%0 Journal Article
%T Ghosts in metric-affine higher order curvature gravity
%A Beltran Jimenez, J.
%A Delhom, A.
%J European Physical Journal C
%D 2019
%V 79
%N 8
%I Springer
%@ 1434-6044
%G English
%F BeltranJimenez+Delhom2019
%O WOS:000479306500020
%O exported from refbase (https://references.ific.uv.es/refbase/show.php?record=4109), last updated on Wed, 13 Oct 2021 07:57:03 +0000
%X We disprove the widespread belief that higher order curvature theories of gravity in the metric-affine formalism are generally ghost-free. This is clarified by considering a sub-class of theories constructed only with the Ricci tensor and showing that the non-projectively invariant sector propagates ghost-like degrees of freedom. We also explain how these pathologies can be avoided either by imposing a projective symmetry or additional constraints in the gravity sector. Our results put forward that higher order curvature gravity theories generally remain pathological in the metric-affine (and hybrid) formalisms and highlight the key importance of the projective symmetry and/or additional constraints for their physical viability and, by extension, of general metric-affine theories.
%R 10.1140/epjc/s10052-019-7149-x
%U https://arxiv.org/abs/1901.08988
%U https://doi.org/10.1140/epjc/s10052-019-7149-x
%P 656-7pp