TY  - JOUR
AU  - Beltran Jimenez, J.
AU  - Delhom, A.
PY  - 2019
DA  - 2019//
TI  - Ghosts in metric-affine higher order curvature gravity
T2  - Eur. Phys. J. C
JO  - European Physical Journal C
SP  - 656
EP  - 7pp
VL  - 79
IS  - 8
PB  - Springer
AB  - 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.
SN  - 1434-6044
UR  - https://arxiv.org/abs/1901.08988
UR  - https://doi.org/10.1140/epjc/s10052-019-7149-x
DO  - 10.1140/epjc/s10052-019-7149-x
LA  - English
N1  - WOS:000479306500020
ID  - BeltranJimenez+Delhom2019
ER  -