We present the effective equations to describe the four-dimensional gravity of a brane world, assuming that a five-dimensional bulk spacetime satisfies the Einstein equations and gravity is confined on the Z2 symmetric brane. Applying this formalism, we study the induced-gravity brane model first proposed by Dvali, Gabadadze, and Porrati. In a generalization of their model, we show that an effective cosmological constant on the brane can be extremely reduced in contrast with the case of the Randall-Sundrum model even if a bulk cosmological constant and a brane tension are not fine tuned.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)