Do the Spirits Rise?

Abstract

A nonlocal gravity model based on $\frac{1}{\square }R$ achieves the phenomenological goals of generating cosmic acceleration without dark energy and of suppressing the growth of perturbations compared to the $\Lambda$CDM model. Although the localized version of this model possesses a scalar ghost, the nonlocal version does not suffer from any obvious problem with ghosts. Here we study the possibility that the scalar ghost mode might be excited through time evolution, even though it is initially absent. We present strong evidence that this does not happen.

20 pages, 7 figures, v2: revised for publication

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Cited by in corpus (8)

• Ghost-free Gauss-Bonnet Theories of Gravity
• Nonlocal Cosmology II --- Cosmic acceleration without fine tuning or dark energy
• Observational Constraints in Nonlocal Gravity: the Deser-Woodard Case
• Primordial bouncing cosmology in the Deser-Woodard nonlocal gravity
• Black hole quasinormal modes and isospectrality in Deser-Woodard nonlocal gravity
• Late-times asymptotic equation of state for a class of nonlocal theories of gravity
• Does nonlocal gravity yield divergent gravitational energy-momentum fluxes?
• Accelerated expansion as manifestation of gravity: when Dark Energy belongs to the left