@Article{BeltranJimenez+Delhom2019,
author="Beltran Jimenez, J.
and Delhom, A.",
title="Ghosts in metric-affine higher order curvature gravity",
journal="European Physical Journal C",
year="2019",
publisher="Springer",
volume="79",
number="8",
pages="656--7pp",
abstract="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.",
optnote="WOS:000479306500020",
optnote="exported from refbase (https://references.ific.uv.es/refbase/show.php?record=4109), last updated on Wed, 13 Oct 2021 07:57:03 +0000",
issn="1434-6044",
doi="10.1140/epjc/s10052-019-7149-x",
opturl="https://arxiv.org/abs/1901.08988",
opturl="https://doi.org/10.1140/epjc/s10052-019-7149-x",
language="English"
}