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Bigravity from gradient expansion

delete2016-05-04
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OA
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Y
Yamashita, Yasuho *
T
Tanaka, Takahiro
DOI:10.1088/1475-7516/2016/05/011delete
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Abstract

Abstract

En 中文
We discuss how the ghost-free bigravity coupled with a single scalar field can be derived from a braneworld setup. We consider DCP two-brane model without radion stabilization. The bulk configuration is solved for given boundary metrics, and it is substituted back into the action to obtain the effective four-dimensional action. In order to obtain the ghost-free bigravity, we consider the gradient expansion in which the brane separation is supposed to be sufficiently small so that two boundary metrics are almost identical. The obtained effective theory is shown to be ghost free as expected, however, the interaction between two gravitons takes the Fierz-Pauli form at the leading order of the gradient expansion, even though we do riot use the approximation of linear perturbation. We also find that the radion remains as a scalar field in the four-dimensional effective theory, but its coupling to the metrics is non-trivial.
Keywords:
gravity
modified gravity
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Journal

Journal of Cosmology and Astroparticle Physics cover
Journal of Cosmology and Astroparticle Physics
IF:
5.9
Papers:
1.3W
Citations:
4.7W

Organization

K
Kyoto University
Scholars:
5.1W
Papers: 4.6W
Citations: 6.1W