Cosmology for quadratic gravity in generalized Weyl geometry
2016 (English)In: Journal of Cosmology and Astroparticle Physics, ISSN 1475-7516, E-ISSN 1475-7516, Vol. 2016, no 4, 46Article in journal (Refereed) Published
A class of vector-tensor theories arises naturally in the framework of quadratic gravity in spacetimes with linear vector distortion. Requiring the absence of ghosts for the vector field imposes an interesting condition on the allowed connections with vector distortion: the resulting one-parameter family of connections generalises the usual Weyl geometry with polar torsion. The cosmology of this class of theories is studied, focusing on isotropic solutions wherein the vector field is dominated by the temporal component. De Sitter attractors are found and inhomogeneous perturbations around such backgrounds are analysed. In particular, further constraints on the models are imposed by excluding pathologies in the scalar, vector and tensor fluctuations. Various exact background solutions are presented, describing a constant and an evolving dark energy, a bounce and a self-tuning de Sitter phase. However, the latter two scenarios are not viable under a closer scrutiny.
Place, publisher, year, edition, pages
Institute of Physics Publishing (IOPP), 2016. Vol. 2016, no 4, 46
Cosmological perturbation theory, Dark energy theory, Modified gravity
IdentifiersURN: urn:nbn:se:kth:diva-195053DOI: 10.1088/1475-7516/2016/04/046ScopusID: 2-s2.0-84988443737OAI: oai:DiVA.org:kth-195053DiVA: diva2:1044278
QC 201611022016-11-022016-11-012016-11-02Bibliographically approved