The Cosmology of Modified Gauss-Bonnet Gravity

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dc.creatorLi, Baojiu
dc.creatorBarrow, John D.
dc.creatorMota, David F.
dc.date2007-05-25
dc.date2007-07-17
dc.date.accessioned2026-07-07T10:55:51Z
dc.date.available2026-07-07T10:55:51Z
dc.descriptionWe consider the cosmology where some function f(G) of the Gauss-Bonnet term G is added to the gravitational action to account for the late-time accelerating expansion of the universe. The covariant and gauge invariant perturbation equations are derived with a method which could also be applied to general f(R,R^abR_ab,R^abcdR_abcd) gravitational theories. It is pointed out that, despite their fourth-order character, such f(G) gravity models generally cannot reproduce arbitrary background cosmic evolutions; for example, the standard LCDM paradigm with Omega_DE = 0.76 cannot be realized in f(G) gravity theories unless f is a true cosmological constant because it imposes exclusionary constraints on the form of f(G). We analyze the perturbation equations and find that, as in f(R) model, the stability of early-time perturbation growth puts some constraints on the functional form of f(G), in this case d^2 f/d G^2 < 0. Furthermore, the stability of small-scale perturbations also requires that f not deviate significantly from a constant. These analyses are illustrated by numerically propagating the perturbation equations with a specific model reproducing a representative LCDM cosmic history. Our results show how the f(G) models are highly constrained by cosmological data.
dc.description10 pages, 4 figures. Referenes updated; to appear in Phys. Rev. D
dc.identifierhttps://arxiv.org/abs/0705.3795
dc.identifierhttp://arxiv.org/abs/0705.3795
dc.identifierPhys.Rev.D76:044027,2007
dc.identifierdoi:10.1103/PhysRevD.76.044027
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/186215
dc.subjectGeneral Relativity and Quantum Cosmology
dc.subjectAstrophysics
dc.subjectHigh Energy Physics - Phenomenology
dc.titleThe Cosmology of Modified Gauss-Bonnet Gravity
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