2007/10/12 by Seokcheon Lee, Lee, Seokcheon · 2 citations
Physics and Astronomy · #Astrophysics (astro-ph) #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #FOS: Physical sciences #General Relativity and Quantum Cosmology (gr-qc) #Relativity and Gravitational Theory #astro-ph #gr-qc
paper · pdf · doi:10.48550/arxiv.0710.2395
12 pages, References added, Detail calculations are added in the appendix
openalex publication_date 2007/10/12 · arxiv created 2008/06/18 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The evolution of linear cosmological perturbations in modified theories of gravity is investigated assuming the Palatini formalism. It has been discussed about the stability problem in this model based on the equivalence between f(R) gravity and the scalar tensor theory. However, we study this problem in the physical frame where the matter is minimally coupled. In general, the stability of the superhorizon metric evolution depends on models. We show that the deviation from the superhorizon metric evolution is null for a specific choice for the nonlinear Einstein-Hilbert action, f(R) ∼ Rn, where n ≠ 0,2,3. Thus the stability of metric fluctuation is guaranteed in these models. We also study the matter density fluctuation in the general gauge and show the differential equations in super and sub-horizon scales.