## Abstract

The model of Dvali, Gabadadze, and Porrati (DGP) gives a simple geometrical setup in which gravity becomes 5-dimensional at distances larger than a length scale λDGP. We show that this theory has strong interactions at a length scale λ_{3} ∼ (λ_{DGP}^{2}/Mp) ^{1/3}. If λ_{DGP} is of order the Hubble length, then the theory loses predictivity at distances shorter than λ_{3} ∼ 1000 km. The strong interaction can be viewed as arising from a longitudinal 'eaten Goldstone' mode that gets a small kinetic term only from mixing with transverse graviton polarizations, analogous to the case of massive gravity. We also present a negative-energy classical solution, which can be avoided by cutting off the theory at the same scale scale λ_{3}. Finally, we examine the dynamics of the longitudinal Goldstone mode when the background geometry is curved.

Original language | English (US) |
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Pages (from-to) | 649-671 |

Number of pages | 23 |

Journal | Journal of High Energy Physics |

Volume | 7 |

Issue number | 9 |

DOIs | |

State | Published - Sep 1 2003 |

## Keywords

- Brane Dynamics in Gauge Theories
- Extra Large Dimensions
- Field Theories in Higher Dimensions

## ASJC Scopus subject areas

- Nuclear and High Energy Physics