Generalized gravity and a ghost

By T. Chiba. 2005

154 citations recorded by the source corpus.

We show that generalized gravity theories involving the curvature invariants of the Ricci tensor and the Riemann tensor as well as the Ricci scalar are equivalent to multi-scalar–tensor gravities with four-derivative terms. By expanding the action around a vacuum spacetime, the action is reduced to that of the Einstein gravity with four-derivative terms, and consequently there appears a massive spin-2 ghost in such generalized gravity theories in addition to a massive spin-0 field.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/4f9ca962ab133f65c75692716c41dd527c97a197

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Citations in the corpus

f(R) Theories Of Gravity (2008, background): “In principle, several kinds of instabilities need to be considered to make sure that f(R) gravity is a viable alternative to GR (Calcagni et al., 2006; Chiba, 2005; De Felice et al., 2006; Sokolowski, 2007a,b,c; Wang, 2005).”
Modified Gravity and Cosmology (2011, background): “Let us now outline how ghost terms arise in these theories, following the discussion of [606, 607, 293].”
Higher derivative theories with constraints : Exorcising Ostrogradski's Ghost (2012, background): “2 Recently, there has been a resurgence of interest in higher derivative theories, particularly within attempts to modify gravity [4–15].”
Equivalence Principle Implications of Modified Gravity Models (2009, unknown): “[8] T.”
f(R) Theories (2010, background): “For example, besides the graviton, another spin-2 particle typically appears, which however, has a kinetic term opposite in sign with respect to the standard one [572, 67, 302, 465, 153, 303, 99].”
Boundary Terms, Variational Principles and Higher Derivative Modified Gravity (2008, background): “Such models are not as diverse as it might seem, since they are essentially all equivalent to various multiple scalar-tensor theories [25, 26, 27, 28, 29, 30, 31].”
Approaches to understanding cosmic acceleration (2009, background): “It has been shown [174, 175] that a necessary but not sufficient condition that the action be ghost-free is that b = −4c, so that there are no fourth derivatives in the linearized field equations.”