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Generalized Gravity and a Ghost

Takeshi Chiba
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Abstract

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 derivatives 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.

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Takeshi Chiba. 2005-03-22. Generalized Gravity and a Ghost. https://doi.org/10.1088/1475-7516%2F2005%2F03%2F008

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