RT Journal Article
T1 Evolution of density perturbations in f(R) theories of gravity
A1 Cruz Dombriz, Álvaro de la
A1 Dobado González, Antonio
A1 López Maroto, Antonio
AB In the context of f(R) theories of gravity, we study the evolution of scalar cosmological perturbations in the metric formalism. Using a completely general procedure, we find the exact fourth-order differential equation for the matter density perturbations in the longitudinal gauge. In the case of sub-Hubble modes, the expression reduces to a second-order equation which is compared with the standard (quasistatic) equation used in the literature. We show that for general f(R) functions the quasistatic approximation is not justified. However, for those functions adequately describing the present phase of accelerated expansion and satisfying local gravity tests, it provides a correct description for the evolution of perturbations.
PB American Physical Society
SN 1550-7998
YR 2008
FD 2008-06
LK https://hdl.handle.net/20.500.14352/50653
UL https://hdl.handle.net/20.500.14352/50653
LA eng
NO © American Physical Society.We would like to thank A. Starobinsky for useful comments and J. A. R. Cembranos and J. Beltránn for theircontinuous encouragement. This work has been partiallysupported by the DGICYT (Spain) under projects FPA2004-02602, FPA 2005-02327, and CAM/UCM 910309and by UCM-Santander PR34/07-15875.
NO DGICYT (Spain)
NO CAM/UCM
NO UCM-Santander
DS Docta Complutense
RD 5 abr 2025