Generalized energy conditions in Extended Theories of Gravity

By Salvatore Capozziello, Francisco S. N. Lobo, J. Mimoso. 2014

145 citations recorded by the source corpus.

In this work, we consider the further degrees of freedom related to curvature invariants and scalar fields in Extended Theories of Gravity (ETG). These new degrees of freedom can be recast as effective fluids that differ in nature with respect to the standard matter fluids generally adopted as sources of the field equations. It is thus somewhat misleading to apply the standard general relativistic energy conditions to this effective energy-momentum tensor, as the latter contains the matter content and a geometrical quantity, which arises from the specific ETG considered. Here, we explore this subtlety, extending on previous work, in particular, to cases with the contracted Bianchi identities with diffeomorphism invariance and to cases with generalized explicit curvature-matter couplings, which imply the non-conservation of the energy-momentum tensor. Furthermore, we apply the analysis to specific ETGs, such as scalar-tensor gravity and f(R) gravity. Thus, in the context of ETGs, interesting results appear such as matter that may exhibit unusual thermodynamical features, for instance, gravity that retains its attractive character in the presence of large negative pressures; or alternatively, we verify that repulsive gravity may occur for standard matter.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/d171f0d0e9cc7c0aa7bff02342c7c0dce0433df7

Citations in the corpus

• Stellar structure models in modified theories of gravity: Lessons and challenges (2019, unknown): “This action belongs to a class of theories for which a part of the field equations can be written as [267, 268, 269] σ(Ψ)(Gμν −Wμν) = κ(2)Tμν, (111)”