easily pass all local tests, including stability of spherical body solution, non-violation of Newton's law, and generation of a very heavy positive mass for the additional scalar degree of freedom.
Titolo: | A class of viable modified f(R) gravities describing inflation and the onset of accelerated expansion | |
Autori: | Cognola, Guido; E., Elizalde; S., Nojiri; S. D., Odintsov; L., Sebastiani; Zerbini, Sergio | |
Autori Unitn: | ||
Titolo del periodico: | PHYSICAL REVIEW D, PARTICLES, FIELDS, GRAVITATION, AND COSMOLOGY | |
Anno di pubblicazione: | 2008 | |
Numero e parte del fascicolo: | 4 | |
Codice identificativo Scopus: | 2-s2.0-41149113355 | |
Codice identificativo WOS: | WOS:000253764800135 | |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1103/PhysRevD.77.046009 | |
Handle: | http://hdl.handle.net/11572/29425 | |
Appare nelle tipologie: | 03.1 Articolo su rivista (Journal article) |